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By Renata Trister DO

Babesia are parasitic protozoans that reproduce in the red blood cells of mammals. The various forms of Babesia complex life cycle live in exchange between ticks (Ixodes) and mammals. Babesia species was first described in 1888 by Victor Babes, a Hungarian pathologist in whose honor the organisms were named.

Babesiosis has long been recognized as a disease of cattle and other domesticated animals, but the first human case was not described until 1957, when a young Croatian farmer contracted the illness and died some days later of renal insufficiency. In the late 1960s, the first North American cases appeared on Nantucket Island, and the disease is now recognized as an emerging and occasionally serious zoonosis in the United States.Adapted over hundreds of millions of years: stealthy”cryptic inhabitants” within vertebrate and invertebrate hosts. Co-infection with Borrelia thought to increase impact.

Babesiosis has been reported in North and South America, Europe, and southern and eastern Asia. In the United States, the primary agent of human babesiosis is Babesia microti, which is transmitted by the bite of Ixodes scapularis, the same tick species that is a vector for Lyme disease. Cases of babesiosis caused by B. microti occur in southern New England and the northern Midwest. Additional cases of babesiosis caused by other species of Babesia occur primarily in the western U.S.; cases from Missouri and Kentucky have also been reported. It is a frequent co infection with Lyme disease.

Babesiosis has a wide spectrum of disease severity. It varies from patient to patient. Most patients experience a viral-like illness lasting anywhere from a few weeks to a few months. A small segment of patients are completely symptom free. In patients with a complicating condition, however – such as underlying immunosuppression – the disease course can be severe and potentially fatal. Primarily transmitted by tick bite, babesiosis can also be transmitted via blood transfusion and maternal-fetal transmission.

Signs and Symptoms
If you think lyme disease is bad-meet Babesia!

Symptoms of babesiosis usually begin 1-6 weeks after infection and are non-specific. Typical early manifestations include: day sweats, night sweats ( occasionally drenching) intermittent fevers, fatigue, headache, chills ,flashing ,air hunger, cough and myalgias. Nausea, vomiting, poor appetite and depression can also occur. Some patients will develop enlarged livers or spleens. The usual disease course lasts weeks to several months, but some patients take even longer to fully recover. Co-infection with Lyme disease or anaplasmosis may complicate the clinical presentation and predispose the patient to more severe disease.
Different strains of Babesia may cause different set of symptoms, yet all can significantly exacerbate a Lyme disease infection.
Babesia and Malaria share the same set of symptoms, and the infections may look the same to a laboratory technician viewing parasites under the microscope.

At the greatest risk for severe babesiosis are the elderly, asplenetic patients, patients with HIV or malignancies, and patients on immunosuppressive medications. In these populations, the disease course is longer and the fatality rate is in the neighborhood of 20%, even with proper antibabesial therapy. The most common serious complication of babesiosis is acute respiratory failure, but heart failure, liver and renal failure, disseminated intravascular coagulation and coma are also well-recognized severe manifestations of babesiosis.


Early symptoms of babesiosis are non-specific making the diagnosis difficult. A simple blood panel can be indicative of an infection. Babesia causes lysis of red blood cells, patients can develop hemolytic anemia, as well as lymphopenia and thrombocytopenia. Elevated serum lactate dehydrogenase levels, hyperbilirubinemia and an elevated erythrocyte sedimentation rate may also be present.

If babesiosis is suspected, microscopic examination of blood smears should be pursued. Giemsa or Wright stains are typically used. DNA of Babesia can also be detected by polymerase chain reaction (PCR) in cases where smears are negative but the diagnosis is still suspected.


Combination therapy with atovaquone (Mepron) and azithromycin is most commonly recommended for treatment of mild to moderate babesiosis. Treatment is usually continued for 7-10 days.
Doxycycline + Plaquenil ( occasionally with Bactrim DS) with other antimalarian drugs, such as Malarone, and anti-malarian herbs can be effective.
Dapsone : is good for both: Babesia and Lyme disease
A combination regimen of oral clindamycin and quinine has also been proven effective, but the rate of adverse reactions is significantly higher with this combination, so it is not recommended for treatment of uncomplicated disease.

For patients with severe babesiosis, however, intravenous clindamycin and (oral) quinine is considered the preferred treatment, again for 7-10 days. In patients with underlying immunosuppression and persistent signs and symptoms, studies have shown an association between longer treatment duration and a positive outcome; therefore, treatment of these individuals should be continued for weeks or months until blood smears are negative for at least two weeks.