The efficacy of treatment on schistosoma mansoni, schistosoma haematobium and soil transmitted helminthes and its effects on antischistosome IgE levels among primary school children in Taveta , Kenya.

Abstract

Helminth infections caused by soil-transmitted helminths (STHs) and schistosomes are among the most endemic, communicable diseases of humans who live in parts of the developing world. All-inclusive strategies for the prevention of worm infections; including regular monitoring of infections, regular deworming and environmental sanitation, have significant impact on child health, growth and cognitive development. Monitoring the prevalence of infection and immunological effect of treatment for primary school children with single and dual schistosomiasis infection has been less researched, reported and documented. This study sought to investigate the infection status of Schistosoma mansoni, Schistosoma haematobium and soil transmitted helminthes in primary school going children in Taveta Sub-county, Kenya. The study also delved into the infection status of the children after treatment and the significance of treatment on IgE production. This was guided by the prevalence and intensities of the worm infections in the school children before and after treatment. Data for this study was collected with the assistance of staff from the local health facility, Taveta district hospital and 4 local primary schools in the area. The sampling frame included 442 primary school children of both sexes in the county. Baseline data on the prevalence and intensity of infection, and antibody levels was collected before the yearly national deworming activity in the first year of the study. Follow-up data was collected at 8 weeks and one year after treatment. Stool and urine samples were examined using the Kato- Katz technique and nucleopore filtration methods respectively. Antibody detection and quantification was done by micro ELISA technique by standard operating procedure with slight modifications, after optimization and standardization. All statistical analyses were conducted in STATA Version 12.0 statistical package. The observed overall prevalence of both S. mansoni and S. haematobium were calculated by sex and age groups. Confidence intervals of 95% (95% CI) were calculated by binomial logistic regression. Differences in prevalence between the two schistosome species were calculated by the Wald test. Comparison of prevalence by sex and age groups (5-7, 8-10, 11-13 and >13 years old) were tested for significance using the Fisher’s exact test. The significance of the factors associated with infection of S. mansoni and S. haematobium in the school children was determined using the multivariable logistic regression model reporting the odds ratio at 5% significance level and 95% confidence intervals. Factors for the infection were selected using forward step-wise variable selection method. Differences in proportions by age, sex and school were assessed by logistic regression and differences in means using chi-square test, relationships were tested by the correlation co-efficient. Risk ratio was used to calculate the risk of infection in the primary school children. The non parametric Wilcoxon sum rank tests (Mann-Whitney 𝑈𝑈 tests) for the independent samples were performed to compare IgE levels against SEA and SWAP in the periods before and after treatment. A quartile regression was performed to check the relationship of the IgE levels with age. The overall prevalence of S. mansoni was 11.8%, (95%CI 8.7%-14.6%) while that of S. haematobium was 24.3 %, (95%CI 20.4%- 28.4%) respectively. Further analysis revealed that out of the 442 primary school children 24 had dual infection (both S. mansoni and S. haematobium). Eight weeks after treatment the overall prevalence of S. mansoni was 1.13% (SD=0.5%, 95%CI 0.15%-2.12%), while that for S. haematobium was 5.58 %( SD=1.5%, 95%CI 2.63%-8.53%) respectively. One year after treatment, the prevalence of S. haematobium and S. mansoni was 16.9% and 4.28% respectively. Prevalence of infection with S. mansoni was significantly reduced for the 13 and above age group in the period of eight weeks and one year after treatment, equally reducing the risk of infection. STH were not prevalent in the study area, this could be attributed to mass deworming and health and hygiene practices in the study area. The average overall IgE levels before treatment as measured by optical density decreased from 0.128 to 0.07 after treatment indicating a decrease which suggests a reduction in infection. The IgE levels increased by 0.000875 for every additional increase in the age of the children and the relationship was found to be significant (P <0.05) after the treatment. This study did not find any association between IgE levels and intensity of infection. This study has generated new knowledge on Schistosomiasis and STH infections and the effects of chemotherapy in primary school children in Taveta.