The World Organization for Animal Health, or OIE, confirmed the first poultry cases in Japan since 2004. The outbreak killed about 4,000 chickens on a farm in the Miyazaki area of southwestern Japan. Authorities killed the remaining 8,000 chickens and have started to incinerate the dead birds. There were no reports of human infections.
Four provinces in southern Vietnam reported outbreaks of bird flu since the beginning of the year. The virus is spreading closer to Vietnam's largest urban center in Ho Chi Minh City, prompting market inspectors to restrict the movement and selling of poultry in the city. The Vietnamese Agricultural Ministry moved to contain the spread by ordering additional poultry vaccinations and requesting reinforcement of animal health teams.
In Thailand, around 2,000 ducks in the Phitsanulok province were infected and killed in the first outbreak since July 2006.
The disease is believed to be spread by migrating birds and poultry smuggling. Keiji Fukuda, coordinator for the global influenza program at the World Health Organization, said the recent cases are following a seasonal pattern of increased outbreaks during the winter months in the northern hemisphere.
While human infection is still rare, health officials fear that the virus could mutate to be spread between humans and trigger a worldwide flu pandemic that could kills millions.
The potential for the H5N1 virus to become a pandemic still remains a threat though health authorities say it remains an animal disease.
"We don't have any evidence of human-to-human transmission; it is one of those things that we're always looking for. But in the recent group of cases, we don't have any evidence that that's what we're seeing," said Fukuda.
Since the first outbreak in 2003, 161 people have died worldwide, most of these in Asia.
On Monday, Indonesia's Ministry of Health confirmed that the death of a 22-year-old woman on Jan. 12 was caused by the H5N1 virus, bringing the human toll in Indonesia to 61 of the 79 confirmed cases, the highest in the world.
An investigation into the woman's death -- the fourth in Indonesia since the beginning of the year -- found reports of dead birds near her house. On Jan. 12, the disease killed a 37-year-old woman who was also believed to be exposed to dead chickens. Her son was confirmed to be infected with the H5N1 virus but her husband, suspected of being infected as well, tested negative.
Indonesia's head of national commission on avian influenza Bayu Krisnamurthi said there was no evidence of a human-to-human transmission.
