A river near the inter-Korean border turned red with the blood of pigs slaughtered as Seoul attempts to curb the spread of African swine fever.

South Korea has culled around 380,000 pigs since the first case of the haemorrhagic disease — which is not harmful to humans but is highly infectious in swine — was reported in September.

Pig cases are nearly always fatal and there is no antidote or vaccine, with the only known way to prevent the disease from spreading being a mass cull of livestock.

A local NGO said that heavy rains last week caused blood from a burial site near the inter-Korean border — where some 47,000 pig carcasses were piled up — to seep into the Imjin River on Sunday, turning some of the stream red.

"It made many people living in the area anxious and worried," Lee Seok-woo, who heads the NGO Yeoncheon Imjin River Civic Network, told AFP.

"What was also hard to endure was the odour. I heard many farmers couldn't work because of the unbearable smell. This should not have happened."

Seoul's environment ministry released a statement Wednesday saying the blood from pig carcasses flowing into the streams had now been "dealt with properly" using suction pumps and other devices, and the situation did not affect tap water in the region.

"We have built banks and other facilities so that the polluted water does not flow into the downstream region," the ministry said, adding: "As of now there is no blood in the stream."

Indonesia buries over 1,000 cholera-hit pigs
Medan, Indonesia (AFP) Nov 12, 2019 –

More than 1,000 cholera-stricken pigs have been buried in Indonesia after their decaying carcasses were plucked from local waterways, a government official said Tuesday.

Hundreds more swines are still floating in rivers and a lake near Medan, the capital of North Sumatra province, as police search for suspects who discarded their bodies.

"They were abandoned about eight days ago so they're decaying and it smelled very bad," local official Muhammad Yunus told AFP.

"We will keep cleaning them up and burying the carcasses until they're gone because people have been complaining about it," he added.

Some 6,000 pigs have died across North Sumatra since September with many dumped into local waterways.

Lab tests found that the animals died of hog cholera but officials said they are also testing to see if any were stricken with African swine fever. Neither are believed to pose a risk to humans.

In 2017, a hog cholera outbreak in Indonesia's East Nusa Tenggara province killed more than 10,000 pigs, causing severe financial losses for local farmers.