Parasites of domestic and wild animals in South Africa. XXIX. Ixodid ticks on hares in the Cape Province and on hares and red rock rabbits in the Orange Free State.

One hundred and seventeen scrub hares, Lepus saxatilis, were examined for ixodid ticks in various regions of the Cape Province. They were infested with 18 tick species and the seasonal abundances of the immature stages of Amblyomma hebraeum, Amblyomma marmoreum, Hyalomma marginatum rufipes, Rhipicephalus appendiculatus and Rhipicephalus glabroscutatum and all stages of Rhipicephalus oculatus and the adults of a Rhipicephalus sp. (near R. oculatus) were determined. Seventy-two scrub hares on 3 farms in the Orange Free State harboured 10 ixodid tick species and the seasonal abundances of the immature stages of H. marginatum rufipes and Hyalomma truncatum and all stages of Rhipicephalus punctatus were determined. Thirty Cape hares, Lepus capensis, examined in the northern Cape Province harboured 5 tick species and the seasonal abundances of the immature stages of H. marginatum rufipes and H. truncatum were determined. Thirty-four Cape hares examined in the south-western Orange Free State carried 6 tick species and the seasonal abundance of immature H. marginatum rufipes was determined on these animals. Twenty-eight Smith's red rock rabbits examined on 2 farms in the south-western Orange Free State were infested with 7 tick species.     

Ticks associated with the three largest wild ruminant species in southern Africa

The objective of this study was to assess the host status of the three largest southern African wild ruminants, namely giraffes, Giraffa camelopardalis, African buffaloes, Syncerus caffer, and eland, Taurotragus oryx for ixodid ticks. To this end recently acquired unpublished data are added here to already published findings on the tick burdens of these animals, and the total numbers and species of ticks recorded on 12 giraffes, 18 buffaloes and 36 eland are summarized and discussed. Twenty-eight ixodid tick species were recovered. All stages of development of ten species, namely Amblyomma hebraeum, Rhipicephalus (Boophilus) decoloratus, Haemaphysalis silacea, Ixodes pilosus group, Margaropus winthemi, Rhipicephalus appendiculatus, Rhipicephalus evertsi evertsi, Rhipicephalus glabroscutatum, Rhipicephalus maculatus and Rhipicephalus muehlensi were collected. The adults of 13 species, of which the immature stages use small mammals as hosts, namely Haemaphysalis aciculifer, Hyalomma glabrum, Hyalomma marginatum rufipes, Hyalomma truncatum, Ixodes rubicundus, Rhipicephalus capensis, Rhipicephalus exophthalmos, Rhipicephalus follis, Rhipicephalus gertrudae, Rhipicephalus lounsburyi, Rhipicephalus lunulatus, Rhipicephalus pravus group and Rhipicephalus simus, were also collected.     

Arthropod parasites of springbok, gemsbok, kudus, giraffes and Burchell's and Hartmann's zebras in the Etosha and Hardap Nature Reserves, Namibia.

A total of 48 springbok, 48 gemsbok, 23 kudus and 6 giraffes were examined for ticks and lice, while 9 Burchell's zebras and 6 Hartmann's mountain zebras were examined only for ticks. Springbok and gemsbok were shot in both the Etosha National Park in the north and the Hardap Nature Reserve in the south of Namibia. All the other animals were shot in the Etosha National Park. A total of 7 ixodid tick species and 8 lice species were recovered. The springbok carried few ticks. The adults of a Rhipicephalus sp. (near R. oculatus) were most numerous on the gemsbok, especially during November. The kudus were the only animals harbouring Rhipicephalus zambeziensis. Adult Hyalomma truncatum, followed by adult Hyalomma marginatum rufipes, were most abundant on the giraffes and adult Rhipicephalus evertsi mimeticus were commonest on the zebras.     

Parasites of domestic and wild animals in South Africa. XXX. Ectoparasites of kudus in the eastern Transvaal Lowveld and the eastern Cape Province.

