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Background African animal trypanosomosis (AAT), transmitted by tsetse flies, is arguably the main disease constraint to integrated crop-livestock agriculture in sub-Saharan Africa, and African heads of state and governments adopted a resolution to rid the continent of this scourge. In order to sustainably reduce or eliminate the burden of AAT, a progressive and evidence-based approach is needed, which must hinge on harmonized, spatially explicit information on the occurrence of AAT and its vectors. Methods A digital repository was assembled, containing tsetse and AAT data collected in Burkina Faso between 1990 and 2019. Data were collected either in the framework of control activities or for research purposes. Data were systematically verified, harmonized, georeferenced and integrated into a database (PostgreSQL). Entomological data on tsetse were mapped at the level of individual monitoring traps. When this was not possible, mapping was done at the level of site or location. Epidemiological data on AAT were mapped at the level of location or village. Results Entomological data showed the presence of four tsetse species in Burkina Faso. Glossina tachinoides, present from the eastern to the western part of the country, was the most widespread and abundant species (56.35% of the catches). Glossina palpalis gambiensis was the second most abundant species (35.56%), and it was mainly found in the west. Glossina morsitans submorsitans was found at lower densities (6.51%), with a patchy distribution in the southern parts of the country. A single cluster of G. medicorum was detected (less than 0.25%), located in the south-west. Unidentified tsetse flies accounted for 1.33%. For the AAT component, data for 54,948 animal blood samples were assembled from 218 geographic locations. The samples were tested with a variety of diagnostic methods. AAT was found in all surveyed departments, including the tsetse-free areas in the north. Trypanosoma vivax and T. congolense infections were the dominant ones, with a prevalence of 5.19 ± 18.97% and 6.11 ± 21.56%, respectively. Trypanosoma brucei infections were detected at a much lower rate (0.00 ± 0.10%). Conclusions The atlas provides a synoptic view of the available information on tsetse and AAT distribution in Burkina Faso. Data are very scanty for most of the tsetse-free areas in the northern part of the country. Despite this limitation, this study generated a robust tool for targeting future surveillance and control activities. The development of the atlas also strengthened the collaboration between the different institutions involved in tsetse and AAT research and control in Burkina Faso, which will be crucial for future updates and the sustainability of the initiative. Graphical Abstract

Background Tsetse flies are vectors of trypanosomes, parasites that cause devastating disease in humans and livestock. In the course of vector control programmes it is necessary to know about the Glossina species present in the study area, the population dynamics and the genetic exchange between tsetse fly populations. Results To achieve an overview of the tsetse fly diversity in Nigeria and at the Nigeria-Cameroon border, tsetse flies were trapped and collected between February and March 2014 and December 2016. Species diversity was determined morphologically and by analysis of Cytochrome C Oxidase SU1 (COI) gene sequences. Internal transcribed spacer-1 (ITS-1) sequences were compared to analyse variations within populations. The most dominant species were G. m. submorsitans, G. tachinoides and G. p. palpalis. In Yankari Game Reserve and Kainji Lake National Park, G. submorsitans and G. tachinoides were most frequent, whereas in Old Oyo National Park and Ijah Gwari G. p. palpalis was the dominant species. Interestingly, four unidentified species were recorded during the survey, for which no information on COI or ITS-1 sequences exists. G. p. palpalis populations showed a segregation in two clusters along the Cameroon-Nigerian border. Conclusions The improved understanding of the tsetse populations in Nigeria will support decisions on the scale in which vector control is likely to be more effective. In order to understand in more detail how isolated these populations are, it is recommended that further studies on gene flow be carried out using other markers, including microsatellites.

Objective Trypanosomosis is a disease of domestic animals and humans resulting from infection with parasitaemic protozoa of the genus Trypanosoma transmitted primarily by tsetse flies. A cross-sectional study was conducted from January-March 2018, to estimate the infection rate of trypanosome in Glossina tachinoides, their distribution, magnitude and involved trypanosome species in Limmu Kosa District of Jimma zone. Results Study methodology involved entomological survey using monoconical traps to study the magnitude of Fly density Flay/Trap/Day (FTD) and tsetse fly dissection to estimate infection rate of trypanosome in vector flies. The study result indicated that there was only one species of Tsetse fly Glossina tachinoides detected with FTD = 4.45. From the total of (n = 284) dissected Glossina tachinoides flies only (n = 5) positive for Trypanosome resulting in 1.76% Infection Rate. Peak trypanosome infections were observed in female tsetse 2.04%, n = 4 and 1.14%, n = 1 in males. Furthermore, 1.06% of Glossina tachinoides were infected by Trypanosome vivax and the remaining 0.70% was Trypanosome congolense. Finally, the study concluded with the recommendation of control and suppression of the vector and parasite was mandatory due to Pathogenic Animal Trypanosomosis.

