| 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 ... | 1992 | 1297957 |
| seasonal occurrence of karoo paralysis in angora goats in relation to the infestation density of female ixodes rubicundus. | the seasonal occurrence of karoo paralysis in relation to the infestation density of female ixodes rubicundus was investigated in an enzootic area of the southwestern orange free state, south africa. young and adult angora goats were exposed to infestation during two paralysis tick seasons. only the young goats became paralysed and their infestation densities (female ticks kg-1 host body weight) were significantly higher than those of healthy animals. the infestation densities on paralysed goats ... | 1992 | 1502788 |
| the seasonal activity of adult ixodid ticks on angora goats in the south western orange free state. | adult ixodid ticks were collected at 2-weekly intervals for a period of 23 consecutive months from 15 to 20 angora goats on a farm in the south western orange free state. a total of 6 ixodid tick species were recovered. rhipicephalus punctatus was the most abundant and prevalent tick. it was present from spring to late summer. ixodes rubicundus was the next most abundant tick and was present mainly from march or april to july with peak numbers present in april or may. the onset of this tick's ac ... | 1991 | 1770478 |
| spatial distribution of the karoo paralysis tick ixodes rubicundus (acari: ixodidae) within a false upper karoo veld type. | spatial distribution of the karoo paralysis tick (ixodes rubicundus) has been studied in a paralysis enzootic area of the southwestern orange free state. significantly more females than males were collected from the vegetation. most ticks (99%) used grass as questing sites at a height of approximately 45 cm (range 10-97 cm), which correlates with the size of host animals. no significant differences between the questing height of male and female ticks were evident. the ticks were found on most of ... | 1991 | 1860416 |
| parasites of cattle in the south western orange free state. | a number of young friesian oxen were slaughtered (one at a time) for parasite recovery for 12 consecutive months, from april 1987 to march 1988, on a farm in the fauresmith district of the south western orange free state. a total of 5 ixodid and one argasid tick species, 2 lice species, plus one nematode species and one cestode species, were recovered. peak numbers of adult hyalomma marginatum rufipes were present from november 1987 to february 1988, while the largest numbers of hyalomma truncat ... | 1990 | 2269986 |
| the dispersion of the karoo paralysis tick, ixodes rubicundus, within a naturally infested population of sheep in south africa. | the ratio of variance to mean (s2/means) of numbers of ixodes rubicundus (males and females) per sheep was used as a measure of the dispersion pattern of this tick within a naturally infested population of sheep. sheep were divided into two groups, one with previous contact with i. rubicundus and the other with no previous contact. samples of 10 sheep from each group were searched for ticks on a weekly basis for 19 weeks during the winter of 1986. in each group, both male and female ticks had an ... | 1990 | 2316179 |
| paralysis of laboratory rabbits by nymphae of ixodes rubicundus, neumann 1904 (acarina: ixodidae) and some effects on the life-cycle following feeding under different temperature conditions. | feeding under constant cold conditions resulted in a marginal shortening of feeding period and a major shortening of the subsequent developmental phase of all stages of ixodes rubicundus neumann 1904, the karoo paralysis tick. paralysis occurred in laboratory rabbits when nymphae were fed on them under constant warm, constant cold and fluctuating ambient winter conditions. this paralysis was found to be dependent on infestation rate and feeding conditions. under constant cold conditions paralysi ... | 1989 | 2726194 |
| the effect of the pattern of attachment weights of female ixodes rubicundus on karoo paralysis in a naturally infested flock of sheep. | the weights of feeding female ixodes rubicundus attaching to sheep was studied in a natural focus of karoo paralysis. the studies showed fewer females in the middle weight ranges and more in the heavier and lighter categories than would be expected if the distribution was normal. weights were also strongly skewed towards the lighter females between 0 and 400 mg. no differences in the pattern of attachment weights occurred over the four experimental groups used, suggesting that previous contact o ... | 1989 | 2800303 |
| seasonal incidence of karoo paralysis in relation to the infestation density of female ixodes rubicundus. | the epidemiology of karoo paralysis, induced by the tick ixodes rubicundus, was investigated in a paralysis-enzootic area of the southwestern orange free state, republic of south africa. sheep became paralysed during the last week of april and the first week of may during the 1985 and 1986 seasons, respectively. paralysis cases were recorded up until july, but most paralysis cases occurred during the first week of may with a second but smaller peak occurring during june. tick numbers on paralyse ... | 1989 | 2815541 |
