The epidemiology of rabies in Zimbabwe. 2. Rabies in jackals (Canis adustus and Canis mesomelas)

Abstract

The epidemiology of rabies in Canis adustus (the side-striped jackal) and Canis mesomelas (the black-backed jackal) in Zimbabwe is described using data collected from 1950-1996. Cases in the two species made up 25.2% of all confirmed cases, second only to domestic dogs. Since the species of jackal cases was not recorded on rabies submission forms, the country was divided into areas according to species dominance and jackal cases were assigned to either C. adustus or C. mesomelas dominant zones or a sympatric zone where the relative status of the species is not known. Jackal rabies in both species is maintained in the commercial farming sector. Jackal rabies in the C. adustus zone occurs as dense epidemics, which begin at a single focus and spread centrifugally. The foci were initiated by rabid dogs, but once initiated the epidemic is maintained by C. adustus independently of other species. The extent of outbreaks in the C. adustus zone was limited by geographical (landuse type and jackal species interface) boundaries. Jackal rabies in C. adustus zones showed two seasonal peaks with the main peak occurring during late summer and the second peak during winter. In the C. mesomelas zone jackal rabies was more sparse but it occurred during most years. C. mesomelas is also able to maintain rabies independently of other species, although the epidemiology of the disease in this species is unclear. Transmission of rabies cycles between the two jackal species zones does not appear to occur as epidemics terminate when crossing the C. adustus and C. mesomelas interface boundaries.