title: Urban schistosomiasis and associated determinant factors among school children in Bamako, Mali, West Africa.
abstract: BACKGROUND
  Schistosomiasis is classically described as a rural disease that occurs in areas with poor sanitary conditions. However, over recent decades, there has been an expansion of schistosomiasis foci towards urban areas faced with a rapid and disordered urbanization. In Bamako, Mali, the impact of environmental change on vector-borne diseases such as schistosomiasis is not well known. This study sought to identify the presence of schistosomiasis transmission hotspots in Bamako. Using this perspective, we aimed to describe the risk factors of the endemization and maintenance of schistosomiasis.
  
  
  METHODS
  A cross-sectional study was carried out in the six municipalities (communes) in Bamako. Environmental information was obtained from earth observation satellites in order to maximize ecological contrasts. Twenty-nine blocks of 200 m x 200 m were identified. We selected a school inside or nearest to each block for urine and stool samples examination. The study cohort was school children aged between eight and 15 years. The Kato-Katz technique and filtration were used for Schistosoma mansoni and S. haematobium ova research in stools and urine, respectively. The schools and snail breeding sites were georeferenced. Four malacological surveys were conducted between October 2011 and February 2012. Bivariate analysis was used to identify independent predictors of being infected with schistosomiasis.
  
  
  RESULTS
  The prevalence rate of S. haematobium was 14.7% (n = 1,761) and that of S. mansoni 1.5% (n = 1,491). Overall, the urinary form was endemic in 76.6% of schools. The infection significantly varied between the municipalities (p < 0.001). It was also more prevalent on the left side of the Niger River than the right side (17.4% vs. 9.5% respectively; p < 0.001). The vicinity to snail breeding sites (OR = 3.677; 95% IC [2.765-4.889]; p < 10 (-3) ) and parents' occupations (OR = 7.647; 95% IC [2.406-24.305]; p < 0.001) were the most important risk factors associated with S. haematobium infection exposure. Biomphalaria pfeifferi, Bulinus truncatus, and B. globosus were the intermediate hosts captured. The schistosome natural infection rates (SNIRs), which were low or nil in October and November, rose to 2.8% in January and 8.3% in February for B. pfeifferi and B. truncatus, respectively.
  
  
  CONCLUSIONS
  Our findings show that there is a high transmission risk for schistosomiasis in Bamako. Appropriate integrated control measures need to be introduced to control the transmission of this disease in the study area.
authors.affiliation: Department of Epidemiology of Infectious Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Techniques and Technologies of Bamako, Box 1805, Bamako, UMI 3189 Mali.
authors.forename: Abdoulaye
authors.initials: A
authors.lastname: Dabo
authors.affiliation: Department of Epidemiology of Infectious Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Techniques and Technologies of Bamako, Box 1805, Bamako, UMI 3189 Mali.
authors.forename: Adama Z
authors.initials: AZ
authors.lastname: Diarra
authors.affiliation: Unité d'entomologie médicale, Equipe 7, Maladies émergentes et moustiques, Institut de Médecine Tropicale du Service de Santé des Armées, Allée du Médecin Colonel Jamot, Parc du Pharo, BP60109, 13262 Marseille Cedex 07, France.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Machault
authors.affiliation: Department of Epidemiology of Infectious Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Techniques and Technologies of Bamako, Box 1805, Bamako, UMI 3189 Mali.
authors.forename: Ousmane
authors.initials: O
authors.lastname: Touré
authors.affiliation: Department of Epidemiology of Infectious Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Techniques and Technologies of Bamako, Box 1805, Bamako, UMI 3189 Mali.
authors.forename: Diarra Sira
authors.initials: DS
authors.lastname: Niambélé
authors.affiliation: Department of Epidemiology of Infectious Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Techniques and Technologies of Bamako, Box 1805, Bamako, UMI 3189 Mali.
authors.forename: Abdoulaye
authors.initials: A
authors.lastname: Kanté
authors.affiliation: Department of Epidemiology of Infectious Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Techniques and Technologies of Bamako, Box 1805, Bamako, UMI 3189 Mali.
authors.forename: Abdoulaye
authors.initials: A
authors.lastname: Ongoiba
authors.affiliation: Department of Epidemiology of Infectious Diseases, Faculty of Medicine, Pharmacy and Dentistry, University of Techniques and Technologies of Bamako, Box 1805, Bamako, UMI 3189 Mali.
authors.forename: Ogobara
authors.initials: O
authors.lastname: Doumbo
keywords: Bamako; Breeding sites; Endemization; Mali; Schistosomiasis; Snails