Precision Solutions for Controlling Fasciolosis in Sheep

The liver fluke is a highly damaging and common parasite that infects a high proportion of sheep flocks and cattle herds globally. In Europe, it is estimated that this parasite costs the livestock industry 635 million annually due to decreased milk yields, fertility and growth rates, and increases in mortality and veterinary treatment costs. Sustainable control of liver fluke is extremely challenging because of climate change and increasing rates of parasite resistance to treatment. Liver fluke must infect a mud snail before infecting livestock, a trait which means that specific infection risk areas are present on farms where this snail resides. However, our understanding of mud snail distribution is poor which further hinders a farmer's ability to manage infection risk in animals through grazing and land management. Furthermore, limited tools are available to farmers and vets to diagnose liver fluke infection. This makes accurately treating liver fluke infections difficult and has led to the overuse of fluke treatment drugs and subsequent resistance development in liver fluke populations.
Our research will aim to develop new solutions for liver fluke control by developing and deploying environmental DNA and protein tools that can determine liver fluke infection risk areas on farms. We will initially assess farmer understanding of liver fluke infection risk areas though a series of interviews, which will also highlight knowledge gaps for future education programmes. We will then use eDNA surveys to map the distribution of mud snails on farmland, which will inform study farmers of fluke infection risk areas and will enhance our fundamental understanding of mud snail ecology, mud snail habitats and their typical characteristics. This aspect of the project will directly engage and collaborate with farmers and veterinarians who will co-create a farmer/veterinarian education programme that will be driven by our research findings and initially identified knowledge gaps.
This project will also identify animal behaviour and performance traits associated with liver fluke infection status. We will monitor the behaviour of lambs experimentally infected and naturally infected with liver fluke using wearable behaviour sensor technologies. Behaviour changes monitored will include activity and motion, as well as lying rates and time. We hypothesise that these behaviours will vary between infected and non-infected lambs and that infected lamb behaviour will change as liver fluke infection progresses. We will also monitor the growth rates of lambs naturally infected with liver fluke with the aim of identifying if lamb performance can be indicative of the need to treat against liver fluke. We hypothesise here that by controlling for grass availability and quality, that lambs falling below a certain threshold of performance will be the ones that benefit from treatment against liver fluke.
Finally, we will investigate which proteins are secreted by various liver fluke stages that are found in the environment. These life stages include eggs, miracidia (larvae that infect mud snails) and cercariae and metacercariae (larval stages that can infect livestock). We hypothesise that unique proteins will be secreted by infective liver fluke larvae and that we can detect these proteins in water samples collected from mud snail habitats on farms. The presence and ability to detect these unique infective fluke larva proteins would allow immediate liver fluke infection risk on pastures to be determined, subsequently informing best practise and enhancing our understanding of fluke infection risk.
This research will benefit farmers by developing tools and knowledge that will enhance the control of liver fluke on their farms. The project will also enhance our fundamental understanding of parasite biology, animal behaviour and mud snail ecology, information that can assist researchers to further optimise parasite and disease control globally.

This project will develop and deploy new solutions for the precise control of fasciolosis in sheep. These solutions will evaluate F. hepatica environmental infection risk on pasture and detect early F. hepatica infections in sheep. The project will directly engage and collaborate with farmers and veterinarians, to explore novel practice-based approaches for fasciolosis control and treatment and to build a knowledge exchange programme driven by the identification of farmer knowledge gaps. Our work will also enhance our fundamental understanding of G. truncatula ecology and fasciolosis epidemiology, diseased animal behaviour and between-life stage parasite protein biomarkers.
1) We will evaluate farmer understanding of fasciolosis risk areas on farmland and their attitudes towards evidence based fasciolosis control. We will also enhance our fundamental understanding of G. truncatula ecology and distribution through eDNA investigations. The information gained will be used to co-create a knowledge exchange programme to educate farmers and veterinarians on fasciolosis risk areas and non-chemical fasciolosis control strategies.
2) We will identify a series of behaviour and performance indicators of F. hepatica infection and fasciolosis occurrence in sheep. The behaviour of lambs experimentally and naturally infected with F. hepatica will be observed, with key sensor measurable behavioural markers of F. hepatica infection identified. We will also record the energy utilisation efficiency of lambs naturally infected with F. hepatica to establish performance thresholds that can indicate treatment requirement.
3) We will identify environmental protein biomarkers specific to F. hepatica life stages (eggs, miracidia, cercariae and metacercariae) and G. truncatula snails of various infection status and develop tools to capture and concentrate these proteins from environmental water samples.