A total of about 17,000 pigs are fattened in the farm, which is located in the village of Nikolovo near Danube River in Ruse Region, the agency said in a statement.
All pigs in the farm will be culled, and meat and products produced from pigs from the farm will be destroyed, the statement said.
The first case of African swine fever in domestic pigs in Bulgaria this year was reported on July 3, and the latest outbreak brought the total number to 17.
However, the previous 16 outbreaks were in backyard farms. As a precautionary measure, 375 domestic pigs were culled so far.