I G Horak

Publications of I G Horak

• The use of milbemycin oxime in a prophylactic anthelmintic programme to protect puppies, raised in an endemic area, against infection with Spirocerca lupi.

  Authors: D J Kok, E J Williams, R Schenker, N J Archer, I G Horak

  Veterinary parasitology. 12/2010; 174(3-4):277-84.

  Spirocerca lupi is primarily a parasite of dogs and other carnivores. Clinical signs of infection are regurgitation, vomiting, weight loss, coughing and dyspnoea. Sudden death can also occur due to aSpirocerca lupi is primarily a parasite of dogs and other carnivores. Clinical signs of infection are regurgitation, vomiting, weight loss, coughing and dyspnoea. Sudden death can also occur due to a ruptured aortic aneurysm. In this study, the Eastern Cape Province of South Africa was identified as an area with a high prevalence of S. lupi. A subsequent investigation, to evaluate the efficacy of milbemycin oxime as a prophylactic agent for canine spirocercosis, involved 58 puppies that were raised in this area in accordance with local husbandry procedures. Approximately half of the puppies served as untreated controls. Puppies in the treatment group received milbemycin oxime (minimum dose of 0.5mg/kg body weight) when they were between 2 and 6 weeks old. They then received five further treatments at approximately 28-day intervals. The treatment was orally administered in tablet form. After the sixth treatment, puppies from both the treated and control groups were euthanized and post-mortem examinations were performed. Twenty-four out of 27 dogs in the untreated control group had become infected by S. lupi. In comparison, only 19 out of 31 dogs in the treatment group had evidence of spirocercosis as demonstrated by aortic nodules. The prophylactic regimen reduced the severity of aortic lesions and prevented 86.5% of S. lupi from becoming established in the thoracic aorta. It also prevented 89.4% of S. lupi from becoming established in the oesophagus and significantly reduced the number of oesophageal nodules. Milbemycin oxime markedly reduced the level and severity of S. lupi infection in treated puppies raised in an endemic area of South Africa. It deserves further evaluation as a potential prophylactic treatment for spirocercosis.

• The efficacy of milbemycin oxime against pre-adult Spirocerca lupi in experimentally infected dogs.

  Authors: D J Kok, R Schenker, N J Archer, I G Horak, P Swart

  Veterinary parasitology. 11/2010; 177(1-2):111-8.

  The aim of this investigation was to determine the efficacy of milbemycin oxime in preventing the oesophageal encapsulation of Spirocerca lupi, following the experimental infection of dogs. TwoThe aim of this investigation was to determine the efficacy of milbemycin oxime in preventing the oesophageal encapsulation of Spirocerca lupi, following the experimental infection of dogs. Two studies were conducted which involved a total of 21 purpose-bred Beagles. Each dog was infected with approximately 40, third stage infective S. lupi larvae. The larvae were dissected from scarabaeid beetles that had been collected from areas endemic for spirocercosis. In the first study, milbemycin oxime (minimum dose 0.5mg/kg body weight) was administered to seven dogs on day 30 post-infection. Seven other dogs served as untreated controls. In the second study, milbemycin oxime (also at a minimum dose of 0.5mg/kg body weight) was administered to four of seven infected dogs on day 28 post-infection. Treatment was repeated at 14- or 28-day intervals. All of the dogs, from both studies, were euthanized 168 or 169 days after infection. All S. lupi were recovered, and lesions in the thoracic aorta and oesophagus were described and quantified. A single treatment with milbemycin oxime was 79.8% effective in preventing the establishment of S. lupi in the oesophagus. This treatment significantly (p<0.05) reduced both the number of S. lupi within the oesophagus and the size of the oesophageal nodules. The efficacy of anthelmintic treatment was increased to 100% when repeat doses of milbemycin oxime were administered at 14- or 28-day intervals. These repeat treatments completely prevented the establishment of S. lupi within the oesophagus and thereby averted the development of oesophageal nodules. As expected, none of the treatment protocols reduced S. lupi related damage within the aorta because the administration of milbemycin oxime only began after the larvae had completed their first stage of migration.

• Efficacy of a spot-on formulation of pyriprole on dogs infested with Sarcoptes scabiei.

