Mathematical analysis of the transmission dynamics of the liver fluke, Opisthorchis viverrini

摘要

Highlights ? Humans, snails and fish are a maintenance-hosts and without them transmission of O. viverrini cannot be sustained. ? Cats and dogs are non-maintenance hosts; they cannot sustain transmission in absence of humans as a definitive host. ? The most effective control interventions are targeting death rates of parasites in humans through regular treatment, the transmission rate from humans to snails through improved sanitation and from fish to humans through safe fish production. Abstract We develop and analyse two population-based models of the transmission dynamics of the worm parasite Opisthorchis viverrini . The life cycle of O.?viverrini includes humans, cats and dogs as definitive hosts; and snails and fish as intermediate hosts. The first model has only one definitive host (humans) while the second model has two additional hosts: the reservoir hosts, cats and dogs. We define reproduction numbers and endemic equilibrium points for the two models. We use prevalence data for the five hosts from two islands in Lao People’s Democratic Republic to estimate distributions of parameter values. We use these distributions to compute the sensitivity index and the partial rank correlation coefficient of the basic reproduction number and the endemic equilibrium point to the parameters. We calculate distributions of the host-specific type-reproduction number to show that humans are necessary to maintain transmission and can sustain transmission without additional reservoir hosts. Therefore interventions targeting humans could be sufficient to interrupt transmission of O. viverrini .