May 13, 2022: The Centers for Disease Control and Prevention listed six Connecticut Counties in the High/Orange category as part of its COVID-19 Community Levels Map. Only Fairfield and New London Counties are listed in the Medium/Yellow category. Residents in these counties should wear a mask indoors in public; stay up to date with COVID-19 vaccines and get tested if they have symptoms. Additional precautions may be needed for residents who are at high risk for severe illness. Visit the CDC COVID-19 Community Levels Map for updates.


Black-legged (Deer) Tick


Anaplasmosis (formerly called human granulocytic ehrlichiosis) is caused by the bacterium Anaplasma phagocytophilum. It is spread to people through the bite of an infected Black-legged (“deer”) tick (Ixodes scapularis). Treatment is available; however if it is delayed, or there are underlying medical conditions, symptoms can become more severe. The best way to prevent anaplasmosis is to prevent tick bites.


About Anaplasmosis

Information for Clinicians


Clinical Guidance 

National Surveillance Case Definition


Connecticut Laboratory Reporting Information

Reportable Laboratory Findings form, OL-15C


Directory of Clinical Testing Services provided by the State Public Health Laboratory

State Public Health Laboratory Contacts – for additional information


Tick-borne Diseases of the United States – a Reference Manual for Healthcare Providers


Connecticut Anaplasmosis Surveillance

In 2008, the Centers for Disease Control and Prevention established a surveillance case definition for anaplasmosis, and the Connecticut Department of Public Health (DPH) added the disease to the list of state-wide reportable diseases. Since 2008, an average of 69 cases (range 22 to 120) have been reported to the DPH annually.  


Connecticut Annual Infectious Diseases Statistics




This page last updated 5/20/2020.