- Deer are not to blame for rising rates of Lyme disease.
- Where there are lots of coyotes, risk of Lyme is high. Where there are lots of foxes, risk is low.
- Healthy predator populations and stable food webs are essential for human health.
Deer frequently take the blame for spreading Lyme disease. But a new study suggests that foxes are a more critical link in a complex web of interactions that have contributed to rising rates of the insidious infectious disease, while deer have nothing to do it with it.
Foxes don't spread Lyme disease directly. Instead, they cull populations of small mammals, which are responsible for the bulk of infectious ticks. Where foxes are thriving, the risk of disease drops. But when fox numbers fall – often because coyotes move in, small mammal populations surge and Lyme disease flourishes.
The study emphasizes how important stable food webs and strong predator populations are for human health.
How Stuff Works: Preventing Lyme Disease
"Small changes in predation can lead to large changes in Lyme disease risk," said ecologist Taal Levi, who completed the study while at the University of California, Santa Cruz, and is now at the Cary Institute for Environmental Studies in Millbrook, NY. "This argues for top predator conservation, or at least that there are unintended consequences for people of losing them."