| [the efficacy of alphamethrin-impregnated ear tags against ticks]. | the efficacy of 3 kinds of alphamethrin-impregnated ear tags was tested against natural amblyomma hebraeum, boophilus decoloratus, rhipicephalus appendiculatus, and rhipicephalus evertsi evertsi infestations of cattle. one type of ear tag was also tested in combination with a tail band of similar material. ticks were counted macroscopically on their predilection sites. counts of b. decoloratus, r. appendiculatus, and r. e. evertsi on all trial animals diminished steadily during the first 7d afte ... | 1989 | 2607535 |
| immune suppression induced by the brown ear tick rhipicephalus appendiculatus neumann, 1901. | the brown ear tick rhipicephalus appendiculatus suppressed in vivo and in vitro immune responses in the rabbit. humoral responses were suppressed during infestation; however, suppression was transient and was unrelated to previous exposure of hosts to similar tick infestations. immune suppression was caused by putative lymphocytotoxic factor(s) in tick salivary secretions as evidenced by in vitro lymphocytotoxicity assays. in an identical study of rhipicephalus zambeziensis, a closely related rh ... | 1989 | 2614605 |
| hybridization model for rhipicephalus appendiculatus and r. zambeziensis by glucose-p-isomerase isoenzymes. | hybrids between rhipicephalus appendiculatus and r. zambeziensis were reared and glucose-phosphate-isomerase isoenzymes were resolved by agarose electrophoresis. by phenotyping hybrids in f1 and f2 generations autosomal transmission of 2 gpi genes was demonstrated. identification of a hybrid phenotype provides a method for identifying hybrids in field collections. | 1989 | 2626261 |
| transmission of theileria parva bovis (boleni strain) to cattle resistant to the brown ear tick rhipicephalus appendiculatus (neumann). | four crossbred bos taurus oxen resistant to rhipicephalus appendiculatus and three tick naive oxen of the same breed, which were all infested with adult r. appendiculatus infected with the boleni strain of theileria parva bovis, acquired theileria infection. all four tick resistant oxen recovered after a mild febrile reaction. two of the tick naive oxen died while the third recovered after a protracted period. it is suggested that tick resistance in cattle may be an important factor in establish ... | 1989 | 2665253 |
| repetitive detection by immunoblotting of an integumental 25-kda antigen in ixodes ricinus and a corresponding 20-kda antigen in rhipicephalus appendiculatus with sera of pluriinfested mice and rabbits. | mice were pluriinfested with nymphs and rabbits, with adult ixodes ricinus. as determined by immunoblotting, greater than 50% of sera from these animals reacted against a tick antigen with a molecular weight of 25 kda, which was detected in total extracts of partially fed i. ricinus females and in tick integumental extract. it was also found in engorged nymphs but was absent from larvae. sera of i. ricinus-infested rabbits and mice or of rabbits infested with rhipicephalus appendiculatus adults ... | 1989 | 2704727 |
| development of resistance in calves to nymphs of rhipicephalus appendiculatus (acarina:ixodidae) during test feeds. | a test of host resistance to infestation by the tick rhipicephalus appendiculatus was repeated 5 times, at weekly intervals, on 2 initially susceptible calves. one hundred nymphs (nn) were used each time. pairs of tick-susceptible rabbits served as controls. the engorged nn were weighed, then allowed to moult individually, and the sex of each was noted after emergence of the adult. during the course of the experiment there was a significant reduction in mean engorged weight (especially in the pr ... | 1989 | 2707106 |
| development rates, fecundity and survival of developmental stages of the ticks rhipicephalus appendiculatus, boophilus decoloratus and b. microplus under field conditions in zimbabwe. | to determine development rates, fecundity and survival of rhipicephalus appendiculatus, boophilus decoloratus and b. microplus, a study was carried out in long and short grass in the highveld of zimbabwe. engorged adult females of the three species and engorged larvae and nymphs of r. appendiculatus were buried beneath the soil in small cages in the rainy, cool and hot seasons in 1980 and 1981. half the number of cages were examined regularly to determine development rates and half were left und ... | 1989 | 2707110 |