Sets of four kudus were shot and examined for arthropod parasites at approximately monthly intervals from April 1981 to March 1983 in the southern part of the Kruger National Park, eastern Transvaal Lowveld. These animals harboured 10 ixodid tick species of which Boophilus decoloratus followed by Amblyomma hebraeum were the most abundant. The seasonal abundances of these ticks and of Amblyomma marmoreum, Rhipicephalus appendiculatus, Rhipicephalus evertsi evertsi and Rhipicephalus zambeziensis were determined. The kudus were also infested with 3 lice and 1 louse fly species, as well as the nymphs of a pentastomid. Sixteen kudus were shot in the Andries Vosloo Kudu Reserve, eastern Cape Province and 9 on an adjacent farm. These animals were infested with 12 tick species. A. hebraeum followed by Rhipicephalus glabroscutatum were the most abundant on kudus in the reserve and R. glabroscutatum followed by Haemaphysalis silacea on the animals on the farm. The seasonal abundances of A. hebraeum, A. marmoreum, H. silacea, R. appendiculatus, R. glabroscutatum and a Rhipicephalus sp. (near R. oculatus) were determined on the kudus in the reserve. The kudus were also infested with 3 lice and 1 louse fly species. Two kudus examined in the Addo Elephant National Park were infested with 6 tick, 1 louse and 1 louse fly species.     

Parasites of domestic and wild animals in South Africa. XXV. Ixodid ticks on sheep in the north-eastern Orange Free State and in the eastern Cape Province

The tick burdens of 115 Merino sheep, slaughtered over a period of 15 consecutive months on a farm in the north-eastern Orange Free State, were determined. A total of 7 ixodid and 1 argasid tick species were recovered and the seasonal abundances of Boophilus decoloratus, Hyalomma marginatum rufipes, Margaropus winthemi and Rhipicephalus evertsi evertsi were determined. One hundred and forty-nine Merino sheep were slaughtered over periods varying from 10 to 25 months on 3 farms in Eastern Province Thornveld in the eastern Cape Province and their tick burdens determined. Fourteen ixodid tick species were recovered from these animals and the seasonal abundances of Amblyomma marmoreum, B. decoloratus, Haemaphysalis silacea, R. evertsi evertsi and Rhipicephalus nitens were ascertained. On a farm in Valley Bushveld in the eastern Cape Province, 2 Dorper sheep were slaughtered each month for a period of 24 consecutive months. These 48 sheep harboured 10 ixodid tick species and the seasonal abundances of A. marmoreum, H. silacea, Rhipicephalus appendiculatus and Rhipicephalus glabroscutatum were determined. A total of 17 ixodid tick species, of which 12 had reached the adult stage, where recovered from the sheep on the 5 farms.     

Parasites of domestic and wild animals in South Africa. XXVI. The mosaic of ixodid tick infestations on birds and mammals in the Mountain Zebra National Park

Sixteen species of ixodid ticks were collected over varying periods of time from 6 species of ground-frequenting birds and 15 species of small and large mammals in the Mountain Zebra National Park, Karoo, Cape Province. Margaropus winthemi followed by Rhipicephalus glabroscutatum and Rhipicephalus evertsi evertsi were the most abundant species. The host preferences of 14 tick species and the seasonal abundances of 13 species were determined. Small numbers of immature stages of only a few tick species were generally recovered from ground-frequenting birds, mice and rats. Amongst the slightly larger animals the smallest number of ticks and species were recovered from springhares and the largest numbers from scrub hares. Amongst the larger mammals, very few ticks were harboured by springbuck and black wildebeest, while heavy infestations of several species were encountered on Cape mountain zebras and eland.     

A study of the justification for intensive tick control in Kenyan rangelands

Sixty male weaner cattle at the National Range Research Station, Kiboko, Kenya were placed in four groups of 15 animals under four different tick control regimens for 16 months. The treatment groups were: spraying with acaricide weekly, spraying every three weeks, spraying whenever group mean tick infestations reached more than 200 per animal (once only in the course of the study) and a control unsprayed group. The cattle were weighed monthly. There were no significant differences between the liveweight gains of the groups during a period of severe drought and during the following period of compensatory weight gain. The untreated group gained more weight than the other groups. Cattle died in all groups, but without significant differences between the groups; the long drought and associated malnutrition were the prime cause of death. Rhipicephalus pravus and R pulchellus were the dominant tick species with fewer Amblyomma gemma, Hyalomma truncatum and small numbers of Boophilus decoloratus and R evertsi. These ticks transmit anaplasmosis, babesiosis and cowdriosis in the study area. Total tick counts reached 750 on individual animals but group means rarely reached more than 200 because of high resistance to ticks in some animals. Host resistance ranking within groups was virtually constant throughout the experiment. The study showed that intensive tick control is not required in the semi-arid areas of Africa.     

