November 10, 2005

 

Japan's recent bird flu not H5N1, agricultural ministry says
 

 

Recent bird flu cases in north-eastern Japan are probably unrelated to the deadly H5N1 virus strain that has ravaged Southeast Asian poultry stocks since 2003 and killed 63 people in the region, an official said Wednesday.

 

Speaking ahead of a government report due out Thursday, Agricultural Ministry spokeswoman Akiko Suzuki said strains recently detected in Ibaraki prefecture, just north of Tokyo, may have entered Japan in vaccines illegally imported from Central America.

 

Ibaraki officials have said they would cull at least 350,000 birds as a precaution after detecting signs of the H5N2 bird flu virus strain-considered far less dangerous than H5N1-at several chicken farms across the prefecture since last week.

 

There have been no confirmed human cases involving the H5N2 strain anywhere in the world, Japanese officials have said.

 

The government study found it unlikely the virus came to Japan from elsewhere in Asia by migratory birds, because the outbreak has so far been highly localized-limited mostly to Ibaraki, Suzuki said.

 

It also ruled out the possibility that the virus came in through pet imports from Asia, because Japan banned all such imports from bird flu-affected areas last year.

 

Tests in Ibaraki showed the virus strain was similar to one detected in Guatemala and Mexico in 1995-02, Suzuki said, adding that the virus may have entered Japan in vaccines illegally imported from those countries by several Ibaraki farms.

 

The virus was then thought to have spread from farm to farm in chickens or their droppings.

 

No Ibaraki farms have admitted using imported vaccines, but Suzuki said the ministry was still investigating.

 

Bird flu vaccines are made by altering viruses to make them safe. Chickens injected with the vaccines develop antibodies that guard them against active viruses.

 

But poorly made vaccines can lead to an outbreak, Suzuki said. Japan has banned bird flu vaccines, saying that eating meat or eggs from vaccinated chickens may not be safe.

 

The WHO has said that eating properly cooked poultry is not believed to transmit bird flu. However, WHO has said likely channels for spreading the virus include handling infected birds or raw meat.

 

Most human cases have been traced to direct contact with sick birds, but health officials fear the H5N1 virus could mutate into a form that passes easily between humans, possibly setting off a deadly flu pandemic.

 

Bird flu hit Japan last year for the first time in decades. There have been several outbreaks of the dangerous H5N1 variety among birds in the country, and one confirmed human case in December, but no human deaths have been reported.

 

WHO has warned governments to be ready for a deadly human pandemic that could kill millions and cost the global economy US$800 billion in a single year.