Onderstepoort J. vet. Res. , 59, 275-283 ( 1992) PARASITES OF DOMESTIC AND WILD ANIMALS IN SOUTH AFRICA. XXXI. ADULT IXODID TICKS ON SHEEP IN THE CAPE PROVINCE AND IN THE ORANGE FREE STATE I. G. HORAK(1l and L. J. FOURIE(2l ABSTRACT HORAK, I. G. & FOURIE, L. J., 1992. parasites of domestic and wild animals in South Africa. XXXI. Adult ixodid ticks on sheep in the Cape Province and in the Orange Free State. Onderstepoort Journal of Veterinary Research, 59, 275-283 (1992) Four to 10 Dorper sheep on each of 12 farms in the Cape Province and 3 farms in the Orange Free State were examined for adult ixodid ticks at approximately 2- to 4-weekly intervals over periods varying from 4 to 18 months, commencing during January, February or April 1989. The farms in the Cape Province were located in the north-west, south-west and south of the province. Those in the Orange Free State were situated in the north-east and in the south. The sheep in the Cape Province harboured 10 species of ixodid ticks and the seasonal abun­ dances of Ixodes rubicundus, Rhipicephalus evertsi evertsi, Rhipicephalus gertrudae and Hyalomma truncatum were determined. The animals in the Orange Free State were infested with 7 tick species and the seasonal abundances of I. rubicundus, R. evertsi evertsi and Hyalomma marginatum rufipes were determined. INTRODUCTION MATERIALS AND METHODS Sheep in sub-Saharan Africa may harbour adults Survey localities of many different ixodid ticks (Theiler, 1962; Yeo­ The farms on which the sheep were examined, man & Walker, 1967; Walker, 1974; Fourie, Horak the regions within which these farms are located and & Marais, 1988b; Horak, Williams & Van Schalk­ the vegetation types of these regions are summa­ wyk, 1991 ). They are, however, good hosts of only a rized in Table 1. few species. Three studies on ticks infesting sheep in South Survey animals Africa have recently been published. Fourie et a/. Four to 10 Dorper sheep, which were individually (1988b) recovered the adults of 6 species from identified, ran with commercial flocks of this breed sheep in the south-western Orange Free State and on each of the 15 survey farms. The camps in which descr!bed the seasonal abundances of Hyalomma the sheep grazed encompassed hilly and/or moun­ margmatum rufipes, Ixodes rubicundus and Rhipi­ tainous as well as level terrain. cephalus punctatus [then identified as Rhipicepha­ Tick collections lus sp. (near R. pravus)]. Horak, Williams & Van ~chal~wyk (1991) recovered 7 ixodid tick species, The marked sheep were examined at approxi­ mcludmg the adults of 3 of them, from sheep in the mately 2- to 4- weekly intervals for periods ranging north-eastern Orange Free State, and 15 species from 4 to 18 months, commencing in January, including the adults of 12, from the eastern Cape February or April 1989. Whole body searches for Province. They determined the seasonal abun­ adult ixodid ticks were conducted on these sheep by dances of Amblyomma marmoreum, Boophilus the owner, or a State Veterinarian, or a stock inspec­ decoloratus, Haemaphysalis silacea, H. margina­ tor. Ticks from each sheep were collected separa­ tum rufipes, Rhipicephalus appendiculatus, Rhipice­ tely and placed in 70 % alcohol in marked vials. phalus evertsi evertsi, Rhipicephalus glabroscuta­ All the ticks were identified and counted under a tum and Rhipicephalus nitens on these animals. In stereoscopic microscope. The total numbers reco­ the third study Walker (1990) described Rhipicepha­ vered of the major tick species have been summa­ lus lounsburyi and Rhipicephalus neumanni and rized in separate tables for each species. The 3 also plotted their distributions. The latter 2 species Hyalommas have been dealt with in a single table parasitize the feet of sheep and other ungulates. and the minor species have been combined in The present paper describes a survey of adult another table. Where collections were made at suffi­ ticks on Dorper sheep on 12 farms in the Cape ciently regular intervals the seasonal abundances of Province and 3 farms in the Orange Free State. This the major tick species are graphically illustrated. If survey was conducted within the distribution range collections were irregular, or particular species of I. rubicundus, with the specific intent of determin­ occurred only in small numbers, seasonal trends for ing the commencement and peak of activity of this these species are mentioned in the text. tick at various latitudes in South Africa. The oppor­ tunity was also taken to collect data on the distri­ RESULTS AND DISCUSSION bution and seasonal abundance of other ticks para­ General sitizing sheep. Certain aspects of the methods employed in this survey can be criticized. Firstly various collaborators <'1 Faculty of Veterinary Science, University of Pretoria, Onderste­ were used to collect the ticks from the sheep, poort 0110 secondly the proposed collection intervals were not 21 < Department of Zoology and Entomology, University of the strictly adhered.to, thirdly the total length and timing Orange Free State, Bloemfontein 9301 of the collection periods were biased in favour of the Received 12 August 1992-Editor seasonal occurrence of I. rubicundus, and finally no 275 PARASITES OF DOMESTIC AND WILD ANIMALS IN SOUTH AFRICA TABLE 1 The regions in which ixodid ticks were collected from Dorper sheep Fann Co-ordinates Nearest town Vegetation type Collection period Far north-western Cape Province Bovlei 30° 12' S, 18° 05'E Mountain Renosterbosveld Jan.