Transmission of influenza reflects seasonality of wild birds across the annual cycle.
Influenza A Viruses (IAV) in nature must overcome shifting transmission barriers caused by the mobility of their primary host, migratory wild birds, that change throughout the annual cycle. Using a phylogenetic network of viral sequences from North American wild birds (2008-2011) we demonstrate a shift from intraspecific to interspecific transmission that along with reassortment, allows IAV to achieve viral flow across successive seasons from summer to winter. Our study supports amplification of IAV during summer breeding seeded by overwintering virus persisting locally and virus introduced from a wide range of latitudes. As birds migrate from breeding sites to lower latitudes, they become involved in transmission networks with greater connectivity to other bird species, with interspecies transmission of reassortant viruses peaking during the winter. We propose that switching transmission dynamics may be a critical strategy for pathogens that infect mobile hosts inhabiting regions with strong seasonality.
Department of Biological Engineering and Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
Nichola J
NJ
Hill
Department of Biological Engineering and Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
Eric J
EJ
Ma
Department of Fisheries, Wildlife and Conservation Biology, University of Minnesota, St. Paul, MN, 55108, USA.|U.S. Geological Survey, Alaska Science Center, Anchorage, AK, 99508, USA.
Brandt W
BW
Meixell
Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA.
Mark S
MS
Lindberg
Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA, 95616, USA.
Walter M
WM
Boyce
Department of Biological Engineering and Division of Comparative Medicine, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
Jonathan A
JA
Runstadler
D025041:Animal Migration; D000818:Animals; D000835:Animals, Wild; D046090:Anseriformes / Q000821:virology*; D009980:Influenza A virus / Q000502:physiology*; D005585:Influenza in Birds / Q000635:transmission* / Q000821:virology; D009656:North America; D012367:RNA, Viral; D012621:Seasons; D013997:Time Factors
D012367:RNA, Viral
Avian influenza; biological rhythms; bird migration; host contact structure; influenza A virus; migratory cycle; seasonality; transmission networks; viral flow; zoonotic disease