With three cases of the potentially deadly avian influenza - also known as bird flu or chicken flu - confirmed in Viet Nam, the United Nations health agency is helping local authorities to probe the outbreak and prevent further spread to humans.
The Geneva-based UN World Health Organization (WHO) today said the presence in two children and an adult of the virus, which normally only infects birds, was confirmed by Hong Kong's National Influenza Centre, a member of WHO's Global Influenza Surveillance Network.
Since the end of October, hospitals in Hanoi and surrounding provinces have admitted 14 people with severe respiratory illness - 13 children and the mother of a deceased child. To date, 11 children and the adult have died. It is not known whether all these cases were caused by the same pathogen, known as avian influenza A(H5N1), and there is no evidence at present of human-to-human transmission.
But last week the virus was identified as the cause of an outbreak in two southern provinces, resulting in the deaths of 40,000 chickens and the culling of 30,000 more. The relationship between the human and poultry outbreaks is not fully understood and WHO and Viet Nam's Ministry of Health are probing the source of the human cases and investigating whether human-to-human transmission occurred.
In the meantime, the agency is urging caution. WHO said it regards every case of transmission of an avian influenza to humans as cause to heighten vigilance and surveillance.
The first human infections with A(H5N1) were identified in 1997 in Hong Kong, where 18 people were infected and 6 died. Genetic studies later linked the outbreak to an epidemic in poultry. WHO said the immediate killing of some 1.5 million poultry is thought to have averted a larger outbreak in humans.