-Oct.89 Olienfontein 30° 14' S, 18° 00' E Kamieskroon Mountain Renosterbosveld Jan.-Jul. 89 Outuin 30° 10' S, 18° 02' E Mountain Renosterbosveld Jan.-Dec. 89 North-western Cape Province Diepvlei 31 ° 40' S, 18° 50' E Succulent Karoo Jan.-Jul. 89 Gifberg 31 ° 47'S, 18° 40' E Vanrhyns- Succulent Karoo Jan.-Oct. 89 dorp Kantoorshoek 31 ° 47' S,18° 45' E Succulent Karoo Jan.89-Feb. 90 South-western Cape Province Pienaarskloof 33°13'S, 20° 02'E Touwsrivier Macchia Jan.89-Jun.90 Rheeboksfontein 33° 44'S,20° 32'E Barrydale Karroid Broken Veld Apr. 89-Jun. 90 Sandfontein 34° 05'S,20° 03' E Bonnievale Karroid Broken Veld Jan. 89-Feb.90 Southern Cape Province Dieniedouw 33° 27'S, 23° 52' E False Macchia Jan.-May89 Klipfontein 33° 20' S,23° 19'E Willow more Karroid Broken Veld Feb.-May89 The Knolls 33° 26'S, 23° 40' E False Macchia Feb.-Jun. 89. Southern Orange Free State Goedemoed 30°35'S,26° 20'E Bethulie False Upper Karoo Feb.89-Jan. 90 N~stern Orange Free State Driefontein 28° 09' S, 27" 59' E Cymbopongon-Themeda Feb.-Nov. 89 Veld Palmietfontein 28° 19' S, 27" 57' E Paul Roux Cymbopogon-Themeda Feb.- Nov. 89 Veld attempt was made to collect immature ticks. The greatest total numbers of ticks were recov­ Nevertheless valuable data on adult ticks infesting ered from sheep on farms in the far north-western, sheep in several regions of South Africa were ob­ the north-western and the southern Cape Province. tained. These include new locality records for a number of species, the commencement of activity The distribution of this tick has recently been re­ and months of peak abundance of I. rubicundus at viewed by Spickett & Heyne (1988). The farms in the different latitudes, and the determination of the current survey lie within or on the fringes of its seasonal abundance of adult Rhipicephalus gertru­ previously known distribution range. It may be intro­ dae in this country. duced to new localities by the large-scale transpor­ A total of 10 ixodid tick species were recovered tation of sheep from infested regions to biotically from the sheep in the Cape Province. Of these /. suitable, uninfested regions in the autumn and rubicundus, R. evertsi evertsi, R. gertrudae and winter months when the adult ticks are present on Hyalomma truncatum can be considered major the animals. species. The sheep in the Orange Free State har­ boured 7 tick species of which /. rubicundus, R. ev­ With the possible exception of the north-eastern ertsi evertsi and H. marginatum rufipes were the Orange Free State, the numbers of ticks recovered most numerous. Fourie et at. (1988b), Walker from sheep from one or more farms in each of the (1990) and Horak, Williams & Van Schalkwyk (1991) regions sampled indicate that these localities are all recorded a total of 22 species on sheep in the Cape suitable for I. rubicundus. Excluding the south­ Province and the Orange Free State during their western Cape Province and the north-eastern recent investigations. To these can now be added Orange Free State, /. rubicundus was the numeri­ Hyalomma marginatum turanicum, Rhipicephalus cally dominant species in each of the regions. The follis and R. gertrudae. disparity in the sex ratio (562 males to 2 449 females) is characteristic for this species, in which Ixodes rubicundus mating generally occurs off the host (Fourie et at., The preferred domesticated hosts of adults of this 1988b). In addition those males which may be species are sheep (Stampa, 1959; Fourie & Horak, present on the host are seldom attached, and hence 1991 ) while the wild hosts are mountain reedbuck, could have been overlooked during sampling. eland and caracals (Horak, Moolman & Fourie, 1987). The preferred hosts of the immature stages The seasonal abundances of I. rubicundus on are rock elephant shrews and red rock rabbits and sheep on "Bovlei" plus " Outuin" in the far north­ possibly also caracals (Stampa, 1959; Horak et at., western Cape Province; on all 3 farms in the north­ 1987; .Fourie, Horak & Van den Heever, 1992). The western Cape Province; on all 3 farms in the south­ numbers of ticks recovered from the sheep on the western Cape Province; and on "Goedemoed" in various farms in the present survey are summarized the southern Orange Free State are illustrated in inTable2.