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African schistosomes in small mammal communities: perspectives from a spatial-temporal survey in the vicinity of Lake Guiers, Senegal.&nbsp

Crocidura olivieri is a large-sized shrew species showing a clear trend towards commensalism in West Africa, where it co-occurs and interacts with a number of rodent species in indoor small mammal communities. Among the rodents present is the house mouse Mus musculus, a major invasive species worldwide. We here test the hypothesis that M. musculus could be part of the diet of C. olivieri in a number of localities of Senegal where the two species are known to coexist. We use a metabarcoding approach based on the high-throughput sequencing of a 133 bp fragment of the COI gene, on DNA extracted from digestive tracts and faeces of a sample of 108 shrews. Beside insects of various groups (ants, beetles and cockroaches especially) representing usual items of shrew’s diet, and traces of domestic mammals and poultry that were probably scavenged, several species of rodents were evidenced. Among them, M. musculus was by far the best represented species, found in 17 of the 54 shrews where at least one prey taxon was identified. This finding tends to confirm the potential role of C. olivieri as predator of house mice, while highlighting the capacity of this species to adapt its diet to environmental conditions.

International audience; Zoonotic pathogens are responsible for most infectious diseases in humans, with rodents being important reservoir hosts for many of these microorganisms. Rodents, thus, pose a significant threat to public health. Previous studies in Senegal have shown that rodents harbour a diversity of microorganisms, including human pathogens. Our study aimed to monitor the prevalence of infectious agents in outdoor rodents, which can be the cause of epidemics. We screened 125 rodents (both native and expanding) from the Ferlo region, around Widou Thiengoly, for different microorganisms. Analysis, performed on rodent spleens, detected bacteria from the Anaplasmataceae family (20%), Borrelia spp. (10%), Bartonella spp. (24%) and Piroplasmida (2.4%). Prevalences were similar between native and the expanding (Gerbillus nigeriae) species, which has recently colonised the region. We identified Borrelia crocidurae, the agent responsible for tick-borne relapsing fever, which is endemic in Senegal. We also identified two other not-yet-described bacteria of the genera Bartonella and Ehrlichia that were previously reported in Senegalese rodents. Additionally, we found a potential new species, provisionally referred to here as Candidatus Anaplasma ferloense. This study highlights the diversity of infectious agents circulating in rodent populations and the importance of describing potential new species and evaluating their pathogenicity and zoonotic potential.

In Lower Casamance, Pterocarpus erinaceus occupies a very important place in agroforestry parks. It is often grown in association with the most important cash crop of the area, groundnut (Arachis hypogea L.). Thus, the objective of this study is to contribute to a better understanding of the interactions between trees and groundnut cultivation in agroforestry parks in Lower Casamance. To this end, in each of the two districts (Tenghory and Kataba 1) three Pterocarpus erinaceus trees were selected in three separate communes. For each P. erinaceus tree selected and following each of the four cardinal directions, three situations were defined: at R/2, at 1.5 R and at 2 R from the trunk, with R the radius of the crown. Thus, 12 yield squares were installed around each selected tree, for a total of 72 yield squares installed in the two districts. The parameters measured were the height of the peanut plants, the number of pods produced per plant, and the yield in flakes and pods. The results show that geographical orientation significantly influenced plant height (p = 0.004) but not the number of pods/plant (p = 0.6). As for the distance to the trunk of Pterocarpus erinaceus, it induced a significant variation in the number of pods/plant (p = 0.009) but did not induce a significant effect on the other parameters. Yields varied between 1.56 Tons M S /ha and 2.02 Tons M S /ha for the hay, and between 1.03 Tons M S /ha and 1.45 Tons M S/ha for the pods. The results of this study constitute a useful source of information for a better management of the productivity of the agroforestry parks of the department of Bignona.

