Severe babesiosis presenting as acute respiratory distress syndrome in an immunocompetent patient.

Babesiosis is a tick-borne illness caused by the intraerythrocytic parasite Babesia microti. Adult respiratory distress syndrome (ARDS) is a complication of B. microti infection and generally presents later in the course of the disease. We present a case of babesiosis presenting with ARDS. A 59-year-old male with history of hypertension and atrial fibrillation presented with one day of progressive shortness of breath. The patient returned from a trip to Massachusetts one day prior. On arrival to the emergency department (ED) the patient was noted to be febrile with tachycardia, tachypnea, and hypoxia and was intubated for respiratory failure. A computed tomography angiography (CTA) was negative for pulmonary embolism and showed bilateral infiltrates. The Berlin criteria for severe ARDS were met. Tick-borne illness was suspected and Wright-Giemsa stained thin blood smear confirmed the diagnosis of babesiosis. The patient was treated with atovaquone and azithromycin for seven days and was successfully extubated on day four of hospitalization. He continued to clinically improve and was discharged home four days later. The case highlights the importance of physicians being aware of the manifold ways in which babesiosis can manifest.