Bruce Smith
Covid and the Human-Wildlife Interface

A variety of zoo animals are becoming infected by Covid19. Some are dying from the disease. Although we can’t be certain, it seems likely these captive wild animals are contracting the disease from zoo workers and human visitors. The susceptibility of some zoo animals to Covid only reinforces health officials’ concerns that wildlife may become a reservoir for Covid’s persistence and continuing threat to mammalian species, including us. Testing of whitetail deer in several Midwestern states has revealed that about one third of sampled animals have tested positive for exposure to SARS-CoV-2, the virus that causes human Covid. Research on the virus’s pathogenicity in whitetails is ongoing. Even if it doesn’t cause significant disease in deer, this abundant wildlife species (an estimated 30 million whitetails inhabit North America) could harbor the virus for some time.
We think of zoonotic diseases as those that can be passed from animals (wild or domestic) to humans. Almost 70% of all infectious human diseases are of animal origin. A few examples are SARS, HIV Aids, Lyme disease, rabies, and all influenzas. However, wild animals also run the risk of infection, disease, and mortality from transmissible zoonotic diseases contracted from humans. Spillover can go both directions.