International audience; Relationships between parasitism and invasion success are increasingly evidenced in the literature. However, the dynamic nature of the major parasite-related processes has been rarely taken into account until now, while the residence time of invaders in colonized regions was shown to be associated to crucial changes in parasite communities. Here, we strive to bridge this gap using a temporal survey of rodent populations along one invasion route of the exotic house mouseMus musculus domesticusthat currently invades North Senegal. In this study, we investigated whether gastrointestinal helminth (GIH) assemblages changed over time in native (Mastomys erythroleucus) and/or invasive (M. m. domesticus) rodent populations sampled at an invasion front, and whether these potential changes may be associated to the invasion success of the exotic mouse. Four years separated two rodent sampling campaigns (2013 and 2016/17) in six localities. Despite being relatively short, the timeframe considered here allowed to evidence significant patterns in rodent communities and their GIH assemblages. At the host community level, we showed that the exotic mouse was now established at all sites, becoming the dominant species in sites where it was not recorded before. At the GIH community level, increased infection of the single shared cestode (Mathevotaenia symmetrica) in both rodent species brought support to the "spill-back" hypothesis. Infection levels of GIH that remained low at the invasion front in invading mice over time also supported the "enemy release" hypothesis. Both hypotheses should deserve further experimental work to demonstrate their role in the invasion success of the house mouse in Senegal.

Population genetic approaches may be used to investigate dispersal patterns of species living in highly urbanized environment in order to improve management strategies for biodiversity conservation or pest control. However, in such environment, population genetic structure may reflect both current features of the cityscape and urbanization history. This can be especially relevant when focusing on exotic commensal rodents that have been introduced in numerous primary colonial European settlements. Accounting for spatial and temporal cityscape heterogeneity to determine how past and recent demographic events may interplay to shape current population genetic structure of synanthropic rodents may provide useful insights to manage their populations. In this study, we addressed these issues by focusing on the house mouse,Mus musculus domesticus, in Dakar, Senegal, where the species may have been introduced as soon as Europeans settled in the middle of the nineteenth century. We examined genetic variation at one mitochondrial locus and 15 nuclear microsatellite markers from individuals sampled in 14 sampling sites representing different stages of urbanization history and different socio-economic environments in Dakar. We used various approaches, including model-based genetic clustering and model-free smoothing of pairwise genetic estimates. We further linked observed spatial genetic patterns to historical and current features of Dakar cityscape using random forest and Bayesian conditional autoregressive models. Results are consistent with an introduction of the house mouse at colonial time and the current genetic structure exhibits a gradient-like pattern reflecting the historical process of spatially continuous expansion of the city from the first European settlement. The genetic patterns further suggest that population dynamics of the house mouse is also driven by the spatial heterogeneity of the current cityscape, including socio-economics features, that translate in habitat quality. Our results highlight the potential importance of accounting for past demographic events to understand spatial genetic patterns of nonnative invasive commensal rodents in highly urbanized environment.

Describing patterns and testing hypotheses on processes driving biological invasions represent major issues in ecology. Addressing these questions requires building adequate data sets, i.e., covering areas and spanning periods adapted to the invasion processes studied. Rodents include major invasive species, among which the black rat Rattus rattus and the domestic mouse Mus musculus have nearly colonized the entire world, from their native Asian range. To do so, they have benefitted from their ability to cope with human-modified environments and to live in the immediate vicinity of Man, who served as a vector of their dispersal between regions and continents. In Senegal, both R. rattus and M. musculus, initially introduced by early West European colonizers some centuries ago, are currently expanding thanks to road traffic and infrastructure development and rampant urbanization that concerns even remote regions of the country. As part of projects aimed at studying (1) the role of invasive black rat populations in the emergence of zoonotic diseases in southeastern Senegal, and (2) the evolutionary consequences of parasites in R. rattus and M. musculus invasions in Senegal, we conducted a series of field campaigns throughout the southern half of the country, between May 2012 and September 2015. The objectives were to catch commensal small mammals using standard trapping procedures, identify them using morphological or molecular tools, and take samples from them upon autopsy, to look for zoonotic parasites and pathogens. Along with data on individual specimens, information on microhabitats was gathered at each trap position. This resulted in the constitution of a data set of more than 13,000 trapnights, which allowed the capture of more than 3,100 small mammals, all characterized by a series of associated biological, geographical, and environmental data. The small mammals concerned are mainly rodents (10 species), shrews, and hedgehogs. The two invasive rodent species were the most numerous, exceeding in numbers all the other species pooled. This data set makes it possible to study coarse to fine-scaled distribution of species of this commensal community in southern Senegal, as well as the possible determinants of this distribution in terms of habitat preferences and/or interspecific interactions. This data set can be freely used for non-commercial purposes and is licensed under a Creative Commons Attribution 4.0 International License.

