Submitted to: Vaccine
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 1, 2000
Publication Date: January 1, 2000
Interpretive Summary: Avian influenza (AI) is a disease of poultry caused by a virus. AI has caused outbreaks of disease in poultry worldwide. Two forms of the disease can occur in poultry: 1) mild form (mildly pathogenic), and 2) severe deadly form (highly pathogenic). This report is a comprehensive review of avian influenza in the 1990's. The report emphasizes the highly pathogenic coutbreaks of avian influenza that occurred in Australia, England, Hong Kong, Italy, Mexico and Pakistan. Information on molecular biology, epidemiology, disease patterns, diagnosis and control are presented.
Technical Abstract: Avian influenza (AI) viruses comprise the vast majority of the type A Orthomyxoviridae. Evolution has produced an enormous array of viral antigenic subtypes and variants based upon the structure of the two surface glycoproteins, the hemagglutinin (HA) and the neuraminidase (NA). These viruses appear to be perpetuated in a nature in a select few wild avian species, but some strains are capable of sporadic and unpredictable entry into other animal populations, including humans. The fate of these occasional entries is likewise unpredictable, and investigators are left only with retrospective analysis. It is clear however, that AI viruses (or some of their genes) have fixed themselves into circulating lineages in some mammalian hosts. In birds, particularly commercial poultry, AI can undergo a dramatic shift and take the unique form of a highly lethal and systemic disease. This has happened at least eight times in this decade on nfour different continents. In this review we explore these outbreaks and what we have learned from them regarding virulence acquisition and interspecies transmission. We further attempt to explore the implications of these outbreaks for the future of both avian and non-avian species and discuss current methods of diagnosis and control of AI.