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.

Grant Number: 5U01AI168622-04
NIH Institute/Center: NIH
Principal Investigator: MIGUEL CABADA