Theileriosis symptoms in cattle

PIRSA is advising cattle producers to be alert to any signs of theileriosis.

Theileriosis is a tick-borne disease which may cause anaemia, weakness and death in animals under stress.

Chief Veterinary Officer Roger Paskin said recent wet weather in southern parts of the state is creating conditions conducive to emergence of disease.

Theileria is a parasite transmitted by bush ticks and infects both red and white blood cells of cattle.

The ticks are carried by multiple hosts, including wildlife, which all enable spread of infection.

It may also spread by multiple use of vaccination guns, ear taggers or other husbandry devices that are contaminated with blood.

Found primarily in high rainfall areas of the state, the disease was first confirmed in South Australia in healthy animals in 2012 with subsequent small clinical outbreaks occurring in 2014, 2016 and 2017.

The greatest areas of risk in the state are in the lower South East, Kangaroo Island, Fleurieu and lower Yorke and Eyre Peninsulas.

Dr Paskin said the disease can be more severe when it moves into new areas, where animals not previously exposed can be affected.

“There is currently no vaccine available and no registered treatment for theileriosis in Australia, so given the nature of this disease spread a quarantine on a property would not be an effective mitigation tool,” he said.

“To protect further animals from possible infections we are therefore relying on producers and veterinarians to be on the lookout for the presence of the disease.

“PIRSA has provided information to veterinarians on theileriosis so if you see cattle showing unusual signs of weakness along with a lack of appetite please contact your local vet for assistance. Advice is also available from your nearest animal health office.”

Other clinical signs of theileriosis include:

  • anaemia
  • lethargy (lack of willingness to walk)
  • weakness
  • fever
  • jaundice (yellowing/pale gums)
  • increased heart rate
  • difficulty breathing (gasping if forced to run)
  • drop in milk production
  • abortions
  • still birth
  • dystocia
  • death.

Theileriosis has no human health implications.

For further information on theileriosis visit

This Agritalk column is compiled by Philippa Clark, Business Services Consultant, Primary Industries and Regions SA (PIRSA), located in Struan. Contact: