H3Africa is developing capacity for health-related genomics research in Africa

BackgroundThe success of current control tools in combatting malaria vectors is well established. However, sustained residual transmission of Plasmodium parasites persists. Mass drug administration (MDA) to humans of the endectocide ivermectin for vector control is receiving increasing attention. However, vectors feeding upon animals escape this promising approach. Zoophagy of mosquitoes sustains both the vector population and endemic population of vector-borne pathogens. Therefore, only a strategy that will combine ivermectin MDAs targeted at humans and their peridomestic animals could be successful at controlling residual malaria transmission.MethodsBurkinabé cattle have been treated with injectable therapeutic dose of ivermectin (0.2 mg/kg of body weight) to render blood meals toxic to field representative populations of Anopheles coluzzii carrying the kdr mutation. Direct skin-feeding assays were performed from 2 to 28 days after injection (DAI) and mosquitoes were followed for their survival, ability to become gravid and fecundity. Membrane feeding assays were further performed to test if an ivermectin blood meal taken at 28 DAI impacts gametocyte establishment and development in females fed with infectious blood.ResultsThe mosquitocidal effect of ivermectin is complete for 2 weeks after injection, whether 12 days cumulative mortalities were of 75 and 45 % the third and fourth weeks, respectively. The third week, a second ivermectin blood meal at sub-lethal concentrations further increased mortality to 100 %. Sub-lethal concentrations of ivermectin also significantly decreased egg production by surviving females, increasing further the detrimental effect of the drug on vector densities. Although females fitness was impaired by sub-lethal ivermectin blood meals, these did not diminish nor increase their susceptibility to infection.ConclusionThis study demonstrates the potential of integrated MDA of ivermectin to both human and peridomestic cattle to target vector reservoirs of residual malaria transmission. Such integration lies in ‘One-Health’ efforts being implemented around the globe, and would be especially relevant in rural communities in Africa where humans are also at risk of common zoonotic diseases.Electronic supplementary materialThe online version of this article (doi:10.1186/s12936-015-1001-z) contains supplementary material, which is available to authorized users.

BackgroundTsetse flies transmit trypanosomes that cause human and African animal trypanosomosis, a debilitating disease of humans (sleeping sickness) and livestock (nagana). An area-wide integrated pest management campaign against Glossina palpalis gambiensis has been implemented in Senegal since 2010 that includes a sterile insect technique (SIT) component. The SIT can only be successful when the sterile males that are destined for release have a flight ability, survival and competitiveness that are as close as possible to that of their wild male counterparts.Methodology/Principal FindingsTests were developed to assess the quality of G. p. gambiensis males that emerged from pupae that were produced and irradiated in Burkina Faso and Slovakia (irradiation done in Seibersdorf, Austria) and transported weekly under chilled conditions to Dakar, Senegal. For each consignment a sample of 50 pupae was used for a quality control test (QC group). To assess flight ability, the pupae were put in a cylinder filtering emerged flies that were able to escape the cylinder. The survival of these flyers was thereafter monitored under stress conditions (without feeding). Remaining pupae were emerged and released in the target area of the eradication programme (RF group). The following parameter values were obtained for the QC flies: average emergence rate more than 69%, median survival of 6 days, and average flight ability of more than 35%. The quality protocol was a good proxy of fly quality, explaining a large part of the variances of the examined parameters.Conclusions/SignificanceThe quality protocol described here will allow the accurate monitoring of the quality of shipped sterile male tsetse used in operational eradication programmes in the framework of the Pan-African Tsetse and Trypanosomosis Eradication Campaign.

