From the Far East, a lesson in how to beat bird flu

As avian flu advances across Europe towards the UK, public health experts in the Far East claimed the first significant victory against the H5N1 virus since the current outbreak began two years ago.

Vietnam, the worst affected country in the world with 93 human cases and 42 deaths, has become the first to successfully contain the disease that threatens to become a global human pandemic, according to the World Health Organisation.

No new cases of avian flu have been reported in humans in Vietnam since last November and in birds since last December, Hans Troedsson, director of the WHO in Hanoi said.

Vietnam's breakthrough in containing the disease comes as the worldwide outbreak was confirmed in India, France and Iran for the first time. India said it was testing dozens of people for the lethal strain after 50,000 birds died in western Maharashtra state. In France, wild ducks found dead near Lyon were confirmed with H5N1. Authorities in Bulgaria put a man in an isolation chamber yesterday and were testing him for bird flu after two of his ducks died.

Indonesia has confirmed that a 19th person had died of bird flu, while Egypt and Nigeria were struggling to cope with the spread of new cases.

Vietnam's containment offers hope to Third World countries struggling with mass culls, and developed economies contemplating an agricultural crisis. It also holds out the prospect that a pandemic of the H5N1 strain, thought to be only a matter of time, might be averted.

In Vietnam, the relief is palpable as Pho Ga, the traditional chicken noodle soup, has reappeared on restaurant menus in Hanoi in the north and Ho Chi Minh city in the south, along with other poultry dishes banned last year. In Hanoi's crowded Hang Be market, traders were doing a brisk trade in freshly-plucked chicken and duck raised by local farmers at 5,000 dong (20p) a kilo at the weekend.

Avian flu has an incubation period of one to two days in poultry and five to seven days in humans and, under WHO guidelines, a country is designated disease-free when no new cases have been recorded for 21 days. Thailand has also recorded no new cases since last November but has been less severely affected than Vietnam with 22 human cases and 14 deaths.

The H5N1 virus first infected humans, causing 14 deaths, in an outbreak in Hong Kong in 1997, which was successfully contained after millions of birds were slaughtered. The current H5N1 outbreak began in late 2003 and has spread across Asia into Europe and to Nigeria in Africa. French scientists confirmed at the weekend that a duck found dead near Lyon had been infected, putting the billion-franc poultry industry at risk.

The success in curbing the disease in Vietnam and Thailand strengthens hope that an avian flu pandemic, which could cause a global economic and medical catastrophe, may be averted. Scientists are especially encouraged that it has been achieved in a part of the world where there are tens of thousands of peasant farmers keeping small flocks of chickens.

Dr Troedsson said that a combination of vaccination, culling and public communication had proved the disease could be halted, even in a less developed country such as Vietnam.

Almost 200 million birds have been vaccinated, and up to five million culled. The Government ordered last year that all chicken prepared for sale must be certified safe and carry an official stamp, although unstamped chicken and duck were still being sold in Hanoi last week.

Dr Troedsson said: "If you had asked me six months ago I would have said we were certain to see new cases of avian flu from December to March in Vietnam which is the cold season when we know flu viruses circulate. Also it was the Tet holiday [Chinese New Year] last month when millions of people return to their families, and chicken is eaten and we feared an outbreak."

He added that although a human flu pandemic was "inevitable", because of the nature of the flu virus and the way it mutated, it might not be caused by the current H5N1 virus.

"It is not inevitable that it has to be H5N1. I am cautiously optimistic - more than I was two years ago - that [a human pandemic] won't be caused by H5N1 because countries like Hong Kong, Vietnam and Thailand have been able to contain it." But Dr Troedsson warned that the H5N1 virus was almost certainly still in Vietnam, and vigilance was essential. Ducks can carry the virus without showing symptoms and previous research has demonstrated it can persist in the soil and water. Monitoring had " improved greatly" over the past two years as a result of action taken by the Vietnamese government but co-ordination between the ministries of health and agriculture had still to be improved, he said.