Institute Of Recherche En Science Of La Sante Irss

Bobo Dioulasso, South Africa

Institute Of Recherche En Science Of La Sante Irss

Bobo Dioulasso, South Africa

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Gimonneau G.,IRD Montpellier | Gimonneau G.,Institute Of Recherche En Science Of La Sante Irss | Bouyer J.,French National Institute for Agricultural Research | Morand S.,Montpellier University | And 4 more authors.
Behavioral Ecology | Year: 2010

Disruptive selection mediated by predation on aquatic immature stages has been proposed as a major force driving ecological divergence and fostering speciation between the M and S molecular forms of the African malaria mosquito, Anopheles gambiae. In the dry savannahs of West Africa where both molecular forms co-occur, the S form thrives in temporary pools filled with rainwater, whereas the M form preferentially breeds in permanent freshwater habitats where predator pressure is higher. Here, we explored the proximal mechanisms by which predation may contribute to habitat segregation between molecular forms using progeny of female mosquitoes captured in Burkina Faso. We show that the S form suffers higher predation rates than the M form when simultaneously exposed to the widespread predator, Anisops jaczewskii in an experimental arena. Furthermore, behavioral plasticity induced by exposure to the predator was observed in the M form, but not in the S form, and may partially explain its habitat use and ecological divergence from the S form. We discuss the role of adaptive phenotypic plasticity in allowing successful colonization of a new ecological niche by the M form and highlight further research areas that need to be addressed for a better understanding of the ultimate mechanisms underlying ecological speciation in this pest of major medical importance. © 2010 The Author.


Philibert A.,University of Ottawa | Bado A.,Institute Of Recherche En Science Of La Sante Irss
BMC Health Services Research | Year: 2014

Background: Although many developing countries have developed user fee exemption policies to move towards universal health coverage as a priority, very few studies have attempted to measure the quality of care. The present paper aims at assessing whether women's satisfaction with delivery care is maintained with a total fee exemption in Burkina Faso. Methods. A quasi-experimental design with both intervention and control groups was carried out. Six health centres were selected in rural health districts with limited resources. In the intervention group, delivery care is free of charge at health centres while in the control district women have to pay 900 West African CFA francs (U$2). A total of 870 women who delivered at the health centre were interviewed at home after their visit over a 60-day range. A series of principal component analyses (PCA) were carried out to identify the dimension of patients' satisfaction. Results: Women's satisfaction loaded satisfactorily on a three-dimension principal component analysis (PCA): 1-provider-patient interaction; 2-nursing care services; 3-environment. Women in both the intervention and control groups were satisfied or very satisfied in 90% of cases (in 31 of 34 items). For each dimension, average satisfaction was similar between the two groups, even after controlling for socio-demographic factors (p = 0.436, p = 0.506, p = 0.310, respectively). The effects of total fee exemption on satisfaction were similar for any women without reinforcing inequalities between very poor and wealthy women (p ≥ 0.05). Although the wealthiest women were more dissatisfied with the delivery environment (p = 0.017), the poorest were more highly satisfied with nursing care services (p = 0.009). Conclusion: Contrary to our expectations, total fee exemption at the point of service did not seem to have a negative impact on quality of care, and women's perceptions remained very positive. This paper shows that the policy of completely abolishing user fees with organized implementation is certainly a way for developing countries to engage in universal coverage while maintaining the quality of care. © 2014 Philibert et al.; licensee BioMed Central Ltd.


Gouagna L.C.,Institute Of Recherche Pour Le Developpement Ird | Bancone G.,University of Rome La Sapienza | Yao F.,Institute Of Recherche En Science Of La Sante Irss | Yameogo B.,Institute Of Recherche En Science Of La Sante Irss | And 5 more authors.
Nature Genetics | Year: 2010

Genetic factors are known to have a role in determining susceptibility to infectious diseases1,2, although it is unclear whether they may also influence host efficiency in transmitting pathogens. We examine variants in HBB that have been shown to be protective against malaria3 and test whether these are associated with the transmission of the parasite from the human host to the Anopheles vector. We conducted cross-sectional malariological surveys on 3,739 human subjects and transmission experiments involving 60 children and 6,446 mosquitoes in Burkina Faso, West Africa. Protective hemoglobins C (HbC, Β6Glu→Lys)4,5 and S (Β6Glu→Val)6,8 are associated with a twofold in vivo (odds ratio 2.17, 95% CI 1.57-3.01, P = 1.0 × 10 -6) and a fourfold ex vivo (odds ratio 4.12, 95% CI 1.90-9.29, P = 7.0 × 10 -5) increase of parasite transmission from the human host to the Anopheles vector. This provides an example of how host genetic variation may influence the transmission dynamics of an infectious disease. © 2010 Nature America, Inc. All rights reserved.


