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Abstract

The tick vectors of heartwater (Cowdria ruminantium infection) in Zimbabwe, Amblyomma hebraeum and Amblyomma variegatum, historically were believed to be confined to the low-lying regions of the south and north-west of the country. However, country-wide surveys performed in 1975-1980 and 1988-1991 demonstrated that both species were also established in western parts of the highveld plateau and had started to encroach on the predominantly heartwater-free central and eastern highveld regions. To determine the current distributions of both the vectors and evaluate the potential threat of heartwater to animals in the highveld, a survey of ticks infesting cattle was performed in 1996 at 2994 locations in small-holder and large-scale commercial farming areas throughout Zimbabwe. Amblyomma hebraeum was collected at 1329 locations, A. variegatum at 72 locations and both A. hebraeum and A. variegatum at 13 locations. The results demonstrated that A. hebraeum was present, as previously recorded, throughout the southern half of the country and appeared to have undergone further limited spread into the central and eastern highveld regions. Only the northern-most region of the country appeared to be free of this species. Amblyomma variegatum was collected mainly in the north-west, as previously recorded, but was also found at isolated locations across the central highveld region and along the eastern border with Mozambique. This species was, however, still absent from the southern half and the northern-most regions of the country. An overlap of the distributions of the two species existed within a zone along the southern and eastern regions of the distribution of A. variegatum. These results suggest that the vectors of heartwater are spreading and threaten to introduce heartwater into intensive livestock-producing regions of the country.

Geographic distribution of the invasive cattle tick Rhipicephalus microplus, a country-wide survey in Benin

“…Where possible, all ticks on the inspected body were removed. On highly tick-infested animals, a sub-sample of the ticks present was collected, but care was taken to collect ticks from the different predilection sites: the base of tail and perianal region, perineum, legs, axillae, hooves, udder, scrotum, belly, dewlap, head and ears (Peter et al, 1998;ICTTD, 2007). The ticks were stored in plastic vials containing 70 % alcohol, which were labelled using the sampling date and the village name.…”

An ecological and epidemiological single‐season survey of Anaplasma and Ehrlichia positive ticks in Victoria Falls National Park, Zimbabwe

“…Tick species that did have relatively low specialist values (e.g., R. decoloratus and A. hebraeum ) may play meaningful roles in transferring pathogens among different animal species. In particular, previous research in Zimbabwe documented the close association of A. hebraeum and A. variegatum on cattle and the prevalence of heartwater (Peter et al, 1998; Peter, Perry, Brian, et al, 1998), so movement of those species between domestic animals and wildlife may create pathogen spillover risk.…”