An atlas of tsetse and animal African trypanosomiasis in Zimbabwe

Abstract

Background In the 1980s and 1990s, great strides were taken towards the elimination of tsetse and animal African trypanosomiasis (AAT) in Zimbabwe. However, advances in recent years have been limited. Previously freed areas have been at risk of reinvasion, and the disease in tsetse-infested areas remains a constraint to food security. As part of ongoing control activities, monitoring of tsetse and AAT is performed regularly in the main areas at risk. However, a centralized digital archive is missing. To fill this gap, a spatially explicit, national-level database of tsetse and AAT (i.e. atlas) was established through systematic data collation, harmonization and geo-referencing for the period 2000–2019. Methods The atlas covers an area of approximately 70,000 km2, located mostly in the at-risk areas in the north of the country. In the tsetse component, a total of 33,872 entomological records were assembled for 4894 distinct trap locations. For the AAT component, 82,051 samples (mainly dry blood smears from clinically suspicious animals) were collected at 280 diptanks and examined for trypanosomal infection by microscopy. Results Glossina pallidipes (82.7% of the total catches) and Glossina morsitans morsitans (17.3%) were the two tsetse species recorded in the north and northwest parts of the country. No fly was captured in the northeast. The distribution of AAT follows broadly that of tsetse, although sporadic AAT cases were also reported from the northeast, apparently because of transboundary animal movement. Three trypanosome species were reported, namely Trypanosoma brucei (61.7% of recorded infections), Trypanosoma congolense (28.1%) and Trypanosoma vivax (10.2%). The respective prevalences, as estimated in sentinel herds by random sampling, were 2.22, 0.43 and 0.30%, respectively. Discussion The patterns of tsetse and AAT distributions in Zimbabwe are shaped by a combination of bioclimatic factors, historical events such as the rinderpest epizootic at the turn of the twentieth century and extensive and sustained tsetse control that is aimed at progressively eliminating tsetse and trypanosomiasis from the entire country. The comprehensive dataset assembled in the atlas will improve the spatial targeting of surveillance and control activities. It will also represent a valuable tool for research, by enabling large-scale geo-spatial analyses.

An Atlas to Support the Progressive Control of Tsetse-transmitted Animal Trypanosomosis in Burkina Faso

“…The methodology to develop the atlas of tsetse and AAT in Burkina Faso is broadly based on the FAO continental atlas [16][17][18], and a similar approach has already been used at the national level in Sudan [19], Mali [20], Kenya [21] and Zimbabwe [22]. The main difference between the continental and the national atlases is that the former is solely based on publicly available data from peer-reviewed journals, while the latter include all published or unpublished data collected in a given country.…”

Efficacy and Toxicity of Fexinidazole and Nifurtimox Plus Eflornithine in the Treatment of African Trypanosomiasis

“…Three clinical trial studies showed that the efficacy of NECT is non-inferior to standard eflornithine monotherapy [ 3 , 5 , 7 ]. In the clinical trial by Schmid et al, the primary outcome was the proportion of patients discharged alive from the hospital [ 12 ].…”

“…Three clinical trials defined cure rate as the absence of trypanosomes in the body fluids and leucocyte count less than 20 cells per μL 18 months after treatment [ 3 , 5 , 7 ]. While the study by Schmid et al, the primary outcome was the proportion of patients discharged from the hospital [ 12 ].…”

“…Annually, about 12,000 cases of sleeping sickness are reported; however, other reports suggest that the actual case count could be five times higher [ 2 ]. HAT is a protozoan parasitic infection that is classically transmitted by the blood-sucking tsetse flies by mainly three species of trypanosomes: Trypanosoma vivax , Trypanosoma congolense , and Trypanosoma gambiense [ 3 ]. The disease goes through two stages: the first is the hemolymphatic phase, which is effectively treated with pentamidine, and the second is the meningo-encephalitic stage.…”

Novel Trypanocidal Inhibitors that Block Glycosome Biogenesis by Targeting PEX3–PEX19 Interaction

“…Moreover, T. brucei has been verified as a valid model system for T. cruzi , for compounds targeting the PEX14 and PEX5 interaction ( Dawidowski et al, 2017 ). Last but not the least, animal infections of livestock (nagana) caused by T. congolense , T. vivax , and T. brucei species, leading to the annual loss of over 4 billion United States dollars are remaining great challenges ( Shereni et al, 2021 ). This demonstrates the importance of using T. brucei as the model organism for drug development.…”