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  • 1.
    Becker-Dreps, Sylvia
    et al.
    University of N Carolina, NC 27599 USA.
    Bucardo, Filemon
    National Autonomous University of Nicaragua, Nicaragua.
    Vilchez, Samuel
    National Autonomous University of Nicaragua, Nicaragua.
    Enrique Zambrana, Luis
    Centre Epidemiol and Health CIDS, Nicaragua.
    Liu, Lan
    University of N Carolina, NC USA.
    Weber, David J.
    University of N Carolina, NC 27599 USA.
    Pena, Rodolfo
    Centre Health Research CIS, Nicaragua.
    Barclay, Leslie
    Centre Disease Control and Prevent, GA USA.
    Vinje, Jan
    Centre Disease Control and Prevent, GA USA.
    Hudgens, Michael G.
    University of N Carolina, NC USA.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Morgan, Douglas R.
    University of N Carolina, NC 27599 USA; Vanderbilt University, TN 37235 USA.
    Espinoza, Felix
    National Autonomous University of Nicaragua, Nicaragua.
    Paniagua, Margarita
    National Autonomous University of Nicaragua, Nicaragua.
    Etiology of Childhood Diarrhea After Rotavirus Vaccine Introduction A Prospective, Population-based Study in Nicaragua2014In: The Pediatric Infectious Disease Journal, ISSN 0891-3668, E-ISSN 1532-0987, Vol. 33, no 11, p. 1156-1163Article in journal (Refereed)
    Abstract [en]

    Background: Nicaragua was the first developing nation to implement routine immunization with the pentavalent rotavirus vaccine (RV5). In this RV5-immunized population, understanding infectious etiologies of childhood diarrhea is necessary to direct diarrhea treatment and prevention efforts. Methods: We followed a population-based sample of children less than5 years in Leon, Nicaragua for diarrhea episodes through household visits. Information was obtained on RV5 history and sociodemographics. Stool samples collected during diarrhea episodes and among healthy children underwent laboratory analysis for viral, bacterial and parasitic enteropathogens. Detection frequency and incidence of each enteropathogen was calculated. Results: The 826 children in the cohort experienced 677 diarrhea episodes during 607.5 child-years of exposure time (1.1 episodes per child-year). At least 1 enteropathogen was detected among 61.1% of the 337 diarrheal stools collected. The most common enteropathogens among diarrheal stools were: norovirus (20.4%), sapovirus (16.6%), enteropathogenic Escherichia coli (11.3%), Entamoeba histolytica/dispar (8.3%), Giardia lamblia (8.0%) and enterotoxigenic E. coli (7.7%), with rotavirus detected among 5.3% of diarrheal stools. Enteropathogenic Escherichia coli and enterotoxigenic E. coli were frequently detected among stools from healthy children. Among children with diarrhea, norovirus was more commonly detected among younger children (less than2 years) and G. lamblia was more commonly detected among older children (2-4 years). The mean age of rotavirus detection was 34.6 months. Conclusions: In this Central American community after RV5 introduction, rotavirus was not commonly detected among children with diarrhea. Prevention and appropriate management of norovirus and sapovirus should be considered to further reduce the burden of diarrheal disease.

  • 2.
    Bialowas, Sonja
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Hagbom, Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Karlsson, Thommie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Sharma, Sumit
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Magnusson, Karl-­Eric
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Intracellularly expressed rotavirus NSP4 stimulates release of serotonin (5-HT) from human enterochromaffin cellsManuscript (preprint) (Other academic)
    Abstract [en]

    Rotavirus (RV) is associated with diarrhoea and vomiting, but the mechanisms behind these symptoms remain unresolved. While RV have been shown to infect and stimulate secretion of serotonin (5-hydroxytryptamine; 5-HT) from human enterochromaffin (EC) cells and to infect EC cells in the small intestine of mice, it remains to identify which intracellularly expressed viral protein (VP) being responsible for this novel property.

    To address this issue, human EC cells were transfected with small interfering RNA (siRNA) targeting the structural (VP4, VP6 and VP7) and the non-structural protein 4 (NSP4) followed by infection with Rhesus rotavirus (RRV). siRNA specific to NSP4 (siRNANSP4) significantly attenuated secretion of 5-HT compared to siRNAVP4, siRNAVP6 , siRNAVP7 and non-targeting (Nt) siRNAnt. Intracellular calcium clamping with BABTA/AM showed that intracellularly expressed NSP4-stimulated secretion of 5-HT from EC cells was calcium-dependent. Furthermore RV down-regulated the 5-HT transporter (SERT) mRNA in ileum but not tryptophan hydroxylase 1 (TPH1) mRNA the rate-limiting enzyme for 5-HT synthesis. The unaffected expression of TPH1 mRNA in the intestinal segments suggests that release of 5- HT primarily originates from pre-made 5-HT rather than from newly synthesised 5-HT mRNA. Moreover, down-regulation of SERT mRNA in ileum presumably resulted in reduced re- uptake of 5-HT by SERT to EC cells and thus increased extracellular 5-HT in the small intestine. Moreover, 7/7 infant mice responded following intraperitoneal administration of 5-HT with rapid (<30 min) diarrhoea in dose-dependent manner. In the light of these results and the fact that both 5-HT and NSP4 can induce diarrhoea in mice, a disease mechanism to RV diarrhoea is proposed.

  • 3.
    Bucardo, F.
    et al.
    Department of Microbiology, University of León (UNAN-León), León, Nicaragua.
    Mercado, J.
    National Center for Diagnostic and Reference, Ministry of Health, Managua, Nicaragua.
    Reyes, Y.
    Department of Microbiology, University of León (UNAN-León), León, Nicaragua.
    González, F.
    Department of Microbiology, University of León (UNAN-León), León, Nicaragua.
    Balmaseda, A
    National Center for Diagnostic and Reference, Ministry of Health, Managua, Nicaragua.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology. Linköping University, Faculty of Medicine and Health Sciences.
    Large increase of rotavirus diarrhoea in the hospital setting associated with emergence of G12 genotype in a highly vaccinated population in Nicaragua.2015In: Clinical Microbiology and Infection, ISSN 1198-743X, E-ISSN 1469-0691, Vol. 21, no 6, p. 603.e1-603.e7Article in journal (Refereed)
    Abstract [en]

    Rotaviruses (RVs) are a major cause of severe diarrhoea in young children. Nicaragua introduced routine immunization with the pentavalent RV vaccine (RV5) in 2006, which greatly reduced the incidence of diarrhoea. A remaining concern has been the possible emergence of new RV strains to which the vaccination has less effect. In this study, 837 children with diarrhoea in hospital settings were investigated for RV between May 2011 and July 2013. RVs were subsequently typed by multiplex PCR and/or sequencing. Fecal anti-RV IgA titres for a subset of RV-infected (n = 137) and noninfected children (n = 52) were determined with an in-house enzyme-linked immunosorbent assay. The RV detection rate was 8% in 2011, followed by a sharp increase to 29% in 2012 and 19% in 2013. This was associated with emergence and predominance of genotype G12 RV, from 0% in 2011 to 66% in 2012 and 82% in 2013, infecting children from 1 month to 10 years of age. Two sequenced G12 strains showed a Wa-like genome with genotype G12-P[8]-I1-R1-C1-M1-A1-N1-T1-E1-H1, similar to the globally emerging G12 strains. Fecal anti-RV IgA analysis showed that most G12-infected and noninfected children had been in contact with either vaccine or wild RV strains, but such antibodies did not prevent symptomatic G12 infection. A marked increase of RV was evident in the hospital setting associated with a nationwide emergence and predominance of RV G12 genotype in a population with high RV5 vaccine coverage.

  • 4.
    Bucardo, Filemon
    et al.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences. Department of Microbiology, University of León, UNAN-León, Nicaragua.
    Carlsson, Beatrice
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology. Linköping University, Faculty of Health Sciences.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Larson, Göran
    University of Gothenburg, Göteborg, Sweden.
    Blandon, Patricia
    Department of Microbiology University of León, Nicaragua (UNAN-León).
    Vilchez, Samuel
    Department of Microbiology University of León, Nicaragua (UNAN-León).
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology. Linköping University, Faculty of Health Sciences.
    Susceptibility of Children to Sapovirus Infections, Nicaragua, 2005–20062012In: Emerging Infectious Diseases, ISSN 1080-6040, E-ISSN 1080-6059, Vol. 18, no 11, p. 1875-1878Article in journal (Refereed)
    Abstract [en]

    We describe the genetic diversity of sapovirus (SaV) in children in Nicaragua and investigate the role of host genetic factors and susceptibility to SaV infections. Our results indicate that neither ABO blood group, Lewis phenotype, nor secretor status affects susceptibility to SaV infection in Nicaragua.

  • 5.
    Bucardo, Filemon
    et al.
    University of Leon.
    Lindgren, Per-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology. Linköping University, Faculty of Health Sciences.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Low Prevalence of Rotavirus and High Prevalence of Norovirus in Hospital and Community Wastewater after Introduction of Rotavirus Vaccine in Nicaragua2011In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 6, no 10Article in journal (Refereed)
    Abstract [en]

    Rotavirus (RV) and norovirus (NoV) are major causes of pediatric diarrhea and are altogether associated with approximately 800,000 deaths in young children every year. In Nicaragua, national RV vaccination program using the pentavalent RV5 vaccine from Merck was implemented in October 2006. To determine whether RV vaccination decreased the overall number of RV infections, we investigated the occurrence of RV and NoV in wastewater in the city of Leon from July 2007 to July 2008 and compared these data with pre-vaccination data. The major finding was the low prevalence of RV compared to NoV in all sampling points (11% vs 44%, pandlt;0.05), and that RV concentration was lower as compared to NoV. RV was observed mainly during the rainy season (July-September), and the majority of all RV detected (6/9) belonged to subgroup (SG) I. The partial VP7-gene obtained from one RV positive sample was similar (99% nt identity) to a G6 VP7-gene of bovine origin and similar to the corresponding gene of the vaccine strain (98%). Furthermore RV G-types 2 and 4 were found in the incoming wastewater. NoV strains were detected throughout the year, of which a majority (20/21) were of genotype GII.4. We conclude that the introduction of RV vaccination reduced the transmission of RV in the community in Nicaragua. However, the burden of diarrhea in the country remains high, and the high prevalence of NoVs in hospital and municipal wastewater is noteworthy. This study highlights the need for further assessment of NoV following RV vaccine introduction.