| the seasonal abundance of adult ixodid ticks on merino sheep in the south-western orange free state. | with the exception of october, when no collections were made, adult ticks were collected at weekly intervals from february 1986 to january 1987 from 20 randomly selected sheep out of a flock of 60. ixodes rubicundus was the most abundant tick and was present from april to september with a peak during may. hyalomma marginatum rufipes was the next most numerous tick. it was recovered throughout the year with peak burdens being recorded from november to april. small numbers of a rhipicephalus sp. ( ... | 1988 | 3210216 |
| a survey of karoo tick paralysis in south africa. | recent research interest in karoo tick paralysis and its vector. ixodes rubicundus, prompted this survey to determine the economic implications of this disease. the survey indicated relatively high losses caused by the condition, identified the stock involved and provided data on the incidence of paralysis and on the control methods employed. recommendations are made to institute chemical control earlier in the season to attempt better containment of the problem. | 1988 | 3393373 |
| prolonged or repeated copulation and male longevity in the tick ixodes rubicundus. | male ixodes rubicundus were found in copula with attached females in 59% of individuals. the number of males attaching to the female integument or to the the host negligible. in laboratory experiments, males enclosed with females in a small vial had significantly longer life spans than solitary males. paired males were found to be in copula on 20-34% of observations. solitary males lost weight while paired males gained weight over a 2-day period. however, the specific energy content of the 2 gro ... | 1988 | 3397822 |
| some wild hosts of the karoo paralysis tick, ixodes rubicundus neumann, 1904 (acari: ixodidae). | a variety of mammal and bird species in the mountain zebra national park, eastern cape province, were examined for ixodes rubicundus. in addition, caracal (felis caracal) from the park and its vicinity as well as from the graaff-reinet region of the karoo were examined. amongst the animals collected, the red rock rabbit (pronolagus rupestris) was a preferred host of the immature stages of the tick. caracal were moderately good hosts of these stages and, with mountain reedbuck (redunca fulvoruful ... | 1987 | 3587926 |
| laboratory investigations on the life-cycle of the karoo paralysis tick (ixodes rubicundus neumann, 1904). | | 1971 | 5164824 |
| a shared epitope found in the major paralysis inducing tick species of africa. | cross-reactivity between all the paralysis inducing tick species of veterinary relevance in africa was demonstrated, by using a monoclonal antibody directed against the paralysis inducing toxin of rhipicephalus evertsi evertsi. western blot results, together with amino acid composition studies indicated that this monoclonal antibody recognizes protein bands of similar molecular mass and amino acid composition in r. evertsi evertsi and ixodes rubicundus. this suggests that the karoo paralysis tox ... | 1994 | 7543039 |
| sequential feeding of ixodes rubicundus on its natural host, elephantulus myurus: effects on tick mass and on engorgement and moulting success. | engorgement, mass at repletion and moulting success of immature ixodes rubicundus after sequential infestations of their natural hosts, rock elephant shrews (elephantulus myurus), were investigated under laboratory conditions. the reaction of e. myurus is characterized by inefficient or non-existent anti-tick immunity which enables immature i. rubicundus to attach and engorge successfully and ensures a high moulting success rate. | 1994 | 7596564 |
| detachment rhythms of immature ixodes rubicundus from their natural host, the rock elephant shrew (elephantulus myurus). | detachment rhythms of immature karoo paralysis ticks (ixodes rubicundus) from their natural host, the rock elephant shrew (elephantulus myurus), were investigated under laboratory and natural conditions. larvae and nymphs detach mainly during the day. peak detachment always occurred after the commencement of artificial as well as natural light cycles. the detachment of larvae appears to be more synchronous than that of nymphs, with a larger percentage of larvae detaching over a shorter period of ... | 1994 | 7596565 |
| the appetence behaviour of two south african paralysis-inducing ixodid ticks. | the appetence responses of the ixodid ticks ixodes rubicundus and rhipicephalus punctatus to various stimuli were quantified under laboratory conditions. a greater percentage of i. rubicundus generally responded to the different stimuli at lower than at higher temperatures while the converse was usually true for r. punctatus. radiation heat and shadowing evoked a response in the greatest percentage of i. rubicundus, whereas co2 and host odour were responsible for a similar reaction in r. punctat ... | 1993 | 7628229 |
| sexual dimorphism in nymphal size of the karoo paralysis tick, ixodes rubicundus. | | 1993 | 7628238 |
