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.  

Cases of Anaplasmosis reported to the DPH from January 1 - December 31, 2019


297 Confirmed


Connecticut Annual Infectious Diseases Statistics




This page last updated 1/14/2020.