Clinical Spectrum of Pulmonary Involvement in Leptospirosis in a Region of Endemicity, with Quantification of Leptospiral Burden

Of 633 consecutively enrolled febrile patients, 321 (50.7%) had antileptospiral IgM antibodies or high titers of antileptospiral antibodies. Seven patients with histories of only urban exposure to leptospires had severe pulmonary manifestations; of these, 5 patients died; 4 of the deaths were caused by pulmonary hemorrhage, and 1 was caused by acute respiratory distress syndrome and multiorgan failure. Real-time, quantitative PCR assay showed high levels of leptospiremia (>or=10(4) leptospires/mL) in most fatal cases; 1 patient, from whom tissue specimens were obtained at autopsy, had >or=10(5) leptospires/g of lung, kidney, and muscle tissue. DISCUSSION. This study demonstrates the underdiagnosis of leptospirosis in a region of high endemicity and the underrecognition of grave pulmonary complications. Pulmonary involvement in leptospirosis was present in urban but not rural areas. Presumptive treatment for leptospirosis should be initiated immediately in the appropriate epidemiological and clinical context.