Ixodid ticks of angora and boer goats,grysbok, common duikers,kudus and scrub hares in Valley Bushveld in the Eastern Cape Province,South Africa

At monthly intervals from February 1983 to January 1984 two Angora goats, two Boer goats, one grysbok, Raphicerus melanotis, one common duiker, Sylvicapra grimmia, one greater kudu, Tragelaphus strepsiceros, and four scrub hares, Lepus saxatilis, were killed on a farm in Valley Bushveld in the Eastern Cape Province, South Africa and examined for ticks. Seven ixodid tick species were collected, of which Rhipicephalus glabroscutatum followed by Amblyomma hebraeum and Rhipicephalus oculatus were the most numerous. Amblyomma hebraeum was mainly a parasite of the two goat breeds, with the Angora goats harbouring greater numbers than the Boer goats, while large numbers of R. glabroscutatum parasitized the goats and the antelopes. Rhipicephalus oculatus was nearly exclusively a parasite of scrub hares. The larvae of A. hebraeum were most numerous on goats from May to July, the nymphs from September to November and the adults from August to December and during February, while the immature stages of R. glabroscutatum were most numerous on these animals from April to July and the adults from August to December. Peak activity periods of the latter tick were somewhat longer on kudus than on goats; the immature stages were most numerous from January to August and the adults from July to February. The larvae of R. oculatus were most numerous on scrub hares from March to May, nymphs from September to November and adults from October to December.     

Parasites of domestic and wild animals in South Africa. XXI. Arthropod parasites of vaal ribbok, bontebok and scrub hares in the western Cape Province

Vaal ribbok (Pelea capreolus), bontebok (Damaliscus dorcas dorcas) and scrub hares (Lepus saxatilis) were slaughtered in the Bontebok National Park at regular intervals and examined for arthropod parasites. Twelve species of ixodid ticks were recovered; the antelope each harboured 9 species and the hares 11. Rhipicephalus nitens was the most prevalent and most abundant tick. The vaal ribbok also harboured large numbers of Ixodes pilosus and the bontebok fairly large numbers of Rhipicephalus glabroscutatum. The vaal ribbok were infested with 2 lice species and the larvae of 3 oestrid fly species. The bontebok harboured 2 lice species and the larvae of 2 oestrid flies, and the scrub hares were infested with a louse species and a flea species. The host preference and seasonal abundance of some of the parasites were determined.     

Delayed-type hypersensitivity test for assessing tick-immune status of cattle in Zambia

Delayed-type hypersensitivity skin reactions were used to assess the tick resistance status of Tonga calves in Zambia. The antigen used in the tests was a homogenate of unfed nymphal Rhipicephalus appendiculatus which had been shown to give protective immunity in guinea pigs to adult female R appendiculatus. There was a significant negative correlation between the intensity of the reactions and the total number of ticks (Amblyomma variegatum, R appendiculatus, Hyalomma truncatum, Boophilus decoloratus and Rhipicephalus species) on the animals.     

Parasites of domestic and wild animals in South Africa. XIX. Ixodid ticks and fleas on rock dassies (Procavia capensis) in the Mountain-Zebra National Park

Five or 6 rock dassies (Procavia capensis) were shot at monthly intervals for 13 consecutive months in the Mountain Zebra National Park and processed for arthropod parasite recovery. Ten species of ixodid ticks and 2 flea species were recovered. The seasonal prevalence of the rock dassie ticks, Haemaphysalis hyracophila and Rhipicephalus distinctus, and of the immature stages of Rhipicephalus arnoldi, a tick that usually infests the red rock rabbit (Pronolagus rupestris), was determined. Only 10 of the approximately 10 000 ticks recovered from the rock dassies belonged to species that may infest domestic livestock.     

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.

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 abundances 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 and Hyalomma marginatum rufipes were determined.     