Trois pyrethrinoides de synthese: OMS 2012 (BAY FCR 1272, cyfluthrine) p.m. 10%, OMS 2013 (BAY NAK 1654, fenfluthrine) p.m. 5%, OMS 3004 (WL 85871, alphamethrine) p.m. 5%, ont ete testes en janvier 1984 en epandage au sol contre G. palpalis palpalis et G. tachinoides dans le foyer de trypanosomiase humaine de Bouafle, Cote d’Ivoire. Pour chaque formulation de produit, deux doses ont ete essayees: 12 g.m.a./ha a une concentration de liquide epandu de 0,016% de matiere active; 48 g.m.a./ha a une concentration de 0,064% de matiere active. Six localites ont ete choisies pour les essais, chacune d’elles ayant ete traitee une seule fois avec une dose unique d’insecticide. Au total, 58 km lineaires de vegetation furent pulverises soit une surface d’environ 29 ha. Les traitements ont ete effectues a l’aide d’atomiseurs portaitifs type SOLO PORT 423 de 5 m de portee. L’evaluation des resultats a ete effectuee pendant 5 mois au moyen de pieges biconiques Challier-Laveissiere. L’OMS 2013 p.m. 5% a 12 g.m.a./ha, a eu un effet insuffisant sur G. palpalis palpalis et G. tachinoides a partir du premier mois apres traitement. A la dose de 48 g.m.a./ha et seulement durant les 3 premiers mois qui ont suivi les epandages, son effet sur ces deux vecteurs a ete modere avec des taux de reduction de la densite apparente par piegeage (D.A.P.) des populations vectrices compris entre 70 et 90%. L’OMS 2012 p.m. 10% a donne des resultats satisfaisants sur G. palpalis palpalis seulement a la dose de 48 g.m.a./ha et durant les 3 premiers mois qui ont suivi les epandages: 92% de reduction de la densite apparente de population 3 mois apres traitement. Sur G. tachinoides, cette formulation a 12 g.m.a./ha a eu un effet satisfaisant seulement durant les 2 premiers mois: 94% de reduction de la DA.P. de population 2 mois apres epandage. A la dose de 48 g.m.a./ha, l’effet de l’OMS 2012 sur l’insecte est demeure satisfaisant pendant toute la duree de l’evaluation avec un taux de reduction de la D.A.P. d’environ 90%, 5 mois apres traitement. L’OMS 3004 p.m. 5% a la dose de 12 g.m.a./ha a eu un effet satisfaisant sur G. palpalis palpalis seulement au cours des 3 premiers mois qui ont suivi le traitement: 97% de reduction de la D.A.P. 3 mois apres epandage. A la dose de 48 g.m.a./ha, l’OMS 3004 a ete la seule formulation a avoir donne des resultats satisfaisants sur ces glossines jusqu’a la fin de l’evaluation avec 91% de reduction de la D.A.P. 5 mois apres traitement. Sur G, tachinoides, l’effet de l’OMS 3004 a la dose de 12 g.m.a./ha a ete tres satisfaisant durant les 3 premiers mois: 99% de reduction 3 mois apres epandage. A la dose de 48 g.m.a./ha, cette formulation a permis d’obtenir 100% de reduction de la D.A.P. de G. tachinoides durant les 4 premiers mois et plus de 99% de reduction de cette D.A.P. 5 mois apres epandage.