| vertical migration of adult ixodes rubicundus, the karoo paralysis tick (acari: ixodidae). | mortality due to karoo paralysis amongst livestock is of considerable economic importance in south africa. indications are that the extent of vertical migration of adult ticks, to reach questing positions on grasses, is influenced by sudden climatic changes. such influences as well as selection of questing substrates were investigated under controlled conditions. vertical migration of adult ixodes rubicundus on copper rods was determined in a square metal arena within a closed glass container in ... | 1994 | 7628241 |
| the effect of feeding immature karoo paralysis ticks ixodes rubicundus (acari: ixodidae) on the metabolic rate of the rock elephant shrew. | the effect of feeding immature karoo paralysis ticks (ixodes rubicundus) on the resting metabolic rate (rmr) of their principal natural host, the rock elephant shrew (elephantulus myurus), was investigated under laboratory conditions. the elephant shrews were artificially infested with numbers of ticks simulating natural burdens. the rmr of the elephant shrews was quantified by measuring the oxygen consumption in an open through-flow system. the rmr of hosts infested only with larvae did not dif ... | 1994 | 7628243 |
| an evaluation of strategic and threshold control measures against the karoo paralysis tick, ixodes rubicundus (acari: ixodidae) in south africa. | paralysis caused by feeding female ixodes rubicundus ticks is a major problem in large areas of south africa. as the life cycle of the tick extends over a period of 2 years, it was hypothesized that strategic treatment of sheep with an acaricide over a 2 year period, timed to kill most engorging females, should markedly lower the biotic potential of the tick. two flocks of sheep grazing in separate paddocks known to be infested with i. rubicundus were treated either strategically or on a thresho ... | 1995 | 7634969 |
| improvement of field sampling methods for adult karoo paralysis ticks, ixodes rubicundus (acari: ixodidae), through addition of host odour. | the responsiveness of ixodes rubicundus ticks on questing substrates and the success of their attachment to non-living substrates were investigated. the purpose of this study was to relate responsiveness to conditions of temperature and humidity, to compare the efficacy of flagging and dragging methods to estimate the size of populations of adult i. rubicundus in the field, and to determine the possible influence of host odour on the efficacy of these methods. responsiveness was tested under var ... | 1995 | 7656732 |
| a quantitative study on preprandial insemination in the karoo paralysis tick ixodes rubicundus (acari: ixodidae). | | 1995 | 7696696 |
| sites of attachment of karoo paralysis ticks (ixodes rubicundus) on three cattle breeds. | the sites of attachment of female karoo paralysis ticks (ixodes rubicundus) were determined on friesian, bonsmara and nguni cattle in the south-western orange free state. the largest proportion of the ticks (> 30%) attached to the forelegs and shoulders of the cattle. contrary to the findings on small stock, no significant differences in the preferred sites of attachment were evident between the breeds of cattle. | 1993 | 8410949 |
| a comparison of ixodes rubicundus (acari: ixodidae) infestations on friesian and bonsmara cattle in south africa. | this study was conducted to compare the relative resistance of crossbred bos indicus x b. taurus bonsmara and b. taurus friesian cattle to ixodes rubicundus (karoo paralysis tick) infestations. during periods of peak abundance of the ticks, friesian oxen harboured almost twice or more than twice as many ticks as either bonsmara oxen or cows. during periods of low tick abundance tick burdens on both cattle breeds were closely similar. it is envisaged that cattle can play an important role in an i ... | 1995 | 8575273 |
| interbreed differences in the efficacy of 1% deltamethrin pour-on to protect small livestock against infestation with ixodes rubicundus (acari:ixodidae). | synthetic pyrethroid pour-on compounds have been developed for use on cattle but many are now also registered for the control of ectoparasites on small ruminants. the breed of small livestock has been known to influence the efficacy of various pour-ons and we hypothesized that differences in the duration of protection afforded by a synthetic pyrethroid pour-on against ticks on small livestock, would be greatest between hairy and woolly breeds. angora goats with mohair, dorper sheep with hairy wo ... | 1996 | 8792585 |
| control of karoo paralysis ticks through vegetation management. | karoo paralysis, caused by feeding ixodes rubicundus females, is a major disease of small stock in south africa. control methods currently practised are almost exclusively chemical based. to limit overdependance on chemicals, vegetation management was investigated as a possible method for control, to be incorporated in an integrated tick management system. laboratory and field experiments were conducted to determine, firstly, the extent of vertical migration and survival of ticks on long and sho ... | 1996 | 8834741 |
| adult ixodid ticks on two cattle breeds in the south-western free state, and their seasonal dynamics. | a study was conducted to compare the species of adult ixodid ticks on friesian and bonsmara cattle and their seasonal dynamics. between five and ten animals of each breed were kept on natural false upper karoo vegetation, typical of the south-western free state. between may 1990 and october 1991, the animals were examined once or twice a month for the presence of adult ticks which were removed, counted and identified. six species of ixodid ticks were recorded. the species composition on the two ... | 1996 | 8848299 |
