Thailand has for years insisted its pig herds remained unaffected by African swine fever, which over recent years has swept through Europe and Asia and killed hundreds of millions of pigs, particularly in China, even as its Southeast Asian neighbours reported outbreaks, Reuters reported on Friday.

A miniature pet pig in Bangkok was found to have died from the disease after it was brought in by its owner for a lab test that was done in early December at Kasetsart University, said Nattavut Ratanavanichrojn, associate dean at the university's Faculty of Veterinary Medicine in Nakhon Pathom province, west of Bangkok.

"African swine fever has been found in Thailand, because we found it," Nattavut told Reuters late on Friday, adding that the university had sent the pig's autopsy result to Thailand's Department of Livestock Development last month.

He added that the owner had two other miniature pigs in the same household that also died later.

The university's discovery follows rising speculation that an African swine fever outbreak is already decimating Thai pig herds, with pig prices surging because of lower pig supply this year.

Thai authorities have repeatedly denied an African swine fever outbreak and previously attributed most farm pig deaths to another viral disease called porcine reproductive and respiratory syndrome (PRRS).

Chaiwat Yothakol, deputy director-general of the Department of Livestock Development, said late on Friday that "the department will investigate whether the pig was really infected with the disease."

"As of now we have not found the disease here," he said.

African swine fever is harmless to humans but fatal to pigs, and there is no vaccine to guard against the virus.

Thailand suspended exports of live pigs starting on Thursday until 5 April to shore up domestic supplies. Authorities estimated Thailand will have just 13 million pigs this year, fewer than the 19 million it usually produces.

Farmgate pig prices in Thailand were quoted at around 105 baht ($3.12) per kg last week, 30% higher than prices from the same period a year ago, data from the Swine Raisers Association of Thailand showed.

Prices of pork in Bangkok were seen this week at around 182.50 baht per kg, nearly 29% higher than in January 2021, according to Thai commerce ministry data.