| resistance in cattle against rhipicephalus appendiculatus with an assessment of cross-resistance to r. pulchellus (acari: ixodidae). | a comparison of the yield of engorged nymphs of rhipicephalus appendiculatus and r. pulchellus was carried out between cattle highly resistant to r. appendiculatus but susceptible to r. pulchellus, and cattle and rabbits susceptible to both species. resistant cattle yielded fewer and smaller r. appendiculatus nymphs than either susceptible cattle or rabbits. more nymphs of both tick species dropped from susceptible cattle but no differences were detected in the mean weight of engorged r. pulchel ... | 1989 | 2714122 |
| parasites of domestic and wild animals in south africa. xxiv. arthropod parasites of bushbuck and common duiker in the weza state forest, natal. | one bushbuck, tragelaphus scriptus, and 1 common duiker, sylvicapra grimmia, were shot each month from may 1983 to may 1984 in the weza state forest, natal, i.e. a total of 13 animals of each species. the bushbuck were infested with 8 ixodid tick species, 2 louse species and a louse-fly species. the common duiker harboured 7 tick species and 2 louse species. ticks of the genus ixodes were the most numerous and prevalent on both antelope species, but no pattern of seasonal abundance was evident. ... | 1989 | 2726195 |
| acquired resistance to ixodid ticks induced by tick cement antigen. | antisera from guinea pigs made resistant to infestation with an ixodid tick of east and central africa, rhipicephalus appendiculatus, were used to identify the tick antigens they recognized by immunoblotting. most of the antigens were found in tick salivary glands and in tick attachment cement. antisera from r. appendiculatus-resistant guinea pigs also recognized some salivary-gland antigens in ticks of other species (r. pulchellus, r. evertsi, amblyomma variegatum and a. gemma). antibodies agai ... | 1989 | 2758939 |
| in-vivo effects of ivermectin on rhipicephalus appendiculatus: the influence of tick feeding patterns and drug pharmacokinetics. | sublethal effects seen amongst rhipicephalus appendiculatus feeding on ivermectin-treated rabbits were diverse and dependent both on drug dose, pharmacokinetics and tick feeding patterns: changes in drug formulation, the time of infestation relative to treatment, and the tick instar used, profoundly influenced acaricidal activity. death was a sequel to paralysis only if tick feeding was interrupted for sufficient time to produce irreversible dehydration. concurrent pharmacokinetic investigations ... | 1989 | 2766894 |
| control of induced infestations of three african multihost tick species with sustained-release ivermectin. | the efficacy of ivermectin, released intraruminally from a 28-day-delivery device was evaluated in two titration studies against induced infestations of adult rhipicephalus appendiculatus, r. evertsi and hyalomma truncatum on cattle. cattle were given a sufficient number of devices to release ivermectin at approximately 20, 40, 60 or 80 micrograms kg-1 day-1 at a steady-state rate 7-28 days after administration. tick mortality was recorded, engorged female ticks were weighed and individually inc ... | 1989 | 2766895 |
| monitoring of naturally acquired and artificially induced immunity to amblyomma variegatum and rhipicephalus appendiculatus ticks under field and laboratory conditions. | the ability of rabbits, goats and cattle to acquire immunity to the ixodid ticks amblyomma variegatum and rhipicephalus appendiculatus was studied under laboratory and field conditions. rabbits were successfully immunized with crude salivary gland extract (sge) and midgut extract (me) obtained from flat or partly fed female r. appendiculatus ticks. the lowest numbers of larvae were produced by females fed on rabbits immunized with unfed midgut extract. similar reductions in larval production cou ... | 1989 | 2766896 |
| formulation of medium for tick cell culture. | we examined the effectiveness of bovine cholesterol concentrate in reducing the high level (10-20%) of fetal bovine serum (fbs) necessary to promote tick cell growth in vitro. tick cell lines isolated from embryos of anocentor nitens (ane 58), boophilus microplus (bme 26), and rhipicephalus appendiculatus (rae 25) were used. they were incubated in l-15 (bme 26) or l-15b (ane 58 and rae 25) supplemented with 10% tryptose phosphate broth (tpb), 5% (ane 58 and bme 26) or 3% fbs, 10-90 microns/ml ch ... | 1989 | 2766897 |
