Babesiosis overview
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Diagnosis |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Ilan Dock, B.S.
Overview
Babesiosis is caused by apicomplexan parasitic organism within the genus Babesia. B. Microti and B. divergens are the two species of Babesia that have been frequently reported as parasitic within human populations. Babesia parasites reproduce in red blood cells, where they can be seen as cross-shaped inclusions (4 merozoites asexually budding but attached together forming a structure looking like a "Maltese Cross") and cause hemolytic anemia, quite similar to malaria.
Babesiosis is a vector-borne illness usually transmitted by ticks. Often referred to as "The Malaria of The North East," babesiosis is a worldwide distributed disease, reported within tick endemic regions such as Asia, Europe, the United States. Key endemic areas within the United States include the northeastern coastal region including islands off the coast of New York, Massachusetts, and Rhode Island.
The most potent risk factors in the development of Babesiosis are a combined effort between environment and season. Babesia parasites are transmitted via tick bites in tick-populated areas.
Historical Perspective
Babesiosis was originally reported by the Romanian scientist, Victor Babes, in 1888. The disease was investigated for its renown infection in domesticated animals and cattle. In 1957, the first human babesiosis infection was documented in a splenectomized, Yugoslavian patient. All patients observed with babesiosis had also undergone a splenectomy, it wasn't until 1969 that the infection was observed within a normal patient.
Pathophysiology
Babesia parasites reproduce in red blood cells, where they can be seen as cross-shaped inclusions (4 merozoites asexually budding but attached together forming a structure looking like a "Maltese Cross") and cause hemolytic anemia, quite similar to malaria.
Note that unlike the Plasmodium parasites that cause malaria, Babesia species lack an exo-erythrotic phase, so the liver is usually not affected.
Causes
Babesiosis is caused by apicomplexan parasitic organism within the genus Babesia. B. Microti and B. divergens are the two species of Babesia that have been frequently reported as parasitic within human populations.
Epidemiology and Demographics
Babesiosis is a vector-borne illness usually transmitted by ticks. Often referred to as "The Malaria of The North East," babesiosis is a worldwide distributed disease, reported within tick endemic regions such as Asia, Europe, the United States. Key endemic areas within the United States include the northeastern coastal region including islands off the coast of New York, Massachusetts, and Rhode Island. Cases have also been reported throughout the United States and Europe, though not as frequently as the United States, Northeastern coast. Reported cases have identified a median age of 62 years and a higher rate of infection amongst males. Other factors contributing the heightened infection rates are, tick activity by season, level of tick exposure, and an individual's medical history.
Risk Factors
The most potent risk factors in the development of Babesiosis are a combined effort between environment and season. Babesia parasites are transmitted via tick bites in tick-populated areas. Transmission occurs more frequently during the spring and summer in correlation with heightened periods of tick activity. Other risk factors include repeated exposure to the following potential I. scapularis and Ixodes rodent hosts; white-footed deer mice, rats, voles, chipmunks, and field mice; As well as blood transfusions from donors living within endemic areas.
Natural History, Complications and Prognosis
Babesiosis causes a disease very similar to Malaria. In mild cases, people may experience mild fevers and anemia. In more severe cases, fevers go up to 105 degrees with shaking chills, and anemia (hemolytic anemia) can become severe. Organ failure may follow including adult respiratory distress syndrome.
Diagnosis
History and Symptoms | Physical Examination | Laboratory Findings | Other Imaging Findings | Other Diagnostic Studies
A wide range of physical findings may be associated with patients suffering from babesiosis. Asymptomatic patients will generally appear healthy without any external signs of infection. However physical examination findings are variable depending on the severity of the infection as well as the patient’s medical history. For patients exhibiting symptoms apparent during physical examination, the most common physical findings may range from a moderate fever and minor display of flu-like symptoms to Hepatomegaly, Petechiae, Ecchymoses and Acute respiratory distress syndrome (ARDS).
Treatment
Medical Therapy | Primary Prevention | Secondary Prevention | Cost-Effectiveness of Therapy | Future or Investigational Therapies
The mainstay of therapy for babesiosis is antimicrobial therapy. Patients with mild or moderate disease are treated with a combination of Atovaquone and Azithromycin. Patients with severe disease are treated with either Clindamycin or Clindamycin and Quinine. In life-threatening cases, exchange transfusion is performed.
Case Studies