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Bird flu transmission to humans may be frequent: study
(Agencies/Xinhua)
Updated: 2006-01-10 14:27
Hundreds to thousands of people may be infected with bird flu, but have mild
symptoms and do not get admitted to hospital, thereby failing to appear in
official figures, Swedish researchers reported Monday.
A survey of 45,478 people in FilaBavi, a Vietnamese demographic surveillance
site with confirmed outbreaks of H5N1 in poulty during April to June 2004, found
as many as 750 developed flu-like symptoms after contact with sick or dead
birds, according to researchers at the Karolinska Institute in Stockholm.
More lab tests should be performed to determine if any of those identified in
the survey had contracted bird flu, the researchers said.
"During the widespread Asian highy pathogenic avian influenza (HPAI) epidemic
in poultry, the disease has been reportedly rare in humans. Our findings,
however, suggest that in populations living in close contact with poultry, in
areas endemic for HPAI, transmission to humans may be frequent," the scientists
say in a report that appears in the latest edition of the U.S. journal Archives
of Internal Medicine.
"The results suggest that the symptoms most often are relatively mild and
that close contact is needed for transmission to humans," the researchers
conclude.
The new finding adds fuel to an ongoing debate over the true number and
severity of human infections with the highly pathogenic H5N1. There have been
146 laboratory-confirmed human cases of H5N1 flu reported to World Health
Organization (WHO) as of Jan. 6. with 76 deaths.
Health officials worry the virus may mutate into a form that can spread among
people, raising fears of a pandemic. A flu that jumped from birds to humans in
1918 killed as many as 50 million people worldwide.
Vietnam has been struggling with an outbreak of the avian influenza H5N1
strain in poultry since late 2003. Professor Peter Dunnill, an expert on
vaccines for avian flu at University College London said rural communities in
Vietnam have been living with bird flu for more than 10 years and may have
developed resistance to it.
The finding comes as Europe - already on edge over the bird flu scare - is
reeling from reports that 15 people in Turkey have been infected with H5N1
influenza, apparently transmitted from poultry, and three children have died.
The latest figures were reported by Turkish authorities; the World Health
Organization has so far confirmed only four cases in Turkey, of which two have
died.
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