  • 6.
    Bucardo, Filemon
    et al.
    National Autonomous University of Leon, Nicaragua.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Impact of vaccination on the molecular epidemiology and evolution of group A rotaviruses in Latin America and factors affecting vaccine efficacy2015In: Infection, Genetics and Evolution, ISSN 1567-1348, E-ISSN 1567-7257, Vol. 34, p. 106-113Article, review/survey (Refereed)
    Abstract [en]

    Despite high rotavirus (RV) vaccine coverage (similar to 83%) and good effectiveness (similar to 77%) against RV-diarrhea hospitalization, RV is still contributing to the burden of diarrhea that persists in hospital settings in several Latin American countries, where RV vaccination is being implemented. Due to the extensive genomic and antigenic diversity, among co-circulating human RV, a major concern has been that the introduction of RV vaccination could exert selection pressure leading to higher prevalence of strains not included in the vaccines and/or emergence of new strains, thus, reducing the efficacy of vaccination. Here we review the molecular epidemiology of RV in Latin America and explore issues of RV evolution and selection in light of vaccination. We further explore etiologies behind the large burden of diarrhea remaining after vaccination in some countries and discuss plausible reasons for vaccine failures. (C) 2015 Elsevier B.V. All rights reserved.

  • 7.
    Bucardo, Filemon
    et al.
    Department of Microbiology, University of León, UNAN-León, Nicaragua.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Carlsson, Beatrice
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology . Linköping University, Faculty of Health Sciences.
    Paniagua, Margarita
    Microbiology, Tumor and Cell Biology Centre, Karolinska Institutet, S-171 77 Stockholm, Sweden.
    Lindgren, Per-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Espinoza, Felix
    Department of Microbiology, University of León, UNAN-León, Nicaragua.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology . Linköping University, Faculty of Health Sciences.
    Pediatric norovirus diarrhea in Nicaragua2008In: Journal of Clinical Microbiology, ISSN 0095-1137, E-ISSN 1098-660X, Vol. 46, no 8, p. 2573-2580Article in journal (Refereed)
    Abstract [en]

    Information about norovirus (NoV) infections in Central America is limited. Through a passive community and hospital pediatric diarrhea surveillance program, a total of 542 stool samples were collected between March 2005 and February 2006 in León, Nicaragua. NoV was detected in 12% (65/542) of the children; of these, 11% (45/409) were in the community and 15% (20/133) were in the hospital, with most strains (88%) belonging to genogroup II. NoV infections were age and gender associated, with children of <2 years of age (P < 0.05) and girls (P < 0.05) being most affected. Breast-feeding did not reduce the number of NoV infections. An important proportion (57%) of NoV-infected children were coinfected with diarrheagenic Escherichia coli. A significant proportion (18/31) of NoV-positive children with dehydration required intravenous rehydration. Nucleotide sequence analysis (38/65) of the N-terminal and shell region in the capsid gene revealed that at least six genotypes (GI.4, GII.2, GII.4, GII.7, GII.17, and a potentially novel cluster termed "GII.18-Nica") circulated during the study period, with GII.4 virus being predominant (26/38). The majority (20/26) of those GII.4 strains shared high nucleotide homology (99%) with the globally emerging Hunter strain. The mean viral load was approximately 15-fold higher in children infected with GII.4 virus than in those infected with other G.II viruses, with the highest viral load observed for the group of children infected with GII.4 and requiring intravenous rehydration. This study, the first of its type from a Central American country, suggests that NoV is an important etiological agent of acute diarrhea among children of <2 years of age in Nicaragua.

  • 8.
    Bucardo, Filemon
    et al.
    University of Leon.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Paniagua, Margarita
    University of Leon.
    Mollby, Roland
    Karolinska Institute.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology . Linköping University, Faculty of Health Sciences.
    Asymptomatic Norovirus Infections in Nicaraguan Children and its Association With Viral Properties and Histo-blood Group Antigens2010In: PEDIATRIC INFECTIOUS DISEASE JOURNAL, ISSN 0891-3668, Vol. 29, no 10, p. 934-939Article in journal (Refereed)
    Abstract [en]

    Background: It has been previously reported that histo-blood group antigens (HBGAs) and particularly secretor status provides protection against symptomatic norovirus infection, but it remains unclear to what extent this includes asymptomatic infections in children. Methods: To explore whether HBGAs or certain viral genotypes are associated with asymptomatic norovirus infections in a pediatric population in Nicaragua, we investigated 163 children andlt;= 5 years of age, without a recent history of diarrhea (andlt;= 10 days). Results: Asymptomatic norovirus infections were observed in 11.7% (19/163), with children andlt;= 6 months of age being most frequently infected (16%). Of the 19 norovirus-positive children, 4 (21%) and 10 (53%) were infected with genogroups GI and GII, respectively, and 4 children (21%) were infected with viruses of both genogroups. Most children had andgt;= 10(6) viral genomes per gram of feces. Nucleotide sequence analysis (15/19) revealed uncommon genotypes, such as, GII. 7 (n = 5) and GII. 2 (n = 3). An interesting observation was the low frequency of norovirus GII. 4 strains among the asymptomatic children. AB blood type, Lewis a (Lea(a+b-)) phenotype and nonsecretor genotype (se(428)se(428)) were not found among the asymptomatic children, but they occurred in population controls. Conclusions: Frequency of asymptomatic norovirus infections was similar to that observed in symptomatic children from Nicaragua. Norovirus GII. 2 and GII. 7 were frequently detected but the globally dominating GII. 4 was infrequent. Host genetic factors previously observed to be associated with protection against symptomatic norovirus infection were not found in this study.

  • 9.
    Bucardo, Filemon
    et al.
    University of Leon UNAN Leon, Nicaragua .
    Reyes, Yaoska
    University of Leon UNAN Leon, Nicaragua .
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Predominance of Norovirus and Sapovirus in Nicaragua after Implementation of Universal Rotavirus Vaccination2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 5, p. e0098201-Article in journal (Refereed)
    Abstract [en]

    Background: Despite significant reduction of rotavirus (RV) infections following implementation of RotaTeq vaccination in Nicaragua, a large burden of patients with diarrhea persists. Methods: We conducted a community-and hospital-based study of the burden of RV, norovirus (NV) and sapovirus (SV) infections as cause of sporadic acute gastroenteritis (GE) among 330 children less than= 5 years of age between September 2009 and October 2010 in two major cities of Nicaragua with a RotaTeq coverage rate of 95%. Results: We found that NV, SV and RV infections altogether accounted for 45% of cases of GE. Notably, NV was found in 24% (79/330) of the children, followed by SV (17%, 57/330) and RV (8%, 25/330). The detection rate in the hospital setting was 27%, 15% and 14% for NV, SV and RV respectively, whereas in the community setting the detection rate of RV was less than 1%. Among each of the investigated viruses one particular genogroup or genotype was dominant; GII.4 (82%) for NV, GI (46%) for SV and G1P[8] (64%) in RV. These variants were also found in higher proportions in the hospital setting compared to the community setting. The GII.4.2006 Minerva strain circulating globally since 2006 was the most common among genotyped NV in this study, with the GII.4-2010 New Orleans emerging in 2010. Conclusions: This study shows that NV has become the leading viral cause of gastroenteritis at hospital and community settings in Nicaragua after implementation of RV vaccination.

  • 10.
    Caliz, Joan
    et al.
    University of Girona.
    Vila, Xavier
    University of Girona.
    Marti, Esther
    University of Barcelona.
    Sierra, Jordi
    University of Barcelona.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Lindgren, Per-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Baneras, Lluis
    University of Girona.
    Montserrat, Genoveva
    University of Girona.
    The microbiota of an unpolluted calcareous soil faces up chlorophenols: Evidences of resistant strains with potential for bioremediation2011In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 83, no 2, p. 104-116Article in journal (Refereed)
    Abstract [en]

    To highlight the effects of a variety of chlorophenols (CP) in relation to the response of an indigenous bacterial community, an agricultural Mediterranean calcareous soil has been studied in microcosms incubated under controlled laboratory conditions. Soil samples were artificially polluted with 2-monochlorophenol (MCP), 2,4,6-trichlorophenol (TCP) and pentachlorophenol (PCP), at concentrations ranging from 0.1 up to 5000 mg kg(-1). Both activity and composition of the microbial community were assessed during several weeks, respectively, by respirometric methods and PCR-DGGE analysis of extracted DNA and RNA. Significant decreases in soil respirometric values and changes in the bacterial community composition were observed at concentrations above 1000 mg kg(-1) MCP and TCP, and above 100 mg kg(-1) PCP. However, the persistence of several active bacterial populations in soil microcosms contaminated with high concentration of CP, as indicated by DGGE fingerprints, suggested the capacity of these native bacteria to survive in the presence of the pollutants, even without a previous adaptation or contact with them. The isolation of potential CP degraders was attempted by culture plating from microcosms incubated with high CP concentrations. Twenty-three different isolates were screened for their resistance to TCP and PCP. The most resistant isolates were identified as Kocuria palustris, Lysobacter gummosus, Bacillus sp. and Pseudomonas putida, according to 16S rRNA gene homology. In addition, these four isolates also showed the capacity to reduce the concentration of TCP and PCP from 15% to 30% after 5 d of incubation in laboratory assays (initial pollutant concentration of 50 mg L(-1)). Isolate ITP29, which could be a novel species of Bacillus, has been revealed as the first known member in this bacterial group with potential for CP bioremediation applications, usually wide-spread in the soil natural communities, which has not been reported to date as a CP degrader.