| 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 decol ... | 1989 | 2773195 |
| viral interference in the tick, rhipicephalus appendiculatus. i. interference to oral superinfection by thogoto virus. | interference between arboviruses in a naturally infected tick vector is reported for the first time. rhipicephalus appendiculatus nymphs were dually infected with thogoto (tho) virus, a tick-borne virus, similar to members of the family orthomyxoviridae. in the first series of experiments examining 'inter-stadial' interference, larvae were orally infected with a temperature-sensitive (ts) mutant, and after moulting the nymphs were superinfected with the wild-type (wt) virus. in the second series ... | 1989 | 2778441 |
| viral interference in the tick, rhipicephalus appendiculatus. ii. absence of interference with thogoto virus when the tick gut is by-passed by parenteral inoculation. | genetic reassortment of thogoto (tho) virus has been demonstrated in dually infected rhipicephalus appendiculatus ticks. however previous results showed that oral superinfection is inhibited by interference. to ascertain the site of tho viral interference, ticks were infected parenterally or orally with a temperature-sensitive (ts) mutant of tho virus. infected ticks were then challenged with wild-type (wt) tho virus via parenteral inoculation. intra-stadial superinfection was carried out by par ... | 1989 | 2778442 |
| immunization against ticks: use of salivary gland antigens and infestations with rhipicephalus appendiculatus (acari: ixodidae) in rabbits. | comparative immunogenicity of salivary gland antigens (sga) derived from adult rhipicephalus appendiculatus (neumann) and experimental infestations with the three stages of the tick was investigated. the best immunization schedule judged by reduction of engorgement weights and hatchability resulted from nymphal and adult tick infestations. inoculation of rabbits with sga in freund's incomplete adjuvant (fia) induced immune responses comparable to those associated with larval infestations, but le ... | 1989 | 2795614 |
| adaptation of field strains of rhipicephalus appendiculatus neumann (acarina: ixodidae) to host resistance. | a comparison of feeding and breeding performance was made between a laboratory strain (ls) and two freshly collected field strains (fs1, fs2) of rhipicephalus appendiculatus. the ls had been cultured for over 30 years on tick-susceptible rabbits. when fed on susceptible rabbits ls produced smaller eggs and unfed larvae, nymphs and adults than those of fs. eggs and larvae from females engorged on cattle were larger than those from females engorged on rabbits. ls and fs females engorged on suscept ... | 1989 | 2797869 |
| transstadial and horizontal transmission of rift valley fever virus in hyalomma truncatum. | we exposed hyalomma truncatum and rhipicephalus appendiculatus to rift valley fever (rvf) virus in order to assess the possible role of these ticks as enzootic/epizootic rvf vectors. the virus replicated in h. truncatum after intracoelomic inoculation, and a minimum transmission rate of 17% was achieved after 15 days intrinsic incubation. the virus persisted at least 58 days in these ticks. virus was also shown to pass transstadially from inoculated h. truncatum nymphs to adults, with peak viral ... | 1989 | 2802027 |
| observations on successive infestations of the rabbit host by the ticks rhipicephalus appendiculatus and r. zambeziensis (acari: ixodidae). | successive infestation of the rabbit host by instars of the brown ear tick rhipicephalus appendiculatus resulted in a progressive decline in engorgement and egg weights of adult instars and a reduction in percentage recovery of nymphs and larvae. repetitive infestation with adults and larvae resulted in increased skin hypersensitivity reactions at the attachment site. successive infestation with r. zambeziensis caused a more significant decline in engorgement and egg weights of adults than for r ... | 1989 | 2806014 |
| isolation of orbiviruses and uukuviruses from puffin ticks. | two viruses were isolated from a pool of three female ixodes uriae ticks found on a dead puffin (fratercula arctica) on a beach at arbroath, scotland. complement fixation tests showed that one of the viruses was an orbivirus belonging to the kemerovo serogroup and was related to cape wrath virus. cross-reactions did not occur in neutralisation tests with 4 kemerovo group viruses previously isolated from i. uriae collected in british seabird colonies. the orbivirus was therefore named arbroath vi ... | 1985 | 2860801 |
