Submitted to: American Veterinary Medical Association Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 8, 1999
Publication Date: N/A
Technical Abstract: In 1997, highly pathogenic (HP) avian influenza (AI) viruses caused outbreaks of disease in poultry in Australia, Hong Kong and Italy. In Hong Kong, an H5N1 AI virus crossed from poultry, and infected 18 humans with six deaths. There was no evidence that AI viruses crossed from poultry-to- humans in the other two outbreaks. Inoculation of mice with seven HP AI viruses resulted in high death losses only with the Hong Kong AI viruses. Death of mice were inconsistent with the other AI viruses. Necrotizing bronchitis and alveolitis were the most consistent lesions, and AI viral antigen was demonstrated in respiratory epithelium and inflammatory cells. However, lesions in mice were mild with Italy/97, moderate with England/91 and moderate-to-severe with the three Hong Kong/97 IA viruses. In addition, mice inoculated with the AI virus isolated from a 3 year old child (Hong Kong/156/97), had AI viral antigen in olfactory epithelium and neurons of autonomic ganglia within the bronchial hilus. No systemic infection or lesions occurred in the mice as was reported in chickens. The ability of Hong Kong AI viruses to infect and cause disease and death in a mammalian animal model may partially explain why these AI viruses crossed from poultry to humans in Hong Kong, but not in previous AI outbreaks.