International audience; Commensal rodent species are key reservoirs for Toxoplasma gondii in the domestic environment. In rodents, different T. gondii strains show variable patterns of virulence according to host species. Toxoplasma gondii strains causing non-lethal chronic infections in local hosts will be more likely to persist in a given environment, but few studies have addressed the possible role of these interactions in shaping the T. gondii population structure. In addition, the absence of validated techniques for upstream detection of T. gondii chronic infection in wild rodents hinders exploration of this issue under natural conditions. In this study, we took advantage of an extensive survey of commensal small mammals in three coastal localities of Senegal, with a species assemblage constituted of both native African species and invasive species. We tested 828 individuals for T. gondii chronic infection using the modified agglutination test for antibody detection in serum samples and a quantitative PCR assay for detection of 7'. gondii DNA in brain samples. The infecting 7'. gondii strains were genotyped whenever possible by the analysis of 15 microsatellite markers. We found (i) a very poor concordance between molecular detection and serology in the invasive house mouse, (ii) significantly different levels of prevalence by species and (iii) the autochthonous T. gondii Africa 1 lineage strains, which are lethal for laboratory mice, only in the native African species of commensal small mammals. Overall, this study highlights the need to reconsider the use of MAT serology in natural populations of house mice and provides the first known data about T. gondii genetic diversity in invasive and native species of small mammals from Africa. In light of these results, we discuss the role of invasive and native species, with their variable adaptations to different T. gondii strains, in shaping the spatial structure of 7'. gondii genetic diversity in Africa.

Risks related to Toxoplasma gondii infection in humans remain poorly known in Senegal. Although rodent surveys could help to assess the circulation of T. gondii, they have seldom been set up in sub-Saharan Africa. The aim of this study was to examine Toxoplasma seroprevalence in rodents from villages and towns across Senegal. Rodents were sampled in 40 localities using a standardised trapping protocol. Detection of T. gondii antibodies was performed on 1205 rodents, using a modified agglutination test (MAT) technique. Seroprevalence data were analysed depending on geography, the local rodent community, and individual characteristics of the rodent hosts. We found 44 seropositive rodents from four different species (Mastomys erythroleucus, Mastomys natalensis, Mus musculus domesticus, Rattus rattus). Toxoplasma seroprevalence was low, averaging 4% in the localities. Higher Toxoplasma seroprevalence (up to 24%) was found in northern Senegal, a region known to be the heart of pastoral herding in the country., Séroprévalence de Toxoplasma gondii chez les rongeurs commensaux au Sénégal, Afrique de l’Ouest. Les risques liés à l’infection par Toxoplasma gondii chez l’homme restent mal connus au Sénégal. Bien que les rongeurs soient considérés comme des marqueurs pertinents de la circulation de T. gondii, peu d’études ont ciblé ces hôtes en Afrique sub-saharienne. Le but de cette étude était d’étudier la séroprévalence de Toxoplasma chez les rongeurs des villes et des villages du Sénégal. Les rongeurs ont été échantillonnés dans 40 localités avec un protocole de piégeage standardisé. La détection des anticorps contre T. gondii a été faite sur 1205 rongeurs avec un test d’agglutination modifié. Les données de séroprévalence ont été analysées en fonction de la géographie, de la communauté locale de rongeurs et de caractéristiques individuelles du rongeur. Nous avons trouvé 44 individus séropositifs, de quatre espèces différentes (Mastomys erythroleucus, Mastomys natalensis, Mus musculus domesticus, Rattus rattus). La séroprévalence moyenne est faible, de l’ordre de 4 % au sein des localités. Les plus fortes séroprévalences (jusqu’à 24 %) ont été observées dans le Nord du Sénégal, une région connue pour être le coeur de l’élevage pastoral dans le pays.

In some tumors, defects in mismatch repair enzymes lead to errors in the replication of simple nucleotide repeat segments. This condition is commonly known as microsatellite instability (MSI) because of the frequent mutations of microsatellite sequences. The primary aim of this study is to evaluate the clinicopathological and survival significance of BAT-25 and BAT-26 instability, in 60 patients with breast cancer. Polymerase chain reaction was used to amplify the following microsatellite repeat loci BAT-25 and BAT-26. Medical records were studied in order to determine clinical data of BAT-25 and BAT-26, analysis was carried out. 60.71% of cancer tissues analyzed were found to be unstable for both markers.BAT-26 instability has an impact on the age (Od: 15.47; CI 1.08-974; 19, P: 0.020) and survival (P: 0.0342) of patients. BAT-26 which has a poly A sequence, can be considered alone as a good marker for the detection of MSI tumors in breast cancer. Key words: Cancer, breast, polymorphism, microsatellites, Senegal.

