Journal of the South African Veterinary Association
versão On-line ISSN 2224-9435
Heartwater is a serious limiting factor for sheep and goat production in the major endemic area of sub-Saharan Africa and therefore most knowledge, research and control methods originate from this region. Whilst the usual or common clinical presentations can be used to make a presumptive diagnosis of heartwater with a good measure of confidence, this is not always the case, and animals suffering from heartwater may be misdiagnosed because their cases do not conform to the expected syndrome, signs and lesions. One aberrant form found occasionally in the Channel Island breeds of cattle and some goats is an afebrile heartwater-like syndrome. The most constant and characteristic features of this heartwater-like syndrome comprise normal temperature, clinical signs associated with generalised oedema, and nervous signs, especially hypersensitivity. The presumption that the disease under investigation is the afebrile heartwater-like syndrome entails a tentative diagnosis based on history and clinical signs and the response to presumed appropriate treatment (metadiagnosis). The afebrile heartwater-like syndrome presents similarly to peracute heartwater but without the febrile reaction. Peracute cases of heartwater have a high mortality rate, enabling confirmation of the disease on post-mortem examination. Recognition of the afebrile heartwater-like syndrome is important to prevent deaths and identify the need for appropriate control measures.