Pooda S.H.,Ministere des Ressources Animales et Halieutiques | Mouline K.,IRD Montpellier | Mouline K.,Institute Of Recherche En Science Of La Sante Irss | De Meeus T.,CIRDES Center International Of Recherche Développement Sur L'elevage En Zone Sub Humide | And 2 more authors.
Parasites and Vectors | Year: 2013

Background: Human and Animal Trypanosomes are major problems for the socio-economic growth of developing countries like Burkina Faso. Ivermectin is currently used to treat humans in mass drug administration programs in Africa, and is also commonly used for veterinary purposes. In this study, we tested the effect of ivermectin injected into cattle on the survival and fecundity of Glossina palpalis gambiensis, the main vector of human and animal trypanosomes in West Africa. Methods. Three cows (local zebu*baoulé crossbreds) were used, and received either no ivermectin (for the control), or ivermectin at therapeutic dose (0.2 mg/kg) and 10 times the therapeutic dose (2 mg/kg) respectively. G. palpalis gambiensis were fed on the cattle for their first bloodmeal, and then either on cattle or on membrane for subsequent meals. Results: Our results showed that survival of Glossina palpalis gambiensis was significantly decreased when they were fed on cattle treated with ivermectin. This decrease in survival ranged from 21% to 83.7% for the therapeutic dose (0.2 mg/kg), up to 8 days after treatment. The effects of a dose of 2 mg/kg were higher with a 78.3% to 93.9% decrease in survival, until 14 days after injection. The therapeutic dose of ivermectin also decreased fecundity, and delayed the first larviposition, but there was no significant effect on hatching rate. Conclusion: Ivermectin injected into cattle may constitute an additional potential tool for the control of Glossina palpalis gambiensis and possibly other vector species. Further studies will be needed to assess its effect on trypanosome transmission, and to define more precisely the adequate dose to be used for control purposes. © 2013 Pooda et al.; licensee BioMed Central Ltd.


Gimonneau G.,IRD Montpellier | Pombi M.,University of Rome La Sapienza | Choisy M.,IRD Montpellier | Morand S.,Montpellier University | And 3 more authors.
Medical and Veterinary Entomology | Year: 2012

In West Africa, lineage splitting between the M and S molecular forms of the major Afro-tropical malaria mosquito, Anopheles gambiae (Diptera: Culicidae), is thought to be driven by ecological divergence, occurring mainly at the larval stage. Here, we present evidence for habitat segregation between the two molecular forms in and around irrigated rice fields located within the humid savannahs of western Burkina Faso. Longitudinal sampling of adult mosquitoes emerging from a range of breeding sites distributed along a transect extending from the heart of the rice field area into the surrounding savannah was conducted from June to November 2009. Analysis revealed that the two molecular forms and their sibling species Anopheles arabiensis are not randomly distributed in the area. A major ecological gradient was extracted in relation to the perimeter of the rice fields. The M form was associated with larger breeding sites mostly consisting of rice paddies, whereas the S form and An. arabiensis were found to depend upon temporary, rain-filled breeding sites. These results support hypotheses about larval habitat segregation and confirm the suggestion that the forms have different larval habitat requirements. Segregation appears to be clearly linked to anthropogenic permanent habitats and the community structure they support. © 2011 The Authors. Medical and Veterinary Entomology © 2011 The Royal Entomological Society.


Roux O.,IRD Montpellier | Roux O.,Institute Of Recherche En Science Of La Sante Irss | Diabate A.,Institute Of Recherche En Science Of La Sante Irss | Simard F.,IRD Montpellier
Freshwater Biology | Year: 2013