1. The worldwide intensification of human-associated exchanges favours the multiplication of biological invasions. Among mammals, rodent species, including the house mouse Mus musculus, are identified as major invaders with profound impacts on native biodiversity, human health and activities. Though contemporary rodent invasions are described on several islands, there are few data describing ongoing house mouse invasions in continental areas. 2. We first outline the known picture of the distribution of the house mouse in Africa. We then describe the ongoing range expansion of the house mouse in Senegal, in order to update its distribution area, assess the location of the invasion front, describe the spatio-temporal dynamics of the invasion at the country scale and evaluate its impact on native small mammal communities. 3. We briefly review the worldwide status of the house mouse, with special focus on its situation in Africa. Focusing on Senegal, we then use historical records and a large body of spatio-temporal indoor trapping data obtained from small mammal communities over the last 30 years to analyse the invasion dynamics of the subspecies at the scale of the country. 4. The geographic range of the invasive house mouse is surprisingly poorly known in Africa. In Senegal, we document a large range expansion of the subspecies in human settlements over the whole country within the last 30 years. The invasion is still ongoing further east and south within the country, and has major consequences for small mammal communities and thus probably for risks associated with zoonotic diseases.

Subsaharan Africa, as in Senegal, breast cancer is the second after that of cervical in women. However, although most of the studies on breast pathology for cancer, the overwhelming majority of breast lesions, palpable or not are benign and some of them ca...

12 pages; International audience; Knowledge of the genetic make-up and demographic history of invasive populations is critical to understand invasion mechanisms. Commensal rodents are ideal models to study whether complex invasion histories are typical of introductions involving human activities. The house mouse Mus musculus domesticus is a major invasive synanthropic rodent originating from South-West Asia. It has been largely studied in Europe and on several remote islands, but the genetic structure and invasion history of this taxon have been little investigated in several continental areas, including West Africa. In this study, we focussed on invasive populations of M. m. domesticus in Senegal. In this focal area for European settlers, the distribution area and invasion spread of the house mouse is documented by decades of data on commensal rodent communities. Genetic variation at one mitochondrial locus and 16 nuclear microsatellite markers was analysed from individuals sampled in 36 sites distributed across the country. A combination of phylogeographic and population genetics methods showed that there was a single introduction event on the northern coast of Senegal, from an exogenous (probably West European) source, followed by a secondary introduction from northern Senegal into a coastal site further south. The geographic locations of these introduction sites were consistent with the colonial history of Senegal. Overall, the marked microsatellite genetic structure observed in Senegal, even between sites located close together, revealed a complex interplay of different demographic processes occurring during house mouse spatial expansion, including sequential founder effects and stratified dispersal due to human transport along major roads.

Several hypotheses (such as ‘enemy release’, ‘novel weapon’, ‘spillback’ and ‘dilution/density effect’) suggest changes in host-parasite ecological interactions during biological invasion events. Such changes can impact both invasion process outcome and the dynamics of exotic and/or endemic zoonotic diseases. To evaluate these predictions, we investigated the ongoing invasions of the house mouse Mus musculus domesticus, and the black rat, Rattus rattus, in Senegal (West Africa). We focused on zoonotic bacterial communities depicted using 16S rRNA amplicon sequencing approach in both invasive and native rodents sampled along two well-defined invasion routes. Overall, this study provided new ecological evidence connecting parasitism and rodent invasion process, with diverse potential roles of zoonotic bacteria in the invasion success. Our results also highlighted the main factors that lie behind bacterial community structure in commensal rodents. Further experimental studies as well as comparative spatio-temporal surveys are necessary to decipher the actual role of zoonotic bacteria in these invasions. Our data also gave new support for the difficulty to predict the direction in which the relationship between biodiversity changes and disease risk could go. These results should be used as a basis for public health prevention services to design reservoir monitoring strategies based on multiple pathogen surveillance.

