Manila, Oct 4 (IANS): More than 3,000 pigs have been culled in the Philippines' Metro Manila area in a bid to contain the outbreak of African swine fever that has so far led to the deaths of more than 20,000 hogs, an official said on Friday.

The latest infection - which was detected in the country's largest conurbation, Quezon City - prompted every swine in a 1-km radius to be culled in line with quarantine protocols, the head of the city's veterinarian office, Ana Maria Cabel, told reporters here.

"Some 5,000 pigs in the area are still pending to be sacrificed," Cabel added.

On Tuesday, the Philippines department of agriculture threatened legal action against hog farmers who fail to follow strict quarantine rules after new cases of the animal disease were confirmed in Quezon City and the northern province of Pangasinan, reports Efe news.

Agriculture Secretary William Dar accused hog traders of propagating the disease by carrying on their business without taking any precautions despite the authorities' warnings.

The Philippines, the world's 10th-largest pork consumer and seventh-biggest importer, had a population of some 12.7 million swine in July. After the first African swine fever outbreak was declared on September 9, about 20,000 pigs have either been culled or died from the disease.

Farms in the central and southern areas of the country have vetoed the arrival of any pigs hailing from the nation's north, including Metro Manila, to prevent an epidemic.

Since the first foci of infection emerged in China in 2018, the disease has propagated across the Asian giant and jumped to neighbouring countries such as Mongolia, Cambodia and Vietnam.

The disease's causative agent, the African swine fever virus of the Asfarviridae family, only impacts pigs and cannot be transmitted to humans, who are therefore completely unsusceptible to contagion.