Athens, Ga. A new study by University of Georgia researchers shows that the common practice of killing wild animals to control disease outbreaks can actually make matters worse in some cases.
In a study published the August 7 edition of the journal Proceedings of the Royal Society B: Biological Sciences, post-doctoral researcher Marc Choisy and Pejman Rohani, associate professor of ecology and UGA Biomedical and Health Sciences Institute researcher, create a detailed mathematical model that demonstrates how the combination of hunting and factors such as birth season and mating season influence disease outbreaks. Their results suggest that wildlife managers and health officials use caution when considering hunting or culling as a means to manage diseases as diverse as rabies, tuberculosis and even avian influenza.
"One consequence of hunting that we show in this paper is that it can increase the probability of dying from the disease," Choisy said. "It can give you results that are contrary to what you expect."
The reasoning behind killing wild animals to control disease outbreaks is simple: fewer animals should result in reduced transmission of disease. Hunting has been used to control badger populations in England, rabies in European foxes and chronic wasting disease in deer and elk populations in the American West. The researchers note that in each instance, disease outbreaks have worsened in response to the hunting.
One reason the policies failed, Choisy and Rohani said, is that they didn't take into account an ecological principle known as compensation. When a portion of the animal population is reduced, those that survive are left with more resources such as food and shelter. As a result of the newly plentiful resources, the death rate decreases and the birth rate increases, compensating and sometimes overcompensating for the loss.