| epidemiology of theileriosis in calves in an endemic area of kenya. | thirty-one calves born into five maasai zebu cattle herds over a period of 1 month in the trans-mara division of kenya, endemic for theileriosis, were recruited for an intensive study of theileriosis. no calves up to 6 months of age died but all developed theileria infections as judged by slide examination and serology. parasitosis by t. mutans schizonts in lymph node smears was usually higher than that of t. parva. the t. mutans schizonts usually occurred at an earlier age but persisted at a pa ... | 1986 | 3085323 |
| quantitative studies on theileria parva in the salivary glands of rhipicephalus appendiculatus adults: search for conditions for high infections. | | 1986 | 3087897 |
| maintenance of theileria parva parva infection in an endemic area of kenya. | the maintenance of theileria parva parva infection in an endemic area of kenya on the shore of lake victoria was studied in the field and laboratory. high prevalences of antibodies against t. parva and t. mutans and intra-erythrocytic piroplasms were detected in local zebu (bos indicus) cattle. the mean infection rate of theileria parasites in the tick, rhipicephalus appendiculatus, in field collections was 1.1%. most of the infection was attributed to t. parva parva by application of field tick ... | 1986 | 3092172 |
| experimental induction of theileria parva lawrencei carrier state in an african buffalo (syncerus caffer). | an african buffalo (syncerus caffer), born in captivity and demonstrated to be theileria-free, and 2 susceptible cattle were inoculated with a theileria parva lawrencei sporozoite stabilate. the buffalo had a very mild disease reaction, while the 2 cattle died of acute theileriosis. it was possible to isolate t. p. lawrencei from the buffalo up to 888 days after infection by the application of non-infected rhipicephalus appendiculatus nymphs and up to 657 days after infection by the establishmen ... | 1987 | 3112701 |
| development and survival of theileria parva parva in rhipicephalus appendiculatus exposed in the trans-mara, kenya. | nymphal rhipicephalus appendiculatus (trans-mara) were fed on a steer infected with a theileria parva parva (kilae 1) stock isolated from an indigenous steer in the trans-mara division, kenya, which had a high piroplasm parasitaemia. a total of 5000 engorged nymphs which had dropped on one day were enclosed in elongated nylon bolting silk tubes in groups of 200-300 and were transported immediately to the trans-mara where they were suspended vertically in the grass cover with one end touching the ... | 1987 | 3112702 |
| the establishment of infection in the salivary glands of rhipicephalus appendiculatus ticks by transplantation of kinetes of theileria parva and the potential use of the method for parasite cloning. | | 1988 | 3130318 |
| immunization of cattle using varying infective doses of theileria parva lawrencei sporozoites derived from an african buffalo (syncerus caffer) and treatment with buparvaquone. | a theileria parva lawrencei isolate in the form of a sporozoite stabilate, derived by feeding clean rhipicephalus appendiculatus nymphal ticks on an african buffalo (syncerus caffer) captured in the laikipia district, kenya, was inoculated into groups of cattle at dilutions between 10(0) and 10(-3). groups of 3 cattle infected with 1 ml inocula at 10(0), 10(-1) and 10(-2) dilutions were treated with 2.5 mg/kg body weight of buparvaquone on day 0 and similar groups were left untreated to act as c ... | 1988 | 3131722 |
| the effect of temperature on the rate of transmission of theileria parva parva infection to cattle by its tick vector, rhipicephalus appendiculatus. | a steer was infected with theileria parva parva kilae stabilate; nymphal rhipicephalus appendiculatus ticks were applied to its ears so that they completed repletion when the steer had a high piroplasm parasitaemia. the engorged nymphs were subsequently incubated at 28 degrees c for 26-29 days to complete moulting, when the adult ticks were divided into two groups; one was incubated at 18 degrees c for 20 days and the other at 18 degrees c for 14 days and then at 37 degrees c for 6 days. groups ... | 1988 | 3143989 |