  Authors: J J Fourie, I G Horak, V de la Puente Redondo

  The Veterinary record. 09/2010; 167(12):442-5.

  To determine the efficacy of a 12.5 per cent spot-on formulation of pyriprole (Prac-Tic; Novartis Animal Health) and that of a combination of 10 per cent imidacloprid and 2.5 per cent moxidectinTo determine the efficacy of a 12.5 per cent spot-on formulation of pyriprole (Prac-Tic; Novartis Animal Health) and that of a combination of 10 per cent imidacloprid and 2.5 per cent moxidectin (Advocate; Bayer Animal Health) against Sarcoptes scabiei on dogs, 20 naturally infested adult dogs were ranked according to their pretreatment mite counts, allocated to one of two groups and housed individually in pens. Two spot-on treatments with each product, 30 days apart, were administered. Mite counts and clinical assessments were performed on each dog two days before treatment, and 28, 60 and 90 days after treatment. Efficacy was measured on the basis of the presence or absence of live mites. Except for day 60 following treatment, on which a single dog in the group treated with pyriprole was positive, no live mites were found on the treated dogs during the assessments on days 28, 60 and 90. Thus, efficacy measured on the basis of this finding (day 90 assessment) was 100 per cent. On final assessment, all dogs treated with pyriprole had 100 per cent resolution of papules, but crusts resembling healing lesions were still present on two dogs. Those treated with imidacloprid and moxidectin had 100 per cent resolution of papules and crusts. Hair regrowth, to greater than 90 per cent of pretreatment hair cover, was observed on all 20 dogs.

• Ixodid ticks on domestic dogs in the Northern Cape Province of South Africa and in Namibia.

  Authors: S Matthee, C Lovely, A Gaugler, R Beeker, H R Venter, I G Horak

  Journal of the South African Veterinary Association. 06/2010; 81(2):126-8.

  The objective of this study was to determine the species composition of ixodid ticks infesting domestic dogs in the northwestern region of the Northern Cape Province of South Africa and in Namibia.The objective of this study was to determine the species composition of ixodid ticks infesting domestic dogs in the northwestern region of the Northern Cape Province of South Africa and in Namibia. Ticks were collected from February 2008 to January 2009 from dogs presented for a variety of reasons at a veterinary clinic in the Northern Cape Province and at 3 clinics in Namibia. The ticks collected at each place were pooled separately for each month at each locality. Eleven ixodid tick species were collected from dogs in the Northern Cape Province and new locality records for Haemaphysalis colesbergensis and Ixodes rubicundus, new locality and host records for Hyalomma glabrum, and a new host record for Rhipicephalus neumanni are reported. Six tick species were collected from dogs at the 3 clinics in Namibia. The most numerous species on dogs in both countries was R. sanguineus. The present results increase the total number of ixodid tick species collected from dogs in South Africa from 25 to 28.

• The efficacy of a topically applied combination of cyphenothrin and pyriproxyfen against the southern African yellow dog tick, Haemaphysalis elliptica, and the cat flea, Ctenocephalides felis, on dogs.

  Authors: J J Fourie, L J Fourie, I G Horak, M G Snyman

  Journal of the South African Veterinary Association. 03/2010; 81(1):33-6.

  The objective of this study was to determine the therapeutic and residual efficacy of a topically applied combination of cyphenothrin (40%) and pyriproxyfen (2%) against the tick HaemaphysalisThe objective of this study was to determine the therapeutic and residual efficacy of a topically applied combination of cyphenothrin (40%) and pyriproxyfen (2%) against the tick Haemaphysalis elliptica and the flea Ctenocephalides felis on dogs. Twelve dogs were infested with 50 ticks 2 days before they were treated and with approximately 100 fleas 6 days before treatment and again 2 days before treatment and with 50 ticks and approximately 100 fleas at weekly intervals thereafter. They were ranked according to their flea counts and sex 5 days before treatment and randomly allocated to an untreated control group of 6 dogs and a treated group of 6 dogs. Ticks and fleas were collected from the dogs 48 h after treatment and 48 h after each infestation and live and dead ticks and live fleas were counted. The counts of ticks and fleas were transformed to geometric means, and efficacy was calculated by comparing these means. The product had a therapeutic efficacy of 83.1% against H. elliptica and 97.5% against C. felis 2 days after treatment. The residual period of protection during which efficacy was > or = 90% was 5 weeks for both H. elliptica and C. felis.

