The epizootiology of the highly pathogenic avian influenza prior to the anticipated pandemic of the early twenty first century

Abstract

The importance of the highly pathogenic avian influenza (AI) as a devastating disease of poultry has markedly increased during the last decade. By April 2006, it has become clear that the highly pathogenic avian influenza viruses of the H5N1 subtype are circulating in Asia, Africa (including Nigeria), Europe and the Americas, with Asia recording several human case fatalities.The introduction of AI viruses of the subtypes H5 and H7 of low pathogenicity (LP) from a reservoir in wild water birds has been at the base of this process. The acquisition of novel traits including lethality to waterfowls, ferrets, felids and humans indicate an expanding host range. Transmission of highly pathogenic H5N1 from domestic fowls back to migratory waterfowl in western China has increased the geographic spread. This has grave consequences for the poultry industry on a transcontinental scale and increases the need for good veterinary vaccines. Since exposure risks for humans are directly linked to the increased presence of potentially zooanthroponotic viruses in domestic poultry, there is justifiably a worldwide public concern. Many questions however, still remain unanswered from the avian and veterinary side of the story. The complexity and the potential impact of the current, zooanthroponotic HPAI H5N1 virus semi-pandemic in birds, therefore demands concerted and prudent actions from scientists, politicians, and the public. Animal Production Research Advances Vol. 2(1) 2006: 50-56