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. 2018 May;98(5):1397-1402.
doi: 10.4269/ajtmh.17-0908. Epub 2018 Mar 8.

Impact of Four Years of Annual Mass Drug Administration on Prevalence and Intensity of Schistosomiasis among Primary and High School Children in Western Kenya: A Repeated Cross-Sectional Study

Bernard O Abudho  1   2 , Eric M Ndombi  3   2 , Bernard Guya  1 , Jennifer M Carter  4 , Diana K Riner  4 , Nupur Kittur  4 , Diana M S Karanja  2 , W Evan Secor  5 , Daniel G Colley  6   4
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Impact of Four Years of Annual Mass Drug Administration on Prevalence and Intensity of Schistosomiasis among Primary and High School Children in Western Kenya: A Repeated Cross-Sectional Study

Bernard O Abudho et al. Am J Trop Med Hyg. 2018 May.

Abstract

Schistosomiasis remains a major public health problem in Kenya. The World Health Organization recommends preventive chemotherapy with praziquantel (PZQ) to control morbidity due to schistosomiasis. Morbidity is considered linked to intensity of infection, which along with prevalence is used to determine the frequency of mass drug administration (MDA) to school-age children. We determined the impact of annual school-based MDA on children across all primary and high school years using a repeated cross-sectional study design in five schools near Lake Victoria in western Kenya, an area endemic for Schistosoma mansoni. At baseline and for the following four consecutive years, between 897 and 1,440 school children in Grades 1-12 were enrolled and evaluated by Kato-Katz for S. mansoni and soil-transmitted helminths (STH), followed by annual MDA with PZQ and albendazole. Four annual rounds of MDA with PZQ were associated with reduced S. mansoni prevalence in all school children (44.7-14.0%; P < 0.001) and mean intensity of infection by 91% (90.4 to 8.1 eggs per gram [epg] of stool; P < 0.001). Prevalence of high-intensity infection (≥ 400 epg) decreased from 6.8% at baseline to 0.3% by the end of the study. Soil-transmitted helminth infections, already low at baseline, also decreased significantly over the years. In this high prevalence area, annual school-based MDA with high coverage across all Grades (1-12) resulted in rapid and progressive declines in overall prevalence and intensity of infection. This decrease was dramatic in regard to heavy infections in older school-attending children.

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Figures

Figure 1.
Figure 1.
Map of the study site schools in the Asembo Bay area of western Kenya. This figure appears in color at www.ajtmh.org.
Figure 2.
Figure 2.
Overall prevalence and intensity (by World Health Organization standard intensity categories) of Schistosoma mansoni infection for school children in the primary and secondary schools studied.
Figure 3.
Figure 3.
Baseline Schistosoma mansoni grade vs. prevalence/intensity curves.
Figure 4.
Figure 4.
Year 1 Schistosoma mansoni Grade vs. prevalence/intensity curves.
Figure 5.
Figure 5.
Year 2 Schistosoma mansoni Grade vs. prevalence/intensity curves.
Figure 6.
Figure 6.
Year 3 Schistosoma mansoni Grade vs. prevalence/intensity curves.
Figure 7.
Figure 7.
Year 4 Schistosoma mansoni Grade vs. prevalence/intensity curves.
See this image and copyright information in PMC

References

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    1. WHO , 2013. Schistosomiasis: number of people treated in 2011. Wkly Epidemiol Rec 88: 81–88. - PubMed
    1. GAHI , 2010. Global Atlas of Helminths Infection. Available at: http://www.thiswormyworld.org/maps/kenya. Accessed October 24, 2017.

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