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The populations of the potential intermediate hosts of Schistosoma mansoni and S. haematobium were studied for a year at transmission sites near three villages in the lower delta of the Senegal River. Biomphalaria pfeifferi, found to be widely distributed and increasingly abundant, appears to be well adapted to the new areas of irrigation (created by the dams at Diama and Manantali) thanks to its ability to withstand changes in temperature and to aestivate. This species is responsible for intense transmission of S. mansoni during the rainy season. In contrast, Bulinus globosus, the species responsible for the transmission of S. haematobium (which occurs during the dry season), had a more limited distribution. The changing distributions of these two snail species appear to be linked to changes in local ecology, themselves the result of the recent programme of water-development in the delta. [ABSTRACT FROM AUTHOR]

Objective To evaluate the impact on schistosomiasis of biennial treatment with praziquantel (PZQ) among school-age children in Burkina Faso, the first country that achieved full national coverage with treatment of more than 90% of the school-age population. Methods A cohort of 1727 schoolchildren (6DS14 years old) was monitored at yearly intervals through a longitudinal survey. Additional groups of schoolchildren were monitored in cross-sectional surveys. Parasitological examinations for Schistosoma haematobium and Schistosoma mansoni were performed, and prevalence and intensity of infection before and after treatment were analysed. Findings Data from the longitudinal cohort show that a single round of PZQ treatment significantly reduced prevalence of S. haematobium infection by 87% (from 59.6% to 7.7%) and intensity of infection by 92.8% (from 94.2 to 6.8 eggs/10 ml of urine) 2 years posttreatment. The impact on infection was also confirmed by a cross-sectional survey 2 years post-treatment. Importantly, the proportion of school-age children with heavy S. haematobium infection decreased from around 25% before treatment to around 2DS3% 2 years post-treatment. Cross-sectional comparison of S. haematobium infection in 7-year-old children in their first year at school, who received treatment through community-based drug delivery, also showed significant reduction in both prevalence (65.9%) and intensity of S. haematobium infection (78.4%) 2 years after single treatment. A significant reduction in S. mansoni infection was also achieved. Conclusion Significant and sustained reduction in S. haematobium infection was achieved by biennial treatment in school-age children in Burkina Faso. This may provide a cost-effective treatment strategy for similar national schistosomiasis control programmes in sub-Saharan Africa. Copyright © 2008 World Health Organization [ABSTRACT FROM AUTHOR]

In many developing countries and especially those in the Indian Ocean, the prevalences of hypertension and obesity have increased markedly over the past decade. In a community-based study set in Antananarivo, the capital of Madagascar, multi-level modelling has now been used to look for associations between blood pressure or body mass index (BMI) and levels of occupation, education and income, among 773 adults. Many (23%) of the subjects had elevated blood pressure (i.e. over 140/90 mmHg). The prevalence of such elevated blood pressure increased with age — with an odds ratio (OR) of 2.16 and a corresponding 95% confidence interval (CI) of 1.81-2.58 for each 10-year increase — but decreased with educational level (high school: OR=0.74; CI=0.41-1.31) and income (fourth quartile: OR=0.66; CI=0.35-1.27). The BMI data indicated that 18.4% of the subjects were underweight, 6.0% were overweight but not obese and 2.4% were obese. Being overweight was directly associated with level of occupation (management level: OR=3.49; CI=1.18-10.29) and income (fourth quartile: OR=3.55; CI=1.48-8.50). Despite the trends, underweight and overweight individuals and cases of elevated blood pressure were found to co-exist in all socio-economic classes. [ABSTRACT FROM AUTHOR]

Discusses the spread of biomphalaria pfeifferi in the Niger River valley, Niger. Implications for the understanding of the transmission of the parasites that cause schistosomiasis in humans; Increase in the number dispersal of the snail in the region; Appearance of biomphalaria in irrigation schemes.

Asseses the impact of the construction of two large dams on the prevalance and intensity of human schistosomiasis in Cote d'Ivoire. Effect of construction of dams on disease; Re-evaluation of schistosoma haematobium and S. mansonin in November 1992; Observations made; Methodology used to conduct study; Results of the study.