An acute febrile illness with headache, myalgia and prostration associated with any of the following symptoms:

• conjunctival suffusion
• meningeal irritation
• an-/oliguria and/or proteinuria
• jaundice
• hemorrhages (from the intestines, lung bleeding is notorious in some areas)
• cardiac arrhythmia or failure
• skin rash

and a history of exposure to infected animals or an environment contaminated with animal urine. Other common symptoms: nausea, vomiting, abdominal pain, diarrhea, arthralgia.

Laboratory criteria for diagnosis

• Isolation (and typing) from blood or other clinical materials by culture of pathogenic leptospires
• Positive serology preferably by the Microscopic Agglutination Test (MAT) using a panel of Leptospira strains for antigens that, ideally, is representative of the locally occurring strains

Case classification

Suspected - a case that is compatible with the clinical description
Probably - not applicable
Confirmed - a suspect case that is confirmed in a competent laboratory

Note: Leptospirosis is difficult to diagnose clinically in areas where diseases with symptoms similar to those of leptospirosis occur frequently.

WHO Division of Emerging and other Communicable Diseases Surveillance and Control (EMC), 20 Avenue Appia, CH-1211 Geneva 27, Switzerland
E-mail: cosivio@who.ch  
outbreakemc@who.ch
Tel: (41 22) 791 2531 / 4687 / 2111
Fax: (41 22) 791 4893 / 0746 attn EMC

The International Leptospirosis Society (ILS)

Rudy Hartskeerl (Secretary), Department of Biomedical Research, NH Swellengrebel Laboratory, Meibergdreef 39, 1105 AZ Amsterdam, The Netherlands
E-mail: bo@mail.support.nl
Tel: (31 20) 566 5441
Fax: (31 20) 697 1841
Home page ILS: http://www.monash.edu.au/informatics/micro/department/ilspage.htm