Infections by the soil-transmitted helminths (STH), including Ascaris lumbricoides, Trichuris trichiura, Ancylostoma duodenale/Necator americanus (hookworms), and Strongyloides stercoralis, disproportionately affect children around the world. Because of their transmission associated with poor sanita...ry conditions and inadequate hygiene practices, higher burden of disease is seen in children from developing countries from sub-Saharan Africa, Southeast Asia, and Latin America. Approximately 267 million preschool-age children (PSAC) and 568 million school-age children (SAC) worldwide are at risk of STH infection as well as impaired child growth and cognitive development from A. lumbricoides, T. trichiura, and hookworm infections, and death due to severe S. stercoralis infection. Thus, their control is a global health priority.
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Soil transmitted helminth (STH) infections are among the most common human infections worldwide with over 1 billion people affected. Many estimates of STH infection are often based on school-aged children (SAC). This study produced predictive risk-maps of STH on a more finite scale, estimated the nu...mber of people infected, and the amount of drug required for preventive chemotherapy (PC) in Ogun state, Nigeria. Georeferenced STH infection data obtained from a cross-sectional survey at 33 locations between July 2016 and November 2018, together with remotely-sensed environmental and socio-economic data were analyzed using Bayesian geostatistical modelling. Stepwise variable selection procedure was employed to select a parsimonious set of predictors to predict risk and spatial distribution of STH infections. The number of persons (pre-school ages children, SAC and adults) infected with STH were estimated, with the amount of tablets needed for preventive chemotherapy. An overall prevalence of 17.2% (95% CI 14.9, 19.5) was recorded for any STH infection. Ascaris lumbricoides infections was the most predominant, with an overall prevalence of 13.6% (95% CI 11.5, 15.7), while Hookworm and Trichuris trichiura had overall prevalence of 4.6% (95% CI 3.3, 5.9) and 1.7% (95% CI 0.9, 2.4), respectively. The model-based prevalence predictions ranged from 5.0 to 23.8% for Ascaris lumbricoides, from 2.0 to 14.5% for hookworms, and from 0.1 to 5.7% for Trichuris trichiura across the implementation units. The predictive maps revealed a spatial pattern of high risk in the central, western and on the border of Republic of Benin. The model identified soil pH, soil moisture and elevation as the main predictors of infection for A. lumbricoides, Hookworms and T. trichiura respectively. About 50% (10/20) of the implementation units require biannual rounds of mass drug administration. Approximately, a total of 1.1 million persons were infected and require 7.8 million doses. However, a sub-total of 375,374 SAC were estimated to be infected, requiring 2.7 million doses. Our predictive risk maps and estimated PC needs provide useful information for the elimination of STH, either for resource acquisition or identifying priority areas for delivery of interventions in Ogun State, Nigeria.
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As a high-burden neglected tropical disease, soil-transmitted helminth (STH) infections remain a major problem in the world, especially among children under five years of age. Since young children are at high risk of being infected, STH infection can have a long-term negative impact on their life, i...ncluding impaired growth and development. Stunting, a form of malnutrition in young children, has been long assumed as one of the risk factors in acquiring the STH infections. However, the studies on STH infection in children under five with stunting have been lacking, resulting in poor identification of the risk. Accordingly, we collected and reviewed existing related research articles to provide an overview of STH infection in a susceptible population of stunted children under five years of age in terms of prevalence and risk factors. There were 17 studies included in this review related to infection with Ascaris lumbricoides, Trichuris trichiura, hookworm, and Strongyloides stercoralis from various countries. The prevalence of STH infection in stunted children ranged from 12.5% to 56.5%. Increased inflammatory markers and intestinal microbiota dysbiosis might have increased the intensity of STH infection in stunted children that caused impairment in the immune system. While the age from 2 to 5 years along with poor hygiene and sanitation has shown to be the most common risk factors of STH infections in stunted children; currently there are no studies that show direct results of stunting as a risk factor for STH infection. While stunting itself may affect the pathogenesis of STH infection, further research on stunting as a risk factor for STH infection is encouraged.
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