Babesiosis Babesiosis Babesiosis is an infection caused by a protozoa belonging to the genus, Babesia. The most common Babesia seen in the United States is B. microti, which is transmitted by the Ixodes tick. The protozoa thrive and replicate within host erythrocytes. Lysis of erythrocytes and the body's immune response result in clinical symptoms. Babesia/Babesiosis is an infection caused by a protozoa Protozoa Nitroimidazoles belonging to the genus, Babesia Babesia Babesiosis is an infection caused by a protozoa belonging to the genus, Babesia. The most common Babesia seen in the United States is B. microti, which is transmitted by the Ixodes tick. The protozoa thrive and replicate within host erythrocytes. Lysis of erythrocytes and the body's immune response result in clinical symptoms. Babesia/Babesiosis. The most common Babesia Babesia Babesiosis is an infection caused by a protozoa belonging to the genus, Babesia. The most common Babesia seen in the United States is B. microti, which is transmitted by the Ixodes tick. The protozoa thrive and replicate within host erythrocytes. Lysis of erythrocytes and the body's immune response result in clinical symptoms. Babesia/Babesiosis seen in the United States is B. microti B. microti A species of protozoa infecting humans via the intermediate tick vector ixodes scapularis. The other hosts are the mouse peromyscus leucopus and meadow vole microtus pennsylvanicus, which are fed on by the tick. Other primates can be experimentally infected with babesia microti. Babesia/Babesiosis, which is transmitted by the Ixodes tick. The protozoa Protozoa Nitroimidazoles thrive and replicate within host erythrocytes Erythrocytes Erythrocytes, or red blood cells (RBCs), are the most abundant cells in the blood. While erythrocytes in the fetus are initially produced in the yolk sac then the liver, the bone marrow eventually becomes the main site of production. Erythrocytes: Histology. Lysis of erythrocytes Erythrocytes Erythrocytes, or red blood cells (RBCs), are the most abundant cells in the blood. While erythrocytes in the fetus are initially produced in the yolk sac then the liver, the bone marrow eventually becomes the main site of production. Erythrocytes: Histology and the body’s immune response result in clinical symptoms. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship usually present with a flu-like illness and jaundice Jaundice Jaundice is the abnormal yellowing of the skin and/or sclera caused by the accumulation of bilirubin. Hyperbilirubinemia is caused by either an increase in bilirubin production or a decrease in the hepatic uptake, conjugation, or excretion of bilirubin. Jaundice. In severe cases, organ damage may occur. The diagnosis is confirmed by the visual presence of parasites within RBCs RBCs Erythrocytes, or red blood cells (RBCs), are the most abundant cells in the blood. While erythrocytes in the fetus are initially produced in the yolk sac then the liver, the bone marrow eventually becomes the main site of production. Erythrocytes: Histology, which are often noted to be in a “ Maltese Cross Maltese Cross Babesia/Babesiosis” configuration. Serological testing and PCR PCR Polymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules. Polymerase Chain Reaction (PCR) are also used in the diagnosis. Azithromycin Azithromycin A semi-synthetic macrolide antibiotic structurally related to erythromycin. It has been used in the treatment of Mycobacterium avium intracellulare infections, toxoplasmosis, and cryptosporidiosis. Macrolides and Ketolides and atovaquone Atovaquone A hydroxynaphthoquinone that has antimicrobial activity and is being used in antimalarial protocols. Antimalarial Drugs are often used in management. Coinfection with Borrelia Borrelia Borrelia are gram-negative microaerophilic spirochetes. Owing to their small size, they are not easily seen on Gram stain but can be visualized using dark-field microscopy, Giemsa, or Wright stain. Spirochetes are motile and move in a characteristic spinning fashion due to axial filaments in the periplasmic space. Borrelia and Anaplasma is common.
Last updated: Sep 3, 2025
For babesiosis Babesiosis Babesiosis is an infection caused by a protozoa belonging to the genus, Babesia. The most common Babesia seen in the United States is B. microti, which is transmitted by the Ixodes tick. The protozoa thrive and replicate within host erythrocytes. Lysis of erythrocytes and the body’s immune response result in clinical symptoms. Babesia/Babesiosis:
For severe disease:
Outside a human host:
Inside a human host:
Life cycle and transmission of Babesia
Image by Lecturio.The incubation Incubation The amount time between exposure to an infectious agent and becoming symptomatic. Rabies Virus period for babesiosis Babesiosis Babesiosis is an infection caused by a protozoa belonging to the genus, Babesia. The most common Babesia seen in the United States is B. microti, which is transmitted by the Ixodes tick. The protozoa thrive and replicate within host erythrocytes. Lysis of erythrocytes and the body’s immune response result in clinical symptoms. Babesia/Babesiosis is 1–4 weeks.