Studying isolation by distance can provide useful demographic information. To analyze isolation by distance from molecular data, one can use some kind of genetic distance or coalescent simulations. Molecular markers can often display technical caveats, such as PCR-based amplification failures (null alleles, allelic dropouts). These problems can alter population parameter inferences that can be extracted from molecular data. In this simulation study, we analyze the behavior of different genetic distances in Island (null hypothesis) and stepping stone models displaying varying neighborhood sizes. Impact of null alleles of increasing frequency is also studied. In stepping stone models without null alleles, the best statistic to detect isolation by distance in most situations is the chord distance DCSE. Nevertheless, for markers with genetic diversities H-S

International audience; Tsetse flies are the cyclical vectors of African animal trypanosomosis (AAT) and human African trypanosomosis (HAT). In March 2010, the Government of Ghana initiated a large scale integrated tsetse eradication campaign in the Upper West Region (UWR) (approximate to 18,000 km(2)) under the umbrella of the Pan-African Tsetse and Trypanosomosis Eradication Campaign (PATTEC). We investigated the structuring of Glossina tachinoides populations within and between the three main river basins of the target area in the UWR. Out of a total sample of 884 flies, a sub-sample of 266 was genotyped at nine microsatellite loci. The significance of the different hierarchical levels was tested using Yang's parameters estimated with Weir and Cockerham's method. A significant effect of traps within groups (pooling traps no more than 3 km distant from each other), of groups within river basins and of river basins within the whole target area was observed. Isolation by distance between traps was highly significant. A local density of 0.48-0.61 flies/m(2) was estimated and a dispersal distance that approximated 11 m per generation [CI 9, 17]. No significant sex-biased dispersal was detected. Dispersal distances of G. tachinoides in the UWR were relatively low, possibly as a result of the fragmentation of the habitat and the seasonality of the Kulpawn and Sissili rivers. Moreover, very high fly population densities were observed in the sample sites, which potentially reduces dispersal at constant habitat saturation, because the probability that migrants can established is reduced (density dependent dispersal). However, the observed spatial dispersal was deemed sufficient for a G. tachinoides-cleared area to be reinvaded from neighboring populations in adjacent river basins. These data corroborate results from other population genetics studies in West Africa, which indicate that G. tachinoides populations from different river basins cannot be considered isolated.

Riverine tsetse (Glossina) as Glossina palpalis gambiensis Vanderplank 1949 and Glossina tachinoides Westwood 1850 are the main vectors for African animal trypanosomoses in Burkina Faso. Vector control has been proven efficient in disease containment, but its success is endangered by the reinvasion of tsetse from neighbouring areas. Thus, identifying relic populations can enhance the success rate of vector control efforts. This is currently carried out through microsatellite analysis which is time-consuming and costly. Recently, matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry-based analysis has become a routine method in microbial species identification. Owing to the rapidness and cost-effectiveness, this approach has been extended towards species identification of higher organisms such as tsetse. Following the recent experiences in distinguishing two genotypes of Prototheca spp., it is of interest to explore the validity of mass spectrometry for tsetse population differentiation. As a preliminary test, we submitted male and female G. palpalis gambiensis and G. tachinoides from Sideradougou and Folonzo, Burkina Faso (distance 60 km) to matrix-assisted laser desorption/ionisation analysis. The wing samples were utilized for protein extraction and mass spectra in a broad mass to charge ratio (2,000-20,000 kDa) were obtained. Specific peaks appeared to represent species, sex and location. Then, a peak list was extracted, containing the peaks in mass-to-charge ratio by revealing their intensities as well. These lists were used to compute a spectral dendrogram and a principle component analysis which displayed the differences among the samples from the two different regions. The results indicate that this technique can be extended with additional tsetse species, ideally with supporting genomic data, to later assist in designing rational vector control strategies.

Trypanosomosis is a parasitic disease that causes serious economic losses in livestock, in sub-Saharan African countries. A cross sectional study was conducted from October 2011 to March 2012 in the eastern part of Dangur district, Benishangul-Gumuz regional state, Ethiopia to determine the prevalence of bovine trypanosomosis and apparent density of tsetse flies. For prevalence study, a total of 543 blood samples were collected from randomly selected animals. Packed Cell Volume (PCV) was determined and samples were examined for the presence of trypanosomes using the buffy coat technique. In total, 46 (8.5%) of the samples were tested positive for trypanosomes. The majority of the infections were caused by Trypanosoma congolense (95.7%), and the remaining was caused by Trypanosoma vivax. The difference between prevalence of trypanosomes among study sites was statistically significant (p

