The prevalence of African animal trypanosomoses and tsetse presence in Western Senegal

Abstract

(Mulligan, 1970) which is widespread in sub-Saharan Africa (Itard et al., 2003). AAT is Summary:In 2005, the Government of Senegal initiated a tsetse eradication campaign in the Niayes and La Petite Côte aiming at the removal of African Animal Trypanosomosis (AAT), which is one of the main constraints to the development of more effective cattle production systems. The target area has particular meteorological and ecological characteristics that provide great potential for animal production, but it is unfortunately still infested by the riverine tsetse species Glossina palpalis gambiensis Vanderplank (Diptera: Glossinidae). The tsetse project in Senegal has adopted an areawide integrated pest management (AW-IPM) approach that targets the entire tsetse population within a delimited area. During the first phase of the programme, a feasibility study was conducted that included the collection of entomological, veterinary, population genetics, environmental and socio-economic baseline data. This paper presents the parasitological and serological prevalence data of AAT in cattle residing inside and outside the tsetse-infested areas of the target zone prior to the control effort. At the herd level, a mean parasitological prevalence of 2.4 % was observed, whereas a serological prevalence of 28.7 %, 4.4 %, and 0.3 % was obtained for Trypanosoma vivax, T. congolense and T. brucei brucei, respectively. The observed infection risk was 3 times higher for T. congolense and T. vivax in the tsetse-infested than in the assumed tsetse-free areas. Moreover, AAT prevalence decreased significantly with distance from the nearest tsetse captured which indicated that cyclical transmission of the parasites by tsetse was predominant over mechanical transmission by numerous other biting flies present. The importance of these results for the development of a control strategy for the planned AW-IPM campaign is discussed.

Ex-ante Benefit-Cost Analysis of the Elimination of a Glossina palpalis gambiensis Population in the Niayes of Senegal

“…Other studies included a parasitological base line data collection in the entire target area (2007) [12], a monitoring of the AAT incidence as of 2009, an environmental monitoring using various ecological indicators (as of 2010) [25], a socio-economic study including the ex-ante transversal study presented here, an assessment of farmer innovation trajectories and an ex-post transversal study planned in 2016.…”

“…Tsetse flies (Diptera: Glossinidae) are the vectors of human African trypanosomosis (HAT) and African animal trypanosomosis (AAT), the former a major neglected human tropical disease, and the latter considered among the greatest constraints to improved livestock production in sub-Saharan Africa [11]. Most domestic animals are susceptible to AAT which was until recently still highly prevalent in the Niayes area [12]. It was a major pathological problem especially for cattle crossed with exotic breeds and Gobra zebus which are very susceptible to trypanosomes.…”

Congopain genes diverged to become specific to Savannah, Forest and Kilifi subgroups of Trypanosoma congolense, and are valuable for diagnosis, genotyping and phylogenetic inferences

“…Differences regarding the development in tsetse fly of different species and in experimental (livestock and mice) and field-infected animals have been observed among T. congolense Savannah, Forest and Kilifi isolates, and also within Savannah isolates (Bengaly et al, 2002a,b;Masumu et al, 2006;Seck et al, 2010;Van den Bossche et al, 2011;Vitoulay et al, 2011;Moti et al, 2012). Evidence from this study showing that highly virulent (Savannah), moderate (Forest) and non-virulent (Kilifi) isolates differ in their CP2 gene repertoires deserve to be better investigated regarding the association of virulence with distinct enzymes.…”

Using species distribution models to optimize vector control in the framework of the tsetse eradication campaign in Senegal

“…In this area, the limits of the distribution of the tsetse target populations were assessed using a stratified entomological sampling frame based on remote sensing indicators (4). The only tsetse species present was Glossina palpalis gambiensis Vanderplank, and it was responsible for the cyclical transmission of three trypanosome species, namely Trypanosoma vivax, T. congolense, and T. brucei brucei, listed in order of importance (5). The high prevalence of animal trypanosomosis in the Niayes (serological prevalence of 28.7% for T. vivax) hampered peri-urban intensification of cattle production (particularly dairy cattle).…”