What you need to know about liver fluke
21 August 2015
MLA's recently released report Priority list of endemic diseases for the red meat industries listed liver fluke as a disease with a $25 million/year impact on sheep, while also affecting goats (sixth most costly goat disease) and cattle. Here, we take a look at just what you need to know to manage this parasite, according to the MLA-funded Wormboss program.
Liver fluke can produce either acute or chronic disease, depending on the size of the infection and how quickly it is acquired.
Acute disease is most common in sheep and usually occurs from late summer to late autumn. Chronic disease is most common in cattle and can occur any time, but is most common from autumn to spring. Disease is due to haemorrhage and tissue damage from migrating immature fluke and from damage to bile ducts and blood loss caused by adult fluke.
Clinical signs include the following:
- bottle jaw (submandibular oedema)
- pale gums and membranes around the eyes
- weight loss and general ill-thrift, leading to reduced production
Liver fluke occurs where the environment suits the intermediate host snails, such as springs, slow-moving streams with marshy banks, irrigation channels and seepages. Therefore, it tends to be more prevalent in the higher rainfall (>600 mm per year) areas of NSW (typically the Tablelands in the eastern part of the state, and nearby coastal areas to the east and slopes to the west), Victoria and Tasmania, and to small areas in Queensland and South Australia. Liver fluke may also be found in irrigation areas.
An increase in the number of affected cattle has been recently noted in the NSW Northern Tablelands.
“We had a dry spring and summer in some areas last year, probably causing stock to forage in hollows, soaks and along creek banks where the snails that are the intermediate host and an essential factor in the liver fluke’s life cycle, are most prevalent,” said Andrew Biddle, NSW Northern Tablelands Local Land Services District Veterinarian.
Processors have to condemn the liver of the affected animal, meaning an additional cost in processing and a reduction in offal supply to customers.
Treatment is by use of flukicides—anthelmintics effective against liver fluke.
Control is by means of strategic treatment with flukicides and grazing management.
As ‘flukey’ areas are confined to certain parts of a farm, grazing of these areas can be managed or even precluded.
Strategic treatments can help to reduce liver fluke populations. One to three treatments may be needed per year, depending on the severity of the problem. The most important treatment is the April–May treatment, and a highly effective flukicide (one based on triclabendazole) should be used.
When introducing animals onto your property:
- avoid introducing animals with liver fluke onto your property
- quarantine and drench all animals that come from a liver fluke area, especially if your property has marshy habitat which may harbour the snail intermediate host
- always request an animal health statement when purchasing stock
Regular monitoring should be undertaken. Testing options include:
- liver fluke egg counts, using faecal samples, or
- an antibody test (ELISA) using blood samples or, in the case of dairy cattle, milk samples
“The first thing producers should do is be aware of whether fluke is present on their property, either through faecal egg counts or through processor feedback. If you have a liver fluke problem on your farm, you should develop an effective drenching strategy that considers all stages of the liver fluke’s life cycle," Andrew said.
For more information about the control of this parasite in your livestock, contact a Northern Tablelands Local Land Services District Veterinarian in Inverell on T: 02 6720 8100, Glen Innes on T: 02 6732 8800, Armidale on T: 02 6770 2000 or Tenterfield on T: 02 6739 1400.
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