The Department of Agriculture, Food and the Marine (DAFM) has issued advice in relation to the predicted risk of disease caused by liver fluke (Fasciola hepatica) infection in livestock, based on advice received from the Liver Fluke Advisory Group.
A liver fluke disease-forecasting model, based on meteorological data provided by Met Éireann with regard to weather conditions last winter and rainfall during the summer and early autumn of this year, predicts that the risk of liver fluke infection ranges from high risk in the counties with an Atlantic coastline in the north-west, west and south, to a moderate risk in the east of the country, less than in other parts of the country. This variation arises from a significantly greater number of days with rain in the Atlantic coastal counties relative to the counties in the east this summer and autumn. June was quite a dry month this year in most parts of the country; however, July and August had sufficient days of rainfall to again provide suitable conditions for propagation of the snail intermediate host.
Liver fluke infection can cause illthrift in cattle and sheep and, if there is very heavy infection, sudden death in sheep. During the first 10 months of this year, there has been a relatively low incidence of acute deaths in sheep caused by liver fluke diagnosed in the DAFM Regional Veterinary Laboratories, relative to previous years (such as 2012). However, due to increased rainfall days in July and August, after drier weather in June, stock owners should remain alert for later-onset liver fluke disease during the remainder of the autumn and the winter months. In assessing the risk of liver fluke disease on any particular farm, variation between individual farms in their soil type, and whether soils are heavy or free-draining, and fluke history, must be taken into account, in addition to weather.
Livestock owners should continue to be vigilant for any sign of illness, illthrift or mortality in their stock and should consult with their veterinary practitioner for diagnosis of liver fluke infection or other cause(s) of these clinical signs, DAFM has advised. Information from abattoir examination of livers of previously sold fattened stock would also be a valuable source of information to inform stock owners of the incidence of liver fluke infection on their own farm or of the efficacy of their control programme.
In areas of high risk and on farms, where liver fluke infection has been diagnosed or there is a prior history, livestock owners should consult with their veterinary practitioner to devise an appropriate control or prevention programme for liver fluke infection for their livestock, according to DAFM. It may be noted that, as with roundworms, resistance to flukicides is a possibility. Moreover, as flukicides differ in their efficacy against fluke stages (immature, early and late matures), it is important that product choice to match the stage of development in livestock is considered when choosing a flukicide. In these situations also, livestock owners should also consult with their veterinary practitioner to devise an appropriate control or prevention programme for liver fluke infection for their livestock, DAFM adds.
Further details on liver fluke and its control and information on flukicide selection is available in Animal Health Ireland’s leaflet ‘Liver Fluke – the facts’, which is availble on AHI’s website.