Russia will slaughter at least 33,000 pigs in the Tver region after an outbreak of African Swine Fever (ASF), a virus that causes lethal hemorrhaging in domestic pigs.

Some reports estimate 33,000 pigs will be slaughtered but Pig Progress claims that the number may be as high as 100,000. Outbreaks began May 2011 in the Tver region and this year at least 21 different outbreaks have been registered. ASF was first introduced to the area in 2007.

The transportation of hogs and their meat from the Tver region has been banned. The area that contains the infected hogs has been quarantined.

The disease, while deadly for pigs, is harmless to humans.