China's agriculture ministry on Friday confirmed the first cases of African swine fever in Beijing, a disease that has spread across the country despite efforts to contain it.
The disease was found on two farms in the Fangshan District in southwest Beijing where 86 out of more than 1,700 pigs died, the ministry said in a statement.
A special task force has since sealed off the farms for culling and disinfection while live pigs and pork products are barred from leaving the area.
Separately, senior ministry officials said during a briefing that 600,000 pigs have been culled since African swine fever was first detected in August in the world's biggest consumer and producer of pork.
It surfaced in northeastern Liaoning province but has now spread to 20 provinces with 73 cases reported.
"As you can see right now, the situation... is still very severe," said deputy director of the bureau of husbandry and veterinary medicine Feng Zhongwu.
"China has frequent trade with affected countries with a huge amount of goods exchanged. Coupled with the long incubation period of the disease and the difficulty of detection, there is a high risk of the disease getting reintroduced."
The ministry has also blamed the spread on backward farming methods, a lack of hygiene and the need to transport pigs long distances for sale.
In early September, government-controlled media said African swine fever had been discovered in just five provinces, with the agriculture ministry saying that the situation was "generally under control".
But it has steadily moved south into pork-producing districts despite efforts to contain it, including culling over half a million livestock and banning the transport of live pigs in affected areas.
Swine fever has already caused a spike in pork prices in China and fuelled growing fears of a major impact on the world's largest pig producer.
The UN Food and Agriculture Organization (FAO) warned in August that the disease could spread to other parts of Asia.
African swine fever is not harmful to humans but causes deadly haemorrhagic fever in domesticated pigs and wild boar.
With no antidote or vaccine, the only known control method is to cull animals.
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