The Behavioral Determinants of Intestinal Schistosomiasis Transmission: Water Contact, Hygienic Practices and Risk Prevention. A study in Northern Senegal

Schistosomiasis (bilharzia) is one of the major parasitic diseases in the world, ranking second only to malaria in terms of its socio-economic and public health importance in tropical and subtropical areas (WHO, 1985; WHO, 2002). At least 200 million people are infected and 600 million at risk. An estimated 85% of all cases occur in Africa. Schistosomiasis is caused by infection with blood-dwelling fl uke worms (trematodes) of the genus Schistosoma. These are transmitted by fresh water snails and contracted through the skin during water contact. Humans can be infected by fi ve different species of the parasite, each of which has its own characteristics and effects. Except where mentioned differently, this thesis considers S. mansoni, the parasite of intestinal schistosomiasis in Northern Senegal

Variations in agronomic and grain quality traits of rice grown under irrigated lowland conditions in West Africa

Rice breeding in West Africa has been largely skewed toward yield enhancement and stress tolerance. This has led to the variable grain quality of locally produced rice in the region. This study sought to assess variations in the agronomic and grain quality traits of some rice varieties grown in this region, with a view to identifying sources of high grain yield and quality that could serve as potential donors in their breeding programs. Forty‐five varieties were grown under irrigated conditions in Benin and Senegal with two trials in each country. There were wide variations in agronomic and grain quality traits among the varieties across the trials. Cluster analysis using paddy yield, head rice yield, and chalkiness revealed that 68% of the total variation could be explained by five varietal groupings. One group comprising seven varieties (Afrihikari, BG90‐2, IR64, Sahel 108, WAT311‐WAS‐B‐B‐23‐7‐1, WAT339‐TGR‐5‐2, and WITA 10) had high head rice yield and low chalkiness. Of the varieties in this group, Sahel 108 had the highest paddy yield in three of the four trials. IR64 and Afrihikari had intermediate and low amylose content, respectively, with the rest being high‐amylose varieties. Another group of varieties consisting of B6144F‐MR‐6‐0‐0, C74, IR31851‐96‐2‐3‐2‐1, ITA222, Jaya, Sahel 305, WITA 1, and WITA 2 had high paddy yield but poor head rice yield and chalkiness. The use of materials from these two groups of varieties could accelerate breeding for high yielding rice varieties with better grain quality for local production in West Africa

Analyse des effects de la pluviometrie sur le PIB Agricole au Senegal

RESUMELe secteur agricole au Sénégal est dominé par les cultures pluviales dont l’arachide et le mil qui occupent la majeure partie des terres cultivables en hivernage. Sa contribution au PIB reste faible par rapport aux secteurs tertiaire et secondaire. Une des principales raisons de cette situation est sa forte dépendance aux conditions climatiques et notamment à la pluviométrie. Dans cette recherche nous nous proposons d’étudier l’analyse des effets de la pluviométrie sur le PIB du sous- secteur agricole au Sénégal. L’étude couvre une période de 35 ans allant de 1980 à 2015 et concerne tout le territoire national. Les résultats des tests économétriques par la technique des Moindres Carrés Ordinaires (MCO) montrent que la variation pluviométrique influence les résultats économiques du secteur agricole. L’étude montre qu’à chaque fois que la pluviométrie baisse, les productions et les valeurs économiques du mil et de l’arachide suivent la même tendance. Ainsi une bonne pluviométrie a un effet positif sur la production agricole qui à son tour influence positivement le PIB agricole. ABSTRACTANALYSIS OF THE EFFECTS OF RAINFALL ON AGRICULTURAL GDP IN SENEGALThe agricultural sector in Senegal is dominated by rainfed crops, with groundnuts and millet occupying most of the land. Its contribution to GDP remains low compared to the tertiary and secondary sectors. One of the main reasons for this situation is its strong dependence on climatic conditions and in particular on rainfall. In this research we propose to study the analysis of the effects of rainfall on the GDP of the agricultural sub-sector in Senegal. The study covers a 35-year period from 1980 to 2015 and concerns the entire national territory. The results of econometric tests using the Ordinary Least Squares (OLS) technique show that rainfall variation influences the economic performance of the agricultural sector. The study shows that each time the rainfall drops, the production and economic values of millet and peanuts follow the same trend. Thus, good rainfall has a positive effect on agricultural production which in turn positively influences agricultural GDP

Hepatitis B testing and treatment in HIV patients in The Gambia - compliance with international guidelines and clinical outcomes

Background Compliance with WHO guidelines on HBV screening and treatment in HIV-coinfected patients is often challenging in resource limited countries and has been poorly assessed in sub-Saharan Africa. Methods Between 2015 and 2016, we assessed physician’s compliance with WHO guidelines on HIV-HBV coinfection in the largest HIV clinic in The Gambia, and the hepatic outcomes in HIV-HBV coinfected patients as compared to randomly selected HIV-monoinfected controls. Results 870 HIV-infected patients regularly seen in this clinic agreed to participate in our study. Only 187 (21.5%, 95% CI 18.8–24.3) had previously been screened for HBsAg, 23 (12.3%, 95% CI 8.0–17.9) were positive of whom none had liver assessment and only 6 (26.1%) had received Tenofovir. Our HBV testing intervention was accepted by all participants and found 94/870 (10.8%, 95% CI 8.8–13.1) positive, 78 of whom underwent full liver assessment along with 40 HBsAg-negative controls. At the time of liver assessment, 61/78 (78.2%) HIV-HBV coinfected patients received ART with 7 (11.5%) on Tenofovir and 54 (88.5%) on Lamivudine alone. HIV-HBV coinfected patients had higher APRI score compared to controls (0.58 vs 0.42, p = 0.002). HBV DNA was detectable in 52/53 (98.1%) coinfected patients with 14/53 (26.4%) having HBV DNA >20,000 IU/L. 10/12 (83.3%) had at least one detectable 3TC-associated HBV resistance, which tended to be associated with increase in liver fibrosis after adjusting for age and sex (p = 0.05). Conclusions Compliance with HBV testing and treatment guidelines is poor in this Gambian HIV programme putting coinfected patients at risk of liver complications. However, the excellent uptake of HBV screening and linkage to care in our study suggests feasible improvements

