Prospective Evaluation of the Specificity of Serological Tests for Human African Trypanosomiasis in Côte d'Ivoire and Guinea

In the last decade, the prevalence of Trypanosoma brucei gambiense (Tbg) human African trypanosomiasis (HAT) has fallen and HAT has been targeted for transmission interruption by 2030. To achieve this goal, disease surveillance remains essential and is based on the identification of cases after screening carried out in the field with a serological test.

The SpeSerTryp study is a prospective evaluation of the specificity of serological field tests for the diagnosis of HAT in Côte d'Ivoire and Guinea. Since the prevalence of HAT is low in these countries, sensitivity will not be assessed.

The main objective is to evaluate and compare the specificity of 5 serological field tests: Bioline HAT 2.0 (Abbott, South Korea), HAT Sero-K-SeT & HAT 2.0 Sero-K-SeT (Coris BioConcept, Belgium ), TDR DCN (USA), and the CATT/T.b. gambiense (Institute of Tropical Medicine Antwerp, Belgium). The secondary objectives are: 1° to assess the specificity of the 5 serological field tests according to malaria status; and 2° to compare the performance of immunological laboratory tests (trypanolysis, ELISA/T.b.gambiense, g-iELISA) and molecular laboratory tests (Trypanozoon RT-qPCR multiplex, SNP RT-qPCR and SHERLOCK) as reference tests to differentiate false positive subjects to serological field tests from subjects who had contact with Tbg. Specificity values will be determined against a composite reference test consisting of the most sensitive HAT parasitological methods. SpeSerTryp is a prospective study that will take place in the endemic health districts of Bonon and Sinfra in Côte d'Ivoire and in the endemic health districts of Forécariah, Dubréka and Boffa in Guinea. In each country, 500 participants will be actively recruited by mobile teams. The inclusion criteria are: Age greater than or equal to 10 years and obtaining signed informed consent. The exclusion criteria are: Severe anemia preventing blood sampling; serious illness preventing the obtaining of informed consent and participation in the study; or history of HAT. After obtaining informed consent, a venous blood sample will be taken (6 mL). This specimen will be used to carry out the 5 serological tests for HAT, the RDT for malaria, and for participants with at least one of the 5 serological tests positive, parasitological confirmation of HAT and molecular and immunological laboratory tests . The duration of participant recruitment is estimated to be around 30 days, while laboratory analyses will take about 6 months. HAT cases identified during the study will be treated in accordance with current national guidelines.

This study will be conducted in accordance with the protocol, the current version of the Declaration of Helsinki, ICH-BPC E6/R2 guidelines, and all national legal and regulatory requirements.