PhD Work

Geographic Determinants of Human Schistosomiasis Transmission in the Sourou Valley, Burkina Faso

Worldwide, the macrogeographic distribution of human schistosomiasis (also bilharziasis) is drawn by climate and the distribution of freshwater bodies, appropriate habitats for snail intermediate hosts of parasites. Infections occur only within parasites and their respective intermediate hosts’ endemic areas which are circumscribed to the tropical areas that contain more than half the population of the earth (Kloss & David, 2002; Engels et al., 2002; Gryseels et al., 2006). According to WHO Experts Committee, 77 countries were hold throughout the world to be endemic areas in which one or more Schistosoma species are being transmitted to human and 55% of those countries are located in SSA (WHO, 2012). On the other hand, the prevalence of infection within endemic communities is strongly determined by the microgeographic variation in the physical environment, human settlement patterns, the distribution of freshwater habitat for snails and the intensity of exposure and contaminative contact by humans and the prevalence of pathogenic worms and host snails (Kloss & David, 2002).
The Sourou Valley straddles with three provinces of the administrative region of the Boucle du Mouhoun at the north-west of Burkina Faso a land-locked country in western SSA, as displays Map 1. The study area is under the influence of a soudano-sahelian climate. Monthly mean air temperatures fluctuate between 24.06 °C in January and 33.27 °C in May (Di-Sourou weather station: 1980-2010). A long dry season contrasts with a short raining one (June-September) with an annual rainfall of 675 mm (1980-2010). Biodiversity potentially, the Sourou Valley is one of the most important wetlands centered on the Sourou River flowing north to south (about 65 km in Burkina Faso) and becomes a tributary of the Mouhoun River (the most important and permanent water flow in the country). It meets potentialities for hydro-agricultural development and is home of anthropogenic (irrigation) and demographic (migration) changes. Therefore the study area is an eco-area for human schistosomiasis transmission. Previous biomedical works have established proofs of the endemic area both to Schistosoma haematobium (parasite responsible for the urinary form of the disease) and Schistosomiasis mansoni (transmitting the intestinal form) (Poda et al., 2001; Dianou et al., 2003; Dianou et al., 2004; Poda et al., 2004; Poda et al., 2006). This geographical study targets to put in perspective the natural and social determinants of human schistosomiasis transmission in the Sourou Valley.


Climate change and water-borne diseases, Burkina Faso



Sourou Valley: