Questing ixodid ticks on the vegetation of sable antelope and multi-herbivore enclosures in Thabazimbi.

André C Uys,Ivan G Horak,Alan Harrison

doi:10.4102/jsava.v86i1.1243

André C Uys, Ivan G Horak + Show 1 more

Open Access

https://doi.org/10.4102/jsava.v86i1.1243

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Abstract

This survey of ixodid ticks was the first to compare the species composition and population dynamics of free-living ticks in intensive, sable antelope breeding enclosures, now commonplace in commercial wildlife ranching in South Africa, with those of multi-herbivore enclosures. The species composition, abundance and seasonal abundance of questing ixodid ticks on the vegetation in intensive breeding enclosures for sable antelope (Hippotragus niger), on which strategic tick control is practised, were compared with those of ticks in a multi-species herbivore enclosure surrounding the breeding enclosures in which no tick control is practised. A total of eight ixodid tick species were collected by drag-sampling the woodland and grassland habitats in each enclosure type monthly from July 2011 to July 2013. Rhipicephalus decoloratus, a potential vector of fatal tick-borne disease in sable antelopes, was the most abundant, accounting for 65.4% of the total number of ticks collected in the sable enclosures, whilst representing only 25.4% of number of ticks collected in the multi-species herbivore enclosure. Rhipicephalus decoloratus and R. evertsi evertsi were more abundant than R. appendiculatus (both p < 0.05) and Amblyomma hebraeum (p < 0.001 and p < 0.01, respectively). Rhipicephalus decoloratus larvae were collected throughout the year, with peak collections in November 2012 and October to December 2013 in the sable enclosures; and in April/May 2012 and February/April 2013 in the multi-species herbivore enclosure. More R. decoloratus were recovered in the second year than in the first year in the grassland habitat of the sable enclosures (V = 7.0, p < 0.05) possibly as a result of acaricide resistance. The apparent temporal over-abundance of R. decoloratus in sable antelope breeding enclosures, in the face of strategic tick control, is of concern and requires further investigation.

Highlights

Problem statementCommercial wildlife ranching has become increasingly popular in the past two decades and has, to a large extent, displaced commercial cattle farming in the bushveld regions of Limpopo Province, South Africa (Schroder, Uys & Reilly 2006)
Rhipicephalus decoloratus, which was collected throughout the year, was the most abundant tick in the intensive sable antelope breeding enclosures, accounting for 65.4% (n = 2281) of all ticks
The ticks most commonly collected on the farm Hoopdal in this survey, namely A. hebraeum, R. appendiculatus, R. decoloratus and R. evertsi evertsi, were the most commonly collected by Schroder et al (2006) on the same farm

Summary

Introduction

Problem statementCommercial wildlife ranching has become increasingly popular in the past two decades and has, to a large extent, displaced commercial cattle farming in the bushveld regions of Limpopo Province, South Africa (Schroder, Uys & Reilly 2006). Animals in the enclosures are subject to tick control and are maintained through dry periods by supplementary feeding (Schroder et al 2006). Commercial ranching of these species has resulted in an increase in the numbers of animals translocated within South Africa and this, in turn, has led to the introduction of hosts and/or ticks into non-endemic areas, resulting in mortalities from tick-borne diseases, tick toxicoses, tick worry and anaemia (McInnes et al 1991; Nijhof et al 2005). Mortalities as a result of tick-borne disease have been reported in a number of wildlife species, including sable and roan antelope, but little is known about which tick species transmit these diseases (Grootenhuis et al 1980; Nijhof et al 2003, 2005; Oosthuizen et al 2008)

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