The World Health Organisation said on Sunday that two Vietnamese sisters who died from bird flu might have contracted the disease from their brother, making it the first ”human to human” transmission of the virus in this outbreak.
The announcement marks yet another worrying development in the spread of the disease.
The WHO said that the women, aged 23 and 30, might have had contact with birds carrying the virus. But its inquiries indicated that ”human to human” transmission was the most likely reason for them contracting the disease.
The unidentified women were taken to hospital on January 13 after attending their brother’s wedding.
He died the following day of respiratory failure, but was cremated before tissue samples were taken from him, so the exact cause of his death is uncertain.
The Vietnamese authorities said last week that the sisters had died of the H5N1 strain of bird flu. The WHO confirmed this only on Sunday, after further testing in Hong Kong.
”In the current family cluster of cases in Vietnam, the WHO considers that limited human-to-human transmission, from the brother to his sisters, is one possible explanation,” it said.
”The investigation failed to reveal a specific event, such as contact with infected poultry or an environmental source, that might explain the source of infection in these cases.
”However, as H5N1 infection in poultry is widespread in Vietnam, direct transmission from poultry to humans cannot be entirely ruled out on the basis of available evidence.”
Further tests are being conducted on the sisters’ bodies to ascertain whether the virus has mutated.
”At present, no evidence indicates that efficient human-to-human transmission is occurring in Vietnam or elsewhere,” the WHO said.
”Human cases are being investigated to identify the source of infection, and evidence to date is reassuring,” the statement added.
The sisters’ bring to 10 the number of bird flu fatalities in Vietnam.
Infected birds have been reported in 44 of the country’s 64 provinces.
Two people have also died from the illness in Thailand, where half a dozen other suspicious deaths are being investigated.
The WHO said that limited human-to-human transmission was recorded in both the outbreak in Hong Kong in 1997 and that in the Netherlands last year.
Neither developed into the worst case scenario of a mutating pandemic.
Bird flu has been recorded in 10 countries, and yesterday China reported five new areas with suspected cases, taking the number of areas identified to 11.
The popular live poultry markets and the processing factories have been closed in the affected areas. – Guardian Unlimited Â