A 12-year follow-up of intestinal schistosomiasis in pre-school-aged children in Assoni Village, Eastern Senegal

Abstract

Background To monitor the prevalence of schistosomiasis in school-aged children (SAC), the National Bilharzia Control Program (PNLB) was set up by the Senegalese authorities; however, geographically isolated Bedik ethnic groups that did not benefit from this program were found to be heavily infected with Schistosoma mansoni. This observation led us to implement a new schistosomiasis control program in 2008 under the aegis of the non-governmental organization “Le Kaïcedrat” and in partnership with the PNLB/WHO to monitor the prevalence of schistosomiasis in this area. In the village of Assoni, where 100% of SAC were infected, analysis of the stools of pre-school-aged children (PSAC) showed that they were massively infected, so we decided to focus our program on them. Methods From 2008 to 2020, we (i) monitored the prevalence of S. mansoni in PSAC in Assoni using double-stool smear preparation, (ii) treated the infected PSAC with a standard dose of praziquantel 40 mg/kg, (iii) ran educational campaigns each year in the village, and (iv) built latrines to improve sanitation and reduce schistosomiasis transmission. Linear regression was used to examine the trend in the annual schistosomiasis prevalence and a two-sided of Chi-squared test was used to compare prevalence between the different age groups of PSAC. Results We observed an extremely high prevalence of schistosomiasis (78%) in PSAC before implementation of the program in 2008. Contamination occurred in very young children, as 64.3% of children under 2 years old were infected. Moreover, prevalence increased with age and reached 96.8% in children 4 to < 6 years old. Our annual interventions in Assoni Village raised awareness among villagers that water bodies were areas of significant infestation, allowed the building of 88 latrines and led to a decrease in prevalence in PSAC as only 11% of these children were infected in 2020. Conclusion Our study allowed Assoni to be the first village in Senegal to treat PSAC since 2014, but only on an individual basis. It also shows that schistosomiasis is difficult to eradicate and that multi-sectorial actions are required to keep its prevalence at a low level. Graphic abstract

Neuroimmunology of Common Parasitic Infections in Africa

“…Schistosomiasis is a neglected tropical disease currently infecting more than 140 million persons, of which 90% of the burden is in the SSA region ( 220 ). The prevalence of schistosomiasis in SSA is high in endemic regions of some countries e.g., above 50% amongst school age children in some communities in Ethiopia ( 221 ), 40-44.1% in Nigeria ( 222 , 223 ), 21.1% in Ghana ( 224 ), 10.05-26.8% in Zimbabwe ( 225 , 226 ), while some countries such as Senegal have reported a decrease from 78% to about 11% in school age children over a 12-year schistosomiasis control program ( 227 ).…”

Schistosomiasis in Humans, 1990-2041: Findings from the Global Burden of Disease 2021 Study and Predictions by Bayesian Age-Period-Cohort Analysis

“…Schistosomiasis is a water-related infectious disease caused by a trematode of schistosomes, spreading through humans contacting with water contaminated by cercariae released by infected snails. In endemic areas, individuals may be repeatedly exposed to schistosomes from childhood or even fetal stages [1,2], leading to chronic infections [3]. Such prolonged chronic infections can result in a range of complications, leading to irreversible damage to the gastrointestinal and urinary systems, as well as an increased risk of developing malignant tumors [4][5][6].…”