Most cases of Lyme disease are carried by a specific group called blacklegged ticks (also known as deer ticks), mainly in the Ixodes family.

Quick Scoop: What kind of ticks carry Lyme?

  • In the United States, the main Lyme-carrying ticks are:
    • Blacklegged tick / deer tick (Ixodes scapularis) – found in the northeastern, mid-Atlantic, and upper midwestern states.
* **Western blacklegged tick (_Ixodes pacificus_)** – found on the West Coast, including California and the Pacific Northwest.
  • These two Ixodes ticks are the primary vectors for the Lyme bacteria Borrelia burgdorferi (and rarely B. mayonii) in humans.
  • Not every blacklegged tick is infected:
    • Infection rates vary by region, from a small fraction up to more than 50% of ticks in some areas.
* A 2025 study in the Northeast found about 50% of adult blacklegged ticks carried Lyme bacteria in certain locations.
  • Other common ticks in the U.S. do not transmit Lyme disease bacteria:
    • Lone star tick (Amblyomma americanum) – can cause other illnesses and alpha-gal allergy, but not Lyme.
* **American dog tick (_Dermacentor variabilis_)**, **Rocky Mountain wood tick (_D. andersoni_)**, **brown dog tick (_Rhipicephalus sanguineus_)** – spread other diseases, but are not known to transmit Lyme bacteria.

How Lyme gets from tick to human

  • Ticks pick up Lyme bacteria when they feed on infected small animals like mice and other rodents, and some birds.
  • Nymphs and adult female Ixodes ticks can then pass the bacteria to people during a blood meal.
  • For transmission to happen:
    • The tick must be a Lyme-capable species (Ixodes blacklegged tick).
* It must itself be infected with _Borrelia_.

* It usually needs to be attached and feeding for **at least about 24 hours** ; risk rises the longer it stays attached.

Quick ID tips (high level)

While proper identification often needs a clear photo or expert, general patterns:

  • Blacklegged / deer ticks (Lyme-capable) :
    • Very small (nymphs about poppy-seed sized; adults about sesame-seed sized).
* Dark brown to black body; females have a reddish-brown back behind a dark “shield.”
  • Larger dog or wood ticks (not Lyme vectors) :
    • Typically bigger, with more mottled or patterned backs.

If you find a tick, saving it in a small container or bag (with the date and where you were bitten) can help a clinician or lab identify it later.

Why this is a trending topic now

  • Rising tick populations and warming climates are expanding Ixodes tick ranges, especially in the Northeast, Midwest, and some western states, so Lyme risk is a recurring seasonal headline each spring and summer.
  • Newer studies (like the one showing ~50% infection rates in some northeastern adult ticks) keep Lyme disease in the news as a significant public health concern.

What to do if you’re worried

If you’ve been bitten:

  1. Remove the tick promptly with fine-tipped tweezers, pulling straight out close to the skin.
  1. Note the time and date you think the tick attached, and where you were geographically.
  1. Contact a healthcare provider if:
    • The tick was likely a blacklegged tick.
    • It may have been attached for more than 24 hours.
    • You develop rash (especially a spreading “bull’s-eye” rash), fever, fatigue, or joint pain within days to weeks.

Bottom line: The ticks that carry Lyme disease are primarily blacklegged ticks in the Ixodes family (deer tick in the East/Midwest and western blacklegged tick on the West Coast), and not every one of them is infected.

Note: Information gathered from public forums or data available on the internet and portrayed here.