Risk factors of visceral leishmaniasis in East Africa: a case-control study in Pokot territory of Kenya and Uganda

BACKGROUND: In East Africa, visceral leishmaniasis (VL) is endemic in parts of Sudan, Ethiopia, Somalia, Kenya and Uganda. It is caused by Leishmania donovani and transmitted by the sandfly vector Phlebotomus martini. In the Pokot focus, reaching from western Kenya into eastern Uganda, formulation of a prevention strategy has been hindered by the lack of knowledge on VL risk factors as well as by lack of support from health sector donors. The present study was conducted to establish the necessary evidence-base and to stimulate interest in supporting the control of this neglected tropical disease in Uganda and Kenya. METHODS: A case-control study was carried out from June to December 2006. Cases were recruited at Amudat hospital, Nakapiripirit district, Uganda, after clinical and parasitological confirmation of symptomatic VL infection. Controls were individuals that tested negative using a rK39 antigen-based dipstick, which were recruited at random from the same communities as the cases. Data were analysed using conditional logistic regression. RESULTS: Ninety-three cases and 226 controls were recruited into the study. Multivariate analysis identified low socio-economic status and treating livestock with insecticide as risk factors for VL. Sleeping near animals, owning a mosquito net and knowing about VL symptoms were associated with a reduced risk of VL. CONCLUSIONS: VL affects the poorest of the poor of the Pokot tribe. Distribution of insecticide-treated mosquito nets combined with dissemination of culturally appropriate behaviour-change education is likely to be an effective prevention strategy

Sécurité Transfusionnelle à l’Hôpital Général de Référence Dr Rau/Ciriri, à l’Est de la République Démocratique du Congo

Objectif : La présente étude avait pour objectif de décrire le profil de la sécurité transfusionnelle à l’Hôpital General de Référence Dr Rau de Ciriri.Méthodes : Une étude transversale rétrospective a été conduite du 1er janvier au 31 juin 2012 auprès des donneurs de sang fréquentant le service de laboratoire de l’Hôpital General de Reference Dr Rau de Ciriri.Résultats : Les séroprévalences globales des marqueurs du virus de l’immunodéficience humaine, des virus des hépatites B et C, et de la syphilis chez les donneurs de sang étaient respectivement de 1,1%, 3,8%, 0,7% et 0,0%. Ces séroprévalence étaient plus élevée dans la catégorie des donneurs familiaux et nouveaux. Aucune investigation n’avait été réalisée chez les donneurs avant le don de sang. Les qualifications immunologique et biologique des poches de sang étaient incomplètes et certaines poches de sang étaient transfusées sans les résultats des marqueurs des virus des hépatites B et C, et de la syphilis.Conclusions : La sécurité transfusionnelle demeure un problème de santé à l’Hôpital Général de Référence Dr Rau de Ciriri. Une sensibilisation de la population sur le don bénévole de sang, une sélection médicale des donneurs et des qualifications immunologique et biologique complètes pourraient réduire les risques transfusionnels dans cette structure sanitaire

Do Permethrin-Treated Screens Repel Sand Flies from Entering Houses ?

The effects of permethrin-treated screens on sand flies entering treated houses were evaluated in Marigat area of Baringo District, Kenya. Screens treated with 0.50 g/m2 a. i. of permethrin 20 % E.C. were fitted inside houses and retreated every 6 months from January 1992 to December 1993. In the treated village, 40.62 % sand flies were caught inside while 67.34 % sand flies were collected outside houses. In the control village, 32.66 % sand flies were collected inside while 59.38 % sand flies were caught outside houses. The number of sand flies collected outside houses in the treated village was higher than those collected inside houses in the same village (X2 = 30.97, df = 11, P = 0.001). Twelve species of sand flies were collected in the area, of which nine species of the Sergentomyia and three species of the Phlebotomus genera. Phlebotomus martini and P. duboscqi, vecfors of visceral and cutaneous leishmaniasis respectively were collected inside houses in both treated and control villages. Permethrin-treated screens fitted inside houses were effective against sand flies as they reduced the number of flies entering houses. However, the treated screens did not seem to have any effect on sand fly species composition. Permethrin-treated screens are an important tool for controlling sand flies in the communities

Multi-Temporal DInSAR to Characterise Landslide Ground Deformations in a Tropical Urban Environment: Focus on Bukavu (DR Congo)

Landslides can lead to high impacts in less developed countries, particularly in tropical environments where a combination of intense rainfall, active tectonics, steep topography, and high population density can be found. However, the processes controlling landslide initiation and their evolution through time remains poorly understood. Here we show the relevance of the use of the multi-temporal differential radar interferometric (DInSAR) technique to characterise ground deformations associated with landslides in the rapidly-expanding city of Bukavu (DR Congo). We use 70 COSMO-SkyMed synthetic aperture radar images acquired between March 2015 and April 2016 with a mean revisiting time of eight days to produce ground deformation rate maps and displacement time series using the small baseline subset approach. We find that various landslide processes of different ages, mechanisms, and states of activity can be identified. Ground deformations revealed by DInSAR are found consistent with field observations and differential GPS measurements. Our analysis highlights the ability of DInSAR to grasp landslide deformation patterns affecting the complex tropical-urban environment of the city of Bukavu. However, longer time series will be needed to infer landside responses to climate, seismic, and anthropogenic drivers

Landslide hazard in the North Tanganyika - kivu rift zones: current knowledge and research perspective

The North tanganyika – Kivu rift zones are areas naturally prone to landsliding where triggering and environmental factors that favour the occurrence of mass movement concentrate. In many places landslide hazard is very high, and anthropogenic factors such as land use change and urban expansion increase the sensibility to slope instability. From seismic to rainfall-induced mass movements we review the current knowledge of the various slope precesses and associated hazards that are present in these equatorial environments. A particular attention is given to urban areas such as Bukavu and Bujumbura where lanslide threat is particularly acute. Research perspectives on landslide inventorying, monitoring, and susceptibility and hazard assesment are presented

Susceptibility status of Anopheles gambiae s.l. to insecticides used for malaria control in Kinshasa, Democratic Republic of the Congo: Statut de la sensibilité des Anopheles gambiae s.l. aux insecticides utilisés pour le contrôle du paludisme à Kinshasa, République Démocratique du Congo

Contexte et objectif. Malgré plusieurs années de lutte, le paludisme demeure toujours la première cause de mortalité infantile sous les tropiques. Actuellement, la stratégie de contrôle vise des actions simultanées contre l’agent causal et le vecteur du paludisme. L’objectif de la présente étude était de décrire la distribution de la sensibilité d'Anopheles gambiae sl aux insecticides à travers la ville de Kinshasa. Méthodes. Des larves d'anophèles ont été collectées, à travers sept sites de Kinshasa, pendant la période allant de septembre 2017 à mai 2018. Des bioessais standard de l'OMS ont été utilisés pour mesurer la sensibilité d'Anopheles gambiae s.l. aux insecticides. La distribution des espèces et le profil de résistance ont été évalués en recourant aux tests diagnostiques moléculaires. Résultats. Deux espèces du complexe gambiae ont été identifiées : An. gambiae (98,3 %) et An. coluzzii (1,7 %). Une variabilité du statut de résistance à la  deltaméthrine par site a été observée. Cependant, une restauration de la sensibilité a été notée après une pré-exposition au butoxyde de pipéronyle (PBO) dans tous les sites présentant une résistance à la deltaméthrine. Conclusion. La présente étude a démontré qu’An. gambiae s.l. était résistant à la perméthrine dans tous les sites retenus. Cependant, la résistance à la deltaméthrine était variable. Le profil de résistance indique que les moustiquaires deltaméthrine+PBO devraient être envisagées pour la lutte anti vectorielle. Context and objective. Despite many years of control, malaria remains the leading cause of child mortality in the tropics. Currently, the control strategy aims at simultaneous actions against the causal agent and the vector of malaria. This study aimed to describe the distribution of the susceptibility of Anopheles gambiae sl to insecticides across the city of Kinshasa. Methods. Anopheles larvae were collected from seven sites in Kinshasa during the period from September 2017 to May 2018. Standard WHO bioassays were used to determine the sensitivity of Anopheles gambiae s.l. to insecticides. The species distribution and the resistance profile were evaluated by polymerase chain reaction. Results. Two species of the gambiae complex were identified: An. gambiae (98.3 %) and An. coluzzii (1.7 %). Variability of deltamethrin resistance status by site was observed; however, a restoration of susceptibility was noted after pre-exposure to piperonyl butoxide (PBO) in all sites with deltamethrin resistance. Conclusion. The present study showed that An. gambiae s.l. was resistant to permethrin in all the selected sites. However, resistance to deltamethrin was variable. The resistance profile indicates that deltamethrin+PBO nets should be considered for vector control

Landslide inventory for hazard assessment in a data- poor context: a regional-scale approach in a tropical African environment

Landslide hazard remains poorly characterized on regional and global scales. In the tropics in particular, the lack of knowledge on landslide hazard is in sharp contrast with the high landslide susceptibility of the region. Moreover, landslide hazard in the tropics is expected to increase in the future in response to growing demographic pressure and climate and land use changes. With precipitation as the primary trigger for landslides in the tropics, there is a need for an accurate determination of rainfall thresholds for landslide triggering based on regional rainfall information as well as reliable data on landslide occurrences. Here, we present the landslide inventory for the central section of the western branch of the East African Rift (LIWEAR). Specific attention is given to the spatial and temporal accuracy, reliability, and geomorphological meaning of the data. The LIWEAR comprises 143 landslide events with known location and date over a span of 48years from 1968 to 2016. Reported landslides are found to be dominantly related to the annual precipitation patterns and increasing demographic pressure. Field observations in combination with local collaborations revealed substantial biases in the LIWEAR related to landslide processes, landslide impact, and the remote context of the study area. In order to optimize data collection and minimize biases and uncertainties, we propose a three-phase, Search-Store-Validate, workflow as a framework for data collection in a data-poor context. The validated results indicate that the proposed methodology can lead to a reliable landslide inventory in a data-poor context, valuable for regional landslide hazard assessment at the considered temporal and spatial resolutions