Greg Ferrier and Jeff Cave DEPI
In recent years the number of cases of Benign Theileriosis has increased in both Gippsland and North East Victoria. Generally, impacts on producers have been relatively low with less than one per cent mortalities observed, though in some cases mortalities have been as high as 25 per cent, impacting significantly on the farm business.
In early May, more than 80 producers met at Running Creek in the Kiewa Valley to participate in discussions on Benign Theileriosis. DEPI District Veterinary Officer Dr John Ryan provided broad information and Dr Andrew Jemmeson (Tallangatta Veterinary Clinic) and Dr Andrew Colson (Ovens and Kiewa Veterinary Centre) shared their clinical experiences of the disease and treatment options. Producers affected by the disease also spoke of their experiences.
The disease, caused by a blood parasite (Theileria orientalis ikeda) is thought to be spread by the bush tick (Haemaphysalis longicornis). Theileriosis is not a notifiable disease.
Bush ticks are known as 'three host' ticks which feed on the animal for one to three weeks then drop off to moult in the pasture or bush for about one week. They survive for up to eight months before re-attaching to animals another two times. Stages range from pinhead-sized larvae (seed ticks) to match-head-sized nymphs through to match-head to pea-sized adult females. Seasonal conditions regulate the speed of each cycle. Current evidence suggests less than 10 ticks are required to transfer Theileria parasites.
Following the meeting, producers indicated they would focus on four main areas back on farm:
1. Review biosecurity
- Quarantine new stock and treat with mectin type drench.
- Check with the vendor/agent if stock have come from a herd/area known to have Theileriosis.
- Check for presence of ticks.
2. Revise existing health management plan
- Regularly monitor stock for tick infestations.
- Maintain stock in as good condition as possible.
3. Nutritional management
- Maintain quality feed supply to enable animals to be in the best condition to respond to possible infections.
- Speak to feed suppliers about iron supplements in the event of an outbreak.
4. Drenching and vaccination practices
- Treat stock for tick infestations as soon as detected.
- Maintain routine vaccinations to ensure good immunity against other diseases.
Further information on Benign Theileriosis
If you would like handouts from the day please contact Greg Ferrier on (02) 6030 4609 or 0438 738 634.