Table 1.

System variables in the SWB model

System variable	Symbols
SWB prevalence strata:
k Δw ≤ w < (k + 1)Δw with worm burden increment Δw	$\begin{array}{c}\hfill \left\{h_k\left(t\right):k=0,1,\dots \right\}\hfill \\ \hfill {\displaystyle {\sum }_k{h}_k=1}\hfill \end{array}$
Demographically structured SWB:
Child	h Ck(t)
Adult	h Ak(t)
Population densities per unit habitat:
Human	H (t)
Snail (susceptible, infected, patent)	N(t) = x(t) + y(t) + z(t)