Mild-to-moderate disease:[2,4‒6]
Severe disease:[2,4‒6]
Epidemiology of infectious diseases is affected by location; therefore, diagnostic and treatment approaches may vary. The following information is based on sources from the US and Europe.
Peripheral blood smear demonstrating Babesia infection:
White arrow indicates pleomorphic, ring-like structures often found in Babesia infections. Black arrow shows the classic “Maltese Cross,” which is pathognomonic for babesiosis.
Blood smear showing RBCs infected with Babesia microti
Image: “Babesia microti” by U.S. Centers for Disease Control. License: Public DomainThe mainstay of treatment is antibiotics and educating individuals on preventive methods to avoid tick bites. Since babesiosis Babesiosis Babesiosis is an infection caused by a protozoa belonging to the genus, Babesia. The most common Babesia seen in the United States is B. microti, which is transmitted by the Ixodes tick. The protozoa thrive and replicate within host erythrocytes. Lysis of erythrocytes and the body’s immune response result in clinical symptoms. Babesia/Babesiosis is relatively rare in the United Kingdom, the following are based on U.S. recommendations:
Treatment indications | Adult dose | Pediatric dose |
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1st-line therapy for mild-moderate diseasea |
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1st-line therapy for severe diseasec |
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Alternative therapy for mild-moderate diseasea |
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Alternative therapy for severe diseasec |
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Precautions should be taken in endemic areas, particularly in individuals at risk for severe disease and complications.
The table below summarizes the characteristics of parasites that infect RBCs RBCs Erythrocytes, or red blood cells (RBCs), are the most abundant cells in the blood. While erythrocytes in the fetus are initially produced in the yolk sac then the liver, the bone marrow eventually becomes the main site of production. Erythrocytes: Histology.
Organism | Babesia Babesia Babesiosis is an infection caused by a protozoa belonging to the genus, Babesia. The most common Babesia seen in the United States is B. microti, which is transmitted by the Ixodes tick. The protozoa thrive and replicate within host erythrocytes. Lysis of erythrocytes and the body’s immune response result in clinical symptoms. Babesia/Babesiosis | Plasmodium Plasmodium A genus of protozoa that comprise the malaria parasites of mammals. Four species infect humans (although occasional infections with primate malarias may occur). These are plasmodium falciparum; plasmodium malariae; plasmodium ovale, and plasmodium vivax. Species causing infection in vertebrates other than man include: plasmodium berghei; plasmodium chabaudi; p. Vinckei, and plasmodium yoelii in rodents; p. Brasilianum, plasmodium cynomolgi; and plasmodium knowlesi in monkeys; and plasmodium gallinaceum in chickens. Antimalarial Drugs |
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Disease | Babesiosis Babesiosis Babesiosis is an infection caused by a protozoa belonging to the genus, Babesia. The most common Babesia seen in the United States is B. microti, which is transmitted by the Ixodes tick. The protozoa thrive and replicate within host erythrocytes. Lysis of erythrocytes and the body’s immune response result in clinical symptoms. Babesia/Babesiosis | Malaria Malaria Malaria is an infectious parasitic disease affecting humans and other animals. Most commonly transmitted via the bite of a female Anopheles mosquito infected with microorganisms of the Plasmodium genus. Patients present with fever, chills, myalgia, headache, and diaphoresis. Plasmodium/Malaria |
Microscopic appearance |
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Reservoir Reservoir Animate or inanimate sources which normally harbor disease-causing organisms and thus serve as potential sources of disease outbreaks. Reservoirs are distinguished from vectors (disease vectors) and carriers, which are agents of disease transmission rather than continuing sources of potential disease outbreaks. Humans may serve both as disease reservoirs and carriers. Escherichia coli | White-footed mouse |
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Transmission | Ixodes tick | Anopheles Anopheles A genus of mosquitoes (culicidae) that are known vectors of malaria. Plasmodium/Malaria mosquito |
Common regions |
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Clinical |
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Diagnosis |
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Management |
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Depends on species, severity, and
resistance
Resistance
Physiologically, the opposition to flow of air caused by the forces of friction. As a part of pulmonary function testing, it is the ratio of driving pressure to the rate of air flow.
Ventilation: Mechanics of Breathing patterns, but may include a combination of:
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Diagnosis Codes:
These codes are used by clinicians to officially record a diagnosis of babesiosis Babesiosis Babesiosis is an infection caused by a protozoa belonging to the genus, Babesia. The most common Babesia seen in the United States is B. microti, which is transmitted by the Ixodes tick. The protozoa thrive and replicate within host erythrocytes. Lysis of erythrocytes and the body’s immune response result in clinical symptoms. Babesia/Babesiosis, a tick-borne parasitic disease that infects red blood cells Red blood cells Erythrocytes, or red blood cells (RBCs), are the most abundant cells in the blood. While erythrocytes in the fetus are initially produced in the yolk sac then the liver, the bone marrow eventually becomes the main site of production. Erythrocytes: Histology, for inclusion in medical records and for public health surveillance Surveillance Developmental Milestones and Normal Growth.
