Case Presentation: A 38-year-old female with no significant PMH presented with diarrhea, chills, and hematuria. One week prior to admission, she developed profuse, watery, non-bloody diarrhea three hours after consuming raw oysters. The next day, she developed headache and chills. She presented to the ED four days prior to admission, treated with IVF, and discharged home. Symptoms continued until the morning of admission, when she developed dark red urine, and came to the ED. She denied any history of insect bites or recent travel. Vitals were significant for fever and tachycardia, with HR=120, T=103.2. On exam, patient was in visible distress with vomiting and rigors. Skin exam showed mottled skin over the extremities, with no other rashes appreciated. Labs were significant for hemolytic anemia and thrombocytopenia, with Hb=10.6, plt=79, LDH elevated at 1723, Haptoglobin < 3. A peripheral smear was negative for schistocytes. On further review of the smear using Giemsa stain, trophozoites consistent with babesiosis were found, with parasitemia of <1%. Patient was started on atovaquone and azithromycin. Babesia IgM and IgG were found to be negative, at titers < 1:16.  Initially, the patient’s anemia worsened (with a nadir Hb=6.6 on hospital day 2), requiring 3 units PRBCs.  Her anemia subsequently improved and her sepsis resolved. She was discharged home on hospital day 9.

Discussion: Babesiosis is a zoonotic illness caused by the protozoan Babesia (most commonly Babesia microti) and primarily transmitted via the Ixodes scapularis tick. Less commonly, infection can be transmitted via transfusion or transplacentally. Typically, symptoms develop approximately 1-6 weeks after exposure. Clinical presentation of the disease can range from asymptomatic infection to ARDS, acute CHF, renal failure, DIC, and death. Severe disease is more common in the elderly and immunocompromised. Symptoms typically begin with fever, fatigue, and malaise. Other clinical manifestations may include headache, neck stiffness, nausea/vomiting, diarrhea, and dark urine. Laboratory diagnosis consists of typical findings on blood smear, PCR, and serology. Serology can remain negative for over a week after development of symptoms. Wright or Giemsa staining reveals oval, round, or pear-shaped trophozoites characterized by light blue cytoplasm and often one or two dots of red chromatin. Merozoites arranged in tetrads, known as Maltese crosses, may also be seen. Mild-to-moderate disease is treated with atovaquone and azithromycin, while severe disease is typically treated with clindamycin and quinine. Exchange transfusion is performed in patients with parasitemia ≥10% and severe anemia, or with pulmonary, renal or hepatic impairment.

Conclusions: Babesiosis can present with severe, often nonspecific, symptoms. A high index of suspicion is required in endemic areas, as patients often do not endorse a history of insect bites, and, unlike in Lyme disease, there is no typical rash.