Positive liver fluke cases begin to rise
The Sustainable Control of Parasites in Sheep (SCOPS) and Control of Worms Sustainably (COWS) have urged farmers to keep up with liver fluke testing as positive cases begin to rise.
It follows a statement made by the groups in October, which predicted that seasonal weather would result in an increase in positive liver fluke cases this winter.
Findings of recent tests and post-mortem examinations have suggested that liver fluke activity at the beginning of autumn had been quite low. However, as a result of wet, mild weather during summer and autumn, cases are now beginning to rise.
The National Animal Disease Information Services (NADIS) forecast has also confirmed the groups’ autumn statement. The forecast also predicts a medium to high risk on the west coast from North Wales to northern Scotland.
Due to unpredictable weather patterns there are expected to be more snail habitats across the UK, increasing the spread of liver fluke. The window for infection will also be more prolonged than previous dry summers.
Farmers are now being urged to remain vigilant with their liver fluke testing. Philip Skuce, principal research scientist at the Moredun Research Institute said: “The coproantigen test can detect the presence of liver fluke a little earlier than faecal egg detection, which is particularly useful when the risk is considered high on a farm.
“But as we head into December, faecal egg count testing methods are likely to be most appropriate, particularly post-housing.”
However, farmers are also being warned of the risks of overusing flukicides, such as closantel. Using flukicides too early will offer no protection to sheep if they are returned to infected pastures, and can even cause adverse effects.
Rebecca Mearns, a veterinary advisor at Biobest, said: “We are concerned about reports that sheep farmers are repeatedly treating sheep with closantel against Haemonchus contortus (the barber’s pole worm). Dosing at intervals of less than six weeks risks adverse effects in sheep, including blindness.
“If farmers then also use the same drug to treat liver fluke, the risks of overdosing are even higher.”
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