An atlas of tsetse and bovine trypanosomosis in Sudan

Abstract

BackgroundAfter a long period of neglect, initiatives are being implemented in Sudan to control tsetse and trypanosomosis. Their planning, execution and monitoring require reliable information on the geographic distribution of the disease and its vectors. However, geo-referenced and harmonized data at the national level are lacking, despite the fact that a number of epidemiological studies were conducted over the years. The Atlas of tsetse and bovine trypanosomosis in Sudan tries to fill this gap.MethodsThe present study includes both a review of historical datasets on tsetse flies and bovine trypanosomosis, as well as the results of recent, targeted field investigations. The review includes both published and unpublished datasets collected in Sudan from 1960 onwards. Targeted field investigations were conducted for trypanosomosis in Blue Nile (2011) and Gezeira States (2012), for tsetse flies in South Darfur (2012) and Blue Nile States (2009 and 2011), and for other trypanosomosis vectors in seven States (Khartoum, Gezeira, White Nile, Blue Nile, North Kordofan, Kassala and Gadarif). The latter surveys, conducted from 2010 to 2012, also enabled us to confirm the absence of tsetse flies in a number of locations.ResultsTsetse fly infestation in Sudan appears to be limited to two relatively small areas at the south-western and south-eastern tips of the Country (South Darfur and Blue Nile State respectively). Glossina morsitans submorsitans is present in both areas, whilst G. fuscipes fuscipes is found only in the latter. In contrast, bovine trypanosomosis is widespread, its presence having being confirmed in eleven States and suspected in all the others. Both mechanical transmission by non-cyclical vectors and animal movement contribute to this broad distribution of trypanosomosis. This is especially the case for Trypanosoma vivax, which was found even in sedentary cattle at hundreds of kilometres of the tsetse belt.ConclusionsThe Atlas provides a spatially-explicit synthesis of the current knowledge of tsetse and bovine trypanosomosis in Sudan. Its various epidemiological outputs are being used to target both trypanosomosis control activities and further data collection exercises. Activities are ongoing to expand the Atlas to non-cyclical vectors and hosts other than cattle.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-016-1485-6) contains supplementary material, which is available to authorized users.

Spatial distribution and trypanosome infection of tsetse flies in the sleeping sickness focus of Zimbabwe in Hurungwe District

“…Human African trypanosomiasis infections contracted in Zimbabwe are diagnosed almost exclusively in Harare or abroad [8, 11], and it is reasonable to speculate that many cases may go undetected. Efforts must be made to bring capacities for sleeping sickness diagnosis closer to the endemic areas and therefore reduce the travel time to equipped health facilities [27, 30].…”

“…The Atlas will broadly follow the methodologies developed by the Food and Agriculture Organization of the United Nations (FAO) for the continental Atlas of tsetse flies and AAT [6, 7]. It will also draw upon the example of other national-level Atlases, such as the one recently developed in Sudan [8]. …”

The animal trypanosomiases and their chemotherapy: a review

“…This lack of definitive knowledge greatly hampers the implementation of surveillance and control strategies (Jones and Davila, 2001). Non-tsetse transmitted T. vivax infection in cattle is also recognized in parts of Africa, for example in regions of Ethiopia, Chad and Sudan (Ahmed et al 2016). Mechanical transmission of T. congolense has been shown under experimental conditions (Desquesnes and Dia, 2003) and can therefore not be excluded from contributing to its spread in Africa (Desquesnes et al 2009).…”

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“…Some species of trypanosomes, in particular T. vivax, can also be transmitted mechanically by other biting flies (most notably Tabanus and Stomoxys spp.) [6,7]. AAT affects ruminants, swine, camels, equines, and carnivores, but the heaviest burden on subsistence livestock keepers in sub-Saharan Africa is caused by bovine trypanosomosis [8].…”