Bird flu crops up again in South Korea

South Korea has found the H5N1 strain of bird flu in chickens at a poultry farm.

The rather depressing news is the country's first case in three years and it is suspected the virus has killed as many as 6,000 chickens at the farm which is situated in the southwest of the country in one of the country's biggest poultry producing areas.

The Agriculture Ministry says initial tests have shown the presence of the H5N1 strain and has ordered the culling of 236,000 poultry within a 500-metre radius of the farm.

Quarantine measures have been imposed in an area around the farm in Iksan, North Cholla province, about 230 kilometers south of Seoul, which lies directly on a path for migratory birds.

The movement of as much as 5 million poultry from 221 farms within a 10-km radius of the farm has also been banned but to date no humans appear to have been infected.

Back in the three month period between December 2003 and March 2004, about 400,000 poultry at South Korean farms were infected with bird flu and as a result 5.3 million birds were culled and millions were spent on successfully preventing the disease from spreading.

During that outbreak in was found that at least nine South Korean workers involved in the cull had been infected with the H5N1 virus, but none developed major illnesses.

The virus has spread steadily since 2003 and outbreaks have been confirmed by the World Organisation for Animal Health in around 50 countries and territories.

North Korea also experienced an outbreak in poultry farms near the capital Pyongyang in February 2005, which led to the culling of more than 200,000 chickens and the vaccination of 1.1 million poultry.

According to the World Health Organisation since 2003 there have been 258 cases of human infection of the H5N1 strain, which has killed 153 people.

Most of those deaths were in Asia and virtually all occurred as a result of handing diseased poultry or birds.

The World Health Organization fears the H5N1 strain may mutate into a virus that can be transmitted from human to human.

South Korean authorities believe there is little risk to humans and suspect the source virus was possibly from migratory birds, tourist traffic, or the smuggling of livestock and produce from abroad.