Age dependency in the transmission dynamics of the liver fluke, Opisthorchis viverrini and the effectiveness of interventions

We introduce a population-based model of the transmission dynamics of the liver fluke Opisthorchis viverrini, that allows the mean worm burden in humans to depend on the host age. We parameterise the model using data on intensity of infection in humans and prevalence data for cats, dogs, fish and snails from two island communities in Lao People’s Democratic Republic. We evaluate the steady state solution using a fixed point iteration and estimate the basic reproductive number. We optimise the coverage level of MDA in an adapted model of five age groups to compare varying coverages across age groups. Our results suggest that although adults have the strongest contribution to transmission and campaigns should target adults, if such targeting is operationally infeasible, achieving moderate coverage levels in all age groups can still have a substantial impact on reducing worm burden.