A spike in animal mortality linked to acute/sub-acute liver fluke disease, with weanlings as young as eight months succumbing to the disease, has led to the Department’s Animal Health Surveillance Unit releasing a liver fluke warning.

The unit, which collates, processes and disseminates animal health and disease information, is warning farmers of unusually late cases of acute liver fluke disease in sheep and sub-acute disease in cattle.

It explains that “over the past few weeks, the Department’s Regional Veterinary Laboratories (RVLs) have reported that post-mortem investigation into a variety of signs, including sudden death, ill thrift, inappetence and weakness in both sheep and cattle have returned a diagnosis of acute/sub-acute live fluke disease (fasciolosis)".

Treatment plan

Farmers who have a previous history of liver fluke on their farm are advised to consult with their private veterinary practitioner to ensure they have an appropriate control plan in place, in light of the current favourable fluke conditions.

“It is vital that all farmers are aware of this risk so late in the year, and that ill thrift, illness or unexplained deaths are investigated by their private veterinary practitioner, who may wish to refer faecal samples for testing or carcasses for post-mortem examination."

Product selection will depend on how animals are being managed at present.

Where treatment is targeted at out wintered animals, then products should be selected which treat at least mature and immature liver fluke parasites.

Where animals have been housed for eight to nine weeks, then there is more scope to select products that target just mature liver fluke.

Abnormal weather

The report highlights that it is very late in the season to have a high number of such cases due to liver fluke, citing that the disease is due at least in part to the unseasonal warm and wet conditions seen in late summer and continuing right up until present time in Ireland.

It states that weather is not the only factor controlling levels of liver fluke disease, but it has provided ideal conditions for the intermediate host, the mud snail, “allowing it to thrive in the ground conditions that it prefers, in slightly acidic muddy soils such as rushy areas or waterlogged areas around troughs, gateways, etc”.

“As stated by this year’s 'Liver Fluke Forecast' the Ollerenshaw Summer Index 2023 predicts infection being prevalent across all areas of Ireland, with the exception of south Leinster where the risk of disease is somewhat lower."