Widespread Recurrence of Bird Flu in Vietnam
Recombinomics Commentary
February 19, 2005
>> Health animal authorities on Friday reported bird flu outbreaks in 19 sites of six provinces, including five in the Mekong Delta region, with more than 7,500 fowls culled.
Hai Duong northern province suffered the heaviest loss with 1,100 ducks and 500 chickens culled in its two districts of Kim Thanh and Gia Loc.
In Long An province, which has been hit the hardest by the outbreak in the country, bird flu recurred in three districts of Ben Luc, Thu Thua and Can Giuoc, killing almost 1,500 poultry.
Avian flu outbreaks were also reported in other Mekong Delta provinces of Ben Tre, Bac Lieu, Tra Vinh and An Giang, said the veterinary department under the Agriculture and Rural Development Ministry. <<
Although the recurrence of bird flu throughout Vietnam is not unexpected, it is cause for concern. The new outbreaks show that controlling H5N1 avian influenza in Vietnam will be difficult and further human-to-human transmission will be likely.
The report in the New England Journal of Medicine describes three patients who were probably infected with H5N1, but initially did not present with respiratory symptoms. The first two patients formed a cluster last year. It was the 10th reported H5N1 cluster and was similar to the other 9. Samples were not collected from the index case, a relative developed an H5N1 lab confirmed infection one or two weeks later, and the index case died.
However, in this cluster both cases initially did not have respiratory illness. Instead gastro-intestinal and neurological symptoms were seen. The WHO has indicated that they will expand the case definition of H5N1 related illnesses, but the extent of spread in Vietnam and elsewhere will not be known until widespread screening results are analyzed.
In addition to broadening the definition of H5N1 illnesses, the WHO should issue an alert to family members caring for relatives with symptoms. The presence of H5N1 in stool samples offers a new route for human-to-human transmission, and the bimodal distribution of disease onset in all familial clusters indicates human-to-human transmission of H5N1 is an ongoing problem In Vietnam, Thailand, and Cambodia.
The failure to test patients outside of these countries leaves open the extent of worldwide spread of H5N1.
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