Changes in agricultural practices and the resulting extinction of wildlife have led to the reduction or disappearance of savannah tsetse species. Riparian tsetse such as Glossina palpalis gambiensis Vanderplank 1949 and Glossina tachinoides Westwood 1850 (Diptera: Glossinidae) continue to persist in peridomestic sites, transmitting trypanosomiasis. At present, little is known about interspecies differences in feeding behaviour in these two species in southeast Mali, or of the phenomenon of multiple bloodmeals. To study these topics, 279 samples of G. p. gambiensis and G. tachinoides containing host DNA, caught in the Sikasso region between November 2008 and April 2009, were analysed by applying host species-specific primers and sequencing. Human accounted for > 66% of G. p. gambiensis bloodmeals, whereas G. tachinoides contained in equal parts DNA of human, cattle or both, showing a significantly higher proportion of multiple host use. Further, the trypanosome infection rate was found to be three-fold higher in G. tachinoides. Logistic regression analysis revealed double-feeding and infection to be independent of one another, but showed infection to be correlated with engorgement in G. p. gambiensis and female sex in G. tachinoides. Enhanced host-seeking activities paired with the high trypanosome infection rate found in G. tachinoides would indicate that this species has a higher vectorial capacity than G. p. gambiensis.

Baseline surveys were conducted in the Upper West Region of Ghana to assess the distribution and densities of tsetse species, as well as the prevalence of bovine trypanosomosis. The entomological survey was designed to cover the suitable tsetse habitats along the three main rivers in the study area (i.e. Black Volta, Kulpawn and Sissili). Results indicated the presence of Glossina tachinoides in all three river basins, whilst Glossina palpalis gambiensis was only found close to the southern limit of the study area. A random sampling of 1800 cattle of the West African Short Horn, Sanga and Zebu breeds from 36 randomly selected grid cells covering the study area showed substantial differences between parasitological and serological prevalences. The average parasitological prevalence was estimated at 2.5% (95% CI: 1.06– 5.77) with the majority of the infections due to Trypanosoma vivax. Most of the infected cattle were found close to the major river systems. The serological prevalence, measured using Enzyme Linked Immunosorbent Assay (ELISA), test was 19% (95% CI: 14.03–25.35). Cattle with anti-trypanosomal antibodies were also found throughout the study area.

Problem statement: A study to determine the composition of tsetse flies species was conducted between January and December, 2007 in Kamuku National Park, Nigeria, using Biconical and Nitse traps. Tsetse flies were trapped along gallery forest in five streams for two trapping days and were collected daily. Approach: All tsetse flies caught were identified to species level, sexed, separated into teneral and non-teneral, hunger staged and Mean Hunger Stage computed. Fly density were calculated, the age structure examined using wing fray techniques for males and ovarian technique for females; the reproductive status of female flies were assessed. Two species of tsetse flies (Glossina palpalis palpalis robineau-desvoidy and Glossina tachinoides Westwood) were caught in total of five hundred and two (502) flies. Out of these, 309(61.6%) Glossina tachinoides and 193(38.4%) G. palpalis were caught. Male catches (309, 61.6%) were significantly (P < 0.05) higher than females (193, 38.4%) also, the teneral flies (289, 57.6%) were more than the non-teneral flies (213, 42.4%). The Mean Hunger Stage (MHS) of 3.6 obtained indicated a hungry fly population. Fly density was generally low (0.1fly/trap/day) and varied between months with highest density (3flies/trap/day) occurring in February and lowest (0.2 fly/trap/day) in July. Results: The estimated mean age for males was 11 days and females were 8 days. The insemination rate of 93.8% generally was high, G. tachinoides recorded 95.5% more than G. palpalis of 91.6%. Whereas parity rate (25.8%) was low; G. palpalis was 37.4% while G. tachinoides parity rate is 17.2%. Conclusion: The study shows that two species of tsetse flies abound in the park although at low densities their presence may bear semblance to Trypanosomiasis and its impact to ecotourism.

Tsetse are the insect vectors of the African trypanosomiases. As with many diseases, transmission of trypanosomiasis varies through space and time. Capturing the variation of both vector and disease has, in the past, been attempted separately in the space and time dimensions, usually using deterministic techniques. Very few efforts have used space-time covariation and have hence missed any correlations that may exist between variation in these two dimensions. Here we propose two novel approaches to space-time analysis derived from space-time geostatistics in a kriging framework. The approaches were developed through analysis of a dataset recording the Apparent Density of Glossina palpalis gambiensis and Glossina tachinoides (Diptera: Glossinidae) in three riparian sites in Burkina Faso over 15 months between 2006 and 2007. This site is fragmented due to human activity in the area. The first approach, Space Time Ordinary Kriging, does not consider the effect of fragmentation. It is used as a benchmark to test the increased explanatory power of the second method, which does account for fragmentation. The second method, Regression Space Time Simple Kriging, is a distinct improvement over the first approach because it allows for a spatial trend in the mean trap catch; this trend is related to, and later predicted from, environmental co-variates. The results indicate the presence of space and time effects on tsetse distribution, dependent on the size of the habitat fragmentation patches. These effects occur at relatively small geographic scales within a season. Whilst such variation has long been suspected, the new methods presented here are able to quantify this variation precisely, so that seasonal and spatial comparisons can now be made both within and between species.

