Enzootic bovine leucosis

Alert

Enzootic bovine leucosis is category 1 restricted matter.

Under Queensland legislation, if you suspect the presence of this disease in any species of animal, you must report it to Biosecurity Queensland on 13 25 23 or contact the Emergency Animal Disease Watch Hotline on 1800 675 888.

Enzootic Bovine Leucosis (EBL) is a lymphoproliferative disease (tumour-causing) caused by infection with Bovine Leukaemia Virus (BLV). EBL was eradicated from the Australian dairy herd in 2012. EBL occurs at very low prevalence in beef cattle

Scientific name

Enzootic Bovine Leucosis

Cause

Bovine leukaemia virus, an exogenous retrovirus

Other names

  • EBL
  • Enzootic Bovine Leukosis

Distribution

Worldwide, including Australia.

The EBL accreditation scheme has eradicated EBL from the Australian dairy herd.

There is a low prevalence of EBL infection in the Australian beef herd and clinical disease in beef cattle is rare.

Affected animals

  • cattle
  • buffalo
  • zebu

Clinical signs

The majority of EBL infected cattle do not show signs of disease.

Only a very small number of infected cattle that become ill, produce clinical signs of disease. These signs may include:

  • loss of condition/weight loss
  • lack of appetite
  • anaemia
  • weakness
  • enlargement (tumours) of superficial lymph nodes
  • other clinical signs may occur specific to the organ systems affected (respiratory, circulatory, digestive, urinary and neurological systems).

Clinical disease is invariably fatal. Death usually occurs within 1 to 5 months.

Impacts

Dairy Cattle

  • production losses due to decrease in milk yield and premature culling
  • loss of access to domestic and international markets.

Beef cattle and buffalo

  • negligible.

How it is spread

  • Movement of infected animals (e.g. introduction of untested beef bull for mating)
  • Sharing contaminated equipment between properties.

Risk period

All year round; however, calves are most at risk of infection.

Monitoring and action

Maintain good biosecurity, including ensuring dairy herds do not have direct contact with untested beef cattle and that contaminated equipment is not shared between herds.

Monitor your cattle for signs consistent with EBL (see symptoms).

Have a private veterinarian investigate loss of condition due to disease.

Laboratory tests on blood or milk samples can detect the presence of virus or antibodies to the virus.

If you believe EBL is present, you must report it to Biosecurity Queensland on 13 25 23 or contact the Emergency Animal Disease Watch Hotline on 1800 675 888.

Control

Pasteurisation inactivates the virus.

Dairy Australia coordinates a national program to maintain confidence in the Australian dairy herd's freedom from EBL. The program includes testing of bulk milk samples and quality assurance audits of all dairy herds.

Detection of EBL infection in a dairy herd will lead to movement restrictions to minimise spread and an eradication program to test and cull infected dairy cattle.

There are no controls on EBL in the beef and buffalo industries.

Further information