Domain | Code | Description |
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ICD-10-CM | B60.0 | Babesiosis Babesiosis Babesiosis is an infection caused by a protozoa belonging to the genus, Babesia. The most common Babesia seen in the United States is B. microti, which is transmitted by the Ixodes tick. The protozoa thrive and replicate within host erythrocytes. Lysis of erythrocytes and the body’s immune response result in clinical symptoms. Babesia/Babesiosis |
ICD-11 | 1F55 | Babesiosis Babesiosis Babesiosis is an infection caused by a protozoa belonging to the genus, Babesia. The most common Babesia seen in the United States is B. microti, which is transmitted by the Ixodes tick. The protozoa thrive and replicate within host erythrocytes. Lysis of erythrocytes and the body’s immune response result in clinical symptoms. Babesia/Babesiosis |
SNOMED CT | 60169009 | Babesiosis Babesiosis Babesiosis is an infection caused by a protozoa belonging to the genus, Babesia. The most common Babesia seen in the United States is B. microti, which is transmitted by the Ixodes tick. The protozoa thrive and replicate within host erythrocytes. Lysis of erythrocytes and the body’s immune response result in clinical symptoms. Babesia/Babesiosis (disorder) |
Evaluation & Workup:
These codes are used to order and bill for the specific diagnostic tests Diagnostic tests Diagnostic tests are important aspects in making a diagnosis. Some of the most important epidemiological values of diagnostic tests include sensitivity and specificity, false positives and false negatives, positive and negative predictive values, likelihood ratios, and pre-test and post-test probabilities. Epidemiological Values of Diagnostic Tests required to identify the Babesia Babesia Babesiosis is an infection caused by a protozoa belonging to the genus, Babesia. The most common Babesia seen in the United States is B. microti, which is transmitted by the Ixodes tick. The protozoa thrive and replicate within host erythrocytes. Lysis of erythrocytes and the body’s immune response result in clinical symptoms. Babesia/Babesiosis parasite, such as a microscopic examination of a peripheral blood smear Peripheral Blood Smear Anemia: Overview and Types or a more sensitive PCR PCR Polymerase chain reaction (PCR) is a technique that amplifies DNA fragments exponentially for analysis. The process is highly specific, allowing for the targeting of specific genomic sequences, even with minuscule sample amounts. The PCR cycles multiple times through 3 phases: denaturation of the template DNA, annealing of a specific primer to the individual DNA strands, and synthesis/elongation of new DNA molecules. Polymerase Chain Reaction (PCR) test.
Domain | Code | Description |
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CPT | 85060 | Blood smear Blood smear Myeloperoxidase Deficiency, peripheral, interpretation by physician with written report |
CPT | 87207 | Smear, primary source with interpretation; special stain for inclusion bodies or parasites |
CPT | 87798 | Infectious agent detection by nucleic acid ( DNA DNA A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine). DNA Types and Structure or RNA RNA A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. RNA Types and Structure), not otherwise specified |
LOINC | 34509-5 | Babesia Babesia Babesiosis is an infection caused by a protozoa belonging to the genus, Babesia. The most common Babesia seen in the United States is B. microti, which is transmitted by the Ixodes tick. The protozoa thrive and replicate within host erythrocytes. Lysis of erythrocytes and the body’s immune response result in clinical symptoms. Babesia/Babesiosis microti DNA DNA A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine). DNA Types and Structure [Presence] in Blood by NAA with probe Probe A device placed on the patient’s body to visualize a target Ultrasound (Sonography) detection |
Procedures/Interventions:
These codes are used to document and bill for a red blood cell exchange transfusion, a critical intervention used only in severe cases of babesiosis Babesiosis Babesiosis is an infection caused by a protozoa belonging to the genus, Babesia. The most common Babesia seen in the United States is B. microti, which is transmitted by the Ixodes tick. The protozoa thrive and replicate within host erythrocytes. Lysis of erythrocytes and the body’s immune response result in clinical symptoms. Babesia/Babesiosis to rapidly reduce the number of infected red blood cells Red blood cells Erythrocytes, or red blood cells (RBCs), are the most abundant cells in the blood. While erythrocytes in the fetus are initially produced in the yolk sac then the liver, the bone marrow eventually becomes the main site of production. Erythrocytes: Histology.
Domain | Code | Description |
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CPT | 36514 | Therapeutic apheresis; for red blood cell exchange |
ICD-10-PCS | 6A550Z5 | Pheresis of Red Blood Cells Red blood cells Erythrocytes, or red blood cells (RBCs), are the most abundant cells in the blood. While erythrocytes in the fetus are initially produced in the yolk sac then the liver, the bone marrow eventually becomes the main site of production. Erythrocytes: Histology, Single Episode |
Medications:
These codes are used to prescribe the combination antimicrobial therapy, such as atovaquone Atovaquone A hydroxynaphthoquinone that has antimicrobial activity and is being used in antimalarial protocols. Antimalarial Drugs and azithromycin Azithromycin A semi-synthetic macrolide antibiotic structurally related to erythromycin. It has been used in the treatment of Mycobacterium avium intracellulare infections, toxoplasmosis, and cryptosporidiosis. Macrolides and Ketolides, that is required to eliminate the Babesia Babesia Babesiosis is an infection caused by a protozoa belonging to the genus, Babesia. The most common Babesia seen in the United States is B. microti, which is transmitted by the Ixodes tick. The protozoa thrive and replicate within host erythrocytes. Lysis of erythrocytes and the body’s immune response result in clinical symptoms. Babesia/Babesiosis parasite from the patient’s bloodstream.
Domain | Code | Description |
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RxNorm | 37731 | Atovaquone Atovaquone A hydroxynaphthoquinone that has antimicrobial activity and is being used in antimalarial protocols. Antimalarial Drugs (ingredient) |
RxNorm | 18631 | Azithromycin Azithromycin A semi-synthetic macrolide antibiotic structurally related to erythromycin. It has been used in the treatment of Mycobacterium avium intracellulare infections, toxoplasmosis, and cryptosporidiosis. Macrolides and Ketolides (ingredient) |
RxNorm | 2592 | Clindamycin Clindamycin An antibacterial agent that is a semisynthetic analog of lincomycin. Lincosamides (ingredient) |
RxNorm | 9078 | Quinine Quinine An alkaloid derived from the bark of the cinchona tree. It is used as an antimalarial drug, and is the active ingredient in extracts of the cinchona that have been used for that purpose since before 1633. Quinine is also a mild antipyretic and analgesic and has been used in common cold preparations for that purpose. It was used commonly and as a bitter and flavoring agent, and is still useful for the treatment of babesiosis. Quinine is also useful in some muscular disorders, especially nocturnal leg cramps and myotonia congenita, because of its direct effects on muscle membrane and sodium channels. The mechanisms of its antimalarial effects are not well understood. Antimalarial Drugs (ingredient) |
ATC | P01AX06 | Atovaquone Atovaquone A hydroxynaphthoquinone that has antimicrobial activity and is being used in antimalarial protocols. Antimalarial Drugs |
Complications & Supportive Procedures:
These ICD-10 codes ICD-10 Codes Babesia/Babesiosis (Clinical) are used to document severe complications that can result from babesiosis Babesiosis Babesiosis is an infection caused by a protozoa belonging to the genus, Babesia. The most common Babesia seen in the United States is B. microti, which is transmitted by the Ixodes tick. The protozoa thrive and replicate within host erythrocytes. Lysis of erythrocytes and the body’s immune response result in clinical symptoms. Babesia/Babesiosis, such as hemolytic anemia Hemolytic Anemia Hemolytic anemia (HA) is the term given to a large group of anemias that are caused by the premature destruction/hemolysis of circulating red blood cells (RBCs). Hemolysis can occur within (intravascular hemolysis) or outside the blood vessels (extravascular hemolysis). Hemolytic Anemia (from the destruction of red blood cells Red blood cells Erythrocytes, or red blood cells (RBCs), are the most abundant cells in the blood. While erythrocytes in the fetus are initially produced in the yolk sac then the liver, the bone marrow eventually becomes the main site of production. Erythrocytes: Histology), ARDS, and kidney failure.
Domain | Code | Description |
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ICD-10-CM | D59.1 | Other autoimmune hemolytic anemias |
ICD-10-CM | J80 | Acute respiratory distress syndrome Acute Respiratory Distress Syndrome Acute respiratory distress syndrome is characterized by the sudden onset of hypoxemia and bilateral pulmonary edema without cardiac failure. Sepsis is the most common cause of ARDS. The underlying mechanism and histologic correlate is diffuse alveolar damage (DAD). Acute Respiratory Distress Syndrome (ARDS) |
ICD-10-CM | N17.9 | Acute kidney failure, unspecified |
ICD-10-CM | R57.1 | Hypovolemic shock Hypovolemic Shock Types of Shock |