Distribution of the Tsetsefly Glossina tachinoides West. and G. morsitans submorsitans New. in the Republic of Niger. The distribution of the tsetseflies Glossina tachinoides W. and G. morsitans submorsitans N. in the Republic of Niger is shown. The tsetseflies are restricted to the rivers Niger, Tapoa and Mekrou. There is only one isolated Glossina spp. breeding area of 6.5 km2 on the eastern river bank of the Niger near the Nigerian frontier. The tsetsefly distribution in the south-western area near the border of Dahome and Upper Volta does not extend further north than Darybangou. Zusammenfassung Das Verbreitungsgebiet der Tsetsefliegenspezies G. tachinoides West. und G. morsitans submorsitans New. in der Republik Niger wurde von Dezember 1970 bis Januar 1972 untersucht. Es ist auf den Niger und seine Nebenflusse Tapoa und Mekrou beschrankt. Seine Nordgrenze befindet sich am Ort Darybangou, im Osten stellt das linke Nigerufer die Begrenzung dar und im Suden endet es beim Orte Boumba. Lediglich 15 km sudlich von Gaya befindet sich noch ein isoliertes, 6,5 km2 groses Glossinenvorkommen. Nach Westen dehnt sich das Verbreitungsgebiet ohne Begrenzung am Flus Mekrou nach Obervolta aus.

Background Animal African Trypanosomiasis (AAT) is caused by several species of trypanosomes including Trypanosoma congolense, T. vivax, T. godfreyi, T. simiae and T. brucei. Two of the subspecies of T. brucei also cause Human African Trypanosomiasis. Although some of them can be mechanically transmitted by biting flies; these trypanosomes are all transmitted by tsetse flies which are the cyclical vectors of Trypanosoma congolense, T. godfreyi, T. simiae and T. brucei. We present here the first report assessing the prevalence of trypanosomes in tsetse flies in Nigeria using molecular tools. Methods 488 tsetse flies of three species, Glossina palpalis palpalis, G. tachinoides and G. morsitans submorsitans were collected from Wuya, Niger State and Yankari National Park, Bauchi State in 2012. Trypanosomes were detected and identified using an ITS1 PCR assay on DNA purified from the ‘head plus proboscis’ (H + P) and abdomen (ABD) parts of each fly. Results T. vivax and T. congolense Savannah were the major parasites detected. Trypanosomes prevalence was 7.1 % in G. p. palpalis, 11.9 % in G. tachinoides and 13.5 % in G. m. submorsitans. Prevalences of T. congolense Savannah ranged from 2.5 to 6.7 % and of T. vivax were approximately 4.5 %. Trypanosoma congolense Forest, T. godfreyi and T. simiae were also detected in the site of Yankari. The main biological and ecological determinants of trypanosome prevalence were the fly sex, with more trypanosomes found in females than males, and the site, with T. congolense subspp. being more abundant in Yankari than in Wuya. As expected, the trypanosome species diversity was higher in Yankari National Park than in the more agricultural site of Wuya where vertebrate host species diversity is lower. Conclusions Our results show that T. congolense Savannah and T. vivax are the main species of parasite potentially causing AAT in the two study sites and that Yankari National Park is a potential reservoir of trypanosomes both in terms of parasite abundance and species diversity. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1585-3) contains supplementary material, which is available to authorized users.

