Leptospirosis is frequently misdiagnosed as a result of its protean and nonspecific presentation. Leptospirosis, a zoonosis with global distribution, commonly occurs in tropical and subtropical regions; most reported cases in the United States occur in Hawaii. All laboratory-confirmed leptospirosis cases in the State of Hawaii from 1974 through 1998 (n=353) were clinically evaluated. The most common presentation involved nonspecific signs or symptoms, including fever, myalgia, and headache. Jaundice occurred in 39% of cases; conjunctival suffusion was described in 28% of these cases. Initiation of antibiotics before the seventh day of symptoms was associated with a significantly shortened duration of illness. Because early recognition and initiation of antibiotic therapy are important, clinicians should familiarize themselves with the clinical presentation of leptospirosis, and when evaluating a patient with a febrile illness, they should obtain exposure and travel histories and entertain the possibility of leptospirosis in the differential diagnosis.

An assay device for the rapid detection of Leptospira-specific immunoglobulin M (IgM) antibodies in human sera is presented. The sensitivity (85.8%) and specificity (93.6%) of the assay compared well (91.9% agreement) with those of an IgM enzyme-linked immunosorbent assay routinely used in the serodiagnosis of leptospirosis. The sensitivity of the assay varied with the stage of the disease. The assay uses stabilized components and is simply performed by the addition of serum and sample fluid to the sample well of the assay device. The assay is read after 10 min, and a positive result is obtained when staining of the test line is observed.As the clinical symptoms and signs of leptospirosis often are nonspecific, the disease is easily mistaken for other major infectious diseases. Manifestations of leptospirosis may vary, and different types of disease may be observed, from relatively mild influenza-like symptoms to severe disease with renal failure, liver impairment, and haemorrhage (Weil's syndrome). Meningismus and (aseptic) meningitis can be observed as well. Because of the wide variety of symptoms, leptospirosis is easily confused with many other fibril illnesses including haemorrhagic fevers, e.g., dengue fever (7). Laboratory testing to confirm the clinical diagnosis thus is essential for optimal treatment and patient management. The laboratory diagnosis of leptospirosis mainly depends on serology (8). The microscopic agglutination test (MAT) (5, 31) is considered the reference test for leptospirosis, but the enzyme-linked immunosorbent assay (ELISA) (2, 15-17, 19, 32, 34, 36) and a number of other tests including the immunofluorescent-antibody test (IFAT) (3), the slide agglutination test (9), the macrocapsule agglutination test (4), and the hemagglutination test (13,28,29) can be used as well. Drawbacks of the standard diagnostic assays like MAT, ELISA, and IFAT are that they are not very easy to perform, require special and expensive equipment, depend on the availability of electricity and refrigeration, or can be applied only by trained personnel. Hence, these assays are available only in a few specialized laboratories. MAT, which is considered the reference test for leptospirosis, is rarely performed by routine diagnostic laboratories.Leptospirosis has been reported from countries all over the world (1). Sporadic cases of leptospirosis may occur in countries with moderate climates. The disease, however, can be endemic in countries with wet and warm climates. People living under poor socioeconomical and hygienic conditions are at particular risk of getting the disease. Outbreaks have been reported (6, 11, 12, 14, 20-23, 27, 30, 33). Most people at risk cannot depend on health care facilities supported by laboratories capable of performing the more complicated standard laboratory assays. We previously developed a dipstick assay for the detection of Leptospira-specific immunoglobulin M (IgM) antibodies in human sera (10,20,(24)(25)(26)35). This assay can be used outside the specialized laboratory and may e...

Leptospirosis is a major public health problem throughout the world. Clinical recognition of leptospirosis is challenging, and the definitive serologic diagnostic assay, the microscopic agglutination test, is timeconsuming and difficult to conduct. Various serologic screening tests have been developed, but their performance among ill persons in the United States has not been established. Eight screening tests were compared using 379 serum samples obtained in 1998 and 1999 from a series of 236 patients (33 with confirmed infection). The median number of days between illness onset and specimen collection was 9. The overall sensitivity, by specimen, for each test was as follows: indirect hemagglutination assay (MRL Diagnostics, Cypress, Calif.), 29%; INDX Leptospira Dip-S-Tick (PanBio InDx, Inc., Baltimore, Md.), 52%; Biognost IgM IFA test (Bios GmbH Labordiagnostik, Gräfelfing, Germany), 40%; Biolisa IgM ELISA (Bios GmbH, Labordiagnostik), 48%; Leptospira IgM ELISA (PanBio Pty Ltd., Brisbane, Australia), 36%; SERION ELISA classic Leptospira (Institut Virion•Serion GmbH, Würzburg, Germany), 48%; LEPTO Dipstick(Organon-Teknika, Ltd., Amsterdam, The Netherlands), 34%; Biosave latex agglutination test (LATEX; Bios GmbH Labordiagnostik), 86%. Test specificity ranged from 85 to 100% among all tests except LATEX, for which the specificity was significantly lower, at 10%. Test sensitivity was particularly low (<25%) for all tests (except LATEX) on specimens collected during the first week of illness. This is the most comprehensive field trial of leptospirosis screening tests reported to date. The data indicate that immunoglobulin M detection tests have limited utility for diagnosing leptospirosis during the initial evaluation of patients seen in Hawaii, a time when important therapeutic decisions are made. Improved leptospirosis screening tests are needed.