Veterinary Research Officer
NSW Department of Primary Industries[DPI]
In 2008 there was an increase in the number of outbreaks of theileriosis in NSW, due to infection by the protozoan parasite, Theileria buffeli. T. buffeli is part of the Theileria buffeli/sergenti/orientalis group. This group is regarded as benign when compared to T. parva (east coast fever) and T. annulata (mediterranean fever) - highly pathogenic strains that are exotic to Australia.
The reason for the increased number of outbreaks is unknown and is being investigated. It is possible that differing pathogenicity of strains as demonstrated by Japanese veterinarians is responsible.
We are providing the following information to veterinary practitioners to increase awareness of the disease and to provide a guide for investigation and diagnosis of outbreaks. NSW DPI is encouraging veterinarians to submit samples to its veterinary laboratory at Menangle to investigate suspect cases.
Charges for tests to confirm/exclude theleriosis will be paid by NSW DPI under its "Better understanding of theileriosis in NSW cattle herds" project. Charges for other tests will be as normal - that is, paid for by the submitter unless there is an existing project which would pay all/part of test charges.
Clinical signs are those associated with severe anaemia and include: lethargy, inappetence, exercise intolerance, tachycardia, tachypnoea, pale to jaundiced mucous membranes, transient pyrexia, abortions, and in dairy cows a drop in milk production. No visual evidence of haemoglobinuria though on occasions urinary dipstick positive. Mortality rate is highest in heavily pregnant cows. Cases have been noted in all age groups.
Commonly see jaundice of carcase, in particular the liver may appear yellow.
Severe regenerative anaemia, blood smear examination reveals Theileria piroplasms within erythrocytes, and hyperbilirubinaemia. There is often elevated GLDH, GGT and AST associated with anoxic liver damage. Fibrinogen levels are generally normal. Theileria infection may be seen as an incidental finding, so other causes of haemolytic anaemia should also be considered and excluded where necessary.
Differentials include: Brassica poisoning (kale anaemia), tick fever (babesiosis and anaplasmosis which are notifiable diseases in NSW), bacillary haemoglobinuria (Clostridium haemolyticum), leptospirosis in calves, post-parturient haemoglobinuria (hypophosphataemia), chronic copper toxicity (mainly in sheep, rare in cattle). Other differentials exist but are less common.
On receipt of samples, a PCV will be performed on EDTA blood and smears (either supplied or made in the laboratory), stained and examined. Additional tests eg full blood count, biochemistry will be at the job manager's discretion. If submitted, ticks will be identified. The cost of these tests will be paid by NSW DPI provided instructions regarding submission of samples are followed.
If one or more affected animals have died and post mortem(s) are performed, testing of EDTA blood from live animals and ticks from any animal will be paid by NSW DPI. Testing of samples from dead animals or samples to exclude other than notifiable diseases, will be charged according to the normal guidelines.
For the purposes of the "Better understanding of theileriosis in NSW cattle herds" project, the following case definition applies.
For further information contact
02 63913870 or