| sex ratio characteristics in ixodes rubicundus (acari:ixodidae), the karoo paralysis tick. | the sex ratio is an important parameter which characterizes the state and dynamics of natural populations of animals. although ixodid ticks are specialized ectoparasites, most species are bisexual and are characterized by a 1:1 sex ratio for their progeny. in natural populations and even in laboratory colonies, biased sex ratios are often observed. ixodes rubicundus, the karoo paralysis tick, parasitizes domestic stock and wild ungulates in south africa. adults quest from vegetation, can mate of ... | 1996 | 8856964 |
| seasonal dynamics of the karoo paralysis tick (ixodes rubicundus): a comparative study on merino and dorper sheep. | karoo paralysis in south africa is induced in livestock by feeding female ixodes rubicundus ticks when infestation densities on hosts exceed certain critical levels. it has been shown previously that angora goats are at a higher risk of being paralysed than merino sheep, and such differences have been related to differences in feeding behaviour and spatial distribution of the two small-stock breeds. we hypothesized that differences in infestation densities with karoo paralysis ticks would also o ... | 1996 | 9173358 |
| spatial and temporal variations in the commencement of seasonal activity in the karoo paralysis tick, ixodes rubicundis. | successful prophylaxis of paralysis, induced in small stock by feeding female ixodes rubicundus, is dependent on the accurate determination of the commencement of seasonal activity by the tick. the commencement of this activity was recorded for 11 consecutive years on a farm in the south-western free state, south africa, and for shorter periods on other farms, some of these in regions with markedly colder climates. the colder the mean minimum atmospheric temperatures during the 2 months precedin ... | 1996 | 9173361 |
| 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 subs ... | 1998 | 10192844 |
| parasites of domestic and wild animals in south africa. xxxviii. ixodid ticks collected from 23 wild carnivore species. | ixodid ticks were collected from 104 wild carnivores belonging to 23 species in various nature reserves and on several farms in all nine provinces of south africa. seven feral cats in a nature reserve were also examined. twenty-four tick species belonging to seven genera were recovered and identified. amongst these ticks we consider the adults of haemaphysalis leachi, haemaphysalis spinulosa, haemaphysalis zumpti, ixodes rubicundus, rhipicentor nuttalli, rhipicephalus simus and rhipicephalus tur ... | 2000 | 11206391 |
| ixodes rubicundus nymphs are short-day diapause-induced ticks with thermolabile sensitivity and desiccation resistance. | the karoo paralysis tick, ixodes rubicundus neumann (acari: ixodidae), is a semi-voltine ixodid that survives stressful environmental conditions using morphogenetic diapause (eggs and engorged nymphs) and desiccation resistance. both photoperiod and temperature influence diapause induction in the engorged nymph. ixodes rubicundus nymphs are typical long-day photoperiodic organisms. the critical photoperiod is approximately 13.5 h light, 10.5 h dark, and they display a thermolabile response. the ... | 2001 | 11583453 |
| photoperiodic control of developmental diapause in nymphs of prostriate ixodid ticks (acari: ixodidae). | extrinsic control of developmental diapause in nymphs of prostriate ticks of the subgenus ixodes sensu stricto (ixodes ricinus and ixodes persulcatus from eurasia and ixodes scapularis from north america) appears to be based on a complex two-step photoperiodic reaction of a short-day/long-day type. diapause control in the subgenus afrixodes (the south african tick ixodes rubicundus) appears to be based on a simple long-day reaction. the option between non-diapause development and diapausing arre ... | 2002 | 14570127 |
| parasites of domestic and wild animals in south africa. xliii. ixodid ticks of domestic dogs and cats in the western cape province. | ticks were collected at monthly intervals for 16 consecutive months from individual dogs by their owners in or close to the town of stellenbosch, western cape province. they were also collected for 27 consecutive months from dogs presented for a variety of reasons at three veterinary clinics in stellenbosch, and from dogs upon admission to an animal welfare shelter. at one of the veterinary clinics ticks were also collected from cats. dog owners collected six ixodid species from their pets and t ... | 2003 | 14621314 |
| elephant shrews as hosts of immature ixodid ticks. | two hundred and seventy-three elephant shrews, consisting of 193 elephantulus myurus, 67 elephantulus edwardii and 13 animals belonging to other species, were examined for ixodid ticks at 18 localities in south africa and namibia. the immature stages of ixodes rubicundus, rhipicentor nuttalli, rhipicephalus warburtoni and a rhipicephalus pravus-like tick were the most numerous of the 18 tick species recovered. substantial numbers of immature rhipicephalus arnoldi, rhipicephalus distinctus and rh ... | 2005 | 16562732 |
