Environmental DNA from Fasciola Parasites as a Novel Biomarker to Improve Agriculture in the UK

Fasciola hepatica, usually termed "the temperate liver fluke", is found worldwide and causes disease known as fasciolosis. This infection caused by helminth parasites, primarily impacts on ruminant production, including within the UK and many other European countries. As a food-borne disease, fasciolosis occurs from the consumption of infective larvae by ruminant animals. Fasciolosis greatly reduces global agricultural outputs in both developing and developed communities, through production inefficiency in millions of ruminants. UK annual economic losses are estimated at £110 million, while internationally the impact is considerably larger, with as an example, India reports $4.8 billion (USD) in loses every year. Fasciolosis is also an important disease of humans, and is acknowledged by the World Health Organization (WHO).
All organisms shed DNA into their environment, this material is known as eDNA. The detection of this eDNA allows the classification of species diversity and abundance in an environment. During certain phases of the Fasciola lifecycle, parasites are present in the environment in order to infect either the snail or animal host (see Figure). It is at these times the parasite also leaves eDNA behind. The improved detection of this eDNA is the central basis of this project. While low levels of eDNA is expected in water or soil, or on plants, new innovative molecular methods will be used to overcome these issues. This will include the third generation technology- droplet digital PCR (ddPCR- see Figure), which greatly increases DNA detection sensitivity and reproducibility. ddPCR also as a fully quantitative method, simplifies the assay and provides better results.
The project will drive a step-change in the way eDNA analysis is considered for the detection of important helminth parasites of agricultural significance. The project will examine a range of environmental samples, including water, soil and grass for the presence of Fasciola parasite activity represented by their eDNA. I will lead field collections, in partnership with long time collaborating sheep farmers of the Belfast region in Northern Ireland. These novel samples will be characterised by the highly sensitive ddPCR technology, in order to provide comprehensive quantitative measurements of parasite/vector (snail) eDNA. eDNA represents a less invasive and less labor intensive approach to disease monitoring.
In detecting parasitic infections earlier, the use of drugs (anthelmintics) can be reduced or avoided. This can be achieved through intelligent pasture management - rotating animals around pastures according to their age, species and season, relative to the perception of infection risk in those pastures. Future applications for the approaches you will develop, will allow farmers to make decisions more effectively through accessing improved, more relevant data from their own farms.