Figure 2.

Prevalence of Schistosoma japonicum infection in humans in two villages during 1981–2017. (1) The adjusted prevalence formula: p’ = $\frac{P_0+\mathsf{\beta }-1}{\alpha +\mathsf{\beta }-1}$ p′: Adjusted prevalence; p₀: Observed prevalence; α: Sensitivity; β: Specificity [10]; (2) The Kato-Katz (KK) 2 slides method was used in 1981–1994: α = 0.64, β = 1 [11]; The indirect hemagglutination assay (IHA) method was used in 1995–2004, but IHA not meet the condition of adjusted formula [10]; The Kato-Katz 3 slides method was used in 2005–2017, α = 0.75, β = 1 [11]; (3) Prevalence were assessed after the transmission season for each year in Sanlian and Guifan villages. (4) The I bars represent 95% confidence intervals.