  • 11.
    de Graaf, M.
    et al.
    Erasmus MC, Netherlands.
    van Beek, J.
    Erasmus MC, Netherlands; National Institute Public Health and Environm RIVM, Netherlands.
    Vennema, H.
    National Institute Public Health and Environm RIVM, Netherlands.
    Podkolzin, A. T.
    Minist Public Health Russia, Russia.
    Hewitt, J.
    Institute Environm Science and Research, New Zealand.
    Bucardo, F.
    University of Leon, Nicaragua.
    Templeton, K.
    Royal Infirm Edinburgh NHS Trust, Scotland.
    Mans, J.
    University of Pretoria, South Africa.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Reuter, G.
    ANTSZ Regional Institute State Public Health Serv, Hungary.
    Lynch, M.
    Mater Misericordiae University Hospital, Ireland.
    Rasmussen, L. D.
    Statens Serum Institute, Denmark.
    Iritani, N.
    Osaka City Institute Public Health and Environm Science, Japan.
    Chan, M. C.
    Chinese University of Hong Kong, Peoples R China.
    Martella, V.
    University of Aldo Moro Bari, Italy.
    Ambert-Balay, K.
    CHU Dijon, France.
    Vinje, J.
    Centre Disease Control and Prevent, GA USA.
    White, P. A.
    University of New S Wales, Australia.
    Koopmans, M. P.
    Erasmus MC, Netherlands; National Institute Public Health and Environm RIVM, Netherlands.
    Emergence of a novel GII.17 norovirus - End of the GII.4 era?2015In: Eurosurveillance, ISSN 1025-496X, E-ISSN 1560-7917, Vol. 20, no 26, p. 21178-Article in journal (Refereed)
    Abstract [en]

    In the winter of 2014/15 a novel GII.P17-GII.17 norovirus strain (GII.17 Kawasaki 2014) emerged, as a major cause of gastroenteritis outbreaks in China and Japan. Since their emergence these novel GII.P17-GII.17 viruses have replaced the previously dominant GII.4 genotype Sydney 2012 variant in some areas in Asia but were only detected in a limited number of cases on other continents. This perspective provides an overview of the available information on GII.17 viruses in order to gain insight in the viral and host characteristics of this norovirus genotype. We further discuss the emergence of this novel GII.P17-GII.17 norovirus in context of current knowledge on the epidemiology of noroviruses. It remains to be seen if the currently dominant norovirus strain GII.4 Sydney 2012 will be replaced in other parts of the world. Nevertheless, the public health community and surveillance systems need to be prepared in case of a potential increase of norovirus activity in the next seasons caused by this novel GII.P17-GII.17 norovirus.

  • 12.
    Gia Phan, Tung
    et al.
    Blood Syst Research Institute, CA 94118 USA; University of Calif San Francisco, CA 94118 USA.
    Charlys da Costa, Antonio
    Blood Syst Research Institute, CA 94118 USA; University of Sao Paulo, Brazil.
    del Valle Mendoza, Juana
    University of Peruana Ciencias Aplicadas UPC, Peru.
    Bucardo-Rivera, Filemon
    Institute Invest Nutr, Peru; University of Leon, Nicaragua.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    ORyan, Miguel
    University of Chile, Chile.
    Deng, Xutao
    Blood Syst Research Institute, CA 94118 USA.
    Delwart, Eric
    Blood Syst Research Institute, CA 94118 USA; University of Calif San Francisco, CA 94118 USA.
    The fecal virome of South and Central American children with diarrhea includes small circular DNA viral genomes of unknown origin2016In: Archives of Virology, ISSN 0304-8608, E-ISSN 1432-8798, Vol. 161, no 4, p. 959-966Article in journal (Refereed)
    Abstract [en]

    Viral metagenomics of feces collected from 58 Peruvian children with unexplained diarrhea revealed several small circular ssDNA genomes. Two genomes related to sequences previously reported in feces from chimpanzees and other mammals and recently named smacoviruses were characterized and then detected by PCR in 1.7 % (1/58) and 19 % (11/58) of diarrheal samples, respectively. Another three genomes from a distinct small circular ssDNA viral group provisionally called pecoviruses encoded Cap and Rep proteins with &lt; 35 % identity to those in related genomes reported in human, seal, porcine and dromedary feces. Pecovirus DNA was detected in 15.5 % (9/58), 5.9 % (3/51) and 3 % (3/100) of fecal samples from unexplained diarrhea in Peru, Nicaragua and Chile, respectively. Feces containing these ssDNA genomes also contained known human enteric viral pathogens. The cellular origins of these circular ssDNA viruses, whether human cells, ingested plants, animals or fungal foods, or residents of the gut microbiome, are currently unknown.

  • 13.
    Gia Phan, Tung
    et al.
    Blood Syst Research Institute, CA 94118 USA University of Calif San Francisco, CA 94118 USA .
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Ouermi, Djeneba
    University of Ouagadougou, Burkina Faso .
    Simpore, Jacques
    University of Ouagadougou, Burkina Faso .
    Nitiema, Leon W.
    University of Ouagadougou, Burkina Faso .
    Deng, Xutao
    Blood Syst Research Institute, CA 94118 USA .
    Delwart, Eric
    Blood Syst Research Institute, CA 94118 USA University of Calif San Francisco, CA 94118 USA .
    New astrovirus in human feces from Burkina Faso2014In: Journal of Clinical Virology, ISSN 1386-6532, E-ISSN 1873-5967, Vol. 60, no 2, p. 161-164Article in journal (Refereed)
    Abstract [en]

    Background: A significant fraction of cases of diarrhea, a leading cause of childhood mortality worldwide, remain unexplained. Objectives: To identify viruses in unexplained cases of diarrhea using an unbiased metagenomics approach. Study design: Viral nucleic acids were enriched from the feces from 48 cases of unexplained diarrhea from Burkina Faso, sequenced, and compared against all known viral genomes. Results: The full genome of a highly divergent astrovirus was sequenced in a sample co-infected with parechovirus 1. RT-PCR identified a single astrovirus infection in these 48 patients indicating a low prevalence. Human astrovirus-BF34 was most closely related to mamastrovirus species 8 and 9 also found in human with which it shared 62%, 74%, and 57% amino acid identities over its protease, RNA dependent RNA polymerase and capsid proteins, respectively. Conclusions: Burkina Faso astrovirus is proposed as prototype for a novel species in the genus Mamastrovirus, here tentatively called Mamastrovirus 20, representing the fifth human astrovirus species.

  • 14.
    Gunaydin, Gokce
    et al.
    Karolinska Institute, Sweden.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Sharma, Sumit
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Hammarstrom, Lennart
    Karolinska Institute, Sweden.
    Association of elevated rotavirus-specific antibody titers with HBGA secretor status in Swedish individuals: The FUT2 gene as a putative susceptibility determinant for infection2016In: Virus Research, ISSN 0168-1702, E-ISSN 1872-7492, Vol. 211, p. 64-68Article in journal (Refereed)
    Abstract [en]

    The histo-blood group antigens (HBGAs) have recently been suggested to serve as attachment factors for rotavirus VP8* (P-genotype) in vitro and associated with susceptibility in vivo. We thus investigated whether rotavirus antibody titers and genotype specific neutralization titers correlate with HBGA status in Swedish individuals. We investigated the effect of inactivating mutations in the secretor FUT2 (rs601338) and Lewis FUT3 genes (rs28362459, rs3894326, rs812936 and rs778986) on serum IgG antibody titers and neutralizing antibody titers to rotavirus strains of the P[8] and P[6] genotypes in Swedish healthy blood donors and patients with IgA deficiency using genotyping, enzyme linked immunosorbent assay and a neutralization assay. Rotavirus-specific serum IgG and neutralizing antibody titers to the Wa strain (G1P[8]), but not to the ST3 (G4P[6]) strain, were significantly higher in secretors (with at least one functional FUT2 gene) than in non-secretors (P&lt;0.001) (with homozygous nonsense mutation in the FUT2 gene). Thus, our results represent that secretors show elevated rotavirus specific serum antibodies, suggesting a higher susceptibility to rotavirus infections, as compared to non-secretors in Sweden. (C) 2015 Elsevier B.V. All rights reserved.

  • 15.
    Gunaydin, Gokce
    et al.
    Karolinska University Hospital, Sweden .
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Hammarstrom, Lennart
    Karolinska University Hospital, Sweden .
    Mutations in Toll-Like Receptor 3 Are Associated with Elevated Levels of Rotavirus-Specific IgG Antibodies in IgA-Deficient but Not IgA-Sufficient Individuals2014In: Clinical and Vaccine Immunology, ISSN 1556-6811, E-ISSN 1556-679X, Vol. 21, no 3, p. 298-301Article in journal (Refereed)
    Abstract [en]

    Double-stranded RNA (dsRNA) triggers immune-mediated responses through toll-like receptor 3 (TLR3), which is involved in innate antiviral defense. Low expression of TLR3 was recently suggested to contribute to susceptibility to rotavirus infection. Thus, we investigated the role of two TLR3 polymorphisms (rs3775291 and rs5743305), both of which resulted in reduced protein function or expression, in healthy blood donors and IgA-deficient (IgAD) individuals. These polymorphisms were associated with elevated rotavirus-specific IgG titers in IgAD individuals but not in healthy individuals. Thus, we propose that TLR3 signaling does not contribute to the rotavirus-specific antibody response in IgA-sufficient individuals, whereas it is associated with elevated antibody titers in IgAD individuals.

  • 16.
    Günaydın, Gökçe
    et al.
    Division of Clinical Immunology, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden.
    Nordgren, Johan
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine.
    Svensson, Lennart
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine.
    Hammarström, Lennart
    Division of Clinical Immunology, Karolinska Institutet at Karolinska University Hospital Huddinge, Stockholm, Sweden.
    TLR3-dependent antibody response against rotavirus in individuals with immunoglobulin A deficiency2013In: Journal of Infectious Diseases, ISSN 0022-1899, E-ISSN 1537-6613Article in journal (Refereed)
  • 17.
    Hagbom, Marie
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Ge, Ray
    School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.
    Lundin, Samuel
    Department of Microbiology and Immunology, Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden.
    Wigzell, Hans
    Microbiology & Tumor biology Center, Karolinska Institute, Stockholm, Sweden.
    Taylor, John A
    School of Biological Sciences and Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.
    Andersson, Ulf
    Department of Women's and Children's Health, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    The Cholinergic Anti-Inflammatory Pathway Contributes to the Limited Inflammatory Response following Rotavirus InfectionManuscript (preprint) (Other academic)
    Abstract [en]

    Rotavirus causes acute gastroenteritis in young children and is characterized by severe diarrhoea and vomiting. Surprisingly, although rotavirus infection results in significant intestinal pathology, the inflammatory response is limited. We tested the novel hypothesis that rotavirus infection stimulates the cholinergic anti-inflammatory pathway to suppress gut inflammation. The role of the vagus nerve and the α7 nicotinic acetylcholine receptor (α7 nAChR) in rotavirus infection were explored in α7 nAChR gene-deficient mice, vagotomized mice and wild-type mice treated with the α7 nAChR antagonist mecamylamine. TNF-α, IL-1β and IL-6 were measured in serum, spleen, duodenum, jejunum and ileum at 48 hours post infection. To determine if modulation of the inflammatory response affects virus shedding, α7 nAChRs was blocked and virus quantified in faeces. To investigate if stimulation of α7 nAChRs could attenuate rotavirus toxin NSP4-induced cytokine release, mouse peritoneal- and human blood-macrophages were treated with nicotine before NSP4 stimulation.

    Our results shows that stimulation of the vagus nerve and α7 nAChRs attenuated the pro- inflammatory response during rotavirus infection and blockade of the α7 nAChR reduced virus shedding from infected mice. IL-6 was increased in duodenum (p<0.05) and serum (p<0.05) of vagotomized mice and in jejunum (p<0.05) and spleen (p<0.05) of α7 nAChR gene-deficient mice. Furthermore, IL-6 mRNA (p<0.01) and TNF-α mRNA (p<0.05) were increased in duodenum of vagotomized animals. Similarly, nicotine attenuated the release of TNF-α (p<0.05) and IL-6 (p<0.05) from macrophages stimulated by NSP4 in vitro, all suggesting that the cholinergic anti- inflammatory pathway contributes to attenuate inflammation during rotavirus infection.

  • 18.
    Hagbom, Marie
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Nybom, Rolf
    Karolinska Institute, Sweden.
    Hedlund, Kjell-Olof
    Swedish Institute Communicable Disease Control, Sweden.
    Wigzell, Hans
    Karolinska Institute, Sweden.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Ionizing air affects influenza virus infectivity and prevents airborne-transmission2015In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, no 11431Article in journal (Refereed)
    Abstract [en]

    By the use of a modified ionizer device we describe effective prevention of airborne transmitted influenza A (strain Panama 99) virus infection between animals and inactivation of virus (greater than 97%). Active ionizer prevented 100% (4/4) of guinea pigs from infection. Moreover, the device effectively captured airborne transmitted calicivirus, rotavirus and influenza virus, with recovery rates up to 21% after 40 min in a 19 m(3) room. The ionizer generates negative ions, rendering airborne particles/aerosol droplets negatively charged and electrostatically attracts them to a positively charged collector plate. Trapped viruses are then identified by reverse transcription quantitative real-time PCR. The device enables unique possibilities for rapid and simple removal of virus from air and offers possibilities to simultaneously identify and prevent airborne transmission of viruses.

  • 19.
    Istrate, Claudia
    et al.
    University of Nova Lisboa, Portugal.
    Sharma, Sumit
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Videira e Castro, Sandra
    University of Nova Lisboa, Portugal.
    Lopes, Angela
    University of Nova Lisboa, Portugal.
    Piedade, Joao
    University of Nova Lisboa, Portugal.
    Zaky, Ahmed
    Institute Marques de Valle Flor, Portugal.
    Lima, Antonio
    Institute Marques de Valle Flor, Sao Tome and Prin; Minist Saude, Sao Tome and Prin.
    Neves, Edgar
    Institute Marques de Valle Flor, Sao Tome and Prin.
    Veiga, Jose
    Institute Marques de Valle Flor, Sao Tome and Prin; Minist Saude, Sao Tome and Prin.
    Esteves, Aida
    University of Nova Lisboa, Portugal.
    High rate of detection of G8P[6] rotavirus in children with acute gastroenteritis in So Tom, and Principe2015In: Archives of Virology, ISSN 0304-8608, E-ISSN 1432-8798, Vol. 160, no 2, p. 423-428Article in journal (Refereed)
    Abstract [en]

    The burden of rotavirus infections greatly affects the low-income African countries. In the absence of epidemiological data on pediatric diarrhea in So Tom, and Principe (STP), a study was conducted from August to December 2011. Rotavirus antigen was detected in 36.7 % of the collected fecal samples (87/237). G8P[6] was identified as the predominant genotype (71.1 % detection rate), while G1P[8] represented only 8.4 %. Phylogenetic analysis of VP7 G8 strains showed clustering within lineage G8d, while VP4 P[6] strains clustered within lineage 1a. Our results represent the first report on rotavirus from STP and show one of the highest detection rates of G8 rotaviruses worldwide.

  • 20.
    Matussek, Andreas
    et al.
    County Hospital Ryhov, Sweden.
    Dienus, Olaf
    County Hospital Ryhov, Sweden.
    Djeneba, Ouermi
    University of Ouagadougou, Burkina Faso.
    Simpore, Jacques
    University of Ouagadougou, Burkina Faso.
    Nitiema, Leon
    University of Ouagadougou, Burkina Faso.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Molecular characterization and genetic susceptibility of sapovirus in children with diarrhea in Burkina Faso2015In: Infection, Genetics and Evolution, ISSN 1567-1348, E-ISSN 1567-7257, Vol. 32, p. 396-400Article in journal (Refereed)
    Abstract [en]

    Sapoviruses (Says) are a common cause of gastroenteritis in children. In sub-Saharan Africa, there is a scarcity of information regarding SaV as an etiological agent of diarrhea. Here, we investigated the prevalence, molecular characterization and clinico-epidemiological features of SaV infections in children less than 5 years of age with diarrhea in Burkina Faso. We further investigated the role of type 1 histo blood group antigens as susceptibility factors. In total, 309 fecal and 208 saliva samples from diarrheal children in Ouagadougou, Burkina Faso, were collected between May 2009 and March 2010. Say was detected using real-time PCR, and genogrouped/genotyped by PCR or sequencing. Saliva samples were ABO, Lewis and secretor phenotyped using in house ELISA assays. We found a high prevalence (18%) and large genetic diversity with all 4 human genogroups, and 9 genotypes/genoclusters circulating during the study period. The SaV infections were generally associated with milder symptoms, and neither ABH, Lewis or secretor phenotypes affected susceptibility to Say infections. (C) 2015 Published by Elsevier B.V.

  • 21.
    Mickiene, Aukse
    et al.
    Lithuanian University of Health Science, Lithuania; Karolinska University Hospital Huddinge, Sweden.
    Pakalniene, Jolita
    Lithuanian University of Health Science, Lithuania.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Carlsson, Beatrice
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Hagbom, Marie
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Lindquist, Lars
    Karolinska University Hospital Huddinge, Sweden.
    Polymorphisms in Chemokine Receptor 5 and Toll-Like Receptor 3 Genes Are Risk Factors for Clinical Tick-Borne Encephalitis in the Lithuanian Population2014In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 9, no 9, p. e106798-Article in journal (Refereed)
    Abstract [en]

    Background: Tick-borne encephalitis virus (TBEV) infections can be asymptomatic or cause moderate to severe injuries of the nervous system. We previously reported that a nonfunctional chemokine receptor 5 (CCR5) and a functional Toll-like receptor 3 (TLR3) predispose adults to clinical tick-borne encephalitis (TBE). This study expands our previous findings and further examines polymorphisms in CCR5 and TLR3 genes in different age and disease severity groups. Methods: 117 children and 129 adults, stratified into mild, moderate and severe forms of TBE, and 103 adults with severe TBE were analyzed. 135 healthy individuals and 79 patients with aseptic meningoencephalitis served as controls. CCR5 delta 32 and rs3775291 TLR3 genotypes were established by pyrosequencing, and their frequencies were analyzed using recessive genetic, genotype and allelic models. Findings: The prevalence of CCR5 Delta 32 homozygotes was higher in children (2.5%), in adults with severe TBE (1.9%), and in the combined cohort of TBE patients (2.3%) than in controls (0%) (pless than0.05). The nonfunctional homozygous TLR3 genotype was less prevalent among the combined TBE cohort (11.5%) than among controls (19.9%) (p = 0.025), but did not differ between children TBE and controls. The genotype and allele prevalence of CCR5 and TLR3 did not differ in children nor adult TBE cohorts stratified by disease severity. However, in the severe adult TBE cohort, homozygous functional TLR3 genotype and wt allele were less prevalent compared to the adult cohort with the whole disease severity spectrum (44.4% vs 59.8% p = 0.022 and 65.2% vs 76.4% p = 0.009; respectively). Conclusions: Independently of age, nonfunctional CCR5D32 mutation is a significant risk factor for development of clinical TBE, but not for disease severity. The polymorphism of TLR3 gene predisposes to clinical TBE in adults only and may be associated with disease severity. Further studies are needed to clarify the role of these polymorphisms in susceptibility to TBEV infection.

