A mathematical study to control Guinea worm disease: a case study on Chad.

Global eradication of Guinea worm disease (GWD) is in the final stage but a mysterious epidemic of the parasite in dog population makes the elimination programme challenging. There is neither a vaccine nor an effective treatment against the disease and therefore intervention strategies rely on the current epidemiological understandings to control the spread of the disease. A novel mathematical model can predict the future outbreaks and it can quantify the dissemination rates of control interventions. Due to the lack of such novel models, a realistic mathematical model of GWD dynamics with human population, dog population, copepod population and the worm larvae is proposed and analyzed. Considering case data from Chad, we calibrate the model and perform global sensitivity analysis of the basic reproduction number with respect to the control parameters and copepod consumption rates. Furthermore, we investigate the impact of three control interventions: awareness of humans, isolation of infected dogs and copepod clearance from contaminated water sources. We also address the impact of combination interventions which leads to the conclusion that the combination of isolating the infected dogs and treating the contaminated ponds is a plausible way for eliminating the burden of GWD from Chad.