| a climate-based model for the development of the ixodid tick, rhipicephalus appendiculatus in east coast fever zones. | east coast fever (theileria parva infection) is an important parasitic disease of cattle in east and central africa. past experimental studies have provided a great deal of information on the dynamics of the life cycle of the tick vector, rhipicephalus appendiculatus. this paper describes a mathematical model based on field observations to explain the close relationship between the tick life cycle and climate. the model provides a basis for the future study of different ecf control programmes us ... | 1988 | 3176300 |
| parasites of domestic and wild animals in south africa. xxiii. helminth and arthropod parasites of warthogs, phacochoerus aethiopicus, in the eastern transvaal lowveld. | a total of 69 warthogs, phacochoerus aethiopicus, were collected from 4 localities within the kruger national park, eastern transvaal lowveld. these animals harboured 16 nematode species, 2 trematodes, 1 or 2 species of adult cestodes and the larval stages of 4 cestodes. no pattern of seasonal abundance could be determined for any of the helminths. the warthogs were also infested with 3 flea species, 1 louse species, 8 ixodid tick species, 1 argasid tick and the nymphae of a pentastomid. the sea ... | 1988 | 3194114 |
| the effect of the brown ear-tick rhipicephalus appendiculatus on the growth of sanga and european breed cattle. | the effects of larvae, nymphs and adults of the brown ear-tick rhipicephalus appendiculatus on the growth of bos indicus x b. taurus (sanga) steers and on b. taurus steers and heifers was measured by exposing groups, maintained in the same pastures, to different levels of tick challenge. larvae and nymphs had no significant effect on liveweight gains, but adults had a large effect. each engorging female tick counted was associated with a loss of 4 g. their effect on the sanga cattle was minimise ... | 1988 | 3245108 |
| requirement for host fc receptors and igg antibodies in host immune responses against rhipicephalus appendiculatus. | guinea pigs sensitized by prior feeding of larval rhipicephalus appendiculatus ticks expressed complete immunity to challenge feeding resulting in 100% tick rejection. passive transfer of 1 ml of serum from animals expressing resistance into naive animals conferred recipients with significant protection (88% tick rejection). successful transfer of resistance was blocked by pretreatment of recipients with rabbit igg but not sheep igg1. passive transfer of igg1 or igg2 purified from tick-sensitize ... | 1988 | 3388733 |
| histology of digestion in nymphs of rhipicephalus appendiculatus fed on rabbits and cattle naive and resistant to the ticks. | | 1987 | 3440695 |
| species characterisation of rhipicephalus appendiculatus and rhipicephalus zambeziensis (ixodidae: acarina) by enzyme-electrophoresis. | | 1987 | 3442428 |
| ecology and phenology of ticks in zambia: seasonal dynamics on cattle. | a study of the seasonality and infestation rates of ticks was carried out in 11 cattle herds in different ecological habitats in zambia between 1980 and 1982. wherever possible supplementary data were obtained from opportunistic collections from cattle and other hosts. analysis of over 1000 tick collections from cattle indicated that infestation rates of the most important species, amblyomma variegatum and rhipicephalus appendiculatus vary in different ecological habitats: (i) in western provinc ... | 1986 | 3451861 |
| biology of rhipicephalus appendiculatus and r. zambeziensis and production of a fertile hybrid under laboratory conditions. | in some areas of eastern and southern provinces of zambia rhipicephalus appendiculatus and r. zambeziensis are sympatric, and numerous intermediate forms as well as typical r. appendiculatus and r. zambeziensis are found. experiments were carried out in order to clarify the taxonomic status of the intermediate forms. biology and hybridization capacities of two strains of r. appendiculatus (a and d) and one strain of r. zambeziensis (h) were studied. infestations on rabbits and calves were perfor ... | 1986 | 3451867 |