  • 22.
    Nitiema, Leon W
    et al.
    University of Ouagadougou.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Ouermi, Djeneba
    University of Ouagadougou.
    Dianou, Dayeri
    Centre for National Resarch Science and Technology, Ouagadougou.
    Traore, Alfred S
    University of Ouagadougou.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology. Linköping University, Faculty of Health Sciences.
    Simpore, Jacques
    University of Ouagadougou.
    Burden of rotavirus and other enteropathogens among children with diarrhea in Burkina Faso2011In: International Journal of Infectious Diseases, ISSN 1201-9712, E-ISSN 1878-3511, Vol. 15, no 9, p. E646-E652Article in journal (Refereed)
    Abstract [en]

    Objective: There is limited information available regarding the etiology of gastrointestinal infections in Burkina Faso. The aim of this study was to investigate the prevalence and epidemiology of enteric pathogens causing gastroenteritis in young children, with a focus on rotavirus, and to investigate the levels of malnutrition and other clinical factors in association with the severity of diarrhea. less thanbrgreater than less thanbrgreater thanMethods: A prospective study was undertaken from May 2009 to March 2010, covering the rainy and dry seasons, at the Saint Camille Medical Center in Ouagadougou, Burkina Faso. A total of 309 children less than 5 years of age with diarrhea were enrolled and examined for rotavirus, bacterial, and parasitic infections, as well as clinico-epidemiological aspects. less thanbrgreater than less thanbrgreater thanResults: At least one enteropathogen was detected in 57.9% (n = 179) of the children. Of these, 32.4% had rotavirus infections, 16.8% bacterial infections (enteropathogenic Escherichia coli 9.7%, Shigella spp 5.8%, and Salmonella spp 2.3%), and 18.8% parasitic infections (Giardia lamblia 11.3%, Trichomonas intestinalis 6.8%, Entamoeba histolytica/dispar 1.3%). During the cold dry period from December 2009 to February 2010, we observed a large increase in diarrhea cases, which was mainly attributed to rotavirus infections, as 63.8% of these diarrhea cases were positive for rotavirus. In contrast, no rotavirus infection was observed during the rainy season (June-September 2009), when the frequency of parasitic infections was high. Rotavirus and parasitic infections were age-related, with rotavirus being more prevalent in young children (andlt;12 months) and parasites more common in older children (andgt;12 months), while bacteria were equally prevalent among all age groups. Rotavirus infections exhibited more severe symptoms compared to bacteria and parasites, and were associated with fever, vomiting, and severe dehydration. Malnutrition, especially acute malnutrition (wasting), was significantly associated with more severe symptoms in rotavirus-induced diarrhea. The undernourished children also exhibited a prolonged duration of diarrheal episodes. less thanbrgreater than less thanbrgreater thanConclusion: This study demonstrates rotavirus as the main etiological agent in pediatric diarrhea in Burkina Faso, and further shows the great severity of rotavirus-induced diarrhea in undernourished children in Burkina Faso.

  • 23.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Norovirus Epidemiology: Prevalence, transmission, and determinants of disease susceptibility2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Norovirus (NoV) is today recognized as the most important agent of acute human gastroenteritis, causing a high number of diarrheal episodes in both adults and children. Outbreaks in hospitals, nursing homes, day-care centers, and from consumption of contaminated food and drinking water are common. Wastewater can be a source of NoV dissemination, e.g. when used for irrigation of crops, or due to shellfish cultivation near the outlet of wastewater treatment plants. Today, at least 25 different genotypes of NoV belonging to two major genogroups (GG) have been observed in humans. These genotypes are associated with different transmission patterns and disease severity in humans. Also host genetic factors, such as presence of ABO antigens and mutations in the FUT2 gene affect susceptibility, and can even render complete resistance to symptomatic infections, but only the most common NoV genotypes have been studied regarding this.

    In this thesis, we wanted to find prevention strategies for NoV disease through four studies of NoV epidemiology: Development of a sensitive real-time PCR assay for detection and quantification of human NoVs, characterization of NoV in children with diarrhea in Nicaragua, investigation of the prevalence and parameters influencing NoV concentration in a wastewater treatment plant in Gothenburg, Sweden, and studying host susceptibility factors in a foodborne NoV outbreak in Jönköping, Sweden.

    First we developed a real-time PCR assay which can detect and quantify NoV in various settings, both in stool samples of patients, and in wastewater samples from which virus was first concentrated using ultracentrifugation. This assay was found to be more sensitive than commercial immunological assays and conventional PCR methods. The assay is furthermore able to differentiate between the two major human genogroups of NoV using melting curve analysis, which provides valuable information about the circulating NoV strains.

    The survey of NoV in pediatric diarrhea in Nicaragua revealed a large impact of NoV, both in community and hospital based settings, with 15% of the severe diarrhea cases attributed to NoV. Peaks of clinically diagnosed NoV gastroenteritis were associated with emerging variants of genotype GGII.4, largely replacing the many different NoV genotypes circulating before the peak of diarrheal cases. Children infected with the GGII.4 genotype were found to shed more virus compared to children infected with other genotypes, which could partly explain the high transmission of GGII.4.

    At the wastewater treatment plant in Gothenburg, both NoV GGI and GGII were detected during a whole year, not only during the winter season when clinical cases are common. This indicates that NoV infections are frequently occurring at clinical and/or sub-clinical levels in the community. During winter, GGII was present in high concentrations, whereas GGI concentration increased to higher levels than GGII in summer, possibly due to the emergence of new genotypes following the winter outbreaks. The levels of NoV GGI were stable during the year, and hence incoming concentrations were affected by dilution factors such as rain. Primary treatment and treatment in a conventional, non-nitrifying activated sludge system reduced the NoV concentration by a factor of about 30. The detection of NoV in outgoing water, together with the low reduction and lack of correlation to indicator bacteria, suggest that better monitoring tools for virus in wastewater are warranted to reduce environmental contamination.

    A foodborne NoV outbreak in Jönköping in October 2007, by a NoV GGI.3 strain, revealed a surprising pattern of host susceptibility. In contrast to previous findings, this strain infected individuals irrespective of secretor status and Lewis (Le) phenotype, with non-secretors and Lea+bindividuals having a higher risk of disease. Individuals with blood group B had a partial protection to symptomatic infection, but none of the host factors investigated mediated complete resistance. Furthermore, we observed differences in susceptibility regarding homozygosity and heterozygosity in the FUT2 gene, with heterozygous secretor-positive individuals being more susceptible to symptomatic NoV infection than homozygous secretors.

    In summary, the developed LUX real-time PCR assay was successfully used in all studies in this thesis, which yielded important information about the prevalence and transmission of NoV. We observed the emergence of GGII.4 variants, causing the majority of diarrheal cases in children, largely replacing the other circulating genotypes, possibly due to better replication leading to a higher viral shedding. After the peak of NoV-induced diarrheal episodes, the incidence of GGII.4 decrease and other strains emerge which can infect people not previously exposed. This was observed in the foodborne outbreak in Jönköping, where individuals expected to be resistant to NoV were infected, and indeed had a higher risk of developing disease. A similar seasonal pattern was also indirectly observed in wastewater, with high levels of GGII in winter, which subsequently declined, followed by an increase of GGI in summer. Taken together, these results provide a better insight into the epidemiology of the virus, which hopefully can lead to better preventive measures for NoV gastroenteritis.

    List of papers
    1. Novel light-upon-extension real-time PCR assays for detection and quantification of genogroup I and II noroviruses in clinical specimens
    Open this publication in new window or tab >>Novel light-upon-extension real-time PCR assays for detection and quantification of genogroup I and II noroviruses in clinical specimens
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    2008 (English)In: Journal of Clinical Microbiology, ISSN 0095-1137, E-ISSN 1098-660X, Vol. 46, no 1, p. 164-170Article in journal (Refereed) Published
    Abstract [en]

    Norovirus is now recognized as the leading cause of nonbacterial acute gastroenteritis in adults, causing numerous outbreaks worldwide. We have developed two novel light-upon-extension (LUX) real-time PCR assays for detection and quantification of norovirus genogroups I and II. The LUX system uses a fluorophore attached to one primer having a self-quenching hairpin structure, making it cost-effective and specific. The assays were evaluated against clinical stool specimens (n = 103) from Sweden and Nicaragua and compared to established methods. The norovirus assay detected more positive stool specimens (47/103) than conventional PCR (39/103) and corresponded to a TaqMan real-time PCR, with the exception of one specimen. Furthermore, the assays correctly identified all (n = 11) coded control specimens in a reference panel containing various genogroups and genotypes. Both LUX real-time PCR assays had a wide dynamic range, detecting from < or = 10(1) to 10(7) genes per reaction, resulting in a theoretical lower limit of < or = approximately 20,000 viruses per gram of stool. No cross-reactivity was noticed with specimens containing other enteric viruses, and by using melting curve analysis we could differentiate between norovirus genogroups I and II.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-17684 (URN)10.1128/JCM.01316-07 (DOI)17959761 (PubMedID)
    Available from: 2009-04-14 Created: 2009-04-14 Last updated: 2017-12-13Bibliographically approved
    2. Pediatric norovirus diarrhea in Nicaragua
    Open this publication in new window or tab >>Pediatric norovirus diarrhea in Nicaragua
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    2008 (English)In: Journal of Clinical Microbiology, ISSN 0095-1137, E-ISSN 1098-660X, Vol. 46, no 8, p. 2573-2580Article in journal (Refereed) Published
    Abstract [en]

    Information about norovirus (NoV) infections in Central America is limited. Through a passive community and hospital pediatric diarrhea surveillance program, a total of 542 stool samples were collected between March 2005 and February 2006 in León, Nicaragua. NoV was detected in 12% (65/542) of the children; of these, 11% (45/409) were in the community and 15% (20/133) were in the hospital, with most strains (88%) belonging to genogroup II. NoV infections were age and gender associated, with children of <2 years of age (P < 0.05) and girls (P < 0.05) being most affected. Breast-feeding did not reduce the number of NoV infections. An important proportion (57%) of NoV-infected children were coinfected with diarrheagenic Escherichia coli. A significant proportion (18/31) of NoV-positive children with dehydration required intravenous rehydration. Nucleotide sequence analysis (38/65) of the N-terminal and shell region in the capsid gene revealed that at least six genotypes (GI.4, GII.2, GII.4, GII.7, GII.17, and a potentially novel cluster termed "GII.18-Nica") circulated during the study period, with GII.4 virus being predominant (26/38). The majority (20/26) of those GII.4 strains shared high nucleotide homology (99%) with the globally emerging Hunter strain. The mean viral load was approximately 15-fold higher in children infected with GII.4 virus than in those infected with other G.II viruses, with the highest viral load observed for the group of children infected with GII.4 and requiring intravenous rehydration. This study, the first of its type from a Central American country, suggests that NoV is an important etiological agent of acute diarrhea among children of <2 years of age in Nicaragua.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-17685 (URN)10.1128/JCM.00505-08 (DOI)18562593 (PubMedID)
    Available from: 2009-04-14 Created: 2009-04-14 Last updated: 2017-12-13Bibliographically approved
    3. Prevalence of norovirus and factors influencing virus concentrations during one year in a full-scale wastewater treatment plant
    Open this publication in new window or tab >>Prevalence of norovirus and factors influencing virus concentrations during one year in a full-scale wastewater treatment plant
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    2009 (English)In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 43, no 4, p. 1117-1125Article in journal (Refereed) Published
    Abstract [en]

