WHO Focuses on Vietnam Flu Cases

The World Health Organization said Sunday that two sisters who died in Vietnam’s Thai Binh province last week were victims of avian influenza and might have contracted the disease from their brother.

If confirmed, the sisters’ cases would represent the first human-to-human transmission of the illness during this outbreak. Until now, health officials had concluded that people who had come down with the disease in Vietnam and Thailand had caught it through direct contact with infected fowl.

The deaths of the two women, ages 23 and 30, plus the death of an 18-year-old man today brought to nine the number of confirmed human bird flu deaths in Vietnam. There also have been three confirmed deaths in Thailand, including a 58-year-old man whose death was reported today. The virus has hit 10 Asian nations, killing millions of chickens and ducks.

“The investigation has not been able to conclusively identify the source of infection for the two sisters,” the WHO said in a statement issued by its Hanoi office. “However, WHO considers that limited human-to-human transmission, from the brother to his sisters, is one possible explanation.”

The WHO and local health officials closely examined the case of the sisters in Thai Binh, 60 miles southeast of Hanoi, because the women were among a cluster of four family members apparently infected by the virus.

Doctors suspect that the women’s 31-year-old brother was the first to come down with the virus. He fell ill and died Jan. 12, the WHO said. His body was cremated soon afterward, so doctors have been unable to verify the cause of his death.

The day after he died, his sisters and his wife were admitted to a hospital suffering from respiratory infections. His wife recovered, but the sisters died Jan. 23. All four had been together at the wedding of the brother and his wife five days before he fell ill.

Tests showed that all three women were suffering from the virulent form of bird flu -- known as H5N1 -- sweeping Asia, but doctors could not determine how they had been infected.

“The investigation failed to reveal a specific event, such as contact with sick poultry, or an environmental source to explain these cases,” the WHO statement said. “At the same time, such exposures cannot be discounted, either. H5N1 infection in poultry is widespread in Vietnam, and direct transmission from poultry to humans cannot be ruled out on the basis of available evidence.”

While the number of human victims of avian flu has been relatively small, health experts fear that if the virus gains a foothold in the human population it could develop the ability to spread easily among people, potentially killing millions worldwide.

During a 1997 bird flu outbreak in Hong Kong that killed six, doctors found “similar instances of limited transmission” of the virus between humans, but these cases never developed into a significant health threat, the WHO said.

“At present, there is no evidence of efficient human-to-human transmission of H5N1 occurring in Vietnam or elsewhere,” the WHO said in the statement. “WHO and health authorities in Vietnam and globally are continuing to assess the evolution of the outbreak and to investigate all new confirmed human cases.”

In Vietnam, bird flu has now been reported in 44 of the country’s 64 provinces. Vietnam, Thailand and other countries hit by the disease have been slaughtering millions of chickens and ducks in hope of containing the outbreak and reducing the number of human cases.

But officials worry that the ongoing slaughter may not be sufficient to bring the disease under control. Some have urged governments to offer farmers adequate compensation so that they will cooperate with the eradication effort and not try to hide or sell diseased fowl. Vietnamese officials “are making a valiant effort to deal with this problem, in their poultry stock and in their treatment of humans,” said WHO spokesman Robert Dietz in Hanoi.

“But Vietnam clearly does not have all the resources it needs to confront this situation. It is clear they will need help from the international community,” he said.