Lyme Disease

What is Lyme Disease?

Lyme Disease is a caused by a type of bacteria called Borrelia burgdorferi. Both humans and pets may become sick from it. Symptoms include fever, headache, fatigue, and a characteristic skin rash that often has the appearance of a "bulls-eye." If left untreated, the infection can spread to joints, the heart, and the nervous system, causing long-term health issues. Most cases of Lyme Disease can be treated with antibiotics.

Do deer spread Lyme Disease?

Deer themselves cannot transmit Lyme Disease to people or other animals. The disease is spread through the bite of an infected tick. Deer are common hosts to this species of tick, known as the Black-legged Tick (sometimes called the Deer Tick). The name "Deer Tick" often gives the impression that these ticks are only found on deer. However, deer are only one of many wildlife species that carry this tick. In fact, the ticks require different hosts at each stage of their complex life cycle. The image below depicts the life cycle of the Black-legged Tick (image from cdc.gov).

Black-legged Tick eggs hatch in the summer. Each female tick can lay thousands of eggs. The tick larvae search for their first hosts after hatching. These hosts are typically birds or small mammals, like mice. The following spring, as the ticks reach the next stage of their life cycle - known as the nymph stage - they need to seek a different host. At this point, the hosts are typically larger, including a variety of small mammals, foxes, coyotes, raccoons, skunks, deer, and humans. By fall, the ticks have reached the adult stage. At that point, they rarely use small mammals as hosts, preferring animals about the size of a dog or larger. Foxes, coyotes, deer, and humans are common hosts for the adult ticks. Due to the timing of this life cycle, the risk of human infection is greatest during the spring and summer, when ticks in the nymph and adult stages are seeking new hosts (CDC, 2011; Tick Research Lab of Pennsylvania, 2020). Not all Black-legged Ticks are infected with Lyme Disease. In 2020, 54.9% of adult Black-legged Ticks and 44.4% of nymphs tested were infected with Lyme Disease (New York State Department of Health, 2021).

It is important to mention here that deer do not actually get Lyme Disease. This is important because it means that, while deer do carry the ticks around and spread them from place to place, they do not infect ticks with Lyme Disease. Ticks are most commonly infected during their larval or nymph stages, when they use smaller animals that are susceptible to the disease as hosts. The White-footed Mouse and Eastern Chipmunk are the most common sources of the disease in the eastern and midwestern United States (Pennsylvania Game Commission, 2022).

Are all the ticks I see in my yard Deer Ticks?

No! We have three species of ticks in New York State that pose a concern for human health - the Black-legged (Deer) Tick, Wood Tick, also called the Dog Tick, and the Lone Star Tick. Wood Ticks and Lone Star Ticks do not carry Lyme Disease (although they may carry other diseases). Wood Ticks are quite common in Western New York. Lone Star Ticks are spreading in New York, but are still relatively uncommon in Erie County. The figure below (taken from cdc.gov) shows a visual comparison of these three tick species. For the blacklegged tick, larvae are about the size of a grain of sand, nymphs are about the size of a poppy seed, and adults are similar in size to a sesame seed. Lone Star Ticks are similar in size. When fully fed, an adult female Black-legged or Lone Star Tick can be as big as a raisin. Wood Ticks (aka Dog Ticks) are larger than the other two species (Cornell College of Agriculture and Life Sciences, 2022).

How do I protect myself and my family from Lyme Disease? (suggestions adapted from cdc.gov)

  • Avoid areas with high grass or shrubs, as these areas are common habitat for Black-legged Ticks. When walking through vegetation or hiking off-trail, wear long plants and long-sleeved shirts, and apply insect repellents such as DEET, picaridin, or lemon-eucalyptus. Treat clothing, footwear, tents, and other gear with a product containing 0.5% permethrin for additional protection.

  • Protect pets from ticks by checking them after outdoor activities, limiting their access to grassy and shrubby areas, and using a veterinary-approved tick prevention product.

  • One of the best ways to protect yourself from Lyme Disease is to carefully check for ticks after outdoor activities. Both nymphs and adults can transmit disease and are likely to attach to humans, so make sure to check for even very small ticks. It is important to check the places can hide, such as on the scalp, in and around the ears, in the belly button, and on the back of the knees. If a tick is attached for less than 24 hours, the chances of Lyme Disease transmission are very low.

  • If you do find a tick, remove it with fine-tipped tweezers. Contact your doctor if you develop a rash or fever. See the CDC's instructions for removing ticks here.

References:

CDC, 2011. The Life Cycle of Blacklegged Ticks. Accessed at https://www.cdc.gov/lyme/transmission/blacklegged.html

CDC, 2021. Tick Removal and Testing. Accessed at https://www.cdc.gov/lyme/removal/index.html

CDC, 2022. Lyme Disease. Accessed at https://www.cdc.gov/lyme/index.html

Cornell College of Agriculture and Life Sciences, 2022. New York State Integrated Pest Management: Tick FAQs. Accessed at https://nysipm.cornell.edu/whats-bugging-you/ticks/tick-faqs/#tick-tube

Cornell College of Agriculture and Life Sciences, 2022. New York State Integrated Pest Management: What do Ticks Look Like? Accessed at https://nysipm.cornell.edu/whats-bugging-you/ticks/what-do-ticks-look/

New York State Department of Health, 2021. Heath Data NY. Accessed at https://healthdata.ny.gov/browse?sortBy=alpha

Pennsylvania Game Commission, 2022. Lyme Disease. Accessed at https://www.pgc.pa.gov/Wildlife/Wildlife-RelatedDiseases/Pages/LymeDisease.aspx

Tick Research Lab of Pennsylvania, 2020. The Tick Life Cycle. Accessed at https://www.ticklab.org/blog/2020/12/01/the-tick-lifecycle/