| a comparison of the tick burdens of wild animals in a nature reserve and on an adjacent farm where tick control is practised. | acaricidal treatment of cattle, sheep and goats on a farm in valley bushveld in the grahamstown district resulted in a reduction in the numbers of certain tick species on kudu (tragelaphus strepsiceros), scrub hares (lepus saxatilis) and crowned guinea fowl (numida meleagris) on the same farm. the tick species most severely affected was amblyomma hebraeum, while haemaphysalis silacea, hyalomma marginatum rufipes and rhipicephalus appendiculatus were affected to a lesser extent. rhipicephalus gla ... | 1986 | 3572954 |
| acquired resistance to rhipicephalus appendiculatus (acari: ixodidae): identification of an antigen eliciting resistance in rabbits. | | 1987 | 3585912 |
| a novel mode of arbovirus transmission involving a nonviremic host. | in nature, infected and uninfected arthropod vectors often feed together on an animal. in mimicking this scenario in the laboratory, uninfected vectors were found to acquire virus while cofeeding on the same host as infected vectors. however, the vertebrate host on which they fed did not develop detectable levels of virus in its blood. these observations were made with thogoto virus, an influenza-like virus of medical and veterinary significance. rhipicephalus appendiculatus ticks were used as t ... | 1987 | 3616608 |
| in vivo reassortment of thogoto virus (a tick-borne influenza-like virus) following oral infection of rhipicephalus appendiculatus ticks. | arboviruses with segmented genomes have the potential to reassort in both their vertebrate hosts and arthropod vectors. reassortment of thogoto virus, a tick-borne orthomyxo-like virus, has been demonstrated following dual infection of hamsters by temperature-sensitive mutants. to investigate whether similar events can occur in ticks, rhipicephalus appendiculatus larvae and nymphs were dually infected by interrupted feeding on viraemic hamsters. wild-type reassortant virus was isolated from the ... | 1987 | 3655743 |
| gynandromorphism in rhipicephalus appendiculatus (acari; ixodidae). | | 1987 | 3662677 |
| histological study of the attachment sites of adult rhipicephalus appendiculatus on rabbits and cattle. | | 1986 | 3744678 |
| tick antigens recognized by serum from a guinea pig resistant to infestation with the tick rhipicephalus appendiculatus. | immune resistance to infestation by an ixodid tick, rhipicephalus appendiculatus, the vector of the cattle disease east coast fever, was induced in a guinea pig by repeated tick infestation. this resistance is expressed as the ability of the host to interfere with tick feeding. resistance to ixodid tick feeding is an acquired response mediated by host antibody. we report the use of antibodies from a resistant host animal, in immunoblotting, to characterize the tick antigens recognized. the major ... | 1986 | 3746565 |
| an immunocytochemical marker for the complex granules of tick salivary glands which traces e-granule shedding to interstitial labyrinthine spaces. | an antigenic protein (12c), previously isolated from salivary glands of rhipicephalus appendiculatus, as a possible factor in host resistance to repeated tick infestation, is labeled by protein a-gold immunocytochemistry in adult feeding ticks. it is a component of the gland's complex a-, d- and e-granules and also appears within the chitinous walls of intercalated ducts. in females, between days 4 and 7 of feeding, labeled e-granules appear also within the labyrinthine spaces of acinus type iii ... | 1986 | 3775758 |
| experimental studies on the transmission cycle of thogoto virus, a candidate orthomyxovirus, in rhipicephalus appendiculatus. | thogoto (tho) virus, a candidate orthomyxovirus, replicated in and was transmitted by larvae, nymphs, and adults of the brown ear tick, rhipicephalus appendiculatus. larvae fed on viremic hamsters (10(7-8) pfu/ml blood) acquired an average of 10(2.5) pfu per tick. following engorgement the titer dropped to 10(1.9) pfu on day 2 but increased by day 6 to 10(3.3) pfu. virus survived transstadially in these ticks as demonstrated by the fact that, on day 10, newly moulted nymphs contained, on average ... | 1986 | 3789274 |
| efficacy of ivermectin against ectoparasites of cattle in south africa. | the efficacy of various formulations of ivermectin administered at the recommended dose rate of 200 micrograms/kg was evaluated in cattle infested with mange mites (sarcoptes scabiei var. bovis.), lice (linognathus vituli and damalinia bovis) and ticks (boophilus decoloratus, amblyomma hebraeum, rhipicephalus appendiculatus and hyalomma spp.) in 8 trials conducted in south africa. mange mites (s. scabiei) were eliminated from animals treated subcutaneously, resulting in marked clinical recovery. ... | 1985 | 3839021 |
