Babesiosis

Babesiosis is a disease caused by parasites that infect red blood cells. There are many different species (types) of Babesia parasites that have been found in animals, and only a few have been found in people. To date, there have been no reported human cases in British Columbia, but the parasite has been found in Ixodes ticks sampled in the Lower Mainland and Gulf Islands. Locally-acquired human cases have been reported in Washington State. Babesia microti is the main species that has been found in people in the United States.

Information for Health Professionals

Laboratory Testing

Causes

The main way Babesia is spread is through the bite of an infected tick. Babesia microti is usually spread by Ixodes ticks.

Other rare ways of becoming infected with Babesia include:

Receipt of a contaminated blood transfusion; or
Transmission from an infected mother to her baby during pregnancy or delivery

Symptoms

Symptoms typically start 1-4 weeks after the exposure and can range in severity from mild to life-threatening. Common symptoms include:

Fever, chills
Muscle aches
Fatigue
Nausea and loss of appetite

Although less common, illness can cause severe symptoms:

Breathing difficulty
Low blood pressure
Kidney failure
Liver injury
Bleeding problems
Confusion and decreased consciousness
Death

Some people may not experience any symptoms despite being infected.

Diagnosis

Laboratory diagnostic testing, which can include the following:

Nucleic acid amplification test (NAAT)
Serology (indirect immunofluorescence antibody (IFA) assay)
Microscopic examination of a peripheral blood smear

Treatment

Treatment with antibiotics is recommended. Awareness and avoidance are best to prevent this disease.

If babesiosis is diagnosed or suspected, your doctor may prescribe antibiotics to ensure the best possible result.

Prevention

Find more information about prevention of babesiosis on the main tick-borne diseases page.