Predation is a major evolutionary force driving speciation. Identifying the stimuli prompting anti-predator responses is essential for unravelling the proximate mechanisms of anti-predator adaptations and for understanding how predation impacts species diversification. Here, we explore for the first time the divergence in the use of cues of predation risk by different incipient species of mosquitoes within the Anopheles gambiae complex. We examined the anti-predator responses to various predation cues by the aquatic larvae of Anopheles arabiensis and the two molecular forms, M and S, of Anopheles gambiae s.s. sampled from wild populations in Burkina Faso naturally exposed to different predator densities. The larvae altered their behaviour in response to various predation cues, shifting from the surface of the water to a less exposed location on the walls of the experimental arena. There were important differences in the use of predation cues between populations sharing the same larval development sites and, within the M form, related to predation pressure at their site of origin. Anopheles arabiensis larvae, which develop in small temporary waterbodies, relied only on physical cues signalling the presence of a predator to mount a vigilance response, whereas the sympatric larvae of the M and S forms of An. gambiae used both physical and chemical cues to fine-tune their response. M-form larvae, developing in permanent aquatic habitats with high densities of predators, responded chiefly to chemical stimuli ensuing from acute predation. Our results suggest that predation might play a role as a disruptive selective force promoting ecological divergence within the An. gambiae complex and, more recently, between the M and S molecular forms. Notably, beyond interspecific differences in the use of predation cues, our study also documented phenotypic differences within the M form based on predation pressure at their site of origin, suggesting that a process of ecological divergence is generating species 'forerunners' within the An. gambiae complex in the wild. © 2013 Blackwell Publishing Ltd.


Sawadogo S.P.,Institute Of Recherche En Science Of La Sante Irss | Costantini C.,Institute Of Recherche En Science Of La Sante Irss | Costantini C.,IRD Montpellier | Pennetier C.,IRD Montpellier | And 3 more authors.
Parasites and Vectors | Year: 2013

Background: The M and S molecular forms of Anopheles gambiae s.s. Giles appear to have speciated in West Africa and the M form is now formally named An. coluzzii Coetzee & Wilkerson sp.n. and the S form retains the nominotypical name (abbreviated here to An. gambiae). Reproductive isolation is thought to be the main barrier to hybridisation; even though both species are found in the same mating swarms, hybrid fertilisations in copulae have not been found in the study area. The aim of the study, therefore, was to determine whether differences in circadian and/or environmental control over the timing of swarming in the two species contribute to reproductive isolation. Methods. The timing of male swarming in these species was recorded four nights per month over four years at five swarming sites in each of two villages. The timing of the start and end of swarming, and the concurrent environmental parameters, temperature, humidity and light intensity, were recorded for n = 20 swarms/month/species. The timing of 'spontaneous' activity at dusk of individual An. coluzzii and An. gambiae males was video-recorded in an actograph outdoors for 21 nights. Results: Of the environmental parameters considered, swarming was most strongly correlated with sunset (r§ssup§2§esup§ > 0.946). Anopheles gambiae started and stopped swarming earlier than An. coluzzii (3:35 ± 0:68 min:sec and 4:51 ± 1:21, respectively), and the mean duration of swarming was 23:37 ± 0:33 for An. gambiae and 21:39 ± 0:33 for An. coluzzii. Accordingly, in principle, whenever both species swarm over the same marker, a mean of 15.3 ± 3.1% of An. gambiae swarming would occur before An. coluzzii males arrived, and 19.5 ± 4.55% of An. coluzzii swarming would occurred after An. gambiae males had stopped swarming. These results are consistent with the finding that An. gambiae males became active in the actograph 09:35 ± 00:22 min:sec earlier than An. coluzzii males. Conclusions: The timing of swarming and spontaneous activity at dusk are primarily under circadian control, with the phase linked closely to sunset throughout the year. The mating activity of these two species is temporally segregated for 15-20% of the swarming period, which may contribute to the observed reproductive isolation of these species in local sympatric populations. © 2013 Sawadogo et al.; licensee BioMed Central Ltd.


Roux O.,CIRAD - Agricultural Research for Development | Roux O.,Institute Of Recherche En Science Of La Sante Irss | Diabate A.,Institute Of Recherche En Science Of La Sante Irss | Simard F.,CIRAD - Agricultural Research for Development
Journal of Animal Ecology | Year: 2014

Predation is a major evolutionary force driving speciation. The threat-sensitive response hypothesis predicts that prey adjust and balance the time spent on a costly antipredator response with other activities that enhance their fitness. Thus, prey able to develop an antipredator response proportional to risk intensity should have a selective advantage. Knowledge on how evolution has shaped threat sensitivity among closely related species exposed to different predation pressures is scarce, prompting investigations to better predict and explain its effect on communities. We explored and compared the antipredator response of aquatic mosquito larvae in three sibling species of the Anopheles gambiae complex, with contrasting larval biologies in Burkina Faso. Anopheles arabiensis and An. gambiae sensu stricto breed in temporary water collections where predator densities are low, whereas Anopheles coluzzii is able to thrive in permanent pools where the predation pressure is much higher. We hypothesized that the increase and decline of behavioural antipredator responses might differ between the three species over time. To test this hypothesis, progenies of field-collected mosquitoes were experimentally exposed to a range of soluble predation cues and their response was monitored for up to 48 h. The three species were all threat sensitive but their reaction norms differed. For the range of concentrations tested, An. coluzzii larvae gradually increased in antipredator response, whereas An. gambiae larvae readily displayed antipredator behaviour at low concentrations leading to a saturation of the response for high cue concentrations. An. arabiensis displayed a narrower reaction norm with low response intensity. Larval instars did not differ in their threat sensitivity. The antipredator behaviour of the three species waned after about 1 h of exposure. Early instars tended to express antipredation behaviour for longer than did older instars. This study provides information on how aquatic prey species with an aerial adult stage manage larval predation risk over time according to cue concentrations and suggests that different predation pressures might play a role as a disruptive selective force fostering habitat segregation and speciation within the An. gambiae complex. The evolution of phenotypic plasticity is further discussed in the light of divergent predation pressures. © 2013 British Ecological Society.