Maize is attacked by many post-harvest pests including Sitophilus spp and Prostephanus spp, which causes remarkable loss during storage. Approxi-mately 30 to 40 % loss in the absence of treatment has been reported world-wide. This study compare genetically Central African and Senegalese popula-tions of Sitophilus zeamais from various agroecological zones using 3 mark-ers namely cytochrome b, cytochrome oxidase and nuclear 28S gene. S. zeamais samples were analyzed on both of two other sites 34 for the 28S gene; 68 for cytochrome b and 36 for the cytochrome oxydase. Results ana-lyzed by AMOVA have shown high genetic variation outside population of each country (6.17 % with Cyt b; 21.45 % with 49.83 % and COI in the case of 28S) and low within subpopulations (-10.06 % for Cyt b, 9.36 % for the COI and -15.23 % for 28S). Majority haplotype is shared between the two popula-tions for 28S and cytochrome b genes and there is a very high haplotype di-versity in populations of Senegal considering the Cytochrome b gene (0.781 + / - 0.00364) while with COI and 28S, high values of diversity are observed in Central African sequences, respectively 1.000 + / - 0.00274 and 0.867 + / - 0.011. Genetic differentiation obtained according to the geographical origin is significant between the two populations; however, it is not at the level of subpopulations. Developed by the three approaches (parsimony, likelihood and Bayesian) phylogenetic trees are resolved and show a speciation of the two populations according to the geographical origin.

This study compared erythrocyte changes between a group of subjects with sickle cell trait (SCT) and controls (subjects without hemoglobinopathy) during a soccer game in two conditions: with and without hydration. Erythrocyte deformability of subjects was assessed by the coefficient of erythrocyte rigidity (Tk) which was calculated before and after football match. Our results showed a significant increase in erythrocyte rigidity (Tk) in SCT at the end of physical activities without hydration; however when water was provided ad libitum their Tk decreased significantly, reaching values of controls. And adequate hydration is recommended in subjects with sickle cell trait during and after exercise.

International audience; Biological invasions provide unique opportunities for studying life history trait changes over contemporary time scales. As spatial spread may be related to changes in parasite communities, several hypotheses (such as the evolution of increased competitive ability (EICA) or EICA-refi ned hypotheses) suggest immune changes in invasive species along invasion gradients. Although native hosts may be subject to similar changes in parasite selection pressures, their immune responses have been rarely investigated in invasion contexts. In this study, we evaluated immune variations for invasive house mice Mus musculus domesticus , invasive black rats Rattus rattus and native rodents Mastomys erythroleucus and Mastomys natalensis along well-characterised invasion gradients in Senegal. We focused on antibody-mediated (natural antibodies and complement) and infl ammatory (haptoglobin) responses. One invasion route was considered for each invasive species, and environmental conditions were recorded. Natural-antibody mediated responses increased between sites of long-established invasion and recently invaded sites only in house mice. Both invasive species exhibited higher infl ammatory responses at the invasion front than in sites of long-established invasion. Th e immune responses of native species did not change with the presence of invasive species. Th ese patterns of immune variations do not support the EICA and EICA refi ned hypotheses, and they rather suggest a higher risk of exposure to parasites on the invasion front. Altogether, these results provide a fi rst basis to further assess the role of immune changes in invasion success.

Understanding why some exotic species become widespread and abundant in their colonized range is a fundamental issue that still needs to be addressed. Among many hypotheses, newly established host populations may benefit from a parasite loss (“enemy release” hypothesis) through impoverishment of their original parasite communities or reduced infection levels. Moreover, the fitness of competing native hosts may be affected by the acquisition of exotic taxa from invaders (“parasite spillover”) and/or by an increased transmission risk of native parasites due to their amplification by invaders (“parasite spillback”). We focused on gastrointestinal helminth communities to determine whether these predictions could explain the ongoing invasion success of the commensal house mouse (Mus musculus domesticus) and black rat (Rattus rattus), as well as the associated drop of native Mastomys species, in Senegal. For both invasive species, our results were consistent with the predictions of the enemy release hypothesis. A decrease of helminth overall prevalence and individual species richness was observed along the invasion gradients as well as lower specific prevalence/abundance (Aspiculuris tetraptera in M. m. domesticus, Hymenolepis diminuta in R. rattus) on the invasion fronts. Conversely, we did not find strong evidence of helminth spill-over or spill-back in invasion fronts, where native and invasive rodents co-occurred. Further experimental research is needed to determine whether and how the loss of helminths and reduced infection levels along invasion routes may result in any advantageous effects on invader fitness and competitive advantage.

