Widespread Bird Flu Infections in the Mekong Delta
Recombinomics Commentary
April 13, 2005
>> Initial testing showed that 71 percent of ducks and 21.4 percent of chickens in Vietnam's 11 southern localities in the Mekong Delta are infected with bird flu virus strain H5.
Up to 80 percent of 2,000 samples taken from ducks raised in Can Tho city alone, which is home to some 1.5 million poultry, were tested positive to H5, local newspaper Youth on Wednesday quoted recent tests by the country's Regional Veterinarian Center as saying.
The situation poses challenges to many localities, because a great number of ducks are raised freely in fields and canals in the delta, which can spread the disease from province to province. <<
The widespread H5N1 infections of ducks and chickens, throughout the Mekong Delta, mirrors results from the beginning of this year. Can Tho was one of the first locations to report high percentages of H5N1 infections in asymptomatic ducks, and the latest data indicates culling efforts did little to reduce the levels H5N1 infections.
At the beginning of the year the detection of the virus in poultry was associated with human cases. All confirmed cases in the south this season have been fatal as have cases in Kampot, the Cambodian province adjacent to the Mekong Delta. However, just before the Tet New Year, reports of human cases in the south abruptly ceased. Reports to WHO also stopped and although there has been some updating, WHO has not provided details on locations of these more recently reported cases.
There have been reports of milder cases in the central highlands and northern Vietnam, but as the size of the clusters of the milder cases grew, follow-up confirmations also halted in the north. The data dearth has been deafening, especially on the human cases.
The widespread infections of poultry with H5N1 suggest that the lack of reports on human cases is not an indication of a lack of human cases, and appears to be just the opposite.
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