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Background: The role of environmental factors in driving adaptive trajectories of living organisms is still being debated. This is even more important to understand when dealing with important neglected diseases and their vectors. Methodology/Principal Findings: In this paper, we analysed genetic divergence, computed from seven microsatellite loci, of 614 tsetse flies (Glossina palpalis gambiensis and Glossina palpalis palpalis, major vectors of animal and human trypanosomes) from 28 sites of West and Central Africa. We found that the two subspecies are so divergent that they deserve the species status. Controlling for geographic and time distances that separate these samples, which have a significant effect, we found that G. p. gambiensis from different landscapes (Niayes of Senegal, savannah and coastal environments) were significantly genetically different and thus represent different ecotypes or subspecies. We also confirm that G. p. palpalis from Ivory Coast, Cameroon and DRC are strongly divergent. Conclusions/Significance: These results provide an opportunity to examine whether new tsetse fly ecotypes might display different behaviour, dispersal patterns, host preferences and vectorial capacities. This work also urges a revision of taxonomic status of Glossina palpalis subspecies and highlights again how fast ecological divergence can be, especially in host-parasite-vector systems. Author Summary: The role of environmental factors in driving adaptive trajectories of living organisms is still being debated. This is even more important to understand when dealing with important and /or neglected diseases and their vectors. In this paper, we analysed genetic divergence, computed from several genetic markers, of 614 tsetse flies (Glossina palpalis gambiensis and Glossina palpalis palpalis, major vectors of animal and human trypanosomes) from 28 sites of West and Central Africa. We found that the two subspecies are so divergent that they deserve the species status. We found that G. p. gambiensis from different landscapes (Niayes of Senegal, savannah and coastal environments) were significantly genetically different, and thus represent different adaptive entities or even subspecies. We also confirm that G. p. palpalis from Ivory Coast, Cameroon and DRC are strongly divergent. These results provide an opportunity to examine whether these different types of tsetse fly might display different behaviour, dispersal patterns, host preferences and vectorial capacities. This work also urges a revision of taxonomic status of Glossina palpalis subspecies and highlights again how fast ecological divergence can be, especially in host-parasite-vector systems. [ABSTRACT FROM AUTHOR]

Background: The Government of Senegal has initiated the "Projet de lutte contre les glossines dans les Niayes" to remove the trypanosomosis problem from this area in a sustainable way. Due to past failures to sustainably eradicate Glossina palpalis gambiensis from the Niayes area, controversies remain as to the best strategy implement, i.e. "eradication" versus "suppression." To inform this debate, we used population genetics to measure genetic differentiation between G. palpalis gambiensis from the Niayes and those from the southern tsetse belt (Missira). Methodology/Principal Findings: Three different markers (microsatellite DNA, mitochondrial CO1 DNA, and geometric morphometrics of the wings) were used on 153 individuals and revealed that the G. p. gambiensis populations of the Niayes were genetically isolated from the nearest proximate known population of Missira. The genetic differentiation measured between these two areas (θ = 0.12 using microsatellites) was equivalent to a between-taxa differentiation. We also demonstrated that within the Niayes, the population from Dakar – Hann was isolated from the others and had probably experienced a bottleneck. Conclusion/Significance: The information presented in this paper leads to the recommendation that an eradication strategy for the Niayes populations is advisable. This kind of study may be repeated in other habitats and for other tsetse species to (i) help decision on appropriate tsetse control strategies and (ii) find other possible discontinuities in tsetse distribution. Author Summary: Tsetse flies transmit trypanosomes to humans (sleeping sickness) and animals (nagana). Controlling these vectors is a very efficient way to contain these diseases. There are several strategies and methods that can be used for control, each being more or less efficient depending on several factors. The Government of Senegal wants to sustainably eliminate trypanosomosis from the Niayes region by controlling the tsetse vector, Glossina palpalis gambiensis. To reach this objective, two different strategies may be used: suppression (decrease in tsetse densities) or eradication (remove all the tsetse in the region until last one). For eradication, the approach has to be area-wide, i.e. the control effort targets an entire pest population within a circumscribed area, to avoid any possible reinvasion. Three different tools (microsatellite DNA, mitochondrial DNA and morphometrics) were used, and all showed an absence of gene flow between G. p. gambiensis from the Niayes and from the nearest known population in the south east of the country (Missira). This genetic isolation of the target population leads to the recommendation that an eradication strategy for the Niayes populations is advisable. This kind of study may be extended to other areas on other tsetse species. [ABSTRACT FROM AUTHOR]

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., (Copyright © 2014 International Atomic Energy Agency 2014. Published by Elsevier B.V. All rights reserved.)

We investigated the genetic diversity and the population structure of 32 Plasmodium falciparum blood sample isolates (25 from Dakar city and suburbs and seven from other localities in Senegal) with two different types of molecular markers, 19 microsatellite and four antigenic determinant loci. Under the same technical procedure, microsatellite loci showed a mean number of alleles greater than that of antigenic loci. Both markers revealed that 15.6% of blood samples were multi-infected. Mean expected heterozygosity calculated from microsatellites and antigens was similar, 0.74 and 0.70, respectively. Significant linkage disequilibrium was observed from microsatellite loci and antigenic determinant loci. This suggests a non-panmictic structure for this sample that could be explained by two non-exclusive hypotheses: (i) a particular mating system (i.e. clonality), and/or (ii) a population structure in P. falciparum (i.e. Wahlund effect). Urban samples could have been drawn from a heterogeneous set of foci with different level of parasitic transmission. Moreover, no relationship was found between multilocus genotypes and different parameters (i.e. age, sex and blood group of parasitized patients; number of trophozoites per microliter of blood). The results are discussed taking into account recently published studies on malaria population biology.