Avian Influenza Ecology in North Atlantic Sea Ducks: Not All Ducks Are Created Equal

Abstract

Wild waterfowl are primary reservoirs of avian influenza viruses (AIV). However the role of sea ducks in the ecology of avian influenza, and how that role differs from freshwater ducks, has not been examined. We obtained and analyzed sera from North Atlantic sea ducks and determined the seroprevalence in those populations. We also tested swab samples from North Atlantic sea ducks for the presence of AIV. We found relatively high serological prevalence (61%) in these sea duck populations but low virus prevalence (0.3%). Using these data we estimated that an antibody half-life of 141 weeks (3.2 years) would be required to attain these prevalences. These findings are much different than what is known in freshwater waterfowl and have implications for surveillance efforts, AIV in marine environments, and the roles of sea ducks and other long-lived waterfowl in avian influenza ecology.

THE PATHOGENESIS OF CLADE 2.3.4.4 H5 HIGHLY PATHOGENIC AVIAN INFLUENZA VIRUSES IN RUDDY DUCK (OXYURA JAMAICENSIS) AND LESSER SCAUP (AYTHYA AFFINIS)

“…with low pathogenicity AIV (LPAIV) in Common Eiders (Somateria mollissima) revealed similar results to the Lesser Scaups inoculated with HPAIV (i.e., susceptibility to infection with no mortality or clinical disease; Hall et al 2015). One difference between the results of the studies is that there was mortality in the juvenile Ruddy Ducks, which could have been due to differences in species or to pathotype combination.…”

“…In contrast, the role of diving ducks in the ecology of AIV is largely unknown, although diving ducks have been implicated in the ecology of the 2016 H7N8 AIV that infected turkeys in Indiana (Xu et al 2017). There are limited reports on AIV surveillance in diving ducks, and they have focused on seaducks (Germundsson et al 2010;Liu et al 2011;Hall et al 2015). Experimental studies with diving ducks are very limited because of the difficulty in obtaining these species.…”

Avian influenza virus prevalence in marine birds is dependent on ocean temperatures

“…In addition, water in bathing/swimming tubs provided for the challenged eiders contained significant amounts of IAV, indicating that similar fecal/oral transmission mechanisms are involved in both taxa of ducks (Hall et al. ). There are undoubtedly other environmental factors involved in virus stability and transmission in marine ecosystems.…”

“…The geographic range of sampling locations extended from Frenchman's Bay (44.484031°N, 68.238643°W) in the north to the Kennebec River estuary (43.759961°N, 69.779834°W) in the south. Swab samples were taken using established methods (Hall et al 2015) and placed in liquid nitrogen vapor shippers for transport to the USGS National Wildlife Health Center and storage at À80°C until analyses.…”

The pathogenesis of a North American H5N2 clade 2.3.4.4 group A highly pathogenic avian influenza virus in surf scoters (Melanitta perspicillata)

“…In contrast, diving ducks forage by diving and swimming underwater. It is increasingly recognized that diving ducks play an underappreciated role in the maintenance and transmission of AIVs, leading to increased research on the contribution of these species to the ecology and evolution of AIVs [ 15 – 17 ]. Diving ducks have been shown to harbor rare AIVs subtypes [ 18 ], and diving ducks contributed to the emergence of North American H7 HPAIV [ 19 ].…”