    Norovirs (NoV) is a leading cause of acute gastroenteritis and is often spread via wastewater contamination. Little is known about how the wastewater treatment process affects norovirus, and which factors influence virus concentrations. To investigate this, we collected wastewater samples monthly during one year at eight different key sites at the municipal wastewater treatment plant in Gothenburg, Sweden. Virus particles were concentrated using ultracentrifugation, viral RNA was subsequently extracted, and transformed into cDNA by reverse transcription. The quantification was performed with real-time PCR assays for NoV genogroups I (GGI) and II (GGII), respectively. We found seasonal changes of NoV genogroups, with the highest concentration of NoV GGII during the winter months, and the highest concentration of NoV GGI during the summer months. Virus transmission in wastewater was more stable for NoV GGI, with NoV GGII demonstrating larger seasonal peaks. Virus reduction took place at similar rates in the primary settling, and in the activated sludge in combination with the secondary settling. Different physicochemical parameters and incoming virus concentrations were correlated to reduction of NoV between different treatment sites. This study gives new information about NoV transmission and virus reduction in a wastewater treatment plant.

    Keywords
    Wastewater treatment, Norovirus, Removal, Physicochemical parameters, real-time PCR
    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-17654 (URN)10.1016/j.watres.2008.11.053 (DOI)
    Note
    Original Publication: Johan Nordgren, Andreas Matussek, Ann Mattsson, Lennart Svensson and Per-Eric Lindgren, Prevalence of norovirus and factors influencing virus concentrations during one year in a full-scale wastewater treatment plant, 2009, Water Research, (43), 4, 1117-1125. http://dx.doi.org/10.1016/j.watres.2008.11.053 Copyright: Elsevier Science B.V., Amsterdam. http://www.elsevier.com/ Available from: 2009-05-09 Created: 2009-04-07 Last updated: 2017-12-13Bibliographically approved
    4. A FUT2 nonsense mutation (G428A) and Lewis-independent norovirus GI.3 outbreak
    Open this publication in new window or tab >>A FUT2 nonsense mutation (G428A) and Lewis-independent norovirus GI.3 outbreak
    Show others...
    2009 (English)Article in journal (Other academic) Submitted
    Abstract [en]

    Background: Norovirus (NoV) is recognized as the commonest cause of acute gastroenteritis among adults. Previous studies have shown that histo-blood group antigens (HBGAs) and secretor status are associated with susceptibility to symptomatic NoV infection, with non-secretors being almost completely resistant to disease. Here we report on a food-borne GI.3 NoV outbreak affecting 33/83 (40%) individuals.

    Methods: Secretor status and HBGA expression in saliva were determined with pyrosequencing and ELISA. Virus characterization was performed by sequencing the N/S region and the complete capsid gene.

    Results: A novel observation was that homozygous carriers of the nonsense FUT2 G428A allele were more susceptible to symptomatic infection than secretors (odds ratio [OR] 1.41 vs 0.71). Consistent with this observation was that Lewis a positive b negative (Lea+b-) individuals showed the highest susceptibility (OR 2.42) compared with other Lewis phenotypes. Blood group B was associated with partial protection (OR 0.27). The capsid gene of the outbreak strain exhibits high amino acid homology with the Kashiwa645 GI.3 strain, previously shown to recognize non-secretor saliva.

    Conclusion: We describe for the first time a NoV outbreak with Lea+b- individuals homozygous for the G428A nonsense mutation in the FUT2 gene being more susceptible for disease than secretor-positive individuals.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-17686 (URN)
    Available from: 2009-04-14 Created: 2009-04-14 Last updated: 2009-04-14Bibliographically approved
  • 24.
    Nordgren, Johan
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Bucardo, Filemon
    Department of Microbiology, University of León, León, Nicaragua.
    Dienus, Olaf
    Microbiological Laboratory, Ryhov County Hospital, Jönköping, Sweden.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology. Linköping University, Faculty of Health Sciences.
    Lindgren, Per-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Correction: Novel Light-Upon-Extension Real-Time PCR Assays for Detection and Quantification of Genogroup I and II Noroviruses in Clinical Specimens (vol 46, pg 164, 2008)2009In: Journal of Clinical Microbiology, ISSN 0095-1137, E-ISSN 1098-660X, Vol. 47, no 4, p. 1285-1285Article in journal (Other academic)
  • 25.
    Nordgren, Johan
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Bucardo, Filemon
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology . Linköping University, Faculty of Health Sciences.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology . Linköping University, Faculty of Health Sciences.
    Lindgren, Per-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Novel Light-Upon-Extension Real-Time PCR Assay for Simultaneous Detection, Quantification, and Genogrouping of Group A Rotavirus2010In: JOURNAL OF CLINICAL MICROBIOLOGY, ISSN 0095-1137, Vol. 48, no 5, p. 1859-1865Article in journal (Refereed)
    Abstract [en]

    We have developed a light-upon-extension (LUX) real-time PCR assay for detection, quantification, and genogrouping of group A rotavirus (RV), the most common cause of acute gastroenteritis in children. The LUX system uses a fluorophore attached to one primer and having a self-quenching hairpin structure, making it cost-effective and specific. We designed genogroup-specific primers having different fluorophores, making it possible to differentiate between the two main genogroups of human group A RVs. The assay was applied on clinical stool specimens from Sweden and Central America (n = 196) and compared to immunological and conventional PCR assays. The genogrouping ability was further validated against a subset of clinical specimens, which had been genogrouped using monoclonal antibodies. Our real-time PCR assay detected and quantified all positive specimens (n = 145) and exhibited higher sensitivity than immunological assays and conventional PCR. The assay exhibited a wide dynamic range, detecting from 5 to andgt; 10(7) genes per PCR, resulting in a theoretical lower detection limit of andlt; 10,000 viruses per gram of stool. No cross-reaction was observed with specimens containing norovirus, sapovirus, astrovirus, or adenovirus. In total, 22 (15%) of the positive clinical specimens were identified as genogroup I, 122 (84%) were identified as genogroup II, and 1 specimen was found to contain a mix of both genogroups. All genogroup I-positive specimens were associated with capsid glycoprotein 2 (G2). No significant difference in viral load was found between genogroups or geographic region. The detection and quantification, combined with the genogrouping ability, make this assay a valuable tool both for diagnostics and for molecular epidemiological investigations.

  • 26.
    Nordgren, Johan
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology . Linköping University, Faculty of Health Sciences.
    Bucardo, Filemón
    Department of Microbiology, University of León, León, Nicaragua.
    Dienus, Olaf
    Microbiological Laboratory, Ryhov County Hospital, Jönköping, Sweden.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology . Linköping University, Faculty of Health Sciences.
    Lindgren, Per-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Novel light-upon-extension real-time PCR assays for detection and quantification of genogroup I and II noroviruses in clinical specimens2008In: Journal of Clinical Microbiology, ISSN 0095-1137, E-ISSN 1098-660X, Vol. 46, no 1, p. 164-170Article in journal (Refereed)
    Abstract [en]

    Norovirus is now recognized as the leading cause of nonbacterial acute gastroenteritis in adults, causing numerous outbreaks worldwide. We have developed two novel light-upon-extension (LUX) real-time PCR assays for detection and quantification of norovirus genogroups I and II. The LUX system uses a fluorophore attached to one primer having a self-quenching hairpin structure, making it cost-effective and specific. The assays were evaluated against clinical stool specimens (n = 103) from Sweden and Nicaragua and compared to established methods. The norovirus assay detected more positive stool specimens (47/103) than conventional PCR (39/103) and corresponded to a TaqMan real-time PCR, with the exception of one specimen. Furthermore, the assays correctly identified all (n = 11) coded control specimens in a reference panel containing various genogroups and genotypes. Both LUX real-time PCR assays had a wide dynamic range, detecting from < or = 10(1) to 10(7) genes per reaction, resulting in a theoretical lower limit of < or = approximately 20,000 viruses per gram of stool. No cross-reactivity was noticed with specimens containing other enteric viruses, and by using melting curve analysis we could differentiate between norovirus genogroups I and II.

