Project Duration: 3 years
Project Team: Dr Mark Robinson, Dr Jason Barley and Dr Aurelie Aubry
Infections by parasitic fluke are an important animal health concern for livestock worldwide. Liver fluke (Fasciola hepatica) historically has been a major focus for producers. However, in recent years there has been an increase in the incidence of rumen fluke (Paramphistomes), resulting in acute disease and death in young sheep and cattle. The exact reasons for this increase in the incidence of rumen fluke is not fully understood. One contributing factor is thought to be the increase in warm wet summers and mild winters as such conditions favour an increase in the numbers of snail intermediate host(s), and thus facilitate the completion of the fluke life cycle.
In Northern Ireland between 2008 and 2012, rumen fluke prevalence in sheep increased from no reported cases to 22%, whilst liver fluke prevalence decreased from 16% to 11%. Despite reported increases in both the incidence and severity of rumen fluke infections, the prevalence of rumen flukes has not been thoroughly investigated in the UK. There is ample evidence that rumen fluke infection can seriously impair the animal’s health and welfare. Clinical signs of rumen fluke infection include sever scour, anaemia, rapid weight loss, low blood protein concentrations, and dehydration. What remains unclear is to what extent rumen fluke infections impair animal welfare in terms of causing pain, distress and how it affects the animals’ metabolic status and behaviour.
Control of these infections relies currently on anthelmintic drugs. There are several drugs which are effective against liver fluke but only one anthelmintic which is also effective against rumen fluke (oxyclozanide). This makes correct diagnosis imperative, especially in acute infections where death can be very rapid in heavily infected animals. A range of diagnostic tools to detect infection (e.g. faecal egg counts) are available but few are used to detect disease in living animals. At the farm level the importance of targeting the correct fluke is not always appreciated, leading to indiscriminate use of “anti-fluke drenches”, which may intensify the problem. Resistance to benzimidazoles has already developed in the liver fluke and can be expected to occur with the rumen flukes if present practices continue, with only one anthelmintic available for rumen flukes this is a particularly worrying situation.
This project will enable the development of tools for its rapid diagnosis and for an assessment of anthelmintic sensitivity of rumen flukes. Such knowledge will provide the platform on which sustainable and practically applicable control strategies can be based for sustainable livestock production.
The overall objective of this project is to address the growing threat to animal health and welfare and livestock sustainability posed by an increased incidence of rumen fluke in sheep and cattle:
Determine prevalence and distribution
- Provide a full understanding of the epidemiology of rumen fluke infections in N. Ireland – prevalence, distribution.
Quantify welfare and performance indicators
- Identify and quantify the impacts of rumen fluke infections on animal welfare, performance and their interactions.
- Develop a rapid diagnostic test which will discriminate between liver and rumen fluke pre-patent infections.
Identify treatment options
- Provide a list of potential lead compounds for new anthelmintics which would work against pre-patent infections.
Disseminate findings to stakeholders
- Facilitate knowledge exchange with farmers, scientists and veterinary practitioners for improved management.
- A better understanding of the epidemiology, biology and impact of rumen infection in the European context.
- The development of tools for its rapid diagnosis and for an assessment of anthelmintic sensitivity.