Abstract:
BACKGROUND : There is currently no scientific evidence regarding the current climatic or other
epidemiological factors that could influence the occurrence of heartwater in South Africa.
OBJECTIVES : The objective was to determine whether climatic changes or other epidemiological
factors influence the occurence of heartwater in South Africa.
METHOD : A survey was conducted to scrutinise these factors using both veterinarians and
farmers working in known areas in which heartwater had previously been confirmed to
establish the value of each of these factors. Based on the observations, meaningful tendencies
were noted, and conclusions drawn.
RESULTS : These include changes in the spatial distribution of heartwater in many areas, with
serious expansion, in some instances, of up to 150 km. In total, 48% of veterinarians and 42%
of farmers reported seeing increase in the number of farms affected by heartwater. Climate
change as a causative factor indicated by observations of increased average temperatures,
milder frosts, less rain and shorter rainy seasons was identified by the majority of farmers but
not by as many veterinarians. Respondents in both groups considered vegetation change an
important factor. Increasing number of wildlife, especially antelope, was seen as a major factor
by most veterinarians and also by many farmers. Both groups identified the movement of
livestock and wildlife as an increasingly important factor that should be of major concern for
both industries because it leads to the avoidable spread of many diseases apart from heartwater.
CONCLUSION : Movement controls should be reinstated and reinforced by vigorously enforced
legislation. The role of genetically determined resistance or resilience to heartwater infection
in ruminants should be investigated. Breeding better adapted animals could provide part of a
sustainable approach to the disease.