  • 27.
    Nordgren, Johan
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology. Linköping University, Faculty of Health Sciences.
    Juste O Bonkoungou, Isidore
    Laboratoire National de Santé Publique du Burkina Faso, Ouagadougou, Burkina Faso, Laboratoire de Biologie Moléculaire, d’Epidémiologie et Surveillance des Bactéries et Virus Transmissibles par les Aliments, CRSBAN/UFR-SVT, Université de Ouagadougou, Ouagadougou, Burkina Faso.
    Nitiema, Leon W.
    Centre de Recherche Biomoléculaire Pietro Annigoni, Saint Camille CERBA/LABIOGENE, Université de Ouagadougou, Ouagadougou, Burkina Faso, Centre de Recherche en Sciences Biologiques, Alimentaires et Nutritionnelles (CRSBAN), Université de Ouagadougou, Ouagadougou, Burkina Faso.
    Sharma, Sumit
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology. Linköping University, Faculty of Health Sciences.
    Ouermi, Djeneba
    Centre de Recherche Biomoléculaire Pietro Annigoni, Saint Camille CERBA/LABIOGENE, Université de Ouagadougou, Ouagadougou, Burkina Faso.
    Simpore, Jacques
    Centre de Recherche Biomoléculaire Pietro Annigoni, Saint Camille CERBA/LABIOGENE, Université de Ouagadougou, Ouagadougou, Burkina Faso.
    Barro, Nicolas
    Laboratoire de Biologie Moléculaire, d’Epidémiologie et Surveillance des Bactéries et Virus Transmissibles par les Aliments, CRSBAN/UFR-SVT, Université de Ouagadougou, Ouagadougou, Burkina Faso.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology. Linköping University, Faculty of Health Sciences.
    Rotavirus in diarrheal children in rural Burkina Faso: High prevalence of genotype G6P[6]2012In: Infection, Genetics and Evolution, ISSN 1567-1348, E-ISSN 1567-7257, Vol. 12, no 8, p. 1892-1898Article in journal (Refereed)
    Abstract [en]

    Group A rotavirus (RVA) is the most common cause of severe gastroenteritis in young children globally, and responsible for a significant number of deaths in African countries. While vaccines are available, trials have shown a lesser efficacy in Africa. One of the reasons could be the prevalence and/or emergence of unusual or novel RVA strains, as many strains detected in African countries remain uncharacterized. less thanbrgreater than less thanbrgreater thanIn this study, we characterized RVA positive specimens from two remote rural areas in Burkina Faso, West Africa. In total 56 RVA positive specimens were subgrouped by their VP6 gene, and G-and P typed by PCR and/or sequencing of the VP7 and VP4 genes, respectively. less thanbrgreater than less thanbrgreater thanNotably, we found a high prevalence of the unusual G6P[6]SGI strains (23%). It was the second most common constellation after G9P[8]SGII (32%); and followed by G1P[8]SGII (20%) and G2P[4]SGI (9%). We also detected a G8P[6]SGI strain, for the first time in Burkina Faso. The intra-genetic diversity was high for the VP4 gene with two subclusters within the P[8] genotype and three subclusters within the P[6] genotype which were each associated with a specific G-type, thereby suggesting a genetic linkage. The G6P[6]SGI and other SGI RVA strains infected younger children as compared to SGII strains (p andlt; 0.05). less thanbrgreater than less thanbrgreater thanTo conclude, in this study we observed the emergence of unusual RVA strains and high genetic diversity of RVA in remote rural areas of Burkina Faso. The results highlight the complexity of RVA epidemiology which may have implication for the introduction of rotavirus vaccines currently being evaluated in many African countries.

  • 28.
    Nordgren, Johan
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Kindberg, Elin
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology . Linköping University, Faculty of Health Sciences.
    Lindgren, Per-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Matussek, Andreas
    Department of Clinical Microbiology, Division of Laboratory Medicine, County Hospital Ryhov, Jönköping, Sweden/Department of Clinical Microbiology, Capio Diagnostik AB, Capio St Görans Hospital, Stockholm, Sweden.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology . Linköping University, Faculty of Health Sciences.
    A FUT2 nonsense mutation (G428A) and Lewis-independent norovirus GI.3 outbreak2009Article in journal (Other academic)
    Abstract [en]

    Background: Norovirus (NoV) is recognized as the commonest cause of acute gastroenteritis among adults. Previous studies have shown that histo-blood group antigens (HBGAs) and secretor status are associated with susceptibility to symptomatic NoV infection, with non-secretors being almost completely resistant to disease. Here we report on a food-borne GI.3 NoV outbreak affecting 33/83 (40%) individuals.

    Methods: Secretor status and HBGA expression in saliva were determined with pyrosequencing and ELISA. Virus characterization was performed by sequencing the N/S region and the complete capsid gene.

    Results: A novel observation was that homozygous carriers of the nonsense FUT2 G428A allele were more susceptible to symptomatic infection than secretors (odds ratio [OR] 1.41 vs 0.71). Consistent with this observation was that Lewis a positive b negative (Lea+b-) individuals showed the highest susceptibility (OR 2.42) compared with other Lewis phenotypes. Blood group B was associated with partial protection (OR 0.27). The capsid gene of the outbreak strain exhibits high amino acid homology with the Kashiwa645 GI.3 strain, previously shown to recognize non-secretor saliva.

    Conclusion: We describe for the first time a NoV outbreak with Lea+b- individuals homozygous for the G428A nonsense mutation in the FUT2 gene being more susceptible for disease than secretor-positive individuals.

  • 29.
    Nordgren, Johan
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Lindgren, Per-Eric
    County Hospital Ryhov, Jonkoping, Sweden .
    Matussek, Andreas
    County Hospital Ryhov, Jonkoping, Sweden Capio St Gorans Hospital, Stockholm, Sweden .
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology . Linköping University, Faculty of Health Sciences.
    Norovirus Gastroenteritis Outbreak with a Secretor-independent Susceptibility Pattern, Sweden2010In: Emerging Infectious Diseases, ISSN 1080-6040, E-ISSN 1080-6059, Vol. 16, no 1, p. 81-87Article in journal (Refereed)
    Abstract [en]

    Norovirus (NoV) is recognized as the commonest cause of acute gastroenteritis among adults. Susceptibility to disease has been associated with histo-blood group antigens and secretor status; nonsecretors are almost completely resistant to disease. We report a foodborne outbreak of GI.3 NoV gastroenteritis that affected 33/83 (40%) persons. Symptomatic disease was as likely to develop in nonsecretors as in secretors (odds ratio [OR] 1.41, 95% confidence interval [CI] 0.46-4.36 vs. OR 0.71, 95% Cl 0.23-2.18, p = 0.57). Moreover, no statistical difference in susceptibility was found between persons of different Lewis or ABO phenotypes. The capsid gene of the outbreak strain shares high amino acid homology with the Kashiwa645 GI.3 strain, previously shown to recognize nonsecretor saliva, as well as synthetic Lewis a. This norovirus outbreak affected persons regardless of secretor status or Lewis or ABO phenotypes.

  • 30.
    Nordgren, Johan
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology . Linköping University, Faculty of Health Sciences.
    Matussek, Andreas
    Department of Clinical Microbiology, County Hospital Ryhov, 55185 Jönköping, Sweden.
    Mattsson, Ann
    Gryaab AB, Gothenburg, Sweden.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology . Linköping University, Faculty of Health Sciences.
    Lindgren , Per-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology . Linköping University, Faculty of Health Sciences.
    Prevalence of norovirus and factors influencing virus concentrations during one year in a full-scale wastewater treatment plant2009In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 43, no 4, p. 1117-1125Article in journal (Refereed)
    Abstract [en]

    Norovirs (NoV) is a leading cause of acute gastroenteritis and is often spread via wastewater contamination. Little is known about how the wastewater treatment process affects norovirus, and which factors influence virus concentrations. To investigate this, we collected wastewater samples monthly during one year at eight different key sites at the municipal wastewater treatment plant in Gothenburg, Sweden. Virus particles were concentrated using ultracentrifugation, viral RNA was subsequently extracted, and transformed into cDNA by reverse transcription. The quantification was performed with real-time PCR assays for NoV genogroups I (GGI) and II (GGII), respectively. We found seasonal changes of NoV genogroups, with the highest concentration of NoV GGII during the winter months, and the highest concentration of NoV GGI during the summer months. Virus transmission in wastewater was more stable for NoV GGI, with NoV GGII demonstrating larger seasonal peaks. Virus reduction took place at similar rates in the primary settling, and in the activated sludge in combination with the secondary settling. Different physicochemical parameters and incoming virus concentrations were correlated to reduction of NoV between different treatment sites. This study gives new information about NoV transmission and virus reduction in a wastewater treatment plant.

  • 31.
    Nordgren, Johan
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Nitiema, Leon W
    University of Ouagadougou.
    Sharma, Sumit
    University of Ouagadougou.
    S Traore, Alfred
    University of Ouagadougou.
    Simpore, Jacques
    University of Ouagadougou.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology. Linköping University, Faculty of Health Sciences.
    Emergence of Unusual G6P[6] Rotaviruses in Children, Burkina Faso, 2009-20102012In: Emerging Infectious Diseases, ISSN 1080-6040, E-ISSN 1080-6059, Vol. 18, no 4, p. 589-597Article in journal (Refereed)
    Abstract [en]

    To obtain more information about rotavirus (ROTAV) genotypes in Burkina Faso, we characterized 100 ROTAVs isolated from fecal samples of children with acute gastroenteritis in the capital city of Ouagadougou, during December 2009 March 2010. Of note, 13% of the ROTAV-positive samples, including those with mixed infections, were positive for the unusual G6 genotype ROTAV strain. The genotypes identified were G9P[8], G6P[6], G1P[6], G3P[6], G1P[8], and G2P[4]. G9P[8] subgroup (SG) II strains dominated during the beginning of the ROTAV season, but later in the season, other G types associated with P[6] and SGI specificity emerged. This emergence was related to a shift in the overall age of infected children; ROTAV SGII infected younger children and induced more severe symptoms. The finding of a high incidence of G6P[6] strains highlights the need for long-term surveillance of ROTAV strains in Burkina Faso, especially when ROTAV vaccination is being considered in several African countries.

