Black-legged (deer) ticks can spread Lyme disease, babesiosis, anaplasmosis, Borrelia miyamotoi and Powassan virus. Black-legged ticks and dog ticks are found throughout Massachusetts; lone star ticks are found in some parts of the state.
The diseases homeowners hear about most
Lyme disease
Lyme disease is caused by bacteria transmitted by infected black-legged ticks. Early signs can include fever, chills, headache, fatigue, muscle and joint aches, swollen lymph nodes, and an expanding erythema migrans rash; not everyone develops the rash.
Babesiosis
Babesiosis is caused by microscopic parasites that infect red blood cells and is spread by infected black-legged ticks. Many people have no symptoms; others can develop fever, chills, headache, body aches, nausea or fatigue.
Anaplasmosis
Anaplasmosis is a bacterial illness transmitted primarily by infected black-legged ticks. Typical symptoms include fever, headache, chills, muscle aches and fatigue.
Other tick-borne illnesses also occur in Massachusetts.
Massachusetts DPH also identifies Powassan virus, Borrelia miyamotoi, tularemia and Rocky Mountain spotted fever as less common tick-borne diseases that still occur in the state. Lone star tick bites can also be associated with alpha-gal syndrome, a tick-associated allergy rather than an infection.
One tick can carry more than one germ.
Black-legged ticks in Massachusetts can carry the germs that cause several different illnesses and can spread more than one type of germ in a single bite.
Watch for symptoms, not just a rash.
Symptoms vary by disease. If you become ill after a known tick bite or possible tick exposure, contact a healthcare professional rather than relying on the presence or absence of a rash.
Why yard-level prevention matters.
Public-health guidance recommends combining yard measures with personal protection: remove leaf litter and brush, keep high-use areas away from wooded or brushy edges when practical, use appropriate repellents, check people and pets for ticks, and promptly remove attached ticks.
Want the homeowner checklist?
The companion page turns public-health guidance into a simple yard and personal-protection routine.
See the Tick Prevention GuidePublic-health sources
Fact-checked against current Massachusetts DPH and CDC guidance on September 14, 2026.
Massachusetts DPH: Tick-borne Diseases · Massachusetts DPH: Tick-borne Disease Prevention · Massachusetts DPH: Monthly Tick Reports · CDC: Lyme Disease Signs & Symptoms · CDC: Babesiosis · Massachusetts DPH: Alpha-gal Syndrome