A herd of 28 Muturu cattle under semi-intensive system of management at the University of Nigeria, Nsukka Agricultural Farm, southeastern, Nigeria, was examined for the presence of trypanosome infection over a one year period (April, 1998 - March, 1999). The aim was to assess the incidence of trypanosomosis and factors that may affect its occurrence variation. Infection was widespread in the herd (67. 9%) during the period. Out of the factors (season, sex and age) only season showed a significant effect on the occurrence of trypanosomosis. The incidence was highest in the third quarter of the year corresponding to the late rainy season period, followed by the fourth quarter (early dry season) and was least in the first quarter (late dry season). This seasonal incidence varied between 2.6% (CL 0.3 - 9.1 %) to 20.3% (CL 12.0 -30.8%) All the infections were due to Trypanosma vivax and the principal tsetse vector was Glossina tachinoides . Parasitaemic animals were able to control anaemia as their PCV's were similar to those of uninfected animals (P>0.05). The importance of these findings in relation to the general epizootiology of trypanosomosis and animal production in the area is discussed. Keywords: Trypanosomosis, muturu cattle, semi-intensive, Nigeria

International audience; The increase of human population, combined with climatic changes, contributed to the modification of spatial distribution of tsetse flies, main vector of trypanosomiasis. In order to establish and compare tsetse presence and their relationship with vegetation, entomological survey was performed using biconical traps deployed in transects, simultaneously with phyto-sociological study, on the Comoe river at its source in the village of Moussodougou, and in the semi-protected area of Folonzo, both localities in Southern Burkina Faso. In Folonzo, the survey revealed a diversity of tsetse with 4 species occurring with apparent densities as follows: Glossina tachinoides (8.9 tsetse/trap/day); G. morsitans submorsitans (1.8 tsetse/trap/day); G. palpalis gambiensis (0.6/trap/day) and G. medicorum (0.15 tsetse/trap/day). In Moussodougou, a highly anthropized area, mainly G. p. gambiensis was caught (2.06 tsetse/trap/day), and rarely G. tachinoides. The phyto-sociological study allowed discrimination of 6 types of vegetation in both localities, with 3 concordances that are riparian forest, shrubby and woody savannah. In Moussodougou, all tsetse were caught in the riparian forest. That was also the case in Folonzo where a great proportion (95 to 99 % following the season) of G. p. gambiensis and G. tachinoides were caught in the gallery, while G. m. submorsitans was occurring as well in the gallery as in the savannah, and G. medicorum in the forest gallery. This study showed that although G. tachinoides and G.p. gambiensis are both riparian, they do not have the same preference in terms of biotope.

International audience; Isolated tsetse populations constitute a target for tsetse control programmes in endemic countries, since their isolation, if demonstrated, allows control without reinvasion risk from neighbouring populations. Population genetic parameters, such as the fixation index, have proven useful to assess isolation status, and should also give important information on the divergence time since isolation. We gathered results obtained from different datasets regarding several examples of putatively totally isolated tsetse populations of different tsetse species: Glossina palpalis gambiensis in Guinea, in the Niayes of Senegal, and in the sacred wood of Bama in Burkina Faso; G. tachinoides from Bitou and Pama in South-East Burkina Faso. The different levels of isolation were compared to differentiation between the two subspecies G. p. gambiensis and G. p. palpalis which both occur allopatrically along the Comoe River in Ivory Coast. We also use some historical evidence to calibrate differentiation speed and give estimates of time since separation for the different cases studied. Discrepancies mostly come from underestimate of effective population sizes, and we propose improving sampling design and genetic markers quality to circumvent such caveats.

African animal trypanosomosis (AAT) is a major constraint to viable and sustainable livestock production systems in Ghana. Under the umbrella of the Pan African Tsetse and Trypanosomosis Eradication Campaign (PATTEC), Ghana is collaborating with Burkina Faso in a sub-regional initiative aiming at creating tsetse-free areas across their common borders. The objective of this thesis was to conduct research to guide project implementation and specifically seeks to i) determine the pre-intervention vector and disease situation of the intervention area, ii) determine tsetse population structuring and the consequences on sustainable tsetse control efforts, iii) evaluate SAT for the control of riverine tsetse species in Ghana and iv) evaluate the environmental risk of the intervention programmes. Results of a baseline survey conducted in the Upper West Region (study area) indicated a wide-spread prevalence of Glossina tachinoides but Glossina palpalis gambiensis was limited to the southern edge of the study area. Average parasitological prevalence in cattle was estimated at 2.5% (95% CI: 1.06–5.77) and serological prevalence measured at 19% (95% CI: 14.03–25.35). The mean Index of Apparent Abundance (IAA) of tsetse was 8.7, 1.9 and 1.3 for samples taken along the Black Volta, Kulpawn and Sissili Rivers, respectively. Investigations of the G. tachinoides populations confirmed significant strucring within and between the three main river-basins of the study area, and indicated a local density of 0.048-0.061 flies/m² and dispersal distance that approximated 11 m per generation [CI 9 - 17]. No significant sex-biased dispersal was detected. However, the observed dispersal was deemed sufficient for a G. tachinoides-cleared area to be reinvaded from neighbouring populations in adjacent river basins The potential of Sequential Aerosol Technique (SAT) to eliminate riverine tsetse species in a challenging subsection (dense tree canopy and high tsetse densities) and the subsequent efficacy of an integrated strategy, one year after the SAT operations, were also investigated. Results indicated failure to achieve elimination, attributed to insufficient penetration of insecticide aerosols in thick riverine forest galleries. However the overall reduction rate due to SAT was important (98%) and the subsequent integrated strategy maintained high levels of tsetse suppression. Finally an environmental impact assessment revealed no significant impact of deltamethrin aerosols on non-targeted aquatic and terrestrial arthropods.