Environmental heterogeneity influences coevolution and local adaptation in host-parasite systems. This also concerns applied issues, because the geographic range of parasites may depend on their capacity to adapt to abiotic conditions. We studied temperature-specific adaptation in the wheat yellow/stripe rust pathogen, Puccinia striiformis f.sp. tritici (PST). Using laboratory experiments, PST isolates from northern and southern France were studied for their ability to germinate and to infect bread and durum wheat cultivars over a temperature gradient. Pathogen origin × temperature interactions for infectivity and germination rate suggest local adaptation to high- versus low-temperature regimes in south and north. Competition experiments in southern and northern field sites showed a general competitive advantage of southern over northern isolates. This advantage was particularly pronounced in the southern 'home' site, consistent with a model integrating laboratory infectivity and field temperature variation. The stable PST population structure in France likely reflects adaptation to ecological and genetic factors: persistence of southern PST may be due to adaptation to the warmer Mediterranean climate; and persistence of northern PST can be explained by adaptation to commonly used cultivars, for which southern isolates are lacking the relevant virulence genes. Thus, understanding the role of temperature-specific adaptations may help to improve forecast models or breeding programmes.

Using the same set of microsatellite markers, we compared the population genetic structure of two Mastomys species, one being exclusively commensal in southeastern Senegal, and the other being continuously distributed outside villages in this region. Both species were sampled in the same landscape context and at the same spatial scale. According to the expectations based on the degree of habitat patchiness (which is higher for commensal populations in this rural area), genetic diversity was lower and genetic differentiation was higher in commensal populations of Mastomys natalensis than in wild populations of Mastomys erythroleucus. Contrasting estimates of effective dispersal and current migration rates corroborates previous data on differences in social structure between the two species. Isolation-by-distance analyses showed that human-mediated dispersal is not a major factor explaining the pattern of genetic differentiation for M. natalensis, and that gene flow is high and random between M. erythroleucus populations at the spatial scale considered.

Times Cited: 0; International audience; Invasive rodents have been responsible for the diffusion worldwide of many zoonotic agents, thus representing major threats for public health. Cities are important hubs for people and goods exchange and are thus expected to play a pivotal role in invasive commensal rodent dissemination. Yet, data about urban rodents' ecology, especially invasive vs. native species interactions, are dramatically scarce. Here, we provide results of an extensive survey of urban rodents conducted in Niamey, Niger, depicting the early stages of rodent bioinvasions within a city. We explore the species-specific spatial distributions throughout the city using contrasted approaches, namely field sampling, co-occurrence analysis, occupancy modelling and indicator geostatistics. We show that (i) two species (i.e. rural-like vs. truly commensal) assemblages can be identified, and that (ii) within commensal rodents, invasive (Rattus rattus and Mus musculus) and native (Mastomys natalensis) species are spatially segregated. Moreover, several pieces of arguments tend to suggest that these exclusive distributions reflect an ongoing native-to-invasive species turn over. The underlying processes as well as the possible consequences for humans are discussed.

International audience; Rodents are involved in the epidemiology of many pathogens and are major pests for agriculture. Local perception and beliefs about rodents and their damages is a key element of control programs. We here present the first survey focusing on the human perception of rodent-associated problems in an African town, namely Niamey, Niger. In total, 170 interviews were conducted in 18 different urban districts where rodents (Mastomys natalensis, Rattus rattus and Mus musculus) are widespread and abundant. Rodent-associated problems were mentioned in almost all instances (96.5 %). Eight different categories of rodent-induced nuisances could be recurrently identified. The most frequently cited one consists in damages on food and food stocks (63.1 %), followed by damages on houses (47.3 %), furniture (19.5 %) and clothes (16.8 %). There was no significant association between damages and districts, which means that the perception of rodent-associated problems did not vary significantly across the city. Our survey strongly suggests that rodents may represent major pests not only for farmers, but also for inhabitants of towns, thus contributing to reinforce economic vulnerability. Finally, no mention of sanitary or medical problems was ever recorded during our survey, thus pointing towards an apparent absence of knowledge about the potential role of rodents in some public health issues.

