Tuesday, September 26, 2006

More On Avian Influenza:
Lest some might think that the article mentioned before on 'Bird Flu' from 'The Conservator' might be a case of an organization, Ducks Unlimited, making a special case for its own interests I went back in Science magazine to look up the topic a bit more thoroughly. The April 21 edition (312, issue 5772, pp 379- 399) has a special topic section on this virus.
The various articles in this section cover a number of different topics from a general overview, through vaccine development, manufacture of anti viral drugs, development of viral resistance to same, preparedness in the event of an outbreak and host species barriers to cross infection. The article that is relevant to what was previously mentioned is titled 'Global Patters of Influenza A Virus in Wild Birds' by B. Olsen et al. The article discusses the epidemiology of influenza A viruses in various wild bird species and their potential as a source for human epidemics.
The basic question of the source of H5N1 outbreaks to date, whether it is connected to wild bird migration or to the international poultry trade can best be summed up by the following paragraph,
"With our current limited knowledge on HPAI (Highly Pathogenic Avian Influenza- Molly) in wild birds, there is no solid basis for including wild birds in control strategies beyond the physical separation of poultry from wild birds. Even in areas with significant outbreaks in poultry virus prevalence in wild birds is low, and the role of wild birds in spreading the disease is unclear. It is clear that the H5N1 problem originated from outbreaks in poultry and that the outbreaks and their geographical spread probably cannot be stopped without implementation of proper control measures in the global poultry industry. However, there is at present no scientific basis for culling wild birds to control the outbreaks and their spread, and this further highly undesirable from a conservationist perspective."

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