Apr 28, 2008 (CIDRAP News) – Animal health officials in Japan were awaiting final tests on four wild swans that recently tested positive for an H5 strain of avian influenza, as authorities in Vietnam and India's Tripura state moved to quash new outbreaks caused by the highly pathogenic H5N1 virus.
Three of the swans were found dead on the shores of Lake Towada in Akita prefecture, in northern Japan, on Apr 21, officials said in a news release, according to a report today from Reuters. The swans were found and tested during heightened surveillance prompted by several outbreaks in South Korea, Japan's neighbor to the southwest.
Authorities have not found any mass bird deaths nearby and said there were no chicken farms within 10 kilometers of the area, Reuters reported.
Japan's last reported H5N1 outbreaks occurred in early 2007, when the virus struck farms in four towns in the southern part of the country and killed a hawk eagle near Kumamoto prefecture, according to reports from the World Organization for Animal Health (OIE).
Elsewhere, veterinary officials in India said on Apr 26 that samples from more birds in Tripura state had tested positive for the H5N1 virus, pushing to three the number of areas hit in the state in the past 2 weeks, the Times of India reported on Apr 26.
Asim Roy Barman, state animal resources department director, told the Times that the two earlier outbreak sites were within 4 kilometers of the border with Bangladesh, which has had extensive H5N1 outbreaks over the past several months. However, he said the latest outbreak was a surprise to officials because it is 50 kilometers from the Bangladesh border.
In early April, Tripura became the second Indian state to report H5N1 outbreaks this year. Nearly all of Tripura state, located in the far northeastern section of India, borders eastern Bangladesh.
In other developments, animal health officials in Vietnam said the H5N1 virus has been detected in another province, Son La in the northern part of the country, the Chinese news agency Xinhua reported today.
The report said Vietnam's Department of Animal Health told a local newspaper that the outbreak occurred among chickens and ducks in a backyard poultry flock. Provincial authorities have isolated the site and disinfected the farm to prevent the spread of the virus, according to the report.
The animal health department, according to Xinhua, said two other locations in Vietnam are also battling the H5N1 virus: Tien Giang province in the south and Can Tho, an independent municipality that is the largest city in the Mekong Delta.
OIE reports on Japanese outbreaks