Bird flu found on a central Dutch poultry farm this month is a mild form of the H7N7 strain of the virus, the Dutch agriculture ministry announced on Wednesday.

According to Dutch media, the virus is a "low pathogenic variety" which is not as dangerous as the strain that hit the country in 2003.

In 2003, the Netherlands was hit hard by an epidemic of the H7N7 strain which led to the cull of 25 million birds, about one quarter of the country's poultry population at the time. One veterinarian died.

Bird flu viruses are divided into subtypes and named on the basis of two proteins on the surface of the virus: hemagglutinin ( H)and neuraminidase (N).

The H5N1 bird flu virus is potentially lethal to humans. H7 infection in humans is rare, but can occur among people who have direct contact with infected birds.

On August 1, the Netherlands reported that it had found traces of bird flu during routine testing at a poultry farm in Voorthuizen in the central Netherlands, but no sick animals have been found.

As a precautionary measure, 25,000 chickens were culled from Voorthuizen and surrounding farms.

Source: Xinhua