The prevalence of trypanosomosis was investigated over a 12-month period, among small ruminants grazing in known sleeping sickness endemic area of central Nigeria and under light riverine tsetse challenge. Analysis of the data from 304 Yankassa sheep and 239 West African DwarfxRed Sokoto goats indicated high mean prevalence (27.62%, confidence limits Cl: 0.232, 0.312). Interspecies difference between sheep (38.16%; 0.382, Cl: 0.332, 0.432) and goats (14.23%; 0.142, Cl: 0.102, 0.182) was highly significant (P0.001). Infections were also significantly higher (P0.05) with agro-pastoral (extensive) management, during the dry season and in adults compared to intensively managed animals, the wet season and young animals, respectively. Trypanosoma vivax was the predominant parasite encountered and accounted for over 49% of the infections. T. congolense and mixed populations were diagnosed at approximately 15% each while T. brucei were absent in caprines. The implications of these findings in the epidemiology of the diseases in both man and domestic animals is discussed.

A 0.125 degree raster or grid-based Geographic Information System with data on tsetse, trypanosomiasis animal production, agriculturerkina> and land use has recently been developed in Togo. This paper addresses the problem of generating tsetse distribution and abundance maps from remotely sensed data, using a restricted amount of field data. A discriminant analysis model is tested using contemporary tsetse data and remotely sensed, low resolution data acquired from the National Oceanographic and Atmospheric Administration and Meteosat platforms. A split sample technique is adopted where a randomly selected part of the field measured data (training set) serves to predict the other part (predicted set). The obtained results are then compared with field measured data per corresponding grid-square. Depending on the size of the training set the percentage of concording predictions varies from 80 to 95 for distribution figures and from 63 to 74 for abundance. These results confirm the potential of satellite data application and multivariate analysis for the prediction, not only of the tsetse distribution, but more importantly of their abundance. This opens up new avenues because satellite predictions and field data may be combined to strengthen or substitute one another and thus reduce costs of field surveys.

Lors d'une etude globale du risque trypanosomien menee dans la zone agropastorale de Sideradougou (Burkina Faso), des troupeaux sentinelles issus de deux systemes d'elevage differents ont ete suivis durant deux ans. L'incidence trypanosomienne mensuelle a ete mesuree et interpretee en fonction des parcours des troupeaux, de leur pratique d'abreuvement et de leur contact avec les glossines ripicoles (Glossina tachinoides et G. palpalis gambiensis). A Nakaka, village d'eleveurs Peuls, la transmission en saison seche est assuree aux points d'abreuvement perennes dans la galerie forestiere. En saison des pluies, les glossines ripicoles se dispersent dans les savanes et infectent les animaux jusque dans les villages. A Pefrou, ensemble de campements d'agriculteurs Bobo, les troupeaux sont composes essentiellement de boeufs de traction. Les animaux issus des campements localises a proximite du cours d'eau s'abreuvent dans les points d'eau des formations riveraines et sont infectes toute l'annee. L'incidence est plus elevee en hivernage et en debut de saison seche, periode ou les glossines sont les plus nombreuses. A l'oppose, les troupeaux des campements eloignes du reseau hydrographique (3 km) sont abreuves au puits et ne frequentent pas les biotopes des glossines. Dans ce paysage essentiellement agricole, les glossines ne se dispersent pas, meme en saison humide. L'incidence dans les troupeaux est quasiment nulle. Ces resultats montrent l'importance des interfaces spatiales et temporelles entre les bovins et les glossines dans l'epidemiologie des trypanosomoses en Afrique de l'ouest. (Resume d'auteur)