Lyme Disease Can be Curbed by Reducing the Number of White-Tailed Deer

Researchers have found a new method to prevent the spreading of Lyme disease - reducing the number of white-tailed deer.

Lyme disease is an infectious disease that is trigged by three species of bacteria and exhibit symptoms like fever, headache and fatigue. Nearly 80 percent of the infected persons suffer from a rash as well. The primary host of this disease is deer including rodents and small mammals. Scientists have been trying to figure whether lowering the number of deer in a given region would lead to a fewer cases of Lyme disease.

After a 13-year study, researchers have now found strong evidence which confirms that reducing the deer population indeed leads to the fall in Lyme disease cases. The finding is based on the survey conducted on 90-98 percent of the permanent residents in Connecticut from 1995-2008.  Based on the survey, the researchers estimated the community's exposure to the disease as well as the frequency and abundance of deer observations.

"We found that reducing deer density by ≥87% resulted in a significant reduction in tick abundance, nearly a 50% reduction in tick infection rate, and an 80% reduction in resident-reported human cases of Lyme disease," the authors wrote. "Our study demonstrated that deer populations can be manipulated to reduce human interactions with deer, infected nymphal ticks, and human risk of contracting Lyme disease."

Once the hunt for deer was initiated, along with a dramatic decline in the number and frequency of deer observations in the community, there was a fall in the number of reported cases of Lyme disease.

There was a strong correlation between resident-reported cases of Lyme disease per 100 households and deer density in the community. Reducing the density of the deer to 5.1 deer per square kilometer led to 76 percent drop in tick abundance, 70 percent reduction in entomological risk index and an 80 percent drop in resident-reported cases of Lyme disease.

"Reducing deer populations to levels that reduce the potential for ticks to successfully breed should be an important component of any long-term strategy seeking to reduce the risk of people contracting Lyme disease," they concluded. "Additionally, good hunter access to deer habitat and a wide variety of management tools (bait, unlimited tags, incentive programs) are important components of a successful deer reduction strategy."

The finding was documented in the Journal of Medical Entomology.