Spotting the Spirochete: Rapid Diagnosis of Leptospirosis in Two Returned Travelers

Leptospirosis is a zoonosis caused by a ubiquitous spirochete of the genus Leptospira and is endemic to the tropics. Human infection occurs through contact with soil or water that has been contaminated with infected animal urine. Fresh water recreational activities (swimming, rafting, and kayaking) in contaminated lakes and rivers have been associated with infection, especially during flood stage. 1‐4 Prompt diagnosis and treatment are important in reducing the morbidity and mortality that can be associated with this illness. The most common method of diagnosis is a 4-fold rise in antibody titers; 5 however, this does not allow for a rapid diagnosis in the acute phase. Two cases were recently diagnosed at our facility with the aid of dark-field microscopy and subsequently confirmed by culture.We propose that this technique may be used effectively in the prompt detection of spirochetes, leading to timely management decisions. Case 1: A 35-year-old white female spent 3 weeks traveling in Ecuador. She spent 2 weeks kayaking in mountain streams at flood stage and the following week kayaking on the coast. There she developed diarrhea that resolved with a short course of ciprofloxacin. Three weeks after returning to the United States, she presented with a 3-day history of fever, chills, nausea,vomiting,myalgias,and headache associated with new onset diarrhea and abdominal cramps. Her initial examination was remarkable only for right upper and lower abdominal tenderness. Her laboratory studies are summarized in the Table. She was empirically treated with oral ciprofloxacin and sent home. She returned to the clinic the following day with persistent symptoms,intense headache, fever, facial flushing, bilateral conjunctival suffusion, and a tense abdomen. A lumbar puncture revealed normal cerebrospinal fluid (CSF). As she now appeared ill, she was admitted to the hospital and treated empirically with intravenous (IV) ampicillin and levofloxacin. Blood cultures that were obtained at the clinic visit were processed for dark-field microscopy by the centrifugation procedure described in the 7th edition of the Manual of Clinical Microbiology. 6 Three of the four blood cultures had visible spirochetes. The residual pellet was inoculated to Fletcher’s medium for culturing leptospira. Meanwhile, the patient was continued on IV ampicillin and supportive care. Her symptoms resolved within 2 days and she was discharged to home on day 3 with amoxicillin. Case 2: A 36-year-old white female had had a neardrowning experience with extensive ingestion of fresh water while she was white-water rafting in Costa Rica. Tw elve days after returning to the United States, she presented as an outpatient with high fevers, chills, myalgias, nausea, and right upper quadrant abdominal pain. After obtaining blood for testing (including cultures for Leptospira spp), she was treated with oral doxycycline. Two days later, her symptoms persisted and she presented to the emergency room. She appeared ill and was unable to tolerate oral antibiotics. She was subsequently admitted and treated with IV doxycycline. Her laboratory results are also summarized in the Table. Her blood was also processed for dark-field microscopy and was found to be positive for spirochetes. These results were reported to the clinicians within 5 hours of the request. She was continued on IV doxycycline and discharged on the third day with a 3-week course of oral doxycycline.