Screening

Active screening of the population is commonly applied in areas where cases of gambiense human African trypanosomiasis (HAT) are known, and is performed by specialised mobile teams applying a combination of immunological and parasitological tests.[Figure caption and citation for the preceding image starts]: Active screening for T b gambiense trypanosomiasis by a specialised mobile teamFrom the collection of Dr P.P. Simarro [Citation ends].com.bmj.content.model.Caption@7cc92937

Cases of gambiense HAT should be diagnosed early to prevent potentially fatal progression of HAT, and for control of the disease (human reservoir). Owing to its chronicity and relatively mild symptoms, first-stage gambiense HAT may go unnoticed. In order to reinforce disease surveillance, active screening is combined with passive screening in selected health facilities. Active screening for rhodesiense HAT is considered less effective because of the acuteness of the disease, the lack of simple serological tests, and animals being the main reservoir.

Population screening is based on Trypanosoma brucei gambiense-specific antibody detection in blood, followed by confirmatory parasitological examination for high specificity. The card agglutination test for trypanosomiasis (CATT) is mainly used in active screening. Individual rapid serodiagnostic tests are mainly used for passive case detection.[39][40] Depending on the setting, different test algorithms (different cut-off for CATT, screening by CATT or rapid diagnostic tests, combinations of parasitological tests, etc.) are in use.​[35][46][118][119]

Increasing surveillance has led to a 93% reduction (from 9875 to 675) in new cases of gambiense HAT reported between 2009 and 2023.[4]​​​​ Repeated large-scale serological screening, followed by effective treatment, can reduce transmission in a short time.[120]

The World Health Organization aims to eliminate gambiense HAT by 2030.[121][122]​​

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