Herd immunity: Disease transmission from wildlife to livestock

Transmission of diseases from wildlife to livestock is a common threat in Alberta, according to new research by University of Alberta biologists. Foothills in the southwestern part of the province are home to wild elk as well as cattle on ranchlands -- and when the species intermingle, the potential for disease to spread grows.


"One of the biggest risks to the livestock industry is the transmission of disease from wildlife to livestock," said Mark Boyce, professor in the Department of Biological Sciences. "There is a long list of diseases that occur between livestock and wildlife, including anthrax, bovine tuberculosis, brucellosis, and many species of worms. And in addition to infecting one another, many of the diseases that are shared by wildlife and livestock are zoonotic, meaning that they also can infect humans."

The researchers used data gathered from combined with cattle management information from 16 cattle operations in southern Alberta to identify locations and times where the probability of disease transmission is high. For example, the highest risk occurs in winter months, when livestock and elk are in the same pastures and accessing the same resources.

Based on these data, the researchers have developed guidelines to help producers minimize the risk of infection.

"Livestock management that minimizes the risk of contact with wildlife will reduce the risk of disease transmission," said Boyce. "This includes keeping cattle in pastures near farm buildings during winter and calving season. It is also important to keep mineral supplements and hay next to ranch buildings, again to reduce the contact between cattle and elk.