Treating heartwater

Heartwater can cause high fever, convulsions and death among sheep, goats and cattle.

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Heartwater (also called cowdriosis) is a tick-borne disease that can easily kill large numbers of animals.

In areas in South Africa where the disease is endemic (sure to occur), deaths from heartwater are three times greater than the combined deaths from babesiosis (a malaria-like disease) and anaplasmosis (another tick-borne disease).

The disease is caused by a blood parasite carried by the bont tick. This tick is about the size of the nail on your small finger and is found mainly in the frost-free, drier parts of the country – and these are where heartwater occurs.

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Sick animals may have a fever of 40°C or higher. You may also notice strange behaviour, such as twisting the head towards the body. Other symptoms include a high-stepping walk, convulsions or very hard kicking.

Animals that die from heartwater often have foam and fluid coming out of the nose. If you open the carcass, you’ll find fluid in the belly, chest and sac surrounding the heart (hence the name of the disease). The lungs will also be swollen with foam and there’ll be fluid in the windpipe.

Speed is all-important. When you notice signs of the disease, it’s critical to treat it immediately with an oxytetracycline product, a long-acting antibiotic that kills the heartwater bacteria. Don’t forget to read the instructions carefully for the correct dosage and treatment method.

Prevention is always better than cure. And in the case of heartwater, you can stop it striking your animals in the first place.
In endemic areas, the disease can usually be controlled by vaccinating the animals, and thereafter only treating for ticks when they become a nuisance. No matter where you farm, though, it’s a good idea to consult your vet about the best way to control the disease in your area.

Heartwater in Southern Africa, by PG Marais (Grootfontein Agricultural College)
Agricultural Research Council.