Deer Ticks: What Are They And Where Do They Live?

Around 900 species of ticks exist worldwide, and the deer tick (also called the blacklegged tick) is one of the most significant species affecting human and pet health in the United States.

Let’s explore how to keep your family members—two- and four-legged—safe from deer ticks.

What Is a Deer Tick?

Deer ticks are much smaller than other common types of ticks and go through a rather complicated lifecycle that can take up to two years.

• Egg—After breeding with a male, an adult female deer tick lays 1,500–3,000 eggs in the environment.

• Larvae—Tiny (less than 1mm in size) six-legged larvae hatch from the eggs. Larvae usually feed on small animals such as rodents, lizards, or birds and are rarely found on pets or people. After the larvae consume a blood meal, they drop to the ground and molt into nymphs.

• Nymph—Deer tick nymphs have eight legs and are about 2mm long, around the size of a poppy seed. They typically feed on the same animal hosts as larvae. After feeding, deer tick nymphs leave their host and molt into adults.

• Adult—Adult deer ticks are about the size of a sesame seed (3mm). They mostly feed on larger animals, such as deer (which is how they get their name), dogs, cats, and people. After adult deer ticks feed, they mate, the female lays eggs, and they die.

Where Is the Deer Tick Found?

Two species of deer ticks are found in the United States:

1. The eastern deer tick (Ixodes scapularis) is common in the midwestern and eastern parts of the United States but has been found as far south and west as Texas and South Dakota.

2. The western deer tick (Ixodes pacificus) lives west of the Rocky Mountains, primarily along the California, Oregon, and Washington coasts.

Deer ticks tend to live in wooded areas that are home to the host species they feed on. They use leaf litter, low bushes, and trees to protect themselves from the elements.

What Diseases Can the Deer Tick Spread?

When a deer tick feeds on the blood of a host animal, it can pick up disease-causing microorganisms and spread them to subsequent hosts.

Health problems caused by deer tick bites include:

• Lyme disease—Lyme disease is caused by Borrelia burgdorferi bacteria, which is spread by deer ticks. Dogs with Lyme disease usually develop symptoms that include a fever, swollen lymph nodes, and painful joints. Kidney disease is also possible.

  • The bullseye rash that often affects people with Lyme disease is not commonly seen in dogs.

  • While cats can also be infected with Borrelia burgdorferi bacteria, they rarely develop symptoms of Lyme disease.

• Anaplasmosis—The bacteria Anaplasma phagocytophilum can cause anaplasmosis in dogs (and less commonly in cats and people).

• Local reactions—Deer tick bites can cause local irritation and infections that usually resolve once the tick is removed.

Deer ticks can also spread other diseases, such as: 

• Hard tick relapsing fever (Borrelia miyamotoi)

• Human babesiosis (Babesia microti)

• Powassan virus

• Ehrlichiosis caused by Ehrlichia muris

However, these diseases are quite rare or primarily infect people.

Are Deer Tick Diseases Treatable?

When a veterinarian diagnoses a pet with Lyme disease or anaplasmosis, they typically prescribe the antibiotic doxycycline, although other antibiotics and medications may be appropriate based on the specific case.

The prognosis in cases of anaplasmosis is excellent—most pets will be cured.

However, Lyme disease is a little different.

A dog’s symptoms will usually get better or go away with treatment, but antibiotics often don’t eliminate the bacteria from the dog’s body.

Relapses are possible, and, unfortunately, most dogs with kidney disease caused by Lyme disease eventually die or are humanely euthanized due to the condition.

A vaccine for Lyme disease prevention is available and should be considered for high-risk dogs.

How To Prevent Deer Tick Bites

Deer ticks can be active all year long and the potential effects of their bites are serious, so at-risk pets should receive effective year-round tick prevention, such as:

• Frontline® Plus, a topical product that controls deer ticks and several other parasites when applied monthly. However, some tick populations have developed resistance to it.

• K9 Advantix™ II, a monthly topical product effective against deer ticks and other parasites. It is highly toxic to cats and should never be used in the species.

• Bravecto®, available as an oral chew for dogs and as a topical liquid for both dogs and cats. This product kills fleas and ticks (including deer ticks), and one dose can last up to 12 weeks.

• Simparica TRIO™, a monthly oral chew used to control ticks, fleas, roundworms, hookworms, and heartworm disease in dogs.

Not all parasite preventives are appropriate for all pets. Read and follow the product’s label closely to avoid toxicity or reactions.

Your veterinarian can help you choose the best form of parasite control for your dog or cat.

If your pet picks up deer ticks from your yard, environmental controls can also be helpful. Outdoor tick control methods include:

• Raking up leaves and mowing your grass frequently

• Removing brush

• Installing a 3-foot zone of wood chips or gravel between your lawn and any adjacent wooded areas

• Discouraging rodents, deer, and other animals from entering your yard by removing sources of food or shelter and installing fences

• Using a a yard and premises spray