Tickborne Diseases

Tickborne diseases are those spread by the bite of an infected tick. These diseases can be caused by bacteria, parasites, or viruses, although the diseases caused by bacteria are most common. Several tick species found in Connecticut can spread types of bacteria that can cause illness in humans, and infection with more than one is possible through one tick bite. Symptoms and treatment for each disease depends on the type of bacteria, parasite, or virus causing the illness. There are no vaccines to prevent these diseases. In Connecticut, surveillance is conducted to identify tickborne diseases spread by ticks in the state and those that might be travel-related (diseases acquired out of the state). The Connecticut Department of Public Health conducts surveillance for the following tickborne diseases:

• Anaplasmosis
• Babesiosis
• Ehrlichiosis
• Hard Tick Relapsing Fever
• Lyme Disease
• Powassan Virus Disease
• Spotted Fever Rickettsiosis
• Tularemia

Blacklegged (“deer”) Tick (Ixodes scapularis)

• Anaplasmosis
• Babesiosis
• Hard Tick Relapsing Fever
• Powassan virus disease (can also be spread by Ixodes cookei)

Lone Star Tick (Amblyomma americanum)

• Ehrlichia chaffeensis
• Tularemia

American Dog Tick (Dermacentor variabilis)

• Spotted Fever Rickettsiosis
• Tularemia

• Reporting Diseases, Emergency Illnesses, Health Conditions, and Laboratory Findings
• Connecticut Provider Reporting Information
• Connecticut Laboratory Reporting Information
• Directory of Clinical Testing Services provided by the State Public Health Laboratory
• Connecticut Annual Infectious Diseases Statistics

Connecticut Agricultural Experiment Station

The Connecticut Agricultural Experiment Station offers tick testing to Connecticut’s municipal and regional health departments for engorged ticks removed from people. Ticks are tested for the causative agents of anaplasmosis (Anaplasma phagocytophilum), babesiosis (Babesia microti), and Lyme disease (Borrelia burgdorferi). Not all ticks carry disease causing pathogens.

• Tick Related Information
• Submitting Ticks for Testing
• Connecticut Tick Testing Summaries
• Tick Management Handbook

Yale School of Public Health - TickNET

Northeast Regional Center for Excellence in Vector-borne Diseases

• Tickborne Diseases of the United States – a Reference Manual for Healthcare Providers
• About Ticks and Tickborne Disease in the United States
• Tick Bite Data Tracker
• Workplace Safety - Tickborne Diseases in Workers
• Vector Control Resources

 

 

Updated 2/20/2026