A WETTER than average summer-autumn period has made counties in the West and North-West more at risk of liver fluke infestation, according to the latest official Dept. of Agriculture forecast on the parasite.

However, at national level, the rate of active infection in one or more animals has dropped from 17% in 2024 to 12% this year.

The Ollerenshaw Summer Index for Fluke, 2025, predicts that the risk of fluke infection is ‘more prevalent’ in the West, North-West and Midlands area.

The Liver Fluke Forecast, November 2025 – compiled by the Dept. of Agriculture, Met Éireann, UCD, Teagasc and Animal Health Ireland – showed that 60 to 68% of herds in Sligo, Leitrim, Roscommon, Mayo and Donegal had signs of fluke at slaughter.

There can be major variations from farm to farm with liver fluke [Fasciola Hepatica] infestation, due to the fact that the intermediate host of the parasite – the mud snail [Galba Truncatula] – occurs far more commonly in soils that are slightly acidic and muddy.

The Dept. of Agriculture has advised farmers that ‘it is important to know’ whether or not liver fluke is present on their farm and to treat accordingly to avoid production losses.

“The Beef HealthCheck reports can be a useful tool to understand liver fluke challenge on-farm and are available to farmers on the ICBF website (beefhealthcheck.icbf.com) for those who have slaughtered animals at a participating factory since 2016.

“This online tool has recently been updated to include more information and benchmarking at the national and county levels: you do not need to be a HerdPlus member to access this tool.

“Visit Beef HealthCheck Map – Animal Health Ireland for county level maps of liver fluke infection levels and further details on the programme,” the Dept. of Agriculture advises.

They also advise farmers in ‘high-risk areas’ and those on farms with a prior history of fluke, to consult with their private veterinary practitioner [PVP] to devise a suitable control programme.

“Testing faecal samples for the presence of liver fluke eggs can help determine both the need for and success of flukicide treatments.

“This is especially important given that resistance to flukicides is becoming increasingly widespread. In addition, bulk milk testing for liver fluke antibodies may be useful in dairy herds to monitor variation in exposure.

“Where feasible, and as a long-term control option, areas of farms that provide suitable habitat for the mud snail such as wet muddy areas should be fenced off,” the Department advises.

Liver fluke in cattle results in ill-thrift and poor performance while in sheep it can be fatal in cases of heavy challenge.

At the Athenry Met Éireann station, every month from June to November [inclusive] have been significantly wetter than the long term average figures for that period.