Impact de la dynamique de peuplement sur la distribution des glossines et des trypanosomoses dans la boucle du Mouhoun (Burkina Faso)

Abstract

In Burkina Faso, the Mouhoun river basin (formerly "Black Volta") constitutes a historical focus of Human (HAT) and Animal (AAT) African Trypanosomoses, both transmitted by tsetse flies. Nowadays, HAT seems to have disappeared from this area, while AAT still causes severe economic losses. In order to explain these different epidemiological situations, we undertook a geographical study based on the analysis of aerial pictures between 1952 and 2007, and field surveys to collect medical, entomological, and veterinary data on trypanosomoses. Our results suggest that in this area, landscapes have been dramatically modified as a consequence of population growth, and in turn have had an impact on the number and distribution of tsetse flies. Combined with the historical medical action on HAT which probably led to the disappearance of T. b. gambiense, this environmental degradation and the development of hydrological structures provide explanations for the local disappearance of HAT, and for the maintenance of AAT. It appears necessary to extrapolate these studies to other areas in order to identify the factors explaining the presence/absence of trypanosomoses in the context of human population growth and climatic changes, in order to help to target priority areas for the control of these diseases. Résumé

La trypanosomose humaine africaine dans l’espace ivoiro-burkinabé : optimisation des stratégies de surveillance épidémiologique

“…En effet, de nombreux burkinabés venant des foyers de THA de Côte d’Ivoire se sont installés dans des zones historiques de la maladie où Glossina palpalis gambiensis et Glossina tachinoides sont encore bien présentes (Rayaisse et al, 2009). Mais toutes les prospections médicales menées dans ces zones n’ont pas identifié de cas de THA (Rouamba et al , 2009 ; Courtin et al, 2010a) et tous les suspects sérologiques identifiés ont été négatifs à la trypanolyse (Jamonneau et al , 2010). Nous confirmons donc les observations de Courtin et al (2010) suggérant que la réintroduction répétée du parasite au Burkina Faso ne semble pas suffisante à une reprise de la transmission en zone de savane pour différentes raisons déjà évoquées dans l’article précité.…”

“…Parmi eux, 24 provenaient de la Côte d’Ivoire (Lankoande & Ouedele, 1982). Lors des prospections médicales menées ces dernières années dans des zones définies comme particulièrement à risque de réémergence dans le contexte de la crise ivoirienne et du rapatriement massif de burkinabés venant des foyers ivoiriens, aucun cas autochtone de THA n’a pu être identifié (Rouamba et al , 2009 ; Courtin et al , 2010a) et les seuls cas dépistés au Burkina Faso sont des cas importés de Côte d’Ivoire (Millogo et al , 1999 ; Simarro et al , 2010). …”

Description of the first sleeping sickness case diagnosed in Burkina Faso since two decades

“…Although the savannah area of Burkina Faso was particularly affected between 1930 and 1980 with tens of thousands of cases [3], the last native case was reported in 1993 in the Bobo-Dioulasso area [4]. No cases have been reported in at-risk areas since 2005, when active mass screening was initiated [5,6]. However, a few cases imported from Côte d’Ivoire are detected every year in Burkina Faso [7].…”

Human African Trypanosomiasis in Suburban and Urban Areas: A Potential Challenge in the Fight Against the Disease

“…Some analysis has shown that riverine species are little affected or not at all by human population growth and are thus likely to remain extant indefinitely [49]. Indeed, in areas both infected by savanna (morsitans group) and riverine species, the number and the distribution of species of morsitans group decreased in the course of time, while those of palpalis group are less affected [50,51]. Moreover, beyond their peridomestic behavior, species of palpalis group exhibit an ability to adapt in big urban centers as soon as microclimatic conditions and host availability are met, with a possibility to transmit trypanosomosis [52] and even a biting nuisance to humans in their houses [53].…”