Heartwater is on the increase due to climate change. It is a fatal disease that mainly affects cattle, sheep and goats and is spread by the bont tick.
By Charl van Rooyen, Senior Journalist at African Farming and Landbouweekblad
The quick onset of heartwater leads to many deaths and up to 90% of animals die if left untreated, said Dr Lea Finkler, a vet from the Agricultural Research Council (ARC) at Irene. Dr Finkler was one of the speakers at the annual Beef Cattle School at the 2025 Thabazimbi Show. The event was co-hosted by the ARC and the Bushveld Kalahari Afrikaner study group. Farmers from all over Limpopo and other provinces attended the school.
The bont tick is a blood sucking parasite of cattle and other livestock and it also affects wild animals. It is a three-host tick, with three different stages that each feed on a different host. About 90% of its life cycle is in the environment where its survival depends on environmental factors such as humidity, temperature and rainfall. It is active during early summer.
The clinical signs of heartwater include a high fever of more than 40 degrees, difficulty breathing, abnormal or aimless walking, an inability to stand, circling and seizures.
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Treatment consists of the early administration of oxytetracyclines, such as Terramycin (reg.no. G0333 of Act 36 of 1947), Terralon LA (reg. no. G2676) and Maxitet LA (reg. no G3580), and tick control with dips or pour-ons to reduce the tick burden, for example Supadip (reg. no. G3349) or Deadline (reg., no. G723).
Bont ticks used to be limited mostly to the coastal regions, but have expanded inland across South Africa over the past 20 years. It is expected that it will occur in most parts of central and eastern South Africa by 2065, as these parts will have a good climate for bont ticks.
Finkler said climate change leads to warmer and more humid conditions, which increase suitable environments for bont ticks and lead to better tick survival and breeding. Inland dry and hot regions that were barriers, are now becoming favourable areas for the bont tick, and areas previously unaffected by heartwater are becoming higher-risk areas of animal diseases.
The implications for farmers are the risk of heartwater in new regions due to ticks spreading. This leads to increased livestock losses due to heartwater. The disease caused losses of about R1,266 billion in 2022 in South Africa. The changing climate also means the tick season is becoming longer, which leads to a general increase in disease transmission.
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Finkler’s recommendations are:
Targeted dipping. Early treatment by quickly administering oxytetracyclines once symptoms appear.
Integrated management by applying genetic selection for tick resistance in livestock, managing of grazing and veld, and monitoring of livestock movement.
Ongoing monitoring and awareness by keeping track of weather/climate projections and tick/heartwater distributions (talk to your neighbors).
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