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Babesiosis is a tick-borne disease that is caused by microscopic parasites that infect red blood cells. There are multiple different species that have been known to infect animals, however, only a few that have been found in humans. The most common species in people is Babesia microti.
Babesia is transmitted by infected Ixodes scapularis ticks (also known as blacklegged ticks or deer ticks). The blacklegged tick, which is common in the Upper Peninsula and spreading in the Lower Peninsula, may also transmit Lyme disease, Anaplasmosis, and Ehrlichiosis.
Everyone is susceptible to babesiosis, but people who spend time outdoors in tick-infested environments are at increased risk of exposure. In Michigan, reports of tick-borne disease are usually seen from spring through autumn when most ticks are active. Like Lyme disease, babesiosis is most likely to be at increased risk during the summer months when blacklegged tick nymphs are active.
Since the Babesia parasites infect the red blood cells and circulate in the blood stream, these pathogens may pose a risk to be transmitted through blood transfusions. Babesiosis may also be a risk during organ transplantation. In addition, there is risk of transmission from an infected mother to her baby during pregnancy or delivery.
Individuals that do not have a spleen, have a weak immune system, have other serious health conditions, and/or are elderly may be at increased risk for developing severe forms of this disease.
What are the signs and symptoms of babesiosis?
Babesia infection can range in severity from asymptomatic to life threatening. If individuals develop symptoms, they typically start within a week or so after the tick bite and may develop within a few weeks or months (or longer). Many people who are infected do not develop any symptoms. However, others may develop flu-like symptoms, including fever, chills, sweats, headaches, body aches, loss of appetite, nausea, and/or fatigue.
Since these parasites infect red blood cells, hemolytic anemia may result (from the destruction of red blood cells). This could cause jaundice (yellowing of the skin) and dark urine.
Babesiosis may be life-threatening especially for those individuals with weakened immune systems, already have serious health conditions, do not have a spleen, and/or are elderly. Severe cases may be associated with a low and unstable blood pressure, severe hemolytic anemia (hemolysis), very low platelet count (thrombocytopenia), disseminated intravascular coagulation (also known as "DIC" or consumptive coagulopathy which can lead to blood clots and bleeding, malfunction of vital organs (such as the kidneys, lungs, and liver), or death.
How can babesiosis be diagnosed?
If you believe that you or a family member may have babesiosis, please consult with your local healthcare provider. Babesiosis can be diagnosed in symptomatic individuals by examining blood specimens microscopically in order to identify Babesia parasites inside red blood cells. To verify the diagnosis, the blood specimens may be sent to a specialized reference laboratory.
What should I do if I have a tick that I want to identify or test?
Knowing what kind of tick bit you may be important in knowing what your risk of disease is. The Michigan Department of Health and Human Services (MDHHS) provides tick identification at no charge to Michigan citizens. There are two ways to have a tick identified, 1) By submitting a photo of your tick, or, 2) by sending the tick to the MDHHS for microscopic identification. If you want to submit a photo of your tick, the MDHHS will make all attempts to identify the tick based on the condition of the tick and the condition of the photos. However, definitive tick identification may only be made by sending the tick for microscopic examination.
Ticks that are submitted from people to the MDHHS for microscopic identification and identified as blacklegged ticks (also known as deer tick) and are alive will be forwarded to the MDHHS Bureau of Laboratories for Lyme disease screening only, at no cost. Ticks that are dead when they are received or are from animals (dog, cat, horse, etc.) will not be tested however, they will be identified to species and life stage.
See the quick reference table for health care providers that includes vector species, incubation period, signs and symptoms, general laboratory findings, laboratory diagnosis, and treatment for the following tickborne diseases: Lyme disease, anaplasmosis, babesiosis, and Rocky Mountain spotted fever.
How can babesiosis be treated?
Those individuals who are not exhibiting any signs or symptoms of babesiosis typically do not need to be treated. However, effective treatment is available for symptomatic people. If you believe that you or a family member may have babesiosis, please consult with your local healthcare provider for more information regarding treatment options. Babesiosis treatment decisions are often individualized depending on the case.
- The Tick Management Handbook
An integrated guide for homeowners, pest control operators, and public health officials for the prevention of tick-associated disease (Connecticut Agricultural Experiment Station)
- CDC: Guidance for Clinicians: Recommendations for Patients After a Tick Bite
- CDC: What To Do After a Tick Bite
- The Clinical Assessment, Treatment, and Prevention of Lyme Disease, Human Granulocytic Anaplasmosis, and Babesiosis: Clinical Practice Guidelines by the Infectious Diseases Society of America