Schistosomiasis and Geohelminth Infections: Prevalence and Treatment Outcomes

Data were entered into the CISA database and then exported to SPSS Statistics for Windows version 20.0 and R version 3.0.1 (IBM, Armonk, NY, USA). Analyses were performed to determine prevalence and intensity reduction, intensity and reinfection rates resulting from Schistosoma haematobium, geohelminths and H. nana infections, 1 and 6 mo after treatment.
Prevalences were calculated as the frequencies of the outcome over the total samples with valid results. The intensity of Schistosoma haematobium infections and of intestinal parasites was recorded according to WHO¹⁵ (Table 1). Also, the age-specific severity of anaemia was defined as recommended by WHO.^{16 (link),17} The prevalence reduction rate (PRR) was calculated as:
$\frac{\begin{array}{c}\hfill \%\mathrm{prevalence}\mathrm{before}\mathrm{the}\mathrm{treatment}-\hfill \\ \hfill \%\mathrm{prevalence}\mathrm{after}\mathrm{the}\mathrm{treatment}\hfill \end{array}}{\%\mathrm{prevalence}\mathrm{before}\mathrm{treatment}}⁎100$
The intensity reduction rate (IRR) was calculated as:
$\frac{\begin{array}{c}\hfill \mathrm{Geometric}\mathrm{mean}\mathrm{of}\mathrm{eggs}\mathrm{before}\mathrm{the}\mathrm{treatment}-\hfill \\ \hfill \mathrm{geometric}\mathrm{mean}\mathrm{eggs}\mathrm{after}\mathrm{the}\mathrm{treatment}\hfill \end{array}}{\mathrm{geometric}\mathrm{mean}\mathrm{before}\mathrm{the}\mathrm{treatment}}⁎100$
The post-treatment reinfection rates were calculated as:
$\frac{\mathrm{Number}\mathrm{of}\mathrm{children}\mathrm{who}\mathrm{became}\mathrm{positive}\mathrm{after}\mathrm{the}\mathrm{treatment}}{\mathrm{Number}\mathrm{of}\mathrm{children}\mathrm{who}\mathrm{turned}\mathrm{negative}\mathrm{after}\mathrm{the}\mathrm{treatment}}⁎100$
χ² McNemar’s, paired sample t and Wilcoxon related samples tests were used to compare difference in the prevalence and intensity of infections. The threshold for significant level was 0.05.