They had been dumped there the night before in the central province’s Ngoc Son Commune.

After confirmation that the pigs were infected with the incurable disease, officials examined and buried them with "proper procedures."

Even though farmers have been asked to report any instance of sickness or death of pigs so they can be dealt with appropriately and prevent the disease from spreading, dead pigs are still being dumped in rivers or on river banks, said Ngoc Son's chairman Thai Van An.

Instances of infected pigs being dumped into local rivers were reported on October 5, 8 and 22.

Nghe An Province first detected African swine fever in March and has since culled almost 64,000 pigs.

The first cases of African swine fever in Vietnam were detected in the northern province of Hung Yen in February. In the next eight months, it steadily spread to central and then southern provinces. As a result, four million pigs - equivalent of 13 percent of national pig stock, were culled.

The Vietnam National University of Agriculture said in July that it has developed a possible vaccine.

According to the World Organization for Animal Health (OIE), as of October 2019, African swine fever was active in 22 other countries beside Vietnam: Bulgaria, Hungary, Latvia, Moldova, Poland, Romania, Russia, Serbia, Slovakia, Ukraine in Europe; China, North Korea, South Korea, Laos, Myanmar, the Philippines, Russia, Timor-Leste in Asia; and Cote D'Ivoire, Kenya, South Africa and Zimbabwe in Africa.