In North America plague mostly affects rodent populations such as chipmunks, ground squirrels, and prairie dogs. These rodent populations serve as the primary reservoir for the disease. Plague can also affect other mammals, such as carnivores and scavengers that feed on rodents. Plague represents a health and safety threat to humans, especially in places where humans and rodents overlap. There are currently about a dozen human plague cases reported each year.
Feline species, such as bobcats, mountain lions, and domestic cats are particularly susceptible to plague while canine species, including coyotes, wolves, and domestic dogs, tend to be somewhat resistant to plague. Because cats are susceptible to plague and can develop the highly contagious form of the disease (pneumonic plague), they can represent a health threat to people who come in contact with them (i.e., hunters, wildlife personnel & pet owners). While canids typically do not tend to develop an active form of plague, they do readily develop antibodies.
NWDP biologists work closely with other WS personnel who conduct wildlife damage management activities to protect human health, agriculture, and natural resources. For example, collecting samples from coyotes taken during wildlife damage management activities is useful because coyotes make frequent contact with rodents through predation and scavenging. If contact is made with an infected rodent, the coyote may develop antibodies (evidence of an immune response), which indicates that plague is likely present in the area. Since 2005, the NWDP has screened nearly 50,000 wildlife samples for plague exposure.
Julianna B. Lenoch, DVM, MPH
Diplomate of the American College of Veterinary Preventive Medicine
USDA/APHIS/WS4101 Laporte Ave
Fort Collins, CO 80521