Avian H5N1: Still an animal virus?

Abstract

As of Feb 6, 2007, the cumulative number of confirrmed human cases of avian influenza A/(H5N1) reported to World Health Organization (WHO) is 272 with 166 deaths. Avian influenza including H5N1 refers to a large group of different influenza viruses of which the primary host is birds. Only on rare occasions do these viruses cross over and infect other species including pigs and humans. Pandemic influenza happens when a new subtype emerges that has not previously circulated in humans. Since H5N1 is a strain of such potential, WHO and other health experts, for this reason, have been priming the world to prepare for this threat along with OIE and FAO calling for culling million of poultry world-wide. During my presentation, I will present a model based on the most recent event of an animal virus ‘crossing over’ to become a human virus, SARS, and argue that the scale of the warnings appears to outstrip the magnitude of the real threat. Culling millions of chicken may not have actually lowered the actual risk and efforts and resources should be directed to research in understanding the molecular and genetic mechanisms underlying the virus-crossing species event. Only then can effective barriers be set up to limit the direct contact of susceptible species; to lower the transmission rate; and avoid establishing/adaptation to a new host. In addition, I shall review recent scientific findings that avian H5N1 remains as an animal virus and the probability and possibility for H5N1 successfully adapting to humans as a new host remains low at this particular moment!