Avian H5N1: an animal virus!

Abstract

As of November 12, 2007, the cumulative number of confirmed human cases of avian influenza A/(H5N1) reported to World Health Organization (WHO) was 335, with 206 deaths. Avian influenza including H5N1 refers to a large group of different influenza viruses for which the primary host is birds and only on rare occasions will these cross over and infect other species including pigs and humans. Pandemic influenza disease occurs when a new subtype emerges that has not previously circulated in humans. Since H5N1 is a strain which posses high potential for causing serious disease in humans, WHO and other health experts 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. I will argue that the scale of the warnings appears to outstrip the magnitude of the real threat. Further, that the culling of millions of chicken may not have actually lowered the actual risk for human health. Rather that efforts and resources should be directed to re search in understanding the molecular and genetic mechanisms which are underlying the virus crossing between species. Only then can effective barriers can then be put in place: specifically to limit the direct contact of susceptible species; to lower the transmission rate; and to avoid establishing/adaptation to a new host. In addition, I shall review recent scientific findings that avian H5N1 has remained an animal virus for the past ten years since the first scientific evidence was obtained that avian H5N1 can infect human without an intermediate host. The probability and feasibility that the avian H5N1 will successfully adapt to human as a new host is therefore assessable in my opinion as remaining low at this particular moment. (This paper was presented at the Fifty-Seventh Western Poultry Disease Conference, April 9-12, 2008)