Leptospirosis is endemic in both urban and rural areas of Sri Lanka and there had been many out breaks in the recent past. Two thousand one hundred and eighty seven cases were reported in 2007 in Sri Lanka while 147 cases were reported from the Kandy District.
Confirmation of leptospirosis in a patient requires serological tests, which become positive usually after 7 days of the illness . Direct microscopic visualization of blood is of value only during the first few days of the acute illness, when leptospiremia occurs.
Dark-field microscopic examination of body fluids such as blood, urine, CSF, and dialysate fluid has been used, but is both insensitive and lacks specificity. The drawbacks of dark-field microscopy on clinical specimens as a diagnostic tool have been that both false positive and false negative diagnosis can be easily made even in experienced hands. Therefore it is unhelpful in the management of patients, as the treatment should begin as early as possible preferably within 5 days to prevent complications. If the patient is not treated for the severe form within 2–3 days after the onset of illness, it may progress in severity and sometimes be fatal. The beginning of early pertinent antimicrobial therapy within 4–5 days after the onset of illness, proper supportive therapy and use of dialysis to treat renal failure has reduced the leptospirosis-related mortality. Therefore clinical criteria have to be employed to screen patients and to decide on treatment.
Medical professionals, especially primary care physicians, who are primarily responsible for the diagnosis and treatment, need to know about the early symptoms and signs, and early clinical laboratory findings.
Validation of clinical criteria using microscopic agglutination test as the gold standard has been done in 1995 by Brato and colleagues in the Philippine General Hospital , but such a study has not been conducted in Sri Lanka. This study was aimed at validating the leptospirosis surveillance case definition, using a Microscopic Agglutination Test (MAT) titre of ≥ 1:800 to confirm leptospirosis.