  • 32.
    Nordgren, Johan
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Nitiema, Léon W
    Centre de Recherche Biomoléculaire Pietro Annigoni Saint Camille CERBA/LABIOGENE, Université de Ouagadougou, Ouagadougou, Burkina Faso.
    Ouermi, Djeneba
    Centre de Recherche Biomoléculaire Pietro Annigoni Saint Camille CERBA/LABIOGENE, Université de Ouagadougou, Ouagadougou, Burkina Faso.
    Simpore, Jacques
    Centre de Recherche Biomoléculaire Pietro Annigoni Saint Camille CERBA/LABIOGENE, Université de Ouagadougou, Ouagadougou, Burkina Faso.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Host Genetic Factors Affect Susceptibility to Norovirus Infections in Burkina Faso2013In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 8, no 7, p. e69557-Article in journal (Refereed)
    Abstract [en]

    Norovirus (NoV) constitutes the second most common viral pathogen causing pediatric diarrhea after rotavirus. In Africa, diarrhea is a major health problem in children, and yet few studies have been performed regarding NoV. The association of histo-blood group antigens (HBGA) and susceptibility to NoV infection is well established in Caucasian populations with non-secretors being resistant to many common NoV strains. No study regarding HBGA and NoV susceptibility has yet been performed in Africa. We collected 309 stool and 208 saliva samples from diarrheal children in Ouagadougou, Burkina Faso; May 2009 to March 2010. NoV was detected using real-time PCR, and genotyped by sequencing. Saliva samples were ABO, Lewis and secretor phenotyped using in house ELISA assays. NoV was detected in 12% (n = 37) of the samples. The genotype diversity was unusually large; overall the 37 positive samples belonged to 14 genotypes. Only children <2 years of age were NoV positive and the GII.4 NoVs were more frequent in the late dry season (Jan-May). NoV infections were observed less in children with the secretor-negative phenotype or blood group A (OR 0.18; p = 0.012 and OR 0.31; p = 0.054; respectively), with two non-secretors infected with genotypes GII.7 and GII.4 respectively. Lewis-negative (Lea−b−) children, representing 32% of the study population, were susceptible to GII, but were not infected with any NoV GI. GII.4 strains preferentially infected children with blood group B whereas secretor-positive children with blood group O were infected with the largest variety of genotypes. This is the first study identifying host genetic factors associated with susceptibility to NoV in an African population, and suggests that while the non-secretor phenotype provides protection; the Lewis b antigen is not necessary for GII infection.

  • 33.
    Nordgren, Johan
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Sharma, Sumit
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Bucardo, Filemon
    University of Leon, Nicaragua.
    Nasir, Waqas
    University of Gothenburg, Sweden.
    Gunaydin, Gokce
    Karolinska Institute, Sweden.
    Ouermi, Djeneba
    University of Ouagadougou, Burkina Faso.
    Nitiema, Leon W.
    University of Ouagadougou, Burkina Faso.
    Becker-Dreps, Sylvia
    University of N Carolina, NC USA.
    Simpore, Jacques
    University of Ouagadougou, Burkina Faso.
    Hammarstrom, Lennart
    Karolinska Institute, Sweden.
    Larson, Goran
    University of Gothenburg, Sweden.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Health Sciences.
    Both Lewis and Secretor Status Mediate Susceptibility to Rotavirus Infections in a Rotavirus Genotype-Dependent Manner2014In: Clinical Infectious Diseases, ISSN 1058-4838, E-ISSN 1537-6591, Vol. 59, no 11, p. 1567-1573Article in journal (Refereed)
    Abstract [en]

    Background. The live oral rotavirus (RV) vaccines have shown a reduced efficacy in Africa. Recent in vitro studies have shown binding of the RV surface protein (VP4) to histo-blood group antigens (HBGAs) in an RV genotype-dependent manner, suggesting them to be putative receptors for RV. The diversity of HBGA phenotypes in different ethnic populations, combined with prevalence/absence of specific RV genotypes, led us to hypothesize whether the genetic variations in HBGAs in a population limit susceptibility to certain RV genotypes, plausibly leading to reduced vaccine efficacy. Methods. Association between HBGAs status and susceptibility to RV P genotypes was investigated in children in Burkina Faso and Nicaragua. In total, 242 children with diarrhea in Burkina Faso and Nicaragua were investigated, 93 of whom were RV positive. Results. In Burkina Faso, the P[8] RV strains (n = 27) infected only Lewis-and secretor-positive children (27/27; P less than .0001), but no Lewis-negative children. In contrast, the P[6] strains (n = 27) infected predominantly Lewis-negative children (n = 18; P less than.0001) but also Lewis-positive children, irrespective of their secretor status. The results from Nicaragua confirmed that all P[8]-infected children (n = 22) were secretor Lewis positive. Conclusions. As VP4 of genotype P[8] is a component of current RV vaccines, our finding that Lewis-negative children are resistant to P[8] strains provides a plausible explanation for the reduced vaccine efficacy in populations with a high percentage of Lewis-negative individuals, such as in Africa. Furthermore, our findings provide a plausible explanation as to why P[6] RV strains are more common in Africa.

  • 34.
    Nordgren, Johan
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Sharma, Sumit
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Kambhampati, Anita
    Centre Disease Control and Prevent, USA.
    Lopman, Ben
    Centre Disease Control and Prevent, USA.
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Innate Resistance and Susceptibility to Norovirus Infection2016In: PLoS Pathogens, ISSN 1553-7366, E-ISSN 1553-7374, Vol. 12, no 4, p. e1005385-Article in journal (Refereed)
    Abstract [en]

    n/a

  • 35.
    Oluwatoyin Japhet, Margaret
    et al.
    Obafemi Awolowo University, Nigeria .
    Adeyemi Adesina, Olufisayo
    Obafemi Awolowo University, Nigeria .
    Famurewa, Oladiran
    Ekiti State University, Nigeria .
    Svensson, Lennart
    Linköping University, Department of Clinical and Experimental Medicine, Molecular Virology. Linköping University, Faculty of Health Sciences.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Molecular epidemiology of rotavirus and norovirus in Ile-Ife, Nigeria: High prevalence of G12P[8] rotavirus strains and detection of a rare norovirus genotype2012In: Journal of Medical Virology, ISSN 0146-6615, E-ISSN 1096-9071, Vol. 84, no 9, p. 1489-1496Article in journal (Refereed)
    Abstract [en]

    Rotavirus (RV) and norovirus (NoV) are considered the most common causes of viral gastroenteritis in children. In this study, the prevalence of RV and NoV infection in 55 children with diarrhea from the rural community Akinlalu in Southwestern Nigeria was investigated using real-time PCR assays. The RV and NoV strains were genotyped by PCR and/or sequencing. RV and NoV infections occurred with a prevalence of 34.5% and 25.5% respectively, with predominance in children andlt;1 year. Most infections occurred during the dry season with increasing prevalence of RV as the dry season progressed (OctoberJanuary). Infections with RV VP6 subgroup (SG) II were more prevalent (27.3%) than SGI (7.3%). Similarly, NoV genogroup II infections were more common (23.6%) than genogroup I (1.8%). Five children out of 55 (9.1%) were co-infected with both RV and NoV. Notably, G12P[8] was the predominant RV strain (36.8%, n?=?7), observed for the first time in Nigeria. The VP7 gene of the G12 strains clustered within lineage III, sharing high nucleotide identity with each other (andgt;99%) indicating introduction in Nigeria from a single donor. Furthermore, a putative novel genotype within genogroup I NoV was detected, which till date has only been reported once in humans. To conclude, a high prevalence of the emerging G12P[8] RV strain was observed for the first time in Nigeria, as well as a putative novel NoV genotype in humans. These results provide new information which can be important for future vaccine evaluations and possible introduction in Nigeria.

  • 36.
    Sharma, Sumit
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Editorial Material: Rotavirus vaccines in developing countries: issues and future considerations in FUTURE VIROLOGY, vol 10, issue 6, pp 663-6662015In: FUTURE VIROLOGY, ISSN 1746-0794, Vol. 10, no 6, p. 663-666Article in journal (Other academic)
    Abstract [en]

    n/a

  • 37.
    Wilhelmsson, Peter
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Fryland, Linda
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Börjesson, Stefan
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Bergström, Sven
    Ernerudh, Jan
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Immunology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Forsberg, Pia
    Linköping University, Department of Clinical and Experimental Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Center, Department of Infectious Diseases.
    Lindgren, Per-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Erratum: Prevalence and Diversity of Borrelia Species in Ticks That Have Bitten Humans in Sweden (vol 48, pg 4169, 2010)2011In: Journal of Clinical Microbiology, ISSN 0095-1137, E-ISSN 1098-660X, Vol. 49, no 1, p. 481-481Article in journal (Other academic)
    Abstract [en]

    n/a

  • 38.
    Wilhelmsson, Peter
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Fryland, Linda
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Börjesson, Stefan
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Nordgren, Johan
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Bergström, Sven
    Umeå University.
    Ernerudh, Jan
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Immunology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Diagnostics, Department of Clinical Immunology and Transfusion Medicine.
    Forsberg, Pia
    Linköping University, Department of Clinical and Experimental Medicine, Infectious Diseases. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Heart and Medicine Centre, Department of Infectious Diseases in Östergötland.
    Lindgren, Per-Eric
    Linköping University, Department of Clinical and Experimental Medicine, Medical Microbiology. Linköping University, Faculty of Health Sciences.
    Prevalence and Diversity of Borrelia Species in Ticks That Have Bitten Humans in Sweden2010In: JOURNAL OF CLINICAL MICROBIOLOGY, ISSN 0095-1137, Vol. 48, no 11, p. 4169-4176Article in journal (Refereed)
    Abstract [en]

    Members of the genus Borrelia are among the most common infectious agents causing tick-borne disease in humans worldwide. Here, we developed a Light Upon eXtension (LUX) real-time PCR assay that can detect and quantify Borrelia species in ticks that have fed on humans, and we applied the assay to 399 such ticks. Borrelia PCR-positive ticks were identified to species level by sequencing the products of conventional PCR performed using Borrelia group-specific primers. There was a 19% prevalence of Borrelia spp. in the detached ticks, and the number of spirochetes per Borrelia PCR-positive tick ranged from 2.0 x 10(2) to 4.9 x 10(5), with a median of 7.8 x 10(3) spirochetes. Adult ticks had a significantly larger number of spirochetes, with a median of 8.4 x 10(4) compared to the median of nymphs of 4.4 x 10(4). Adult ticks also exhibited a higher prevalence of Borrelia (33%) than nymphs (14%). Among the identified species, Borrelia afzelii was found to predominate (61%) and was followed by B. garinii (23%), B. valaisiana (13%), B. burgdorferi sensu stricto (1%), B. lusitaniae (1%), and B. miyamotoi-like (1%). Also, 3% of the ticks were coinfected with multiple strains of B. afzelii. Notably, this is the first report of B. lusitaniae being detected in ticks in Sweden. Our LUX real-time PCR assay proved to be more sensitive than a corresponding TaqMan assay. In conclusion, the novel LUX real-time PCR method is a rapid and sensitive tool for detection and quantification of Borrelia spp. in ticks.

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