Heartwater : a simple disease with a peculiar distribution that has exasperated farmers and scientists for eons

Abstract

Heartwater (previously cowdriosis) is a disease caused by a rickettsia, Ehrlichia ruminantium (previously Cowdria ruminantium). It was first recognised and recorded in South Africa by the Voortrekker Louis Trichardt in 1838. It affects many ruminants and is present in all countries in Africa south of the Sahara, some islands around Africa and in the Caribbean. The disease is transmitted by the Amblyomma (bont or patterned) tick and if not treated, usually results in death. Symptoms include high fever, hypersensitivity with other nervous signs, and generalised oedema seen as accumulation of fluid in the lungs, brain, thoracic cavity and pericardial sac. The distribution of the disease corresponds closely to that of its vectors. (Read full abstract in the WAHVM 2020 proceedings https://repository.up.ac.za/handle/2263/74425)