Field observations on the use of rapid diagnostic tests for Human African Trypanosomiasis in Nigeria

Introduction Human African Trypanosomiasis (HAT) is a Neglected Tropical Disease targeted for elimination by 2030. Control efforts have reduced prevalence, but diagnostic challenges for field surveillance persist. Rapid Diagnostic Test kits (RDTs), used as frontline diagnostic tools for field surveillance, are often based on Variant Surface Glycoproteins (VSGs), which undergo constant mutations and exhibit considerable geographical diversity. Some VSGs are absent in Cameroon and Nigerian trypanosome strains/isolates. Method This study evaluated the reliability of HAT RDTs using human and animal blood samples from Nigeria. Seropositive samples from ELISA and CATT were tested with Abbott Bioline HAT 2.0 RDT. Result All ELISA and CATT seropositive human samples tested negative on the RDT, whereas two seropositive animal samples were positive on the RDT. The animal samples were positive on the test line 1, which is the ISG 65. This implies that the RDT kit was unable to detect seropositive samples from Nigeria, and therefore raises concerns about the reliability/suitability of this RDT for HAT field surveillance in Nigeria. Conclusion This study emphasizes the importance of incorporating diverse Trypanosoma strains into RDT development and ensuring validation across all endemic areas for effective field surveillance and disease control.