Avian influenza remains a global threat, says WHO
November 25, 2009 1:05 am
MANILA, Nov. 24 — The World Health Organization (WHO) warned on Monday that newly confirmed cases of avian influenza or A(H5N1) in poultry in Egypt, Indonesia, Thailand and Vietnam were a reminder that the virus continues to pose a threat to humans.
The WHO said the presence of H5N1 in poultry poses a health risk in two ways: first, it places those in direct contact with birds — usually rural folk and farm workers — at risk of catching the often-fatal disease; second, the virus could undergo a process of “reassortment” with another influenza virus and produce a completely new strain.
The most obvious risk is of H5N1 combining with the pandemic influenza A(H1N1) 2009 virus, producing a flu virus that is as deadly as the former and as contagious as the latter.
"We don't know if this is possible, but we are certainly aware of the risk. We are on alert for this development," said Dr Shin Young-soo, WHO Regional Director for the Western Pacific.
Reassortment occurs when the genes of two or more types of influenza virus mix in a host animal — often a pig, duck or chicken — and form an entirely new strain of the virus that is new to humans.
In April, after the reassortment of avian, swine and human strains of influenza in pigs in Mexico, a novel influenza virus — the pandemic influenza A(H1N1) 2009 virus — emerged in humans. This virus spread quickly around the world and has probably infected millions of people, killing thousands.
“Influenza viruses are unpredictable. In areas where A(H1N1) is endemic, we and our partners and national governments are working to build surveillance systems to identify changes in the behavior of the virus. We are also focusing on early-response capacity to reduce the potential threats to human health," Shin said.
Since 2003, outbreaks of A(H5N1) have been reported in poultry flocks in 60 countries in Asia, Europe and North Africa. The virus is now considered endemic in Egypt, Indonesia and Vietnam. (PNA)
DCT/FMB
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