| structural and histochemical changes in the salivary glands of rhipicephalus appendiculatus during feeding. | | 1985 | 3980145 |
| epidemiology of tick-borne diseases of cattle in zimbabwe. iii. theileria parva group. | a survey of the occurrence of antibodies to theileria parva using the ifa test in calves up to one year old at 244 localities in zimbabwe revealed that the parasite occurred throughout the country although the prevalence of positive serological reactors was generally low. outbreaks of theileriosis in high rainfall areas in the north, east and west of the country were attributed to theileria parva bovis transmitted from cattle to cattle by rhipicephalus appendiculatus. outbreaks in high and low r ... | 1985 | 3992667 |
| the brown ear tick rhipicephalus appendiculatus neumann (acarina: ixodidae) and associated tick species on wild and domestic hosts at muguga, kenya. | during a study of an experimental population of rhipicephalus appendiculatus and its transmission of bovine theileriosis to cattle, some supplementary information was obtained on the role of rodents and the small carnivores in the development and maintenance of r. appendiculatus populations. observations were also made on other common tick species found on these hosts. a total of 530 individual hosts were examined during the 4-yr period, of which the majority included, among the carnivores, the ... | 1985 | 3998963 |
| screening of medicinal plants of rwanda for acaricidal activity. | a series of 108 samples from 42 medicinal plants of rwanda have been screened for acaricidal activity against the female tick rhipicephalus appendiculatus. two plants, solanum dasyphyllum (fruits) and neorautanenia mitis (roots) showed apparent acaricidal activity in the petroleum ether fraction. | 1985 | 4021518 |
| [ultrastructural characteristics of the salivary glands of of the tick ixodes persulcatus. ii. type iii alveoli of the sucking female]. | electron microscope observations were conducted to study changes in the cellular structure of iiid type alveoli of feeding females of i. persulcatus. within the first 1-2 days of feeding granulosecreting glandular cells "d" and "e" get free of secretory inclusions. after that cells "d" degenerate completely and cells "e" undergo morphological transformations and start to fulfil osmoregulatory functions. from the third day of feeding cytoplasm of cells "e" and basal intersticial cells form a comp ... | 1985 | 4069743 |
| effects of tick infestation on boran (bos indicus) cattle immunised against theileriosis in an endemic area of kenya. | boran (bos indicus) heifers were immunised by infection with local theileria parva parva, t p lawrencei and t mutans stocks and treated with parvaquone and later exposed to natural tick and tick-borne disease challenge in the trans-mara division of kenya. the theileria species parasites in the challenge were maintained in african buffalo and cattle and the tick vectors were supported by several species of wild bovidae and domestic livestock present in the area. thirty immune cattle were observed ... | 1985 | 4081331 |
| east coast fever: 60co-irradiation of theileria parva in its tick vector, rhipicephalus appendiculatus. | | 1974 | 4213045 |
| theileria parva: variation in the infection rate of the vector tick, rhipicephalus appendiculatus. | | 1974 | 4213496 |
| transmission of theileria lawrencei (serengeti) by the ixodid tick, rhipicephalus appendiculatus. | | 1973 | 4213512 |
| some experiments on the transmission of theileria mutans (theiler, 1906) and theileria parva (theiler, 1904) by the ticks amblyomma variegatum (fabricius, 1794) and rhipicephalus appendiculatus neumann, 1901, in uganda. | | 1974 | 4607395 |
| uptake of 3 h-thymidine during artificial feeding of rhipicephalus appendiculatus ticks infected with theileria parva. | | 1972 | 4622849 |
| some effects of irradiation on theileria parva in the salivary glands of the tick rhipicephalus appendiculatus. | | 1972 | 4626453 |
| a rapid technique for the detection of theilerial parasites in the salivary glands of the tick rhipicephalus appendiculatus. | | 1972 | 4627335 |
| attempts to transmit babesia (nuttallia) microti in laboratory mice by the tick rhipicephalus appendiculatus. | | 1972 | 4652920 |
