The comprehensive epidemiological status of human African trypanosomiasis in Nigeria: meta-analysis and systematic review of the full story (1962–2022)

Human African trypanosomiasis (HAT) in Nigeria is caused primarily by Trypanosoma brucei gambiense (gHAT), which has historically been a major human and animal health problem. This study aims to examine the status of gHAT in Nigeria over the past 60 years. The World Health Organization (WHO) set two targets to eliminate HAT as a public health concern by 2020 and terminate its global transmission by 2030. The former target has been achieved, but accurate monitoring and surveillance are important for maintaining this success and delivering the second target. Although recent cases in Nigeria are rare, accurately estimating the national seroprevalence and actual prevalence of gHATs remains challenging. To address this, a meta-analysis reviewed studies on gHATs in Nigeria from databases such as Embase, Global Health, Ovid Medline, Web of Science, and Google Scholar. Ten studies were included, ranging between 1962 and 2016, covering 52 clusters and 5,671,877 individuals, even though databases were scrutinized up to 2022. The seroprevalence ranged from 1.75 to 17.07%, with an overall estimate of 5.01% (95% CI 1.72–9.93). The actual gHAT prevalence detected by parasitological or PCR methods was 0.001 (95% CI 0.000–0.002), indicating a prevalence of 0.1%. Notably, the seroprevalence was greater in southern Nigeria than in northern Nigeria. These findings suggest that the disease might be spreading unnoticed due to the increased movement of people from endemic areas. This study highlights the paucity of studies in Nigeria over the last 60 years and emphasizes the need for further research, systematic surveillance, and proper reporting methods throughout the country.