One-Health Approach to Study Human Fasciola hepatica Transmission and Inform Strategic Control

PROJECT SUMMARY/ABSTRACT Fascioliasis in an important zoonic infection with a worldwide distribution. It is a significant public health problem in poor rural communities in countries of South America, Middle East, Asia, and Africa. School age children bear a disproportionate burden of the diseases suffering from anemia and stunted growth. Fasciola causes substantial economic losses in livestock production in developed and developing countries. It has a complex epidemiology stemming from its capacity to infect multiple definitive hosts and more than 30 species of snails and adapt to multiple environments. Despite Fasciola’s inclusion in the WHO neglected tropical diseases list very little progress in parasite control has been achieved. Mass treatment has been the preferred control intervention in human and livestock. However, a single drug, triclabendazole, is recommended for treatment and control in humans and preferred for livestock. Concerns for decreasing efficacy of triclabendazole have been raised in endemic countries. Tools to predict fascioliasis risk and guide preventive interventions have focused on livestock. Most models have ignored human infection risk and factor associated with vulnerability such as treatment failure, poverty, and susceptibility. Out TMRC application proposes using a comprehensive One Health approach to study human transmission of Fasciola in two sites of the Peruvian highlands. Our approach will consider the spatial and temporal association of fascioliasis in snail intermediate hosts, livestock, human, and the environment. Importantly we will include studies to tackle factors that modify the risk of infection among human such as weather and land use, hinder diagnosis and surveillance such as the lack of simple diagnostic tests to use in all hosts, and the potential effects of chronic infection on treatment response and infection susceptibility. We will use agent-based modeling to identify crucial steps in transmission and potential areas of intervention that could be address simultaneous with a large impact on transmission and small impact on the environment and drug effectiveness. At the end of our TMRC we expect to gain substantial insights into human Fasciola transmission and to identify potential integrated control interventions, simple sensitive tools to diagnose and surveil infection, and immune mechanisms behind drug effectiveness and infection susceptibility.