High risk of liver fluke

The annual liver fluke forecast published by the Department of Agriculture and released this week predicts that liver fluke infection will be prevalent across all areas of Ireland, with the exception of south Leinster, where the risk of disease is ‘somewhat lower’.

The map displays the Ollerenshaw Summer Index 2023 showing the high risk areas, with these high values attributed to the warm, wet conditions experienced from July through to October.

The forecast advises farmers to be vigilant of the signs of fluke, taking into account ill-thrift and poor performance, while prior liver fluke history is viewed as an important indicator.

Post-mortem analysis of fallen animals and abattoir records of the health of liver fluke are also seen as valuable sources of information.

Advice on sheep treatment states “a drug effective against early immature as well as late immature and mature flukes should be used to protect against acute disease. In addition, sheep should be moved from affected pasture to prevent re-infection”.

Selecting products with an active ingredient which targets just mature liver fluke parasites is of limited value when the greatest risk at present is from early immature and late immature stages of the liver fluke life cycle.

As there is no flukicide, with persistent activity outwintered sheep are at risk of picking up a fresh infection and as such, regular treatment may be warranted. The traditional advice included treatment in November, January and April for high risk outwintered flocks.

The latest advice is to develop a treatment protocol in consultation with your vet and carry out strategic faecal egg sampling. This approach is seen as critical to reduce the rate at which flukicide resistance is growing.

The forecast also highlights a greater risk of rumen fluke disease. The presence of fluke eggs in faecal samples of animals which are performing well does not convey a need for treatment. Treatment is only advised where characteristic signs including rapid weight loss and diarrhoea are seen.

The Agri-Food and Biosciences Institute (AFBI) in Northern Ireland has not released its liver fluke forecast yet, but going on the results of surrounding counties, it is likely that the risk will be high in the west and moderate to high in all other areas.