Research Partner:                University of Liverpool

Project Duration:                 October 2014 – September 2017

Category:                                 Beef & Sheep

PhD Student:                         Tessa Walsh

 

Tessa WalshFasciola hepatica, the common liver fluke, is a parasite of sheep and cattle that severely affects the health and welfare of infected animals, but also has major economic consequences for UK livestock production. The prevalence of infection has increased considerably in recent years due to changes in climate, changing farming practices and increased animal movements. There are also growing concerns over the development of resistance to the drugs most commonly used to treat infection in sheep and the lack of drugs licensed for use in dairy cattle.

Existing diagnostic tests all have their limitations.  Faecal egg counts (FEC) are slow, lack sensitivity and can be problematic for large, extensively managed herds. Other options include bulk milk tank testing for dairy herds, or testing individual serum or milk samples which specifically detect the presence of antibodies to fluke. Recently, it has been proven that fluke specific antigens can be detected in the faeces of infected animals; however there are concerns over the sensitivity of this method compared to FEC. None of these methods are able to detect animals at risk of acute fasciolosis, which is a major concern of sheep farming. Often farmers have little warning and can lose up to 10% of their flock in a matter of days.

There is clear need for fast and accurate diagnosis of liver fluke infection. The aim of this project is to develop a pen side test which farmers can use with drops of blood collected from ear pricks of individual cattle and sheep to detect one of the major fluke secretory products, Cathespin L. This will enable early identification of currently infected individuals at drying off periods for dairy cattle, or during housing for beef cattle and possibly sheep in the autumn and allow for targeted treatments. This project will ultimately address the growing concern over resistance and also benefit the local farming and wider UK economy.

 

Results:

A new pen-side diagnostic test has been developed which could be used in the future to diagnose infections with liver fluke on farm. This test is the first point of care test which is targeted to the diagnosis of liver fluke in animals. It is based around lateral flow technology; the same technology which is used in the human pregnancy test. These types of tests are ideal to be used on farm as they are fast and simple to use, meaning they require very little training in order to be used.

The test detects host antibodies against flukes and can confirm exposure to infection at approximately 2-4 weeks post infections. It is much faster than current diagnostic tests, providing results in approximately 5-10 minutes. This would allow farmers to take control of fluke on farm, making informed decisions on treatments. It could allow for targeted treatments and help to move away from blanket drug treatments which increase the spread resistance.

This test is still a prototype, and there is still further validation needed before. This would include confirming true test sensitivity and specificity through field trials and ensuring the test works well with whole blood samples. Once this has been achieved, we would look to make this test commercially available.