| 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-eigh ... | 2007 | 17933365 |
| ixodid ticks on domestic dogs in 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 we ... | 2010 | 21247023 |
| tick paralysis in australia caused by ixodes holocyclus neumann. | ticks are obligate haematophagous ectoparasites of various animals, including humans, and are abundant in temperate and tropical zones around the world. they are the most important vectors for the pathogens causing disease in livestock and second only to mosquitoes as vectors of pathogens causing human disease. ticks are formidable arachnids, capable of not only transmitting the pathogens involved in some infectious diseases but also of inducing allergies and causing toxicoses and paralysis, wit ... | 2011 | 21396246 |
| a new species of ixodes (acari: ixodidae) from south african mammals. | abstract a new tick species belonging to the african subgenus afrixodes morel, 1966, namely, ixodes ( afrixodes ) fynbosensis n. sp., is described. the female of i. fynbosensis is easily differentiated from the other african ixodes species by a large, tapering triangular ventrolateral spur on palpal segment i. nymph and larva of i. fynbosensis can be distinguished from those of other members of afrixodes by a combination of the following characters: pointed hypostome, long auriculae, long and ac ... | 2010 | 21506796 |
| the namaqua rock mouse (micaelamys namaquensis) as a potential reservoir and host of arthropod vectors of diseases of medical and veterinary importance in south africa. | the role of endemic murid rodents as hosts of arthropod vectors of diseases of medical and veterinary significance is well established in the northern hemisphere. in contrast, endemic murids are comparatively understudied as vector hosts in africa, particularly in south africa. considering the great rodent diversity in south africa, many of which may occur as human commensals, this is unwarranted. | 2014 | 25127720 |
| tick-borne infections in human and animal population worldwide. | the abundance and activity of ectoparasites and its hosts are affected by various abiotic factors, such as climate and other organisms (predators, pathogens and competitors) presenting thus multiples forms of association (obligate to facultative, permanent to intermittent and superficial to subcutaneous) developed during long co-evolving processes. ticks are ectoparasites widespread globally and its eco epidemiology are closely related to the environmental conditions. they are obligatory hematop ... | 2015 | 27047089 |
| history and development of research on wildlife parasites in southern africa, with emphasis on terrestrial mammals, especially ungulates. | the history of wildlife parasitology in south africa, and to some extent southern africa, is reviewed, giving a brief overview of the early years and following its development from the founding of the onderstepoort veterinary institute in 1908 until the turn of the century. an emphasis is placed on game species. the main findings on protozoan parasites, including those of carnivores, are presented, starting in the 1890s and leading up to the first decade of the 21st century. important developmen ... | 2014 | 25830101 |
| tick holocyclotoxins trigger host paralysis by presynaptic inhibition. | ticks are important vectors of pathogens and secreted neurotoxins with approximately 69 out of 692 tick species having the ability to induce severe toxicoses in their hosts. the australian paralysis tick (ixodes holocyclus) is known to be one of the most virulent tick species producing a flaccid paralysis and fatalities caused by a family of neurotoxins known as holocyclotoxins (hts). the paralysis mechanism of these toxins is temperature dependent and is thought to involve inhibition of acetylc ... | 2016 | 27389875 |
| distribution of endemic and introduced tick species in free state province, south africa. | the distributions of endemic tick vector species as well as the presence of species not endemic to free state province, south africa, were determined during surveys or opportunistic collections from livestock, wildlife and vegetation. amongst endemic ticks, the presence of rhipicephalus appendiculatus was confirmed in the north of the province, whilst rhipicephalus decoloratus was collected at 31 localities mostly in the centre and east, and ixodes rubicundus at 11 localities in the south, south ... | 2015 | 26244582 |
| differential feeding success of two paralysis-inducing ticks, rhipicephalus warburtoni and ixodes rubicundus on sympatric small mammal species, elephantulus myurus and micaelamys namaquensis. | rodents are recognised as important hosts of ixodid ticks and as reservoirs of tick-borne pathogens across the world. sympatric insectivores are usually inconspicuous and often overlooked as hosts of ticks and reservoirs of disease. elephant shrews or sengis of the order macroscelidea are small insectivores that often occur in sympatry with rodents in southern africa. sengis are invariably parasitised by large numbers of immature ticks while sympatric rodents are infested with very few. the reas ... | 2012 | 22521977 |