China says bird flu vaccinations effective

BEIJING, Mar 20 (Reuters) China's bird flu vaccines are the best in the world and no healthy-looking poultry has been confirmed infected with the H5N1 strain of the disease, state media today quoted the agriculture minister as saying.

The number of bird flu outbreaks in poultry dropped to 32 last year from 50 in 2004, and most of the cases were in areas where vaccines were not properly used, the official China Daily quoted minister Jia Youling as saying.

Julie Hall, in charge of the World Health Organisation's outbreak response in China, has said that studies are needed to see if China's vaccination programme might be ''masking'' the virus, which has killed about 100 people in Asia and the West Asia since 2003.

The risk of asymptomatic poultry came to light earlier this month when a man died in southern Guangdong province after visiting several live poultry markets and officials later said he probably caught the disease from live but H5N1-infected birds.

But Jia said there were no apparently healthy yet infected birds in China.

''So far there has been no confirmed case of a healthy, live chicken being a carrier of the virus,'' he said. ''China's experience has shown that vaccination is a very effective way to control bird flu.'' The three poultry outbreaks this year were also in areas where ''vaccination efforts failed to meet standards'', Jia added.

The WHO backed China's plan to vaccinate billions of poultry last year.

''As long as we stick to the vaccination programme, we will dramatically reduce the likelihood of bird flu outbreaks this year,'' Jia said.

''Our vaccines are the most effective in the world.'' In a 2004-2005 survey, researchers found seemingly healthy but H5N1-infected chickens in poultry markets in south China, including Guangdong, just north of Hong Kong.

The development is unsettling. Chickens usually die within 24 hours of being infected with H5N1 but, without signs of disease, the virus is harder to detect, control and also much easier to pass on to unsuspecting humans.

Bad vaccines for poultry can ''mask'' diseases. The vaccines protect birds, which often don't show symptoms, but do not guard against infection and the birds can shed the virus in their faeces.

The virus then spreads to more birds, mutates and can even jump species barriers, for example, into humans.

China's Harbin Veterinary Research Institute, which is linked to the Ministry of Agriculture, makes flu vaccines for poultry. The ministry approves these vaccines and controls their sale and distribution.

REUTERS KD PM1056