Submitted to: Waterbird Society
Publication Type: Abstract Only
Publication Acceptance Date: 7/13/2007
Publication Date: 10/31/2007
Citation: Brown, J.D., Swayne, D.E., Stallknecht, D.E. 2007. Experimental H5N1 HPAI infections in waterbirds: clinical response and viral shedding patterns [abstract]. In: Proceedings of the International Waterbird Society, October 30-November 3, 2007, Barcelona, Spain. p. 84.
Technical Abstract: Since 2002 H5N1 highly pathogenic avian influenza (HPAI) viruses have caused mortality in numerous wild avian species in Southeast Asia. During the winter of 2005/2006, outbreaks of H5N1 HPAI virus occurred in wild birds and domestic poultry in several European countries and a growing body of epidemiologic evidence suggests that migratory waterfowl played a role in this geographic spread. Based on mortality data from field reports, some H5N1 HPAI viruses are highly virulent for certain species of anseriforms. In this study, thirteen species of anseriforms and charadriiforms were inoculated intranasally with a H5N1 HPAI virus to evaluate the clinical response and range of viral shedding within these two avian orders. Black swans were the most susceptible species and generally were found dead without exhibiting clinical disease. Mute swans, whooper swans, trumpeter swans, wood ducks, laughing gulls, herring gulls, bar-headed geese, and cackler geese were moderately to highly susceptible, with a mortality rate ranging from 40 to 100%, and clinical signs in these species were primarily neurologic. Redheads, mallards, blue-winged teal, and Northern pintails were refractory to disease. Viral shedding was higher in respiratory secretions than in the feces and generally was positively associated with the susceptibility and severity of disease exhibited by a species. Based solely on the duration of asymptomatic viral shedding, an important parameter for evaluating a species ability to spread H5N1 HPAI, mute swans, bar-headed geese, cackler geese, and wood ducks pose the greatest potential risk to disseminate H5N1 HPAI virus.