No abstract

No abstract

BackgroundThe application of the sterile insect technique (SIT) requires mass-production of sterile males of good biological quality. The size of the project area will in most cases determine whether it is more cost effective to produce the sterile flies locally (and invest in a mass-rearing facility) or import the sterile flies from a mass-rearing facility that is located in another country. This study aimed at assessing the effect of long distance transport of sterile male Glossina palpalis gambiensis pupae on adult male fly yield.MethodsThe male pupae were produced at the Centre International de Recherche-Développement sur l’Elevage en zone Subhumide (CIRDES), Bobo-Dioulasso, Burkina Faso, and shipped with a commercial courier service in insulated transport boxes at a temperature of ±10°C to Senegal (±36 h of transport). Upon arrival in the insectary in Dakar, the pupae were transferred to an emergence room and the flies monitored for 3–6 days.ResultsThe results showed that the used system of isothermal boxes that contained phase change material packs (S8) managed to keep the temperature at around 10°C which prevented male fly emergence during transport. The emergence rate was significantly higher for pupae from batch 2 (chilled at 4°C for one day in the source insectary before transport) than those from batch 1 (chilled at 4°C for two days in the source insectary before transport) i.e. an average (±sd) of 76.1 ± 13.2% and 72.2 ± 14.3%, respectively with a small proportion emerging during transport (0.7 ± 1.7% and 0.9 ± 2.9%, respectively). Among the emerged flies, the percentage with deformed (not fully expanded) wings was significantly higher for flies from batch 1 (12.0 ± 6.3%) than from batch 2 (10.7 ± 7.5%). The amount of sterile males available for release as a proportion of the total pupae shipped was 65.8 ± 13.3% and 61.7 ± 14.7% for batch 1 and 2 pupae, respectively.ConclusionsThe results also showed that the temperature inside the parcel must be controlled around 10°C with a maximal deviation of 3°C to maximize the male yield.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-015-0869-3) contains supplementary material, which is available to authorized users.

The impact of landscape fragmentation due to human and climatic mediated factors on the structure of a population of Glossina palpalis gambiensis Vanderplank (Diptera: Glossinidae) was investigated in the Mouhoun river basin, Burkina Faso. Allele frequencies at five microsatellite loci, and metric properties based on 11 wing landmarks, were compared between four populations. The populations originated from the Mouhoun river and one of its tributaries. The average distance between samples was 72 km with the two most widely spaced populations being 216 km apart. The sampling points traversed an ecological cline in terms of rainfall and riverine forest ecotype, along a river enlarging from downstream to upstream and oriented south to north. Microsatellite DNA comparison demonstrated structuring between the populations, but not complete isolation, with an overall Fst = 0.012 (P < 0.001). Wing geometry revealed significant centroid size and shape differences between populations, especially between the two most distant populations. There was no significant correlation between gene flow and geographic distance at this scale, but there was a positive correlation in females between metric distances (wing shape differences) and geographic distances that might be attributed to the cline of environmental conditions. The impact of the fragmentation of riparian landscapes on tsetse population structure is discussed in the context of control campaigns currently promoted by Pan African Tsetse and Trypanosomosis Eradication Campaign.

Le polymorphisme de quatre catégories de marqueurs du génome — 11 systèmes de groupes sanguins, 5 locus des protéines du lait, 2 locus de protéines sanguines et 33 microsatellites, soit au total 51 locus — a été analysé dans quatre populations ou « races » bovines d’Afrique de l’Ouest : les races taurines Somba et Lagunaire, la population de zébus Peuls soudanais et la population Borgou, qui provient du métissage entre taurins et zébus, en vue de caractériser le polymorphisme de la race Somba et d’évaluer sa distance génétique avec les trois autres populations, notamment la race Lagunaire avec laquelle elle présente une forte ressemblance phénotypique. Quelles qu’aient été les catégories de marqueurs ou les méthodes utilisées, les quatre populations se sont séparées nettement les unes des autres. Au niveau des groupes sanguins, les différences les plus nettes ont été observées entre les taurins et les zébus, notamment dans les systèmes A, B et S. On a retrouvé par ailleurs chez les zébus la forte fréquence des allèles AlbS et HbB, ainsi que la prédominance bien connue de l’haplotype αs1-CnC, β-CnA2, κ-CnA qui contraste avec celle de l’haplotype αs1- CnB, β-CnA1, κ-CnB chez les taurins africains. Au niveau des microsatellites, l’analyse factorielle des correspondances a souligné le rôle discriminant de l’allèle ETH 225139, dont la fréquence a été très élevée chez la race Somba, et celui des allèles Hel 13182 et INRA 037114 qui ont paru spécifiques respectivement des zébus et de la race Lagunaire. Les fréquences de ces allèles dans la population Borgou ont été sensiblement intermédiaires entre celles des zébus et celles des taurins. Dans le cadre d’une démarche visant à établir dans quelle mesure la connaissance du génotype d’un animal aux 33 marqueurs microsatellites permettait d’identifier sa population d’origine, une proportion de 97 p. 100 d’animaux bien classés a été obtenue, les erreurs de classement s’étant limitées à des zébus incorrectement qualifiés de Borgou et vice versa.