Submitted to: Proceedings of the International Conference on Emerging Infectious Diseases
Publication Type: Abstract Only
Publication Acceptance Date: 2/1/2008
Publication Date: 3/16/2008
Citation: Lipatov, A.S., Kwon, Y.K., Suarez, D.L., Lager, K., Swayne, D.E. 2008. Comparison of pig and ferret models for evaluation of respiratory versus alimentary transmission of H5N1 high pathogenicity avian influenza virus [abstract]. Program and Abstracts Book of the International Conference on Emerging Infectious Diseases, March 16-19, 2008, Atlanta, Georgia. p. 139.
Technical Abstract: Background: H5N1 high pathogenicity avian influenza viruses (HPAIV) have caused over 300 human infections and over 200 deaths since 2003. The majority of the cases have involved close direct or indirect contact with infected poultry but a few cases have incriminated consumption of uncooked poultry products. This study compares transmission of H5N1 HPAIV in pig and ferret models via the respiratory and alimentary exposure routes. Methods: Groups of pigs and ferrets were intranasally (IN) or intragastrically (IG) challenged with 4 different H5N1 HPAIV in amnioallantoic fluid or given infected poultry meat orally or IG. Individual animals were examined for evidence of infection, clinical signs, gross and microscopic lesions and sites of virus replication. Results: IN exposure of pigs with 4 H5N1 viruses produced variable respiratory infection, most severely with Clade 1 and 2.2 viruses. The pigs exhibited bronchiolitis and alveolitis which were less severe, but similar to lung lesions observed in human H5N1 cases. Viral antigen was only visualized in lower respiratory tract in histiocytes and bronchiolar epithelium. IG exposure to virus in liquid failed to produce infection. However, pigs fed infected chicken meat became infected, and virus was isolated from nasal swabs and turbinates, and tonsil. IN exposure of ferrets produced respiratory infection with 2 isolates, systemic and fatal infection with 1 isolate and asymptomatic with 1 isolate. Ferrets feed infected meat developed respiratory and olfactory bulb infection with 1 virus and systemic infection with another. IG exposure to any virus in liquid failed to produce infection. However, IN virus in liquid, or oral feeding or IG exposure to chicken meat infected with 1 isolate produced fatal infection. At the early stage of infection, specific lesions in intestine, liver and pancreas without pulmonary lesions suggested that H5N1 virus could invade through alimentary tracts exposed to infected raw poultry meat. Conclusions: Pigs and ferrets were infected with H5N1 viruses by respiratory or alimentary exposure although the outcome was dependent on virus strain and host. Importantly, consumption of infected raw meat produced systemic and fatal infection via pharyngeal exposure and, likely, initial alimentary infection in the ferrets with one H5N1 HPAIV.