Submitted to: Emerging Infectious Diseases
Publication Type: Peer reviewed journal
Publication Acceptance Date: 10/10/2007
Publication Date: 1/1/2008
Citation: Brown, J.D., Stallknecht, D.E., Swayne, D.E. 2008. Experimental infection of swans and geese with highly pathogenic avian influenza virus (H5N1) of Asian lineage. Emerging Infectious Diseases. 14(1):136-142. Interpretive Summary: The potential role of wild birds in spreading H5N1 highly pathogenic avian influenza (HPAI) virus in Asia, Europe, and Africa is unclear. To better understand this, four species of swans and two species of geese were exposed to H5N1 HPAI virus and evaluated for virus growth and shedding, and clinical signs of disease. The virus caused high death losses in swans but some swans and geese became infected and shed virus into the environment for several days before becoming ill. These indicate H5N1 HPAI virus can infect some wild birds and spread the virus before becoming ill, but the outcome is highly dependent on individual species. This provides an explanation for the observed deaths in migratory swans and geese in Eurasia.
Technical Abstract: The potential role of wild birds in the epidemiology of H5N1 highly pathogenic avian influenza (HPAI) virus in Asia and their contribution to the spread of H5N1 virus to Europe and Africa is unclear. In order to address this, we experimentally infected four species of swans and two species of geese with H5N1 HPAI virus to evaluate their susceptibility, clinical response, and viral shedding. The highest mortality rates were observed in swans and species-related differences in clinical response and viral shedding were evident. These results suggest that the potential for H5N1 HPAI viral transmission and movement may be highly dependent on individual species and they provide an explanation for observed mortality that has been associated with H5N1 HPAI-related mortality in Anseriformes in Eurasia.