An explainer on African swine fever

BEIJING — African swine fever continues to affect pigs in China and other Asian nations even as authorities try to halt the spread of the disease.

African swine fever is typically spread through bites by infectious ticks, contact through infected animals, contact with objects containing the virus, or by ingesting the meat of infected animals, according to the European Food Safety Authority.

The disease is spread by the DNA virus of the Asfarviridae family, according to the World Organization for Animal Health.

African swine fever affects only porcine species. Warthogs are naturally resistant to the virus but can expose wild boars to infection.

Domestic pigs can contract the disease through exposure to infected wild boars, to which the disease is endemic.

Symptoms include high fever, redness on the ears, abdomen, legs as well as diarrhea, as stated by the World Organisation for Animal Health.

There currently is no approved vaccine to prevent the spread of the disease among pigs.

Asian countries such as Mongolia, China, North Korea, Laos and Cambodia have all been hit by the virus.

Vietnam has been hit particularly hard, with 10 percent of its herd — some 2.8 million animals — having been culled.

The disease is fatal for pigs. It, however, isn't transmissible to humans.