• Species composition and geographic distribution of ticks infesting cattle, goats and dogs in a temperate and in a subtropical region of south-east Africa.

  Authors: I G Horak, N Nyangiwe, C De Matos, L Neves

  The Onderstepoort journal of veterinary research. 09/2009; 76(3):263-76.

  The species and distribution of ticks infesting cattle, goats and dogs in the eastern region of the Eastern Cape Province, South Africa and Maputo Province, Mozambique were determined fromThe species and distribution of ticks infesting cattle, goats and dogs in the eastern region of the Eastern Cape Province, South Africa and Maputo Province, Mozambique were determined from collections made from these animals at 72 localities in the former region and 30 in the latter. Eleven ixodid and one argasid species were recovered in the Eastern Cape Province and 15 ixodid species in Maputo Province. The most common ticks infesting cattle and goats in both provinces were Amblyomma hebraeum, Rhipicephalus (Boophilus) microplus, Rhipicephalus appendiculatus and Rhipicephalus evertsi evertsi. The dominant species on dogs were Haemaphysalis elliptica and Rhipicephalus simus. The geographic distributions of the major species and some of the minor species in both regions were plotted. The partial or complete displacement of the indigenous tick Rhipicephalus (Boophilus) decoloratus by the introduced species R. (B.) microplus was a major feature of both surveys.

• The comparative prevalence of five ixodid tick species infesting cattle and goats in Maputo Province, Mozambique.

  Authors: C De Matos, C Sitoe, L Neves, J O Nöthling, I G Horak

  The Onderstepoort journal of veterinary research. 06/2009; 76(2):201-8.

  This study compares the prevalence of ixodid tick species on cattle and goats in Maputo Province. Adult ticks as well as the nymphs of three species, and only the adults of two species were collectedThis study compares the prevalence of ixodid tick species on cattle and goats in Maputo Province. Adult ticks as well as the nymphs of three species, and only the adults of two species were collected from sets of five cattle at 21 localities throughout the province and compared with those collected from similar sets of goats at the same places. Amblyomma hebraeum adults and/or nymphs were present on cattle and on goats at all 21 localities, and 90 cattle and 22 goats were infested with adult ticks. Rhipicephalus (Boophilus) microplus adults and/or nymphs were collected from cattle at 20 and from goats at 15 localities, and 92 cattle and 34 goats were infested [Chi-square test (chi2), P<0.001]. The total length of several maturing female R. (Boophilus) microplus collected from cattle and goats exceeded 5 mm, indicating that they successfully engorge on both host species. Rhipicephalus appendiculatus adults and/or nymphs were present on cattle at 15 and on goats at 13 localities, but 28 cattle and only one goat were infested with adult ticks (chi2, P<0.001). Adult Rhipicephalus evertsi evertsi were recovered from cattle at 20 and from goats at 17 localities, and 74 cattle and 69 goats were infested. Adult Rhipicephalus simus were collected from cattle at 18 and from goats at 11 localities (Fisher's exact test, P=0.04), and 60 cattle and 14 goats were infested (chi2, P<0.001). These findings underscore the advisability of including goats in acaricide application programmes designed for the control of tick-borne diseases in cattle at the same locality.

• A century of tick taxonomy in South Africa.

  Authors: I G Horak

  The Onderstepoort journal of veterinary research. 03/2009; 76(1):69-74.

  Eighty ixodid tick species, 25 argasid tick species and Nuttalliella namaqua occur in South Africa. Twenty-one of the 80 ixodid species and two of the argasid species occur only in this country,Eighty ixodid tick species, 25 argasid tick species and Nuttalliella namaqua occur in South Africa. Twenty-one of the 80 ixodid species and two of the argasid species occur only in this country, while N. namaqua is present only in South Africa and Namibia. Forty-six of the 80 ixodid species and 16 of the 25 argasid species as well as N. namaqua have been described as new species since 1908. People working in South Africa have written or contributed to the descriptions of 24 of these 63 new species, while foreign researchers have described the remainder. New species indigenous to South Africa are still being discovered, while the names of some species, well known because of their veterinary importance, have been altered.

