Liver fluke

Description



Liver fluke (Fasciola hepatica) is a parasite that can infect a broad range of host, including humans and ruminants. Final hosts in which sexual maturity can occur include livestock such as sheep, cattle, horses, pigs, goats, alpacas and deer.

Different forms of infections occur in ruminants. The chronic form is rarely fatal in cattle but often fatal in sheep while the subacute or acute form seen primarily in sheep is often fatal and can occur in conjunction with “black disease” (caused by Clostridium novyi type B infection).

Clinical signs vary in severity from distended, painful abdomen and anaemia (acute form) to illthrift, submandibular oedema and reduced productivity (chronic form).

Diagnosis and tests available

Diagnosis

Diagnosis is based on clinical history, serology, faecal antigen, faecal egg count, response to treatment and post-mortem examination in the field.

Tests available

Test

Sample(s) required

Days of the week test is conducted

Turnaround time1

Liver fluke antibody ELISA3

Milk

Thursday and Friday

Up to 5 days

Liver fluke antibody ELISA (single or pool of 5)2

Clotted blood (red top tube)

Thursday and Friday

Up to 5 days

Egg count WormTest - Fluke (pool of 2 or 5)

Faeces

Monday to Friday

1-2 days

1 Turnaround times are provided as a guide only. For specific information about your submission please contact Customer Service.
2 Please clearly specify on the submission form if samples are to be pooled.
3 This test is not NATA accredited.

Specimen requirements

Blood (without anti-coagulant)

  • 10 ml of blood (including at least 2 ml of serum) from affected animals and their cohorts
    • Collected into a plain red top tube.
    • Submit chilled

Faeces

  • 30 g of faeces from each of at least ten animals in the flock or herd previously diagnosed with liver fluke and treated in the previous five months.
    • Clearly label samples to identify which animal(s) have been sampled when submitting pooled samples.
    • Submit chilled

Milk

  • Milk from affected animals and their cohorts
    • Submit chilled

Further information

See the fact sheet: Liver fluke disease in sheep and cattle.

Note

Faecal samples may be tested individually, or pooled in groups of up to five samples. Pooling reduces costs. Submitters should nominate if they wish the samples to be tested in pools. If pooling is not requested, the laboratory will test the individual samples.

The antibody ELISA is available for the detection of infection with both immature and adult fluke. Titres appear 6-8 weeks (cattle) or 4-6 weeks (sheep) after infection and remain high for at least 12 weeks after the infection has been removed. Antibodies remain high in untreated subacute and chronic stages. The false negative rate is low in both cattle (2.5%) and sheep (nil). The test is not suitable for other species.

The antibody ELISA is the only diagnostic method for the detection of acute and subacute fascioliasis, which typically occurs in NSW from autumn to early winter and in late spring.

NSW DPI recommends that ten animals be bled and a pooled fluke ELISA requested for herd diagnosis. The samples will be tested as two pools of five samples in the laboratory.

Antibody ELISA is more sensitive than faecal egg counts for the detection of chronic fascioliasis in both cattle (30% more infected animals detected) and sheep (15-20% more infected animals detected).

Faecal egg counts are only of value in chronic fascioliasis where fluke eggs are being excreted (patent infection); they are of no value in acute and subacute infections