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close this bookWHO Recommended Surveillance Standards (WHO; 1999; 157 pages)
View the documentAcknowledgements
View the documentAcronyms
View the documentIntroduction
View the documentNational Coordination of Communicable Disease Surveillance
View the documentExplanatory notes
View the documentSurveillance activities: criteria and WHO Department
View the documentCommunicable disease contacts in Regional Offices
close this folderDiseases
View the documentB20-B21-B22-B23-B24 AIDS
View the documentA22 Anthrax
View the documentA23 Brucellosis
View the documentA00 Cholera
View the documentA81.0 Creutzfeldt-Jakob disease
View the documentA90, A91 Dengue fever (A90) including Dengue haemorrhagic fever (DHF) & Dengue shock syndrome (DSS, A91)
View the documentA36 Diphtheria
View the documentB72 Dracunculiasis (Guinea worm disease)
View the documentA98.3, A98.4 Ebola-Marburg viral diseases
View the documentA83.0 Japanese encephalitis
View the documentB74 Lymphatic filariasis
View the documentB96.3 Haemophilus influenzae type b
View the documentB15-B17 Acute viral hepatitis
View the documentB20-B24 HIV infection
View the documentJ10, J11 Influenza
View the documentA96.2 Lassa fever
View the documentA48.1 Legionellosis
View the documentB55.1, B55.2 Cutaneous leishmaniasis
View the documentLeishmania / HIV co-infections
View the documentB55.0 Visceral leishmaniasis
View the documentA30 Leprosy
View the documentA27 Leptospirosis
View the documentB50-54 Malaria
View the documentB05 Measles
View the documentA39 Meningococcal disease
View the documentA87 Viral meningitis
View the documentB73 Onchocerciasis
View the documentA37.0 Pertussis
View the documentA20 Plague
View the documentA36 Poliomyelitis
View the documentA82 Rabies
View the documentA02.0 Salmonellosis
View the documentB65 Schistosomiasis
View the documentA50-52 Syphilis
View the documentA33 Tetanus, neonatal
View the documentB56-0, B56-1 African trypanosomiasis
View the documentB57 American trypanosomiasis
View the documentA15-A19 Tuberculosis
View the documentA75.3 Scrub typhus
View the documentA95.9 Yellow fever
open this folder and view contentsSyndromes
View the documentAnnex 1 Software free and in the public domain
View the documentAnnex 2 Proposed surveillance definitions
View the documentAnnex 3 Role and use of Geographic Information Systems (GIS) and mapping for epidemiological surveillance
 

A27 Leptospirosis

RATIONALE FOR SURVEILLANCE

This zoonosis with worldwide distribution occurs seasonally in countries with a humid subtropical or tropical climate. It is often linked to occupation, sometimes in outbreaks. Feral and domestic animal species may serve as sources of infection with one of the Leptospira serovars. Infection is transmitted to humans through direct contact with (the urine of) infected animals or a urine-contaminated environment, mainly surface waters, soil and plants. The course of disease in humans ranges from mild to lethal. Leptospirosis is probably underreported in many countries because of difficult clinical diagnosis and lack of diagnostic laboratory services. Surveillance provides the basis for intervention strategies in human or veterinary public health.

RECOMMENDED CASE DEFINITION

Clinical description

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

 

• conjunctival suffusion
• meningeal irritation
• anuria or oliguria and/or proteinuria
• jaundice
• haemorrhages (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 include nausea, vomiting, abdominal pain, diarrhoea, arthralgia.

Laboratory criteria for diagnosis

 

• Isolation (and typing) from blood or other clinical materials through culture of pathogenic leptospires

• Positive serology, preferably Microscopic Agglutination Test (MAT), using a range of Leptospira strains for antigens that should be representative of local strains


Case classification

Suspected: A case that is compatible with the clinical description. Probable: 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.

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 must be investigated.

Routine reporting of aggregated data of confirmed cases from intermediate to central level. Hospital-based surveillance may give information on severe cases of leptospirosis. Serosurveillance may give information on whether leptospiral infections occur or not in certain areas or populations.

International: The International Leptospirosis Society* collects worldwide data:

Royal Tropical Institute (KIT), Department of Biomedical Research, NH Swellengrebel Laboratory, Meibergdreef 39,1105 AZ Amsterdam, The Netherlands

 

Tel: 31 20 566 5441
Fax: 31 20 697 1841
E-mail: r.hartskeerl@kit.nl
ILS home page: http://www.med.monash.edu.au/micro/department/adler/ilspage.htm

RECOMMENDED MINIMUM DATA ELEMENTS

Individual patient record for reporting and investigation

 

• Age, sex, geographical information, occupation
• Clinical symptoms (morbidity, mortality)
• Hospitalization (Y/N)
• History and place of exposure (animal contact, environment)
• Microbiological and serological data
• Date of diagnosis
• Rainfall, flooding

Aggregated data for reporting

 

• Number of cases
• Number of hospitalizations
• Number of deaths
• Number of cases by type (causative serovar/serogroup) of leptospirosis

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).

Frequency distribution of signs and symptoms by case and causative serovar (tables).

Reports of outbreaks, reports of preventive measures, surveillance of the human population and populations of feral and domestic animals.

PRINCIPAL USES OF DATA FOR DECISION-MAKING

 

• Assess the magnitude of the problem in different areas and risk groups/areas/conditions
• Identify outbreaks
• Identify animal sources of infection
• Monitor for emergence of leptospirosis in new areas and new risk (occupational) groups
• Design rational control or prevention methods
• Identify new serovars and their distribution
• Inform on locally occurring serovars for a representative range in the MAT

SPECIAL ASPECTS

Serology by Microscopic Agglutination Test (MAT) may provide presumptive information on causative serogroups. Attempts should be made to isolate leptospires, and isolates should be typed to assess locally circulating serovars.

Questioning the patient may provide clues to infection source and transmission conditions. Animal serology may give presumptive information on serogroup status of the infection Isolation followed by typing gives definite information on serovar.

CONTACT

Regional Offices

See Regional Communicable Disease contacts on section "Communicable disease contacts in Regional Offices".

Headquarters: 20 Avenue Appia, CH-1211 Geneva 27, Switzerland

Communicable Diseases Surveillance and Response (CSR)

 

E-mail: cosivio@who.ch / outbreak@who.ch
Tel: (41 22) 791 2531/4687/2111
Fax: (41 22) 791 4893/0746 attn CSR
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