Sawadogo W.R.,Laboratoire Of Biologie Moleculaire Et Cellulaire Of Cancer | Sawadogo W.R.,Institute Of Recherche En Science Of La Sante Irss | Schumacher M.,Laboratoire Of Biologie Moleculaire Et Cellulaire Of Cancer | Teiten M.-H.,Laboratoire Of Biologie Moleculaire Et Cellulaire Of Cancer | And 3 more authors.
Biochemical Pharmacology | Year: 2012

Traditional pharmacopeia is strongly involved in the continuous search for the well being of African populations. The World Health Organization (WHO) estimates that 80% of the population of developing countries relies on traditional medicine for their primary care needs. Medicinal plants are the major resource of this folk medicine where several species are used for the treatment of diseases with an inflammatory and/or infectious component as it is the case of old wounds, skin diseases and malfunctions affecting internal organs such as liver, lung, prostate and kidney. Many of these pathologies described by practitioners of traditional medicine have similarities with certain cancers, but the lack of training of many of these healers does not allow them to establish a link with cancer. However, ethnobotanical and ethnopharmacological surveys conducted by several researchers allowed to identify plants of interest for cancer treatment. Most scientific investigations on these plants demonstrated an anti-inflammatory or antioxidant effect, and sometimes, antiproliferative and cytotoxic activities against cancer cells were reported as well. The emergence of resistance to cancer chemotherapy has forced researchers to turn to natural products of plant and marine origin. In the West African sub-region, research on natural anti-cancer molecules is still in its infancy stage because of very limited financial resources and the scarcity of adequate technical facilities. However, several plants were investigated for their anticancer properties through north-south or south-south partnerships. In this review, we will review the role of West African traditional pharmacopeia in cancer treatment as well as medicinal plants with anti-cancer properties. © 2012 Elsevier Inc.


Wirtz A.L.,Center for Public Health and Human Rights | Schwartz S.,Center for Public Health and Human Rights | Ketende S.,Center for Public Health and Human Rights | Anato S.,Arc en ciel | And 7 more authors.
Journal of Acquired Immune Deficiency Syndromes | Year: 2015

Background: Female sex workers (FSWs) are vulnerable to violence within and beyond the workplace. Violence is associated with increased burden of HIV, possibly explained through physiologic or behavioral causal pathways. These analyses sought to determine the relationship between lifetime sexual violence with unprotected, condomless vaginal intercourse (UVI) among FSWs in West Africa. Methods: FSWs (aged ≥18 years) were recruited into a cross-sectional study through respondent-driven sampling in two West African countries, Togo and Burkina Faso. A total of 1380 participants were enrolled from January to July 2013, and completed a sociobehavioral questionnaire and HIV testing. Measures included sex work history, lifetime experiences of violence victimization, sexual practices, and UVI (past month). Crude and adjusted robust log binomial regression was conducted to estimate prevalence ratios (PrR) as a measure of association between UVI with clients and the primary exposure, forced sex. Results: Self-reported lifetime physical abuse (47.3%), forced sex (33.0%), and any violence (57.9%) were common. Almost one-quarter (23.9%) reported recent UVI with clients. History of forced sex was independently associated with recent UVI with clients [vs. none, adjusted PrR: 1.49; 95% confidence interval (CI): 1.18 to 1.88], with evidence of partial mediation by difficult condom negotiation with regular (aPrR: 1.83; 95% CI: 1.43 to 2.34) and new clients (aPrR: 1.60; 95% CI: 1.13 to 2.29). Discussion: These data demonstrate the significant relationship between sexual violence experienced by FSWs and unprotected sex with clients. Comprehensive interventions reducing vulnerabilities to violence combined with improved condom negotiation are needed to address the complex influences of condom use during sex work as a means of ultimately lowering HIV acquisition and transmission. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

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