Increased Surveillance of Bird Flu in Vietnam
Recombinomics Commentary
January 6, 2005
>>All 3 of these most recent cases have occurred in the southern part of the country, where poultry outbreaks have been recurring since December 2004.
Close contacts of these cases are being monitored for any signs of illness. Health authorities in Viet Nam, supported by WHO staff, have undertaken several measures to strengthen case detection. Avian influenza viruses become more active when temperatures turn cooler. Activities associated with the approach of the Lunar New Year festivities in early February 2005 may also increase the risk of further human cases.<<
The three laboratory confirmed cases of H5 infections in southern Vietnam has led to increased surveillance as flu season begins as noted by today's WHO advisory. Although efficient human-to-human transmission of H5N1 has not been reported, analysis of available sequences from summer infections of chickens in Hau Giang indicates that the H5N1 in southern Vietnam was genetically stable.
A recent report on detection of H5N1 cases in Thailand last season suggests more cases were missed than were official classified, even though the missed cases frequently had recent prior exposure to sick or dying chickens.
A new season brings in new sequences, which could generate recombinants with novel properties, including more efficient human-to-human transmission, so increased vigilance is welcome.
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