• Ixodid ticks on dogs belonging to people in rural communities and villages in Maputo Province, Mozambique.

  Authors: C De Matos, C Sitoe, L Neves, N R Bryson, I G Horak

  The Onderstepoort journal of veterinary research. 07/2008; 75(2):103-8.

  The species composition and geographic distribution of ixodid ticks infesting domestic dogs owned by people in rural communities and villages in Maputo Province was established by collecting ticksThe species composition and geographic distribution of ixodid ticks infesting domestic dogs owned by people in rural communities and villages in Maputo Province was established by collecting ticks from dogs at each of 27 localities spread throughout the province. Ticks were collected from a total of 132 dogs, and nine species belonging to four genera were identified. One dog was infested with six species, three with five and 13 with four species. Haemaphysalis elliptica followed by Rhipicephalus simus were present on dogs at most localities, and their geographic distribution in Maputo Province has been mapped for the first time.

• The prevalence and distribution of Argas walkerae (Acari: Argasidae) in the eastern region of the Eastern Cape Province, South Africa.

  Authors: N Nyangiwe, B Gummow, I G Horak

  The Onderstepoort journal of veterinary research. 04/2008; 75(1):83-6.

  The prevalence and geographic distribution of the fowl tampan, Argas walkerae Kaiser & Hoogstraal, 1969 was determined in the eastern region of the Eastern Cape Province, South Africa by inspectingThe prevalence and geographic distribution of the fowl tampan, Argas walkerae Kaiser & Hoogstraal, 1969 was determined in the eastern region of the Eastern Cape Province, South Africa by inspecting two fowl houses in the vicinity of each of 72 randomly selected communal cattle dip-tanks. Tampans were collected from 102 (70.8%) of the 144 fowl houses in the neighbourhood of 57 (79.2%) of the 72 selected dip-tanks, and the localities of the collections were mapped. Argas walkerae was present in fowl houses from the warm coastal regions of the Indian Ocean in the south to the cold and mountainous Drakensberg in the north-east of the Province. Taking into account the probable sensitivity of the sampling method, it is estimated that A. walkerae is likely to be present in fowl houses belonging to between 74 and 84% of communities making use of cattle dip-tanks in the eastern region of the Eastern Cape Province, and that when it is present, between 64 and 75% of fowl houses will be infested. The geographic distribution of A. walkerae seemed to be more strongly associated with the presence of fowls and fowl houses containing raw or processed wood in their structure than with climate.

• Redescription of Haemaphysalis (Rhipistoma) elliptica (Koch, 1844), an old taxon of the Haemaphysalis (Rhipistoma) leachi group from East and southern Africa, and of Haemaphysalis (Rhipistoma) leachi (Audouin, 1826) (Ixodida, Ixodidae).

  Authors: D A Apanaskevich, I G Horak, J L Camicas

  The Onderstepoort journal of veterinary research. 10/2007; 74(3):181-208.

  Koch originally described only the male of Haemaphysalis (Rhipistoma) elliptica (Koch, 1844), which he named Rhipistoma ellipticum. For the past century, however, this name has been considered aKoch originally described only the male of Haemaphysalis (Rhipistoma) elliptica (Koch, 1844), which he named Rhipistoma ellipticum. For the past century, however, this name has been considered a junior synonym of Haemaphysalis (Rhipistoma) leachi (Audouin, 1826), or a nomen nudum. We redescribe here the male and larva of H. (R.) elliptica and describe the female and nymph for the first time. Our redescription is based on the male holotype, plus numerous specimens from southern and East Africa. The adults of this tick parasitize domestic and wild carnivores, and the immature stages infest rodents in these regions. For comparative purposes redescriptions of all parasitic stages of H. (R.) leachi are provided. It parasitizes the same hosts as H. (R.) elliptica in Egypt, and in northeastern, Central, West and East Africa.

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

  Authors: I G Horak, H Golezardy, A C Uys

  The Onderstepoort journal of veterinary research. 10/2007; 74(3):231-42.

  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,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.

