A rise in the liver fluke parasite, which can significantly affect livestock production around the world, could now be helped by a new predictive model of the disease meant to help reduce its prevalence. The model was developed by scientists with the University of Bristol in the U.K.

Cattle or sheep grazing on pastures where the parasite is present can become infected with liver fluke, which develops in the liver of infected animals and leads to a disease called fascioliasis, the researchers said. Current estimates suggest that liver fluke contributes to around £300 million annually in lost productivity across U.K. farms and $3 billion globally.

Until now, risk predictions have been based on rainfall estimates and temperature, without considering the life cycle of the parasite and how it is controlled by levels of soil moisture, the announcement said. Combined with shifts in disease timing and distribution attributed to climate change, this has made liver fluke control increasingly challenging.

The Bristol team has now developed a new tool to help farmers mitigate the risk to their livestock. The model, which works by explicitly linking liver fluke prevalence with key environmental drivers, especially soil moisture, will help farmers decide whether to avoid grazing livestock on certain pastures where liver fluke is more prevalent or to treat animals based on when the risk of infection will be at its peak.

Importantly, the model can be used to assess the effects of potential future climate conditions on infection levels and guide interventions to reduce future disease risk, the university said.

Ludovica Beltrame, one of the study’s researchers from Bristol’s School of Civil, Aerospace & Mechanical Engineering, said, “In recent decades, the prevalence of liver fluke has increased from 48% to 72% in U.K. dairy herds. This new tool will help farmers in managing the risk associated with liver fluke and offers a more robust approach to modeling future climate change impacts.”

Professor Thorsten Wagener from Bristol’s Cabot Institute added, “Water-related diseases can be difficult to eradicate using medicine alone, as resistance to available drugs is increasing. We need predictive models of disease risk that quantify how strongly infection risk is controlled by our rapidly changing environment to develop alternative intervention strategies.”

The five-year study comprising engineering, biology and medical researchers from the University of Bristol, Queen’s University Belfast, the University of Liverpool and Scotland Rural College was funded by the U.K.'s Engineering & Physical Sciences Research Council, the Royal Society and Bristol’s Cabot and Elizabeth Blackwell institutes.

The paper, "A Mechanistic Hydro-Epidemiological Model of Liver Fluke Risk" was published in the Journal of the Royal Society Interface.

The aim of the new model is ultimately to guide disease management. The model is open source and available for other researchers through GitHub, the researchers said.