HANOI (REUTERS, WASHINGTON POST) - Vietnam has culled more than 1.2 million farmed pigs infected with African swine fever, the government said on Monday (May 13), as the virus continues to spread rapidly in the South-east Asian country.

Pork accounts for three-quarters of total meat consumption in Vietnam, a country of 95 million people. Most of its 30 million farm-raised pigs are consumed domestically.

The virus was first detected in Vietnam in February and has spread to 29 provinces, including Dong Nai, which supplies around 40 per cent of the pork consumed in Ho Chi Minh City, Vietnam's southern economic hub.

"The risk of the virus spreading further is very high and the evolution of the outbreak is complicated," the government said in a statement.

It said many provinces had failed to detect outbreaks and cull infected pigs properly due to a lack of funds and the space needed for burying the dead pigs.

The disease has also spread quickly across neighbouring China.

The United Nations Food and Agriculture Organisation (FAO) in March advised Vietnam to declare the swine fever outbreak a national emergency.

According to the Singapore Food Agency, Vietnam is not approved to export pork to Singapore. However, China is on the agency's list of approved pork exporting nations.

The virus, which is not communicable to humans, can be spread by live or dead pigs, domestic or wild, and via pork products. Symptoms in animals include high fever, weakness, skin lesions, diarrhea, vomiting and difficulty breathing. Death can occur within a week of infection.

There is no treatment or vaccine for the disease, and the only way to stop it is to cull all affected or exposed swine herds. If that occurs, there will not be enough surplus pork in the world to make up for the anticipated shortfall in Chinese production.

Affected animals have now been reported in every province in China, and the disease has spread to neighbouring Mongolia and Cambodia.

At least 129 outbreaks have been reported since African swine fever was first identified in August, reducing the China's hog population by 40 million and leading to the extermination of an estimated 1 million hogs, according to China's National Bureau of Statistics.

Experts believe infection numbers and the number of culled pigs have been immensely under-reported.