• Ticks (Acari: Ixodidae) collected from animals in three western, semi-arid nature reserves in South Africa.

  Authors: H Golezardy, I G Horak

  The Onderstepoort journal of veterinary research. 04/2007; 74(1):81-5.

  The objective of this study was to make an inventory of the ixodid tick species infesting wild animals in three western, semi-arid nature reserves in South Africa. To this end 22 animals in theThe objective of this study was to make an inventory of the ixodid tick species infesting wild animals in three western, semi-arid nature reserves in South Africa. To this end 22 animals in the Kgalagadi Transfrontier Park, 10 in the West Coast National Park and 16 in the Karoo National Park were examined. Fourteen tick species were recovered, of which Hyalomma truncatum, Rhipicephalus exophthalmos and Rhipicephalus glabroscutatum were each present in two reserves and the remainder only in one. The distributions of two of the 14 tick species recovered, namely Rhipicephalus capensis and Rhipicephalus neumanni, are virtually confined to the western semi-arid regions of southern Africa. Hyalomma truncatum, R. capensis and R. glabroscutatum were the most numerous of the ticks recovered, and eland, Taurotragus oryx, were the most heavily infested with the former two species and gemsbok, Oryx gazella, and mountain reedbuck, Redunca fulvorufula, with R. glabroscutatum.

• Climate change and the genus Rhipicephalus (Acari: Ixodidae) in Africa.

  Authors: J M Olwoch, A S Van Jaarsveld, C H Scholtz, I G Horak

  The Onderstepoort journal of veterinary research. 04/2007; 74(1):45-72.

  The suitability of present and future climates for 30 Rhipicephalus species in Africa are predicted using a simple climate envelope model as well as a Division of Atmospheric Research Limited-AreaThe suitability of present and future climates for 30 Rhipicephalus species in Africa are predicted using a simple climate envelope model as well as a Division of Atmospheric Research Limited-Area Model (DARLAM). DARLAM's predictions are compared with the mean outcome from two global circulation models. East Africa and South Africa are considered the most vulnerable regions on the continent to climate-induced changes in tick distributions and tick-borne diseases. More than 50% of the species examined show potential range expansion and more than 70% of this range expansion is found in economically important tick species. More than 20% of the species experienced range shifts of between 50 and 100%. There is also an increase in tick species richness in the south-western regions of the sub-continent. Actual range alterations due to climate change may be even greater since factors like land degradation and human population increase have not been included in this modelling process. However, these predictions are also subject to the effect that climate change may have on the hosts of the ticks, particularly those that favour a restricted range of hosts. Where possible, the anticipated biological implications of the predicted changes are explored.

• Goats as alternative hosts of cattle ticks.

  Authors: N Nyangiwe, I G Horak

  The Onderstepoort journal of veterinary research. 03/2007; 74(1):1-7.

  The objective of this study was to compare the presence on goats and cattle of adult ticks that usually infest cattle. To this end ticks collected from sets of five goats were compared with thoseThe objective of this study was to compare the presence on goats and cattle of adult ticks that usually infest cattle. To this end ticks collected from sets of five goats were compared with those collected from sets of five cattle at 72 communal dip-tanks in the eastern region of the Eastern Cape Province. Amblyomma hebraeum was present on goats at 25 and on cattle at 39 dip-tanks, and a total of 61 goats and 138 cattle were infested. Adult Rhipicephalus (Boophilus) microplus was present on goats at 48 and on cattle at 69 dip-tanks, and a total of 113 goats and 242 cattle were infested. The lengths of 84 of 148 female R. (Boophilus) microplus collected from the goats exceeded 5 mm or more, indicating that they could successfully engorge on these animals. The differences between the proportions of dip-tanks at which A. hebraeum or R. (Boophilus) microplus was present on goats and cattle and also between the proportions of goats and cattle that were infested were significant (Chi-square test, P < 0.01). Adult Rhipicephalus appendiculatus was present on goats at 70 and on cattle at 67 dip-tanks, and a total of 296 goats and 271 cattle were infested. The proportion of dip-tanks at which cattle were infested did not differ significantly from the proportion of tanks at which goats were infested (Fischer's exact probability test, P = 0.44), but the proportion of infested cattle was significantly lower than the proportion of infested goats (Chi-square test, P < 0.05). Adult Rhipicephalus evertsi evertsi was present on goats and cattle at all 72 sampling localities, and a total of 334 goats and 316 cattle were infested. The proportion of infested cattle was significantly lower than the proportion of infested goats (Chi-square test, P < 0.05). These results underscore the necessity of including goats in any tick control programme designed for cattle at the same locality.

