Case report – tick fever in the Darwin region

Above. Left: swollen spleen at post-mortem. Right: tick fever parasite within red blood cells

During October 2020, a property in the Darwin region found 10 head out of approximately 200 heifers dead over the course of one week.

The cattle had been brought onto the property from the tick free area around 6 weeks previously. The cattle had been back-lined and vaccinated for tick fever when they arrived.

A weak heifer who could not stand was euthanased. Post-mortem by a government Veterinary and Livestock Biosecurity Officer found an enlarged spleen and yellowing (jaundice) of the tissues. Samples were collected and submitted to the Berrimah Veterinary Laboratory for testing, which showed Babesia bigemina parasites inside the red blood cells.

A diagnosis of tick fever (also known as red water) was made. Tick fever is a disease is caused by microscopic parasites transmitted to cattle by the cattle tick. Tick fever is present in the tick infected areas of the NT, and cause significant losses when cattle from tick-free areas (which have no immunity) are moved to tick infected areas.

There is a vaccine available to prevent tick fever, and producers should vaccinate cattle from tick free areas well in advance of moving them to tick infected areas. The vaccine has a short shelf life and care must be taken to keep it cold and administer it properly. It can take about a month for full immunity to develop and cattle must be kept tick free during this time.

More information

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