Nakatt, Lemat, Gaye, Papa Mouhamadou, Moukah, Mohamed Ouldabdallahi, Niang, Binta, Basco, Leonardo, Ranque, Stephane, and Ould Mohamed Salem Boukhary, Ali
Background: Urogenital schistosomiasis due to Schistosoma haematobium is a major public health problem in Mauritania, but little is known about its epidemiology in many areas of the country, particularly in the lake zones. The objectives of the present parasitological and malacological study were to assess the prevalence and intensity of urogenital schistosomiasis among school children in Kankossa and Oued Rawdha lakes, southern Mauritania, and determine the species of intermediate host snails and the prevalence of snails with schistosome. Methods: A school-based epidemiological survey was conducted in two villages in the lake areas of Kankossa and Oued Rawdha. Urine samples were collected from 450 state primary school children and Koranic school children and examined for the presence of S. haematobium eggs using filtration technique. Water bodies adjacent to human settlement were surveyed for Bulinus and Biomphalaria snails that may potentially be intermediate hosts of S. haematobium. Morphological, molecular, and proteomic (i.e. matrix-assisted laser desorption ionization time-of-flight mass spectrometry [MALDI-TOF MS]) identification of collected snails were conducted, and their infection status was assessed by real-time polymerase chain reaction (RT-PCR) using the highly repetitive DraI gene. Results: The prevalence of urogenital schistosomiasis was 35.6% and 15.8% in Kankossa and Oued Rawdha villages, respectively, corresponding to 'moderate' prevalence (i.e., 10–49% infected schoolchildren). Urogenital schistosomiasis prevalence was higher in boys (30.0%) than in girls (21.2%; P < 0.05), and in Koranic schools pupils (37.1%) than in state schools (20.5%; P < 0.05) pupils. Multiple regression analysis showed that sex (odds ratio [OR]: 1.64; 95% confidence interval [95% CI]: 1.06–2.57; P = 0.03) and Koranic school level (OR: 1.79; 95% CI: 1.06–3.04; P = 0.03) were independently and significantly associated with urogenital schistosomiasis. Based on molecular and proteomic identification, both B. senegalensis and B. umbilicatus colonized the water bodies of Oued Rawdha, whereas both B. forskalii and B. truncatus colonized those of Kankossa. The DraI RT-PCR detected S. haematobium complex DNA in 8 of 66 (12.1%) analysed snails: one B. truncatus and one B. forskalii in Kankossa and five B. senegalensis and one B. umbilicatus in Oued Rawdha. Conclusion: Urogenital schistosomiasis is moderately prevalent in the lake zones of Kankossa and, to a lesser extent, Oued Rawdha, located in southern Mauritania. Mass drug administration campaigns with praziquantel should be conducted to reduce the prevalence of urogenital schistosomiasis among school-aged children in the lake zone of Kankossa and Oued Rawdha village. Further parasitological and malacological studies should be conducted in other villages located in the Mauritanian lakes in the southern Sahelian zones and the northern oasis areas to strengthen our knowledge of the current epidemiological situation and implement appropriate urogenital schistosomiasis control strategies. Author summary: Urogenital schistosomiasis or bilharzia is caused by blood flukes transmitted in the urine. These parasites require compatible freshwater snails to develop and infect humans who come in contact with contaminated water. The adult females release thousands of eggs into the urinary tract, which may cause bloody urine, obstruction of urine flow, and many other urinary tract diseases. As in other developing countries, urogenital schistosomiasis is an important issue in Mauritania, where most previous studies on this disease have been concentrated along the Senegal River, the only permanent river in the country. In this work, we chose two places where schistosomiasis has never been studied before: Kankossa, where there is a permanent lake, and Oued Rawdha, where temporary ponds are present during part of the year. We found that 26% of school children had Schistosoma eggs in their urine, more in boys than girls, and more in younger children (6–8 years old) than in older children. We also identified the snail species responsible for disease transmission in these two sites. These data would be useful to organize mass treatment with appropriate medicines, kill the snails, disseminate the information to prevent community members from urinating in water bodies, and improve sanitary conditions. [ABSTRACT FROM AUTHOR]