Environmental heterogeneity influences coevolution and local adaptation in hostparasite systems. This also concerns applied issues, because the geographic range of parasites may depend on their capacity to adapt to abiotic conditions. We studied temperature-specific adaptation in the wheat yellow/stripe rust pathogen, Puccinia striiformis f.sp. tritici (PST). Using laboratory experiments, PST isolates from northern and southern France were studied for their ability to germinate and to infect bread and durum wheat cultivars over a temperature gradient. Pathogen origin x temperature interactions for infectivity and germination rate suggest local adaptation to high- versus low-temperature regimes in south and north. Competition experiments in southern and northern field sites showed a general competitive advantage of southern over northern isolates. This advantage was particularly pronounced in the southern home site, consistent with a model integrating laboratory infectivity and field temperature variation. The stable PST population structure in France likely reflects adaptation to ecological and genetic factors: persistence of southern PST may be due to adaptation to the warmer Mediterranean climate; and persistence of northern PST can be explained by adaptation to commonly used cultivars, for which southern isolates are lacking the relevant virulence genes. Thus, understanding the role of temperature-specific adaptations may help to improve forecast models or breeding programmes.

Sera obtained from dairy cattle in communal corral herds located near the city of Bamako in Mali, West Africa were sceeened using the microscopic agglutination test against 26 serovars representing 15 serogroups of Leptospira interrogans. Forty five percent (44.8%; 288/642) were positive to one or more serovars. This seroprevalence rate likely reflects infection since vaccination against leptospiral infection has not been practiced i Mali. The rate was higher among females. The most common titers were against antigens of serovars cynopteri (14.7%), hardjo (13.3%), pomona (9.2%), nona (8.1%), kambale (6.5%), grippotypyosa (6.4%), hebdomadis (6.2%), and pyrogenes (5.2%).

Contact: fax: +33 4 9962 3345. E-mail address: carine.brouat@ird.fr; International audience; Contrasting host and parasite population genetic structures can provide information about the population ecology of each species and the potential for local adaptation. Here, we examined the population genetic structure of the nematode Neoheligmonella granjoni at a regional scale in southeastern Senegal, using 11 microsatellite markers. Using the results previously obtained for the two main rodent species of the host community, Mastomys natalensis and Mastomys erythroleucus, we tested the hypothesis that the parasite population structure was mediated by dispersal levels of the most vagile host. The results showed similar genetic diversity levels between host and parasite populations, and consistently lower levels of genetic differentiation in N. granjoni, with the exception of one outlying locus with a high F. The aberrant pattern at this locus was primarily due to two alleles occurring at markedly different frequencies in one locality, suggesting selection at this locus, or a closely linked one. Genetic differentiation levels and isolation by distance analyses suggested that gene flow was high and random in N. granjoni at the spatial scale examined. The correlation between pair-wise genetic differentiation levels in the parasite and its main host was consistent with the hypothesis tested. Models of local adaptation as a function of the dispersal rates of hosts and parasites suggest that opportunities for local adaptation would be low in this biological system. (C) 2011 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

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Rodent diagnosis has long remained obscured by the co-existence of cryptic species in many lineages. However, alternative and accessible methods, such as cytotaxonomy and DNA-based methods, are now available that allow biologists to accurately monitor biodiversity through the production of well documented lists of unambiguously species-specific identifications. As a continuation of our previous surveys of West African rodents, we here present the first rodent inventory of rodents from Northern Cameroon (as well as one locality in Western Chad) that fully relies on karyotypic and/or sequencing data. Doing so, we assess the presence of 18 species in this poorly documented region. Among them, we found several African spiny mice that could be referred as to A. johannis, a poorly documented species. Moreover, several Arvicanthis individuals could be aggregated with previously studied but still enigmatic specimens of ANI-2 and ANI-4 sensu Volobouev et al., 2002a , Volobouev et al., 2002b , thus suggesting that they may all belong to one single species, namely A. rufinus. In addition, one specimen was shown to belong to a new biological species (Praomys sp.) that will deserve further taxonomic investigations. Finally, several Taterillus specimens were found with 2n = 28–30 chromosomes and a XX/XY1Y2 sex chromosome system. On the basis of these new results as well as a reinterpretation of previously published data, we propose to refer these individuals as to the poorly documented Taterillus lacustris. Altogether, our data suggest that Northern Cameroon is a “phylogeographical node” for several rodent lineages which may be at least partly explained by the past changes within the Lake Chad basin. Keeping this in mind, there is little doubt that biodiversity will undergo important modifications in the coming decades, following the increasing aridity and the drastic reduction of Lake Chad.

Constituant un véritable tournant dans les relations entre l’Afrique et l’Europe, la décision de l’UE de privilégier le multilatéralisme dans ses rapports avec le continent africain met à nu les économies africaines. Les pourparlers sur la libéralisation des produits et sur la suppression des barrières tarifaires font partie du dispositif du futur accord de partenariat économique. Suscitant remous et controverses, les discussions sont ardues et complexes. Pourtant, en dépit de ces écueils, l’Afrique et l’Europe progressent dans la définition d’un nouvel instrument commercial., Kane Elimane Mamadou. Les accords de partenariats économiques, à l’épreuve des relations entre l’Afrique et l’Union européenne. In: Recherches Internationales, n°85, 2009. L’Afrique et le Monde. pp. 67-87.

Diplôme : Dr. d'Universite

International audience

Contact: Fax: +33499623345. E-mail: brouat@mpl.ird.fr; International audience; We studied patterns of variation in parasite communities of 2 closely related species of Mastomys rodents. These 2 species live in sympatry in South-eastern Senegal, but differ drastically in their habitat choice. We asked (a) whether the host species have the same parasites; (b) whether there is any observable pattern relative to the host species/habitat type in the structure of parasite communities; (c) whether the variability in parasite community for each host species is related to habitat characteristics. We analysed 220 and 264 individuals of each host species, sampled respectively in 10 and 11 trap sites. Twenty parasite taxa were recorded, and the majority were nematodes. Between-host species comparisons showed that helminth communities were slightly more diversified in M. natalensis. Many parasite species were found in both Mastomys. However, various helminth taxa varied in frequency and abundance between host species. Within each host species, helminth diversity, prevalence and/or abundance of some parasites were correlated with habitat or host population factors that may influence parasite life-cycles, such as village structure, or the presence/absence of a pool. Our results suggest that habitat characteristics have a strong impact on helminth community structure.

While the studies linking the germ line mtDNA mutations to cancer raise many ambiguities because of its high genetic variability, the study of somatic mutations of this one, is proved to be decisive in the identifying of mutations involved in the genesis and evolution of tumors. In the present study, we determined the implication of the Cytochrome b mutations in the evolution of breast benign tumors among Senegalese women. This one is about, with the sequencing-PCR, to research mutations of Cytochrome b, to evaluate their importance among a benign tissues group compared to another healthy tissues group; and thence, to determine the effect of the natural selection on the observed variability. The analysis of mutations profiles of Cytochrome b in benign tissues allowed seeing that 50% of them have led to a change in amino acid and 12.5% to a shift in the reading frame. Moreover, the analysis of selection signature indicated that these mutations were subjected to a positive selection. The results also revealed that the population of benign cells was growing rapidly from an ancestral population sparse. These observations have enabled to accept the hypothesis that Cytochrome b mutations would be involved in the evolution of breast benign tumors among Senegalese women.

Background Preventive chemotherapy against schistosomiasis has been implemented since 2005 in Mali, targeting school-age children and adults at high risk. A cross-sectional survey was conducted in 2010 to evaluate the impact of repeated treatment among school-age children in the highly-endemic region of Segou. Methodology/Principal Findings The survey was conducted in six sentinel schools in three highly-endemic districts, and 640 school children aged 7–14 years were examined. Infections with Schistosoma haematobium and S. mansoni were diagnosed with the urine filtration and the Kato-Katz method respectively. Overall prevalence of S. haematobium infection was 61.7%, a significant reduction of 30% from the baseline in 2004 (p, Author Summary Schistosomiasis or bilharzia is caused by infection with the trematode Schistosoma spp. It is widely prevalent in Mali, causing a major public health problem. One of the major control measures is mass treatment of population at risk, particularly school-age children, using the drug praziquantel. Mali started such mass drug treatments in 2005 and a cross-sectional survey was conducted in 2010 in highly endemic region Segou to evaluate the impact of the programme comparing with the baseline data collected in 2004. The repeated treatment significantly reduced the intensity of infection which is closely related to the morbidity of schistosomiasis, however, the prevalence persists with little reduction in the highly endemic region. The results suggest that more intensified control measures be implemented in order to achieve the goal of schistosomiasis elimination, possibly more frequent treatments, improved coverage and improved water and sanitation.