Parasite more common in coastal areas has the capacity to cause significant losses to both cows and calves further inland

An increase in cases has already been reported around Inverell.

Theileria are parasites that are endemic in parts of Australia and are carried and transmitted by ticks.

After last year's wet conditions, district vets are reporting high numbers of theileria infection (called theileriosis) in areas where it is not often observed.

The disease caused significant losses on a property near Narrabri during an outbreak about 10 years ago.

More recently it was a problem for landholders on the eastern side of Walcha in 2017.

Northern Tablelands Local Land Services District Veterinarian and Inverell resident Andrew Biddle has sounded the local warnings.

"When ticks feed on cattle the parasite enters the red blood cells and these cells are then destroyed," Mr Biddle said.

"If large numbers of red cells are destroyed the ability of blood to carry oxygen is reduced and the animal will become ill."

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The theileria parasite can be introduced into new areas by bringing in cattle from endemic areas, typically by moving coastal cattle inland.

It has the capacity to cause significant losses to both cows and calves, with young, dry stock generally much less affected.

In non-endemic regions, or in nave cattle brought into endemic regions, disease is usually seen between six to 12 weeks after exposure to infected ticks.

Nave heavily pregnant cows and heifers are often most severely affected, and the introduction of these classes of cattle should be avoided.

Clinical signs of bovine anaemia caused by theileriosis include weakness and lethargy, exercise intolerance, difficulty breathing, anaemia and/or jaundice, reduced milk production, and abortion or stillbirths in pregnant cows.

"As these signs are often symptomatic of many other conditions, it is important to confirm diagnosis via a blood sample taken by a veterinarian," Mr Biddle said.

"Unlike animals who have been bred and raised in theileria-endemic regions, cattle introduced from inland or southern areas are at risk of being nave to this disease which can lead to illness or death and render bulls temporarily infertile."

Current treatment options for cattle that are affected with theileria are limited and responses to treatment are often poor, especially in severely affected animals.

A factsheet on theileriosis can be found at the NSW DPI website: https://www.dpi.nsw.gov.au/biosecurity/animal/info-vets/theileria

For further information contact your private veterinarian or your nearest Local Land Services office on 1300 795 299.

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