title: Temporal Variation in Sindbis Virus Antibody Prevalence in Bird Hosts in an Endemic Area in Sweden.
abstract: Sindbis virus (SINV) is a mosquito-borne bird virus that occasionally causes human disease in Fennoscandia, suggested to have cyclic 7-year intervals between outbreaks. Reliable data on human infections in Sweden is however lacking. Here we investigated the SINV antibody prevalence among birds in a Swedish area endemic to SINV to scrutinize if a cyclic variation in antibody prevalence is present in the natural host of SINV. Serum from birds were sampled in the summers of 2002-2004 and 2009 in the floodplains of the River Dalälven in central Sweden, with 2002 and 2009 representing hypothesized years of SINV outbreaks. A total of 963 birds from 52 species (mainly passerines) were tested for the presence of SINV antibodies using a plaque reduction neutralization test. The highest SINV antibody prevalence was found in Turdidae species, specifically Fieldfare, Redwing and Song thrush in which more than 70% of sampled individuals had antibodies to SINV in 2009. The SINV antibody prevalence significantly varied between years with 2% in 2002, 8% in 2003, 14% in 2004 and 37% in 2009. Antibodies were found equally often in hatchlings and in adults and increased from early to late in the season. Clearly, the SINV antibody prevalence was not elevated in the bird hosts in the predicted outbreak year 2002, thus solid evidence of a cyclic occurrence of SINV in Sweden is still lacking.
authors: Zoonosis Science Center, Department of Medical Biochemistry and Microbiology (IMBIM), Uppsala University, Uppsala, Sweden.|Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom.
authors: Jenny Christina
authors: http://orcid.org/0000-0003-2489-4400
authors: JC
authors: Hesson
authors: Zoonosis Science Center, Department of Medical Biochemistry and Microbiology (IMBIM), Uppsala University, Uppsala, Sweden.|Swedish Biological Mosquito Control Project, Nedre Dalälvens Utvecklings AB, Gysinge, Sweden.
authors: Jan O
authors: JO
authors: Lundström
authors: Zoonosis Science Center, Department of Medical Biochemistry and Microbiology (IMBIM), Uppsala University, Uppsala, Sweden.
authors: Atalay
authors: A
authors: Tok
authors: Department of Aquatic Resources, Institute of Coastal Research, Swedish University of Agricultural Sciences, Öregrund, Sweden.
authors: Örjan
authors: Ö
authors: Östman
authors: Zoonosis Science Center, Department of Medical Biochemistry and Microbiology (IMBIM), Uppsala University, Uppsala, Sweden.|Laboratory of Clinical Microbiology, Uppsala University Hospital, Uppsala, Sweden.
authors: Åke
authors: Å
authors: Lundkvist
mesh_terms: D018354:Alphavirus Infections / Q000453:epidemiology / Q000276:immunology / Q000662:veterinary*; D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood*; D000914:Antibodies, Viral / Q000097:blood*; D001715:Bird Diseases / Q000453:epidemiology / Q000276:immunology / Q000821:virology*; D004196:Disease Outbreaks; D005260:Female; D009500:Neutralization Tests; D015995:Prevalence; D012845:Sindbis Virus / Q000276:immunology*; D020308:Songbirds / Q000097:blood / Q000821:virology; D013548:Sweden / Q000453:epidemiology
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral