Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: April 13, 2007
Publication Date: March 1, 2008
Citation: Swayne, D.E. 2008. High pathogenicity avian influenza in the Americas. In: Swayne, D.E., editor. Avian Influenza. Ames, Iowa: Blackwell Publishing. p. 191-216. Technical Abstract: From 1924 to 2004, there were eight HPAI epidemics in the Americas: fowl plague in USA during 1924-25 and 1929, H5N9 HPAI in Canada during 1966, H5N2 HPAI in USA during 1983-84, H5N2 HPAI in Mexico during 1994-95, H7N3 HPAI in Chile during 2002, H7N3 HPAI in Canada during 2004, and H5N2 HPAI in USA during 2004. There were many common features of these outbreaks including recognition of most frequent gross lesions of edema and cyanosis of comb and wattles, petechia in mucosa of proventriculus and ventriculus (gizzard), and petechia in fat of heart and viscera. In most outbreaks, control was accomplished by identification of infected and dangerous contact premises; quarantine of these premises, enhancements to biosecurity, elimination of infected poultry; movement restrictions on people, equipment and birds; surveillance for virus and antibody evidence of infections in poultry, and C&D of equipment and facilities. Several new features were recognized during these outbreaks. First, the 1983-84 epidemic was the first documented cases of a LPAI virus mutating and becoming a HPAI virus. Second, from this outbreak, came the development of national and international molecular criteria for the classification of AI viruses as HP which is now used in addition to in vivo chicken pathotyping for declaration of a HPAI virus. Third, the development of the rapid RRT-PCR diagnostic test during the 2002 H7N2 LPAI LPM closure program in the USA and its initial deployment for use in the Chilean H7N3 HPAI outbreak was a success.