Abstract:
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 heartwaterlike
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.
