A 26-year-old woman in Thailand who died of avian influenza earlier this month probably contracted the disease from her daughter, researchers said this week. But World Health Organization (WHO) scientists are cautiously optimistic that the development is not the start of a major outbreak. Meanwhile, several global health groups are calling for increased vaccination of Southeast Asia's poultry flocks in a bid to corral the dangerous H5N1 virus.
Researchers say the woman, who lived in the Bangkok area, had returned to a rural village in northern Thailand to care for her sick daughter, who probably contracted the virus from local chickens. The daughter was cremated before researchers could collect tissue samples that could confirm her illness. But tissue samples from the mother proved positive for H5N1. The woman's sister has also tested positive for the virus and is in a hospital isolation ward.
Evidence to date suggests a case of "nonsustained, dead-end transmission," says WHO virologist Klaus Stöhr. Similar cases have been documented in the past. But until the WHO collaborating center in Atlanta, Georgia, analyzes the new samples, experts won't know definitively whether the virus has mutated to a more dangerous form. So far, says Stöhr, Thai authorities have detected no increase in respiratory disease among villagers or health workers who cared for the patients.
To keep the virus in check, governments should be vaccinating and not just culling poultry flocks, the United Nations Food and Agriculture Organization and the World Organisation for Animal Health said in a 28 September statement. China and Indonesia already have vaccination programs. But Thailand and other nations do not, in part because poultry exporters fear importing countries will ban products from vaccinated birds, which don't exhibit flu symptoms but can still carry the virus.