Determining Pair Interactions from Structural Correlations

We examine metastable configurations of a two-dimensional system of interacting particles on a quenched random potential landscape and ask how the configurational pair correlation function is related to the particle interactions and the statistical properties of the potential landscape. Understanding this relation facilitates quantitative studies of magnetic flux line interactions in type II superconductors, using structural information available from Lorentz microscope images or Bitter decorations. Previous work by some of us supported the conjecture that the relationship between pair correlations and interactions in pinned flux line ensembles is analogous to the corresponding relationship in the theory of simple liquids. The present paper aims at a more thorough understanding of this relation. We report the results of numerical simulations and present a theory for the low density behavior of the pair correlation function which agrees well with our simulations and captures features observed in experiments. In particular, we find that the resulting description goes beyond the conjectured classical liquid type relation and we remark on the differences.Comment: 7 pages, 6 figures. See also http://rainbow.uchicago.edu/~grier

Controlling structural distortion in the geometrically frustrated layered cobaltate YBaCo4O7+{\delta} by Fe substitution and its role on magnetic correlations

Effects of Fe-substitution on the crystal structure and magnetic correlations of the geometrically frustrated antiferromagnets YBaCo4-xFexO7+{\delta} (x = 0, 0.2, 0.4, 0.5, 0.6, and 0.8) have been studied by neutron diffraction, M\"ossbauer spectroscopy, and ac susceptibility. The compounds YBaCo4-xFexO7+{\delta} have a special layered-type crystal structure with an alternating Kagom\'e (6c site) and triangular (2a site) layers along the c axis. Fe3+ ions are found to be substituted at both the crystallographic 2a and 6c sites of Co ions. M\"ossbauer results show a high spin state of Fe3+ ions in a tetrahedral coordination. A reduction in the distortion of the Kagom\'e lattice has been observed with the Fe-substitution. The correlation length of the short-range antiferromagnetic ordering decreases with the Fe-substitution. The sharpness of the magnetic transition also decreases with the Fe-substitution.Comment: 26 pages, 8 figures, 3 table

Prévalence et facteurs de risque des mammites subcliniques dans les élevages traditionnels de Kaolack au Sénégal

Les mammites subcliniques sont des affections incideuses de la glande mammaire mais qui impactent négativement la production de la vache laitière. Il s’avère nécessaire de faire le diagnostic en vue de les contrôler.Objectif : Le présent travail avait pour objectif de déterminer la prévalence des mammites subcliniques dans les élevages traditionnels de la région de Kaolack au Sénégal.Méthodologie et résultats : Au total 101 vaches en lactation des élevages traditionnels de la zone périurbaine de Kaolack ont fait l’objet de l’étude. Le California Mastitis Test (CMT) et le Comptages des Cellules Somatiques (CCS) avec le Delaval cells counter (Delval, Tumba, Suède), ont été utilisés pour analyser les échantillons de lait prélevés. Les prévalences ont été de 11,9% et de 10,9% en utilisant le CMT et le CCS respectivement. Il n’y a pas eu de différence significative entre prévalences obtenues par les deux tests (p=0,824). La prévalence des mammites chez les vaches métisses (12,5%) a été significativement plus élevée que celle des vaches de race locale Gobra (11,8%) (p=0,007). Par contre, le rang de mise bas n’a eu aucun effet sur la survenue des mammites (Odds ratio = 1,542 ; 95% IC : [0,884-2,690]).Conclusion : La prévalence des mammites obtenue dans les élevages traditionnels permet de dire qu’il faut envisager une prise en charge efficace des vaches malades et améliorer la production laitière. A la lumière de nos résultats, le test de CMT qui est fiable rapide simple et efficace peut être un bon moyen de détection rapide des mammites subcliniques dans les élevages traditionnelsMots clés : California Mastitis Test, Comptage Cellules Somatiques, Mammite subclinique, vache laitière, SénégalSubclinical mastitis is an insidious infection of the mammary gland which negatively affects the production of the dairy cow. Thus, it is necessary to make the diagnosis in order to control it.Objective: The objective of this study was to determine the prevalence of subclinical mastitis in traditional livestock (cows) in the region of Kaolack in Senegal.Methodology and results: A total of 101 lactating cows from traditional Kaolack peri-urban farming were studied. The California Mastitis Test (CMT) and Somatic Cell Counts (CCS) using Delaval cells counter (Delval, Tumba, Sweden) were utilized to analyze the milk samples. The prevalences were 11.9% and 10.9% using CMT and CCS respectively. There was no significant difference between the prevalences obtained by the two tests (p = 0.824). The prevalence of mastitis in crossbred cows (12.5%) was significantly higher than that of local Gobra cows (11.8%) (p = 0.007). On the other hand, the calving rank had no effect on the occurrence of mastitis (Odds ratio = 1.542 ; 95% CI : [0.884-2.690]). Conclusion: The prevalence of mastitis obtained in traditional livestock suggests that effective management of sick cows should be considered in order to improve dairy production. In light of our findings, the CMT test which is reliable fast simple and effective can be a good means of rapid detection of subclinical mastitis in traditional dairy farms.Keywords: California Mastitis Test, Somatic cell count, Subclinical mastitis, dairy cow, Senega