Although the identity of COVID-19’s patient zero is still unknown, the virus is widely suspected to have originated in a Wuhan wet market. And one thing is crystal clear: These informal slaughterhouses, along with their more formal counterparts in the factory farming industry, are the perfect place to spread disease.

Crowding animals into confined, unsanitary conditions to be slaughtered—mixing blood, guts and feces—creates a petri dish for pathogens. These informal and formal “flu factories” can quickly spread a bat- or bird-borne disease among intermediary animals that humans consume.

Slaughterhouses and meat-packing plants are also among the worst COVID-19 hot spots for humans. Some of the largest outbreaks in North America occurred in meatpacking plants. According to the U.S. Centers for Disease Control and Prevention, the virus is spreading quickly at these…