The geographic distribution of ticks in the eastern region of the Eastern Cape Province

Abstract

The objective of the study was to determine the species composition and geographic distribution of ticks in the eastern region of the Eastern Cape Province. Ninety out of a total of 1 057 communal cattle dip-tanks in the region were selected by means of a table of random numbers, and 72 of these were eventually allocated to the survey. At each of the chosen dip-tanks an attempt was made to collect ticks from five cattle, five goats, five dogs and two hen coops, and free-living ticks from the vegetation by means of flannel strips, and ticks were collected from January 2004 and 2005 to May 2004 and May 2005 respectively. The geographic coordinates of the dip-tanks at which the ticks were collected were recorded, and used for plotting the distributions of the various tick species. The ticks were stored in 70 % ethyl alcohol in internally labelled vials for later identification and counting. Eleven ixodid tick species were collected from cattle, goats, dogs and the vegetation, namely Amblyomma hebraeum, Haemaphysalis elliptica, Haemaphysalis spinulosa, Hyalomma marginatum rufipes, Ixodes pilosus group, Rhipicephalus (Boophilus) decoloratus, Rhipicephalus (Boophilus) microplus, Rhipicephalus appendiculatus, Rhipicephalus evertsi evertsi, Rhipicephalus sanguineus and Rhipicephalus simus. Of these R. e. evertsi and R. appendiculatus were the most numerous, and constituted 38.8 % and 34.9% of the 13 768 ticks collected respectively. They were followed by R. (B.) microplus (17.4 %) and A. hebraeum (5.3%). Two argasid tick species were collected, namely Otobius megnini from the ear canals of two cattle, and Argas walkerae from fowl houses. A. walkerae was collected from 102 (70.8%) of 144 fowl houses in the vicinity of 57 (79.2%) of the 72 selected dip-tanks, and seemed to be present only when there was wood in the structure of the fowl house. Adult A. hebraeum was present in areas where there are trees and bush as well as grass, particularly along the coast, but also surprisingly far inland beyond the distribution limits previously illustrated for it. R. (B.) microplus, R. appendiculatus and R. e. evertsi were present throughout the survey area region, and from their distribution maps there are strong indications that the exotic R. (B.) microplus is displacing the indigenous R. (B.) decoloratus in this region. A large percentage of goats were infested with the adults of ticks normally associated with cattle, namely A. hebraeum, R. (B.) microplus, R. appendiculatus and R. e. evertsi. A more significant finding, however, is the large proportion of R. (B.) microplus females measuring 5 mm or more in length on the goats, a good indication that they were successfully completing their life cycles. In the light of these findings, it is imperative to include goats in any tick control programme aimed at controlling a tick-borne disease outbreak in sympatric cattle. Eight ixodid tick species were collected from the dogs, and H. elliptica, followed by R. appendiculatus and R. simus were present on these animals at the largest number of dip-tanks. The kennel tick R. sanguineus, a parasite of dogs in urban environments, was collected from dogs only at two localities.