12/5/2024:
Liver fluke disease is caused by the liver fluke, a flatworm that affects the liver. The liver fluke’s eggs end up in the soil via the droppings of infected animals. Larvae emerge from these that develop in an intermediate host into tailed larvae. The intermediate host, a mud snail, thrives in particular on wet (low-lying) grassland and on the banks of ditches and trenches. After a while, the larvae are excreted by the snail and then attach themselves as infectious cysts to the
grass. Grazing animals ingest these cysts and consequently get infected with the liver fluke.
In the autumn, acute liver fluke infections may be seen as a result of ingestion of infectious liver fluke cysts some weeks earlier. Mass migration of liver fluke larvae causes damage to the liver. Signs of anaemia such as pale mucous membranes, lethargy, growth retardation and sudden mortality are consistent with acute liver fluke infections. The Liver Fluke Forecasting Working Group used to issue provisional and definitive predictions annually (in mid-September and mid-November respectively), based on various findings and data, including snail counts and determination of the infectious stages of the liver fluke within the snails.
GD advises avoiding grazing as far as possible on high-risk wet plots, as well as monitoring any infections. Testing lambs for antibodies against liver flukes can show whether they have come into contact with liver fluke during their first year in the meadow. Antibodies remain present for a long time, so blood tests on adult sheep do not say anything about the moment when they came into contact with liver flukes. Examination of the droppings can show the presence of eggs and thereby of the adult stage of the liver fluke. In the event of losses, pathological examination can exclude an acute liver fluke infection as the cause.
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