The MSPCA recognizes the widespread concern regarding Lyme disease and the need for more information and education on the issue. The pervasive but incorrect common name, “deer tick,” suggests a correlation between deer and tick-borne Lyme disease, and has led communities to increase deer hunting in a futile attempt to reduce the threat of Lyme disease. In fact, however, recent studies have found that large deer populations dilute, or lessen, the number of disease-carrying ticks in an area. This is because deer can act as a food source for the ticks without transmission of Lyme disease compared to white-footed mice or other rodents that are transmitters.[i]
Ticks do not require a specific host and can thrive, for example, by feeding on white-footed mice and other small animals. Some of these animals are in fact more efficient hosts—meaning they are better able to transmit a bacterial infection to feeding ticks—than are deer. One study, in 2017, found that even the removal of 70% of a local deer population had no effect on tick density.
In order to effectively reduce the number of Lyme disease cases, the number of disease-carrying ticks needs to be reduced—not the number of deer. Read more about the arguments against expanded deer hunting on our website.
Recommendations
The following tactics may be effective in reducing the number of tick-borne diseases:
1. Increase public education
According to the Assistant State Epidemiologist in Maine’s Department of Health and Human Services, education is the key to prevention because “a deer tick will not transmit Lyme disease if removed within 24 to 36 hours.”[ii] Communities should focus on increasing public education about ticks, including how to reduce the chance of sustaining a tick bite and what to do if bitten. The Massachusetts Department of Public Health recommends that people protect themselves from ticks by using repellents, staying out of tall grassy areas, and checking for ticks every day.
2. Install deer treatment bait stations and bait boxes for mice and other small mammals
Deer treatment bait stations (“4-poster devices”) can be more effective than killing deer because the treatment kills the ticks that are carrying the disease. Recommended by the American Lyme Disease Foundation, these bait stations work by attracting deer with bait, which is situated so that, while eating, deer rub up against applicators that apply a pesticide to their ears, heads, necks and shoulders, which is dispersed to the rest of the body through grooming.[iii] The pesticide, permethrin, is EPA approved and safe for the deer, and acts to kill most of the ticks before they can reproduce. Read a news article about Barnstable’s Lyme Disease Program, which utilizes deer treatment stations.
“Bait boxes” for mice and other small mammals use fipronil, also used in Frontline spot treatments for cats and dogs; this approach has been shown to reduce tick infections.
3. Modify habitat to reduce the number of ticks in high-use areas
Habitat modification can also be used to reduce the number of ticks in recreational areas. Places with “low-lying vegetation, shrubs, and grasses surrounding campgrounds or backyards should be close cropped or mowed to discourage tick movement and nesting. An approved residual insecticide should then be broadcast into the surrounding vegetation to establish an effective chemical barrier. A similar process, but on a smaller scale, can be followed for well-defined hiking trails. Control needs to be inclusive of the nymphal stage, when ticks are most likely to transmit the disease to humans.[iv]
The MSPCA’s Living With Wildlife philosophy involves effective strategies that are long lasting; reducing deer herds will not successfully address the tick-borne disease. We agree with the many professionals who recognize that this issue needs to be addressed through education, prevention, and innovative pesticide and habitat modification methods that directly impact tick populations.
For additional information on Lyme disease, visit:
Endnotes
[i]Huang, Ching-I, et al. “High Burdens of Ixodes Scapularis Larval Ticks on White-Tailed Deer May Limit Lyme Disease Risk in a Low Biodiversity Setting.” Ticks and Tick-Borne Diseases, vol. 10, no. 2, Feb. 2019, pp. 258–268., doi:10.1016/j.ttbdis.2018.10.013.; Mysterud, Atle, et al. “Contrasting Emergence of Lyme Disease across Ecosystems.” Nature Communications, vol. 7, no. 1, 16 June 2016, doi:10.1038/ncomms11882.
[ii] Hu, Linden. “Patient Education: What to Do after a Tick Bite to Prevent Lyme Disease (Beyond the Basics).” UpToDate, Wolters Kluwer, 13 May 2019, www.uptodate.com/contents/what-to-do-after-a-tick-bite-to-prevent-lyme-disease-beyond-the-basics.
[iii] Wong TJ, et al. Nd. The Effectiveness and Implementation of 4-Poster Deer Self-Treatment Devices for Tick-borne Disease Prevention: A Potential Component of an Integrated Tick Management Program. The Centers for Disease Control. https://www.cdc.gov/climateandhealth/docs/4postertickbornedisease.pdf
[iv] Kilpatrick, A. Marm, et al. “Lyme Disease Ecology in a Changing World: Consensus, Uncertainty and Critical Gaps for Improving Control.” Philosophical Transactions of the Royal Society B: Biological Sciences, vol. 372, no. 1722, 24 Apr. 2017, p. 20160117., doi:10.1098/rstb.2016.0117.
