The national atlas of tsetse flies and African animal trypanosomosis in Ethiopia

Abstract

Background With the largest cattle population in Africa and vast swathes of fertile lands infested by tsetse flies, trypanosomosis is a major challenge for Ethiopian farmers. Managing the problem strategically and rationally requires comprehensive and detailed information on disease and vector distribution at the national level. To this end, the National Institute for Control and Eradication of Tsetse and Trypanosomosis (NICETT) developed a national atlas of tsetse and African animal trypanosomosis (AAT) for Ethiopia. Methods This first edition of the atlas focused on the tsetse-infested areas in western Ethiopia. Data were collected between 2010 and 2019 in the framework of national surveillance and control activities. Over 88,000 animals, mostly cattle, were tested with the buffy-coat technique (BCT). Odour-enhanced traps were deployed in approximately 14,500 locations for the entomological surveys. Animal- and trap-level data were geo-referenced, harmonized and centralized in a single database. Results AAT occurrence was confirmed in 86% of the districts surveyed (107/124). An overall prevalence of 4.8% was detected by BCT in cattle. The mean packed cell volume (PCV) of positive animals was 22.4, compared to 26.1 of the negative. Trypanosoma congolense was responsible for 61.9% of infections, T. vivax for 35.9% and T. brucei for 1.7%. Four tsetse species were found to have a wide geographic distribution. The highest apparent density (AD) was reported for Glossina pallidipes in the Southern Nations, Nationalities and People's Region (SNNPR) (3.57 flies/trap/day). Glossina tachinoides was the most abundant in Amhara (AD 2.39), Benishangul-Gumuz (2.38), Gambela (1.16) and Oromia (0.94) regions. Glossina fuscipes fuscipes and G. morsitans submorsitans were detected at lower densities (0.19 and 0.42 respectively). Only one specimen of G. longipennis was captured. Conclusions The atlas establishes a reference for the distribution of tsetse and AAT in Ethiopia. It also provides crucial evidence to plan surveillance and monitor control activities at the national level. Future work on the atlas will focus on the inclusion of data collected by other stakeholders, the broadening of the coverage to tsetse-free areas and continuous updates. The extension of the atlas to data on control activities is also envisaged. Graphical Abstract

A Potential Entomological and Epidemiological Drivers for Reemergence of Human African Trypanosomiasis in Ethiopia after 55 Years

“…In particular, our study confirms that in the study zone two species of tsetse flies occur (i.e. G. pallidipes and G. fuscipes), and that T. vivax and T. congolense are the dominant species of trypanosomes circulating in cattle [42]. The overall apparent density of tsetse fly was found to be very much high (AD = 164.5) per trap per day which is in contrast to the study reported that less AD of tsetse fly was recorded in Benishangul Gumuz in Ethiopia [43].…”

A potential Entomological and epidemiological drivers for Reemergence of Human African Trypanosomiasis in Ethiopia after 55 Years

“…In particular, our study con rms that in the study zone two species of tsetse ies occur (i.e. G. pallidipes and G. fuscipes), and that T. vivax and T. congolense are the dominant species of trypanosomes circulating in cattle [42]. The overall apparent density of tsetse y was found to be very much high (AD = 164.5) per trap per day which is in contrast to the study reported that less AD of tsetse y was recorded in BenishangulGumuz in Ethiopia [43].…”

The elimination of human African trypanosomiasis: Monitoring progress towards the 2021–2030 WHO road map targets

“…These new cases were detected in the Southern Nations, Nationalities, and Peoples’ Region (SNNPR); more specifically, they were infected in Kucha Alfa, Denba Gofa and Melekoza districts (Gamo and Goffa zones respectively) [ 44 ]. These areas are known to be endemic for bovine trypanosomiasis [ 45 ].…”