Baseline Mapping of Schistosomiasis and Soil Transmitted Helminthiasis in the Northern and Eastern Health Regions of Gabon, Central Africa: Recommendations for Preventive Chemotherapy

Abstract

In order to follow the Preventive Chemotherapy (PC) for the transmission control as recommended by WHO, Gabon initiated in 2014 the mapping of Schistosomiasis and Soil Transmitted Helminthiasis (STH). Here, we report the results of the Northern and Eastern health regions, representing a third of the land area and 12% of its total population. All nine departments of the two regions were surveyed and from each, five schools were examined with 50 schoolchildren per school. The parasitological examinations were realized using the filtration method for urine and the Kato-Katz technique for stool samples. Overall 2245 schoolchildren (1116 girls and 1129 boys), mean aged 11.28 ± 0.04 years, were examined. Combined schistosomiasis and STH affected 1270 (56.6%) with variation between regions, departments, and schools. For schistosomiasis, prevalence were 1.7% across the two regions, with no significant difference (p > 0.05) between the Northern (1.5%) and the Eastern (1.9%). Schistosomiasis is mainly caused by Schistosoma haematobium with the exception of one respective case of S. mansoni and S. guineensis. STH are more common than schistosomiasis, with an overall prevalence of 56.1% significantly different between the Northern (58.1%) and Eastern (53.6%) regions (p = 0.034). Trichuris trichiura is the most abundant infection with a prevalence of 43.7% followed by Ascaris lumbricoides 35.6% and hookworms 1.4%. According to these results, an appropriate PC strategy is given. In particular, because of the low efficacy of a single recommended drug on T. trichiura and hookworms, it is important to include two drugs for the treatment of STH in Gabon, due to the high prevalence and intensities of Trichuris infections.

Prevalence, infection intensity and geographical distribution of schistosomiasis among pre-school and school aged children in villages surrounding Lake Nyasa, Tanzania

“…This cross-sectional survey(s) involved a random selection of 150–250 pre-school and school aged children from the list of the registered students in school attendance book on the day of sample collection. The sampling technique used in this study has been described elsewhere 11 , 30 .…”

Schistosomiasis with a Focus on Africa

“…Mapping and geospatial analysis of schistosomiasis is important to monitor transmission trends and prevalence, leading to better understanding of the disease burden and risk factors for infection, which will in turn result in more targeted control efforts and improved surveillance procedures. Mapping studies have gradually increased in Africa [ 201 , 259 , 318 , 319 , 320 , 321 , 322 ]. Communities that have performed mapping have been able to effectively scale up treatment and monitor applied control strategies [ 21 ].…”

Schistosomiasis Elimination: Beginning of the End or a Continued March on a Trodden Path

“…Mintsa Nguema et al [23] report the results of mapping the prevalence of schistosomiasis in Gabon (primarily caused by S. haematobium ), together with the situation with regard to soil transmitted helminthiases (STH) in the northern and eastern regions of the country, which covers 12% of the population. While many STH infections were found to be very common, schistosomiasis prevalence was only 1.7% across the two regions investigated, with no significant difference between them.…”