Tick alert on cattle disease

TASMANIAN cattle farmers have been warned to be on the lookout for unusual symptoms in their stock after the discovery of a serious tick-borne disease in a locally bred animal.

For the first time, a case of Theileriosis has been detected in a homebred cow in the state’s North-West.

Veterinary consultant Bruce Jackson said Theileriosis had previously caused significant stock losses in New South Wales and Victoria. Theileriosis is caused by a protozoan parasite Theileria orientalis ikeda, that attaches to and destroys cattle red blood cells.

Dr Jackson said this results in anaemia and jaundice and made the inside lining of the cattle’s eyelids pale and yellowish. Severely affected cattle are depressed, have a high temperature and cannot walk very far. Pregnant cows often abort their calves and deaths are common.

The disease is spread by the bush tick Haemaphysalis longicornis, which is has not been found in Tasmania yet.

Dr Jackson said with the large number of cattle imported into the state each year however, the risk of the bush tick getting into the state is high. The tick has specific environments it can survive in and areas in the state’s NortWest and on irrigated farm in parts of the North and NorthEast have been identified as risk areas.

Bush ticks survive on sheep, horses, pigs, goats, birds and wildlife and once established cannot be eradicated.

Dr Jackson said it was extremely difficult to stop them coming into the state through the usual border quarantine methods. The bush tick has not been identified in Tasmania yet, and Dr Jackson said if it remains uncommon, the disease will also remain rare.

“As it happens, we’re just about to start this coming spring to start looking for the bush tick because the modelling shows that it could survive in Tasmania,” Dr Jackson said.

“If the tick’s not here the disease probably won’t be very significant apart from a bit of spill over from imported cattle. “If it is here, then it could be more serious. In NSW and Victoria when this strain came in the cattle had no immunity and they had significant losses.”

Symptoms from the disease can present quickly so Dr Jackson said farmers should keep a close eye on their stock and contact their veterinarian if they are concerned. Cattle with the disease can be treated, but it must be administered soon after infection.

Dr Jackson said if ticks are found on cattle, producers should contact an entomologist from the Department of Natural Resources and Environment to get a formal identification.

If bush ticks are discovered on a property or Theileriosis is diagnosed, there are no quarantine or regulatory requirements that need to be adhered to and the property’s identification will be kept confidential.