Case Presentation:

A 73‐year‐old white male with a PMH of hypertension presented with a 5‐ to 6‐month history of intermittent fevers. During the initial onset he noted low‐grade fevers which progressed to range from 101°F to 104°F in the week prior to admission. Other symptoms included lethargy, chills, and significant diaphoresis. The patient had an extensive remote travel history with visits to South America, the Panama Basin, and Eastern Europe. Within the past year his travel was limited to Ohio, Texas, and Connecticut. He was adequately immunized prior to international trips, but reported no prophylaxis in malaria endemic areas. On examination he was febrile to 103°F. His pulse was 81 BPM, blood pressure was 83/53 mm Hg, RR 18 per minute, and oxygen saturation was 100% while breathing ambient air. Cardiac, respiratory, abdominal, neurological, and dermatological exams were normal. ECG showed normal sinus rhythm. Pertinent laboratory values included: Hb 7 g/dL. platelet count 102,000/μL, AST 69U/L, total bilirubin 2 mg/dL, and LDH 670 units/L. Radiological imaging including chest x‐ray and computed tomography of the abdomen and pelvis were normal. The initial working diagnosis was an unknown infectious process. The patient was started on broad‐spectrum antibiotics. His cultures including blood and urine were negative after the first 24 hours. Taking into account patient anemia, fevers, and suggestive hemolysis on laboratory analysis, thick and thin peripheral blood smears were obtained. After evaluation, intracellular Maltese‐cross bodies were identified in erythrocytes. Clinical management for babesiosis was initiated with atovaquone and azithromycin with resolution of symptoms.


Babesiosis is caused by the intra erythrocyte protozoa Babesia microti, endemic to the northern and midwestern United States. Its usual hosts are vertebrate animals, but it may infect humans through the Ixodes tick vector. Symptoms vary from chronic intermittent fevers to fulminant multiorgan failure. Hemolytic anemia and thrombocytopenia are commonly seen. Differential diagnoses include mycobacterial infections, spirochetal infections such as Lyme disease and ehrlichiosis, hematological malignancies, and malaria. Secondary malaria from the exoerythrocytic hepatic phase of Plasmodium vivax and Plasmodium ovale should be suspected, even several years after Travel To endemic regions, especially if the patient never received primaquine treatment. Diagnosis can usually be made by examination of thin blood smears that show pathognomonic merozoites arranged in the tetrads called Maltese crosses and pear‐shaped B microti protozoa. Other diagnostic tests include PCR‐based amplification of the protozoal rRNA gene and indirect immunofluorescent serologic testing.


This case highlights nonbacterial causes of chronic fevers that need to be kept in the differential diagnosis in patients with history of travel to different parts of Americas who are often under the care of hospitalists.

Author Disclosure:

H. Husseinzadeh, none; P. Mehta, none; S. Suri, none.