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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
 

B56-0, B56-1 African trypanosomiasis

(Sleeping sickness)

RATIONALE FOR SURVEILLANCE

The leading principle for sleeping sickness control is the reduction of human reservoir through treatment of infected individuals and the reduction of man-fly contact through adapted vector control. An intercountry approach for surveillance/control activities is essential and supported by WHO. The objective of surveillance is the precise identification and proper epidemiological assessment of all endemic foci.

RECOMMENDED CASE DEFINITION

Clinical description

In the early stages, a painful chancre*, which originates as a papule and evolves into a nodule may be found at the primary site of tsetse fly bite. There may be fever, intense headache, insomnia, painless lymphadenopathy, anaemia, local oedema and rash. In the later stage, there is cachexia, somnolence and signs of central nervous system involvement. The disease may run a protracted course of several years in the case of Trypanosoma brucei gambiense. In case of T. b. rhodesiense, the disease has a rapid and acute evolution. Both diseases are always fatal without treatment.

 

*The painful chancre is very rare in T. b. gambiense infection.

Laboratory criteria for diagnosis

Presumptive: serological: card agglutination trypanosomiasis test (CATT) for T. b. gambiense only or immunofluorescent assay (IFA) for T. b. rhodesiense mainly and possibly for T. b. gambiense.

Confirmative: parasitological: detection (microscopy) of trypanosomes in blood, lymph nodes aspirates or CSF.

Case classification

Suspected: A case that is compatible with the clinical description and/or a history of exposure.**

Probable: A case with a positive serology with or without clinical symptoms in persons without previous history of trypanosomiasis diagnosis or treatment.

Confirmed: A case with positive parasitology, with or without clinical symptoms.***

 

** In the early stage or even early in the late stage of the disease there are often no clinical signs or symptoms which can be associated with the disease. Suspicion is then based on local risk of contracting the disease and local disease historical background.

*** Confirmed positive healthy carriers are a major public health risk. As a reservoir of parasites, they disseminate the disease, and must be treated as soon as possible.

RECOMMENDED TYPES OF SURVEILLANCE

• The surveillance system will use a village-based definition using 4 classes:

 

• Village of unknown epidemiological status
• Suspected village
• Endemic village
• Disease-free village

• In the context of control programmes, surveillance provides valuable village-based data, with the precise geographic location of each village using global positioning system (GPS). Data are analysed using geographical information systems (GIS)

• In areas not covered by control activities, surveillance provides valuable case-based information. Results of serological surveys based on micro-card agglutination trypanosomiasis tests (micro-CATT) will be indicators of endemicity

• Information collected at village level is aggregated at intermediate/central level and reported to WHO

RECOMMENDED MINIMUM DATA ELEMENTS

Village-based data

In addition to the number of parasitologically confirmed cases (presence of trypanosomes shown), and to the number of probable cases (suspected cases with positive serology), the system should include information on:

 

• strategy used
• village geographic coordinates (latitude, longitude)
• name
• administrative levels
• village type
• population at last census/date of last census, estimated population
• school (levels)
• health infrastructures (type, activities)
• protected sources of water

RECOMMENDED DATA ANALYSES, PRESENTATION, REPORTS

Mapping: at intermediate and central level: map of villages and their endemic status.

PRINCIPAL USES OF DATA FOR DECISION-MAKING

 

• Knowledge of endemic and suspected areas to direct control activities
• Epidemiological monitoring of endemic foci
• Assessing impact of control programmes

SPECIAL ASPECTS

 

• Use of Global Positioning System (GPS) to define village geographic coordinates
• Sensitivity of parasitological techniques is low and depends on laboratory facilities and personnel skills

CONTACT INFORMATION

WHO Regional Office for Africa (AFRO)

Dr A. Kabore, A/Director, Prevention and Control of Diseases (DDC)

 

Direct telephone 1 407 733 92 36,
fax 1 407 733 9009

Dr P. Lusamba, A/Regional Adviser, Emerging and other Communicable

Diseases Control (EMC)

 

Direct telephone: 1 407 733 9338, 26311 40 38 23
Fax: 1 407 733 9009
E-mail:

ADIKPETOE@WHO.ORG
LUSAMBAP@WHOAFR.ORG
SAMBAE@HTSD.COM at INET
ALEMUW@WHOAFR.ORG

Following the temporary closure of the AFRO office in Brazzaville, the above contact information may not be valid; a temporary office is available in Harare

 

Tel: 263 4 706 951/707 493
Fax: 2634 705619/702 044

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

Communicable Diseases Surveillance and Response (CSR)

 

E-mail: janninj@who.ch /Surveillancekit@who.ch
Tel: (41 22) 791 3779
Fax: (41 22) 791 4878
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