June 21, 2012
New Research: Lyme Disease More Closely Tied to Red Foxes Than to Deer
by Scott Bestul
High whitetail numbers have been blamed for the spread of Lyme disease for years. But according to the latest research, we might be pointing our finger at the wrong critter. According to this story in a recent issue of Scientific American, a sharp decline in red fox populations may have gone a long way to making Lyme disease go viral in the last decade.
The red fox, as most of us know, is an efficient predator of small mammals like the white-footed mouse; known to be one of the prime hosts of the Lyme-carrying “deer” tick. Red fox numbers are in a general decline across the country, thanks largely to ever-growing coyote populations. Coyotes eat foxes whenever the populations overlap, which is frequently. Though both canines dine on mice, foxes take the greatest toll on the little rodents. So when fox numbers dive, mouse populations climb and ticks follow suit.
So why have whitetails been getting all the blame for the spread of Lyme disease? Well, deer are another preferred target of ticks, and as whitetail populations boomed in the 1980s and ’90s, we transferred—somewhat righteously—the blame for the illness to them. But when researchers took a new look at the spread of Lyme disease, they found it more closely mirrored the steady rise of coyotes than it did deer. In states like Wisconsin, for example, whitetail populations have been steady or declining for the last decade, while coyote numbers continue to rise. Interestingly, incidence of Lyme disease in the Badger State has risen 280 percent from 1997-2007, according to this story in the Milwaukee Journal-Sentinel, with 2,376 cases reported just last year. To further solidify the link, researchers found that an area in western New York—home to a healthy red fox population—was devoid of Lyme disease.
What to make of all this? First off, we should give ourselves a collective pat on the back; hunter harvest data helped researchers establish these links and take a new look at Lyme disease. Second, if you’re a coyote trapper or hunter, keep doing your thing and help give the red fox a break. And finally, this new research serves as yet another reminder of the inter-connectedness of all wildlife species and the importance of understanding all relationships in the natural world.