Small mammals as hosts of immature ixodid ticks

Two hundred and twenty-five small mammals belonging to 16 species were examined for ticks in Free State, Mpumalanga and Limpopo Provinces, South Africa, and 18 ixodid tick species, of which two could only be identified to genus level, were recovered. Scrub hares, Lepus saxatilis, and Cape hares, Lepus capensis, harboured the largest number of tick species. In Free State Province Namaqua rock mice, Aethomys namaquensis, and four-striped grass mice, Rhabdomys pumilio, were good hosts of the immature stages of Haemaphysalis leachi and Rhipicephalus gertrudae, while in Mpumalanga and Limpopo Provinces red veld rats, Aethomys chrysophilus, Namaqua rock mice and Natal multimammate mice, Mastomys natalensis were good hosts of H. leachi and Rhipicephalus simus. Haemaphysalis leachi was the only tick recovered from animals in all three provinces.     

Parasites of domestic and wild animals in South Africa. XXXVII. Ixodid ticks on cattle on Kikuyu grass pastures and in Valley Bushveld in the eastern Cape Province

Individual calves, exposed to infestation for 14 d on dry-land Kikuyu grass pastures on the coast near Alexandria, were slaughtered at approximately monthly intervals over a period of 2 years and examined for ticks. Although seven species were recovered total tick burdens were for the most part low. Changing the acaricide with which other cattle on the farm, but not the survey calves, were treated from an organophosphate-based compound to a synthetic pyrethroid resulted in a marked sustained reduction in the number of ticks on the calves. Successive pairs of yearling cattle exposed to infestation on a farm in Valley Bushveld were slaughtered at monthly intervals over a period of 2 years and examined for ixodid ticks. Eleven species were recovered, of which Amblyomma hebraeum, Haemaphysalis silacea, Rhipicephalus appendiculatus and Rhipicephalus glabroscutatum were the most abundant and prevalent. Adult A. hebraeum were generally most numerous from early to late summer, adult R. appendiculatus from mid to late summer, and adult R. glabroscutatum from spring to mid-summer.     

Reliminary survey of ticks (Acari: Ixodidae) on cattle in Central Equatoria State, Southern Sudan

In a preliminary survey conducted in 2005, the species composition and seasonality of ticks infesting cattle in Central Equatoria State, Southern Sudan was determined. Three locations were selected (Gumbo, Khor Rumla and Nyaing) and surveyed every 3 months. Two cattle herds in each of the three locations were visited four times during the study period. Total body collections of ticks were made from each of five cattle (Nilotic Zebu breed) kept in six different herds. Four tick genera and ten species were identified. The tick species identified were Amblyomma lepidum, Amblyomma variegatum, Boophilus annulatus, Boophilus decoloratus, Hyalomma marginatum rufipes, Hyalomma truncatum, Rhipicephalus appendiculatus, Rhipicephalus evertsi evertsi, Rhipicephalus praetextatus and Rhipicephalus sanguineus group. The highest number of ticks was collected in October during the rainy season. A finding of great significance was that R. appendiculatus, vector of East Coast fever, has now firmly established itself throughout the year with possible implications for cattle production in Central Equatoria State.     

Observations on the efficacy of ivermectin in the control of cattle ticks in Zambia

The efficacy of multiple subcutaneous injections (200 micrograms/kg) of ivermectin in the control of naturally occurring tick infestations on traditionally managed Tonga-IIa (Sanga type) calves and yearlings was assessed in two field trials. In the first trial Boophilus decoloratus infestations were decreased following treatments at monthly intervals. In the second trial, with weekly and two weekly treatment intervals, infestations of Rhipicephalus appendiculatus were controlled less effectively than infestations of Amblyomma variegatum or Hyalomma truncatum. However, no engorging females of any of the tick species were found on treated animals. In treated cattle, significantly greater liveweight gain occurred than can be attributed to the control of tick infestations alone.     

Ticks on crested francolins, Francolinus sephaena, and on the vegetation on a farm in Limpopo Province, South Africa

Ticks were collected at approximately bi-monthly intervals between June 1996 and June 1997 from crested francolins, Francolinus sephaena, and from the vegetation on a mixed cattle and wildlife farm in Limpopo Province, South Africa. The birds were infested with the immature stages of 13 tick species, of which Amblyomma hebraeum, Amblyomma marmoreum and Hyalomma marginatum rufipes were the most numerous and prevalent. Ten ixodid tick species were collected from the vegetation, of which the immature stages of Rhipicephalus appendiculatus, Rhipicephalus (Boophilus) decoloratus and Rhipicephalus evertsi evertsi were the most numerous. No adult ticks were collected from the birds and only two from the vegetation. The restricted home range of crested francolins implies that they could serve as a source of tick infestation only for other animals within the same habitat as the birds.     

