A national atlas of tsetse flies and African animal trypanosomosis in Ghana

Abstract

Tsetse-transmitted African animal trypanosomosis (AAT) remains a widespread and major constraint to sustainable development and food security in vast areas of sub-Saharan Africa. In Ghana, like in most endemic countries, data on the occurrence of the tsetse vector and the disease are available at the country level, but for a long time information has been scattered and poorly harmonized, thus hampering proper analysis and evidence-based decision-making. The Tsetse and Trypanosomosis Control Unit (TTCU) in Ghana collated, harmonized, georeferenced and centralized in a single database (the ‘atlas’) all the available field data on tsetse and AAT occurrence for period 1992–2025. For the tsetse component, 3087 trapping records corresponding to 2864 trapping locations and 26,121 flies caught were included. For the AAT component, 740 herd-level records were assembled (393 survey sites and 26,653 tested animals). Both tsetse and AAT were found to be widespread in Ghana. Three of the 10 historically reported tsetse species were detected: Glossina tachinoides, G. palpalis, and G. morsitans. G. palpalis is the only one with a country-wide distribution, while G. tachinoides is more common in the northern part of the country and G. morsitans populations are smaller, more fragmented and mainly confined to protected areas. In the Upper West region, major tsetse control operations were carried out in 2010, whose gains in terms of reduction of fly densities seem to have been sustained over time. As regards animal trypanosomosis, almost 90% of the data were collected on cattle. The average prevalence of bovine trypanosomosis is 7.7% (825/10,766) with the buffy coat technique, which was used on over two thirds of the randomly selected samples. Predictably, higher prevalence was measured with more sensitive but less frequently used diagnostics, i.e. antibody enzyme-linked immunosorbent assay (Ab-ELISA) (22%, 720/3277) and polymerase chain reaction (PCR) (17%, 332/1949). The national atlas of tsetse and AAT in Ghana, already developed by 2018, was regularly updated ever since. It is now the pillar of data management for the TTCU, and it is used to measure and drive country progress along the progressive control pathway for AAT. The open data policy will also enable to maximize the atlas reuse and impact.