• An examination of the infracommunities and component communities from impala (Aepyceros melampus) in the Kruger National Park, South Africa.

  Authors: N J Negovetich, K J Fellis, G W Esch, I G Horak, J Boomker

  The Journal of parasitology. 01/2007; 92(6):1180-90.

  The intestinal helminth parasites of the impala from the Kruger National Park, South Africa, were examined to describe the parasite community structure. Demographic variation and the associatedThe intestinal helminth parasites of the impala from the Kruger National Park, South Africa, were examined to describe the parasite community structure. Demographic variation and the associated differences in behavior were used to further investigate the patterns of community composition. Monte Carlo simulations were performed to test for differences in species richness and mean abundance between the various demographic groups, and nonmetric multidimensional scaling ordination was used to compare community composition. Seventeen species of nematodes, totaling more than 1.3 million worms, were recovered. Males harbored a greater number of nematode species than did females, but adult females were more heavily infected than their male counterparts. Lambs acquired infections early in life, and their parasite community composition rapidly approached that of the older animals. The parasite community in the juvenile and adult males was significantly different from the community of the adult females. These data suggest that social and feeding behavior of the different age-sex classes structure the parasite component community of impala. Additionally, the distinction between common and rare parasites, and their classification in other herbivores, implies complex transmission dynamics that includes extensive species sharing within the Kruger National Park.

• Ixodid ticks on dogs in the eastern region of the Eastern Cape Province, South Africa.

  Authors: N Nyangiwe, I G Horak, N R Bryson

  The Onderstepoort journal of veterinary research. 01/2007; 73(4):305-9.

  The objective of this study was to determine the species composition and geographic distribution of ixodid ticks infesting domestic dogs in the eastern region of the Eastern Cape Province.The objective of this study was to determine the species composition and geographic distribution of ixodid ticks infesting domestic dogs in the eastern region of the Eastern Cape Province. Seventy-two communal cattle dip-tanks within this region were randomly selected as survey localities and their geographic coordinates recorded. In addition to ticks that were collected from five cattle and five goats at each of the dip-tanks, ticks were also collected from five dogs whenever possible. No dogs were available at 19 dip-tanks and no ticks were collected from dogs at 13 dip-tanks, while ticks were collected from 132 of 200 dogs at 40 dip-tanks. Eight ixodid tick species were collected from these dogs, and Haemaphysalis leachi followed by Rhipicephalus appendiculatus and Rhipicephalus simus were present on dogs at the largest number of dip-tanks. Seven dogs were simultaneously infested with three tick species and one with four species. The geographic distributions of Amblyomma hebraeum, H. leachi, R. appendiculatus and R. simus recovered from the dogs lay within the ranges previously reported for these ticks.

• Effect of burning on the numbers of questing ticks collected by dragging.

  Authors: I G Horak, G J Gallivan, A M Spickett, A L F Potgieter

  The Onderstepoort journal of veterinary research. 10/2006; 73(3):163-74.

  Sixteen experimental burn plot replicates, in groups of four, in four landscape zones of the Kruger National Park, South Africa, and from which wildlife are not excluded, have been subjected toSixteen experimental burn plot replicates, in groups of four, in four landscape zones of the Kruger National Park, South Africa, and from which wildlife are not excluded, have been subjected to fixed, regular burning regimens since 1954. In 1999, a study to determine the effect of burning on ixodid ticks questing for hosts from the vegetation of the plots was initiated, and six sub-plots, with identical histories, within each of two of the burn plot replicates in Combretum collinum/Combretum zeyheyri woodland on granite, were selected. With few exceptions these 12 sub-plots, as well as unburned vegetation adjacent to each of the replicates, were sampled for ticks at monthly intervals for a period of 39 months by dragging with flannel strips. The existing regimen of burning during August or during October on individual sub-plots was continued during this time. A total of 14 tick species was recovered from the plots of which nine could be considered major species. Sufficient numbers for statistical analysis of only eight species were, however, collected. Burning appeared to have little short-term effect on the number of ticks recovered. In the longer term, the response varied from no change, an increase, or a decrease in the numbers of ticks collected each year after burning. Tick species, life cycle, seasonality, questing strategy, host preference and host utilization of the habitat were important determinants of the effect of burning.