Tick infestation of Borana cattle in the Borana Province of Ethiopia

A study was conducted to identify and determine burdens of ticks infesting Borana cattle in the Borana Province of Ethiopia. Rhipicephalus pulchellus, Rhipicephalus pravus, Rhipicephalus muhsamae, Rhipicephalus praetextatus, Rhipicephalus evertsi evertsi, Amblyomma gemma, Amblyomma variegatum, Amblyomma cohaerens, Amblyomma lepidum, Hyalomma truncatum, Hyalomma marginatum rufipes and Boophilus decoloratus were identified on the cattle. Their burdens ranged from 658-1,554 with a mean of 1,205 ticks per animal. Out of the total 6,025 ticks collected, about 82% were R. pulchellus, followed by R. pravus (about 8%) and A. gemma (5%). The other nine species of ticks accounted for only 5% of the total burdens. It is suggested that a strategic tick control method, aimed mainly at reducing the R. pulchellus burdens, with the objective of allowing a reasonable number of ticks to remain on cattle for the maintenance of endemic stability to tick-borne diseases be instituted.     

Tick diversity, abundance and seasonal dynamics in a resource-poor urban environment in the Free State Province

The objectives of this study were to determine the diversity, seasonal dynamics and abundance of ticks infesting cattle in urban, small-scale farming communities in and around Botshabelo and Thaba Nchu in the eastern Free State Province, South Africa. A total of ten cattle, ear-tagged for individual identification, were investigated monthly at each of five localities. Adult ticks were removed from the right hand side of each animal and placed in containers filled with 70% ethanol. They were subsequently identified and their numbers quantified. Immature Otobius megnini were counted but not removed. A total of 244,538 adult ticks of ten different species were collected over the 12-month study period. The tick species, in decreasing order of relative abundance, were: Boophilus decoloratus (87.26%), Rhipicephalus evertsi evertsi (6.86%), Hyalomma marginatum rufipes (2.42%), Otobius megnini (1.85%) Rhipicephalus follis (0.76%), Rhipicephalus gertrudae (0.54%), Rhipicephalus sp. (0.21%), Ixodes rubicundus (0.08%), Hyalomma truncatum (0.01%) and Margaropus winthemi (0.004%). The three most abundant species, namely B. decoloratus, R. evertsi evertsi and H. marginatum rufipes, occurred at all localities but with significant differences in abundance. M. winthemi ticks occurred only in the Thaba Nchu area and were not found at any of the there localities in Botshabelo. Significant differences in tick burdens between the six warm months (September to February) and the six cooler months (March to August) were found for most of the species recorded. Boophilus decoloratus occurred in significantly higher numbers in autumn (March to May) and winter (June to August) compared to spring (September to November) and summer (December to February), with 76.8% of the total B. decoloratus burden occurring during the cooler months.     

Ehrlichia ruminantium variants which do not cause heartwater found in South Africa

In 1994 a batch of apparently healthy goats was selected for intended export to the USA from a heartwater-free and vector tick-free region of South Africa. The animals were tested serologically for heartwater, using either or both an IFA and an ELISA test, and 52% were found to be serologically positive. A PCR assay based on Ehrlichia ruminantium 16S gene sequences gave positive results for 54% of the animals, suggesting that apparently non-pathogenic E. ruminantium variants existed in this heartwater-free area. To identify and characterise the agents responsible for the positive serological and PCR results, ticks and animal blood samples were collected from two of the three farms involved in the original survey during two successive seasons of expected peak tick activity. Ticks were kept alive for a minimum of 3 weeks to allow digestion of any blood meal before being processed. Over the two seasons, 28% of the livestock and 15% of the ticks sampled were found to be carrying E. ruminantium. E. ruminantium 16S and pCS20 sequences were detected in all of the four tick species collected from the livestock (Rhipicephalus evertsi evertsi, Rhipicephalus evertsi mimeticus, Hyalomma truncatum, Hyalomma marginatum rufipes), suggesting that some of the species may act as vectors. Animals generally carried multiple E. ruminantium 16S genotypes, whereas ticks rarely carried more than one. Infection levels in both animals and ticks were too low to generate a marked response when a blood stabilate was sub-passaged in a clean sheep, preventing the subsequent establishment of any of the organisms in culture.