A27 Leptospirosis |
RATIONALE FOR SURVEILLANCE Leptospirosis is a zoonosis with a world-wide distribution. It occurs most frequently in countries with a humid subtropical or tropical climate, often seasonally, often linked to certain occupations, sometimes in outbreaks. A wide variety of feral and domestic animal species may serve as sources of infection with one of the many Leptospira serovars. The infection is transmitted to humans by direct contact with (the urine of) infected animals or a urine-contaminated environment, mainly surface waters, soil and plants. The course of the disease in humans ranges from mild to lethal. Leptospirosis is probably overlooked and underreported in many countries due to the difficult clinical diagnosis and the lack of diagnostic laboratory services. Surveillance provides the basis for intervention strategies in human or veterinary public health. |
RECOMMENDED CASE DEFINITION Clinical description An acute febrile illness with headache, myalgia and prostration associated with any of the following symptoms:
and a history of exposure to infected animals or an environment contaminated with animal urine. Other common symptoms: nausea, vomiting, abdominal pain, diarrhoea, arthralgia Laboratory criteria for diagnosis
Case classification Suspected: A case that is compatible with the clinical description Note: Leptospirosis is difficult to diagnose clinically in areas where diseases with symptoms similar to those of leptospirosis occur frequently. |
RECOMMENDED TYPES OF SURVEILLANCE Immediate
case-based reporting of suspected or confirmed cases from peripheral level (hospital
/general practitioner/laboratory) to intermediate level. All cases should be investigated. Comment: Serosurveillance may give information on whether leptospiral infections occur or not in certain areas or populations. |
RECOMMENDED MINIMUM DATA ELEMENTS. Individual patient record for reporting and investigation
Aggregated data for reporting
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RECOMMENDED DATA ANALYSES, PRESENTATION, REPORTS Number
of cases by age, sex, occupation, area, date of onset, causative serovars/serogroups,
(presumptive) infection source, transmission conditions (graphs, tables, maps). |
PRINCIPAL USES OF DATA FOR DECISION MAKING:
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SPECIAL ASPECTS Serology by MAT may provide presumptive information on causative serogroups. Attempts should be made at isolation of leptospires and isolates should be typed to
assess locally circulating serovars. |
CONTACT Headquarters WHO Division of Emerging and other Communicable Diseases Surveillance and Control
(EMC) |