title: Long-term variation in influenza A virus prevalence and subtype diversity in migratory mallards in northern Europe.
abstract: Data on long-term circulation of pathogens in wildlife populations are seldom collected, and hence understanding of spatial-temporal variation in prevalence and genotypes is limited. Here, we analysed a long-term surveillance series on influenza A virus (IAV) in mallards collected at an important migratory stopover site from 2002 to 2010, and characterized seasonal dynamics in virus prevalence and subtype diversity. Prevalence dynamics were influenced by year, but retained a common pattern for all years whereby prevalence was low in spring and summer, but increased in early autumn with a first peak in August, and a second more pronounced peak during October-November. A total of 74 haemagglutinin (HA)/neuraminidase (NA) combinations were isolated, including all NA and most HA (H1-H12) subtypes. The most common subtype combinations were H4N6, H1N1, H2N3, H5N2, H6N2 and H11N9, and showed a clear linkage between specific HA and NA subtypes. Furthermore, there was a temporal structuring of subtypes within seasons based on HA phylogenetic relatedness. Dissimilar HA subtypes tended to have different temporal occurrence within seasons, where the subtypes that dominated in early autumn were rare in late autumn, and vice versa. This suggests that build-up of herd immunity affected IAV dynamics in this system.
authors.affiliation: Centre for Ecology and Evolution in Microbial Model Systems (EEMiS ), Linnaeus University, , Kalmar 391 82, Sweden, Department of Population Health, College of Veterinary Medicine, Southeastern Cooperative Wildlife Disease Study, University of Georgia, , Athens, GA 30602, USA, International Research Center in Agriculture for Development (CIRAD)-UPR AGIRs, Animal and Integrate Risk Management, , Campus international de Baillarguet, Montpellier 34398, France, Department of Virology, Erasmus Medical Center, , Rotterdam, The Netherlands, Section of Infectious Diseases, Department of Medical Sciences, Uppsala University, , Uppsala 751 85, Sweden.
authors.forename: Neus
authors.initials: N
authors.lastname: Latorre-Margalef
authors.forename: Conny
authors.initials: C
authors.lastname: Tolf
authors.forename: Vladimir
authors.initials: V
authors.lastname: Grosbois
authors.forename: Alexis
authors.initials: A
authors.lastname: Avril
authors.forename: Daniel
authors.initials: D
authors.lastname: Bengtsson
authors.forename: Michelle
authors.initials: M
authors.lastname: Wille
authors.forename: Albert D M E
authors.initials: AD
authors.lastname: Osterhaus
authors.forename: Ron A M
authors.initials: RA
authors.lastname: Fouchier
authors.forename: Björn
authors.initials: B
authors.lastname: Olsen
authors.forename: Jonas
authors.initials: J
authors.lastname: Waldenström
mesh_terms: D025041:Animal Migration / Q000502:physiology; D000818:Animals; D001715:Bird Diseases / Q000453:epidemiology* / Q000821:virology*; D004372:Ducks; D004784:Environmental Monitoring / Q000706:statistics & numerical data*; D005060:Europe / Q000453:epidemiology; D014644:Genetic Variation; D032521:Immunity, Herd / Q000276:immunology; D009980:Influenza A virus / Q000235:genetics*; D005585:Influenza in Birds / Q000453:epidemiology*; D015995:Prevalence; D012621:Seasons
keywords: disease dynamics; diversity; host–pathogen interactions; influenza A virus; mallards; prevalence