Highly Pathogenic Avian Influenza Seaduck Challenge Study

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This project seeks to improve our understanding of the susceptibility and pathogenesis of pertinent strains of avian influenza viruses in diving duck species.

The Challenge: The susceptibility and pathogenesis of highly pathogenic avian influenza virus (HPAI) has not been characterized in numerous duck species, especially diving ducks (genera Melanitta, Aythya, and Oxyura), some of which migrate across the continental US. The few studies available (on Tufted duck, Aythya fuligula) suggest that they may shed high amounts of virus, but it is unclear whether they have the capacity to spread HPAI long distances.

The Science: This project is in collaboration with the U.S. Department of Agriculture Southeast Poultry Disease Research Laboratory. The pathobiology of HPAI H5N2 was characterized in two diving duck species, Ruddy ducks (Oxyura jamaicensis) and Lesser Scaup (Aythya affinis) whereby adult ducks and hatching eggs for both species were obtained from captive breeding colonies at the Patuxent Wildlife Research Center, Patuxent, MD and exposed to three doses of highly pathogenic avian influenza. Virus shed, clinical disease, mortality, gross and microscopic lesions were evaluated.  Due to the valuable information gained from this initial work we currently expanding this project to include new species and strains of avian influenza virus.

The Future: This study will help fill an important gap in our current state of knowledge on HPAI in wild birds, and would serve as input factors for disease transmission risk models. Understanding disease transmission in migratory wild birds has important consequences for human and environmental health and the economy; in recent outbreaks, wild birds were implicated as long-distance vectors for HPAI.