• The host status of African buffaloes, Syncerus caffer, for Rhipicephalus (Boophilus) decoloratus.

  Authors: I G Horak, H Golezardy, A C Uys

  The Onderstepoort journal of veterinary research. 10/2006; 73(3):193-8.

  The objective of this study was to assess the host status of African buffaloes, Syncerus caffer, for the one-host tick Rhipicephalus (Boophilus) decoloratus. To this end the R. (B.) decoloratusThe objective of this study was to assess the host status of African buffaloes, Syncerus caffer, for the one-host tick Rhipicephalus (Boophilus) decoloratus. To this end the R. (B.) decoloratus burdens of ten buffaloes examined in three north-eastern KwaZulu-Natal Province (KZN) nature reserves were compared with those of medium-sized to large antelope species in these reserves and in the southern Kruger National Park (KNP), Mpumalanga Province. The R. (B.) decoloratus burdens of the buffaloes were considerably smaller than those of the antelopes in the KNP, but not those in the KZN reserves. The life-stage structure of the R. (B.) decoloratus populations on the buffaloes, in which larvae predominated, was closer to that of this tick on blue wildebeest, Connochaetes taurinus, a tick-resistant animal, than to that on other antelopes. A single buffalo examined in the KNP was not infested with R. (B.) decoloratus, whereas a giraffe, Giraffa camelopardalis, examined at the same locality and time, harboured a small number of ticks. In a nature reserve in Mpumalanga Province adjacent to the KNP, two immobilized buffaloes, from which only adult ticks were collected, were not infested with R. (B.) decoloratus, whereas greater kudus, Tragelaphus strepsiceros, examined during the same time of year in the KNP harboured large numbers of adult ticks of this species. African buffaloes would thus appear to be resistant to infestation with R. (B.) decoloratus, and this resistance is expressed as the prevention of the majority of tick larvae from developing to nymphs.

• Parasites of domestic and wild animals in South Africa. XLVII. Ticks of tortoises and other reptiles.

  Authors: I G Horak, I J McKay, B T Henen, Heloise Heyne, Margaretha D Hofmeyr, A L De Villiers

  The Onderstepoort journal of veterinary research. 10/2006; 73(3):215-27.

  A total of 586 reptiles, belonging to 35 species and five subspecies, were examined in surveys aimed at determining the species spectrum and geographic distribution of ticks that infest them. OfA total of 586 reptiles, belonging to 35 species and five subspecies, were examined in surveys aimed at determining the species spectrum and geographic distribution of ticks that infest them. Of these reptiles 509 were tortoises, 28 monitor or other lizards, and 49 snakes. Nine ixodid tick species, of which seven belonged to the genus Amblyomma, and one argasid tick, Ornithodoros compactus were recovered. Seven of the ten tick species are parasites of reptiles. Amongst these seven species Amblyomma marmoreum was most prevalent and numerous on leopard tortoises, Geochelone pardalis; Amblyomma nuttalliwas present only on Bell's hinged tortoises, Kinixys belliana; and most Amblyomma sylvaticum were collected from angulate tortoises, Chersina angulata. Amblyomma exornatum (formerly Aponomma exornatum) was only recovered from monitor lizards, Varanus spp.; most Amblyomma latum (formerly Aponomma latum) were from snakes; and a single nymph of Amblyomma transversale (formerly Aponomma transversale) was collected from a southern African python, Python natalensis. All 30 Namaqualand speckled padloper tortoises, Homopus signatus signatus, examined were infested with O. compactus. The seasonal occurrence of A. sylvaticum and the geographic distribution of this tick and of A. marmoreum, A. nuttalli, A. exornatum, A. latum and O. compactus are illustrated.