HONG KONG (REUTERS) - Hong Kong has confirmed its second case of African swine fever, in a further sign that the virus is continuing to spread beyond mainland China, with the government ordering a cull of 4,700 animals.

The case of the disease, fatal to pigs but harmless in humans, was found in a slaughterhouse in the New Territories, bordering China's southern province of Guangdong, health chief Sophia Chan said late on Friday (May 31).

The slaughter house was closed from Friday night for disinfection.

Hong Kong's first case was confirmed three weeks ago, prompting the government to order the cull of 6,500 pigs to prevent the spread of the virus.

The disease has spread to every province on the Chinese mainland since its initial detection in August 2018.

On Friday, China said it had detected the virus in pigs being illegally transported to its south-western province of Guizhou.