Susceptibility of North American Ducks and Gulls to H5N1 Highly Pathogenic Avian Influenza Viruses

• Main Authors: Justin D. Brown, David E. Stallknecht, Joan R. Beck, David L. Suarez, David E. Swayne
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Sterna hirundo
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.170.6176; http://www.cdc.gov/ncidod/EID/vol12no11/pdfs/06-0652.pdf

(HPAI) viruses have been associated with deaths in numerous wild avian species throughout Eurasia. We assessed the clinical response and extent and duration of viral shedding in 5 species of North American ducks and laughing gulls (Larus atricilla) after intranasal challenge with 2 Asian H5N1 HPAI viruses. Birds were challenged at ≈10 to 16 weeks of age, consistent with temporal peaks in virus prevalence and fall migration. All species were infected, but only wood ducks (Aix sponsa) and laughing gulls exhibited illness or died. Viral titers were higher in oropharyngeal swabs than in cloacal swabs. Duration of viral shedding (1–10 days) increased with severity of clinical disease. Both the hemagglutination-inhibition (HI) and agar gel precipitin (AGP) tests were able to detect postinoculation antibodies in surviving wood ducks and laughing gulls; the HI test was more sensitive than the AGP in the remaining 4 species. Free-living birds in the orders Anseriformes (ducks, geese, swans) and Charadriiformes (gulls, terns, shore birds) have traditionally been considered the natural reservoirs for avian influenza viruses (AIVs) (1,2). However, before 2005, no evidence showed that highly pathogenic avian influenza (HPAI) viruses were maintained in wild bird populations. Rather, HPAI viruses evolved independent of wildlife reservoirs when wild-type AIVs were introduced and adapted to domestic poultry populations (3). One exception occurred in 1961 when a high proportion of deaths in common terns (Sterna hirundo) in South Africa was attributed to an H5N3 HPAI virus without evidence of prior infection in domestic poultry (4). However, this tern