| the effect of immersion in water on the immature stages of the ixodid ticks-rhipicephalus appendiculatus neumann 1901 and amblyomma variegatum fabricius 1794. | | 1973 | 4787718 |
| observations on the development and survival of the ixodid tick rhipicephalus appendiculatus neumann, 1901 under quasi-natural conditions in kenya. | | 1973 | 4802546 |
| observations on the numbers of the tick rhipicephalus appendiculatus on the ears of zebu cattle in relation to hierarchical status in the herd. | | 1973 | 4807702 |
| the development of theileria parva in the salivary glands of the tick, rhipicephalus appendiculatus. | | 1968 | 4984381 |
| the use of parasympathomimetic drugs to stimulate salivation in the tick rhipicephalus appendiculatus, and the transmission of theileria parva using saliva obtained by this method from infected ticks. | | 1969 | 4986780 |
| theileria parva: comparative infection rates of adult and nymphal rhipicephalus appendiculatus. | | 1971 | 4995423 |
| some effects of irradiation on the tick rhipicephalus appendiculatus. | | 1972 | 5039341 |
| a technique for injecting radio-active tracers into flat rhipicephalus appendiculatus. | | 1972 | 5071083 |
| ifection of rhipicephalus appendiculatus ticks with theileria parva, using a rabbit's head perfusion technique. | | 1970 | 5498934 |
| infection of the tick rhipicephalus appendiculatus with theileria parva using an artificial feeding technique. | | 1970 | 5499333 |
| toxaphene-resistant ticks occurring on cattle in uganda: boophilus decolaratus, rhipicephalus evertsi and rhipicephalus appendiculatus. | | 1970 | 5526750 |
| the feeding behaviour on rabbits and in vitro of the ixodid tick rhipicephalus appendiculatus neumann, 1901. | | 1968 | 5740553 |
| a study of the life history of the tick rhipicephalus appendiculatus--the main vector of east coast fever--with reference to its behaviour under field conditions and with regard to its control in sukumaland, tanzania. | | 1968 | 5753464 |
| organ culture of rhipicephalus appendiculatus with maturation of theileria parva in tick salivary glands in vitro. | a technique is described for the organ culture of rhipicephalus appendiculatus ticks. whole, unfed adult ticks with the dorsal integument removed, known as backless tick explants, were cultured in enriched leibovitz' l-15 medium in which they remained active for at least 32 days at 28 degrees c and 9 days at 36 degrees c. development of theileria parva, as demonstrated by methyl green-pyronin staining, occurred in the salivary glands of infected backless tick explants held for 8 days at 28 degre ... | 1980 | 6110322 |
| monitoring theileria parva infection in adult rhipicephalus appendiculatus ticks. | a rapid method is described for preparing and staining salivary glands of rhipicephalus appendiculatus ticks infected with theileria parva. the technique, involving the use of a modified methyl green pyronin stained minimizes the risk of losing material and allows examination of stained glands within minutes of preparation. the technique was applied in a series of studies in which ticks were either infected with t. parva under different conditions, or maturation of parasites in adult ticks was s ... | 1981 | 6163125 |
| assessment of theileria infections in rhipicephalus appendiculatus ticks collected from the field. | collections of adult rhipicephalus appendiculatus ticks were made from bait cattle and vegetation at two field sites in areas of kenya in which east coast fever caused by theileria parva is endemic. these ticks, together with two experimentally infected batches of ticks, were examined for infection with theileria by four methods. whole salivary glands were stained with methyl green pyronin or feulgen's stain. whole ticks were ground in medium, the suspensions were filtered and centrifuged and th ... | 1981 | 6166132 |
| the incorporation of radio-labelled nucleic acid precursors by theileria parva in bovine blood and salivary glands of rhipicephalus appendiculatus ticks. | | 1981 | 6173342 |
| incorporation of 3h-hypoxanthine by theileria parva during development in the feeding adult tick rhipicephalus appendiculatus. | | 1983 | 6187700 |
| morphology of normal and theileria parva-infected salivary glands of rhipicephalus appendiculatus (acari: ixodoidea). | | 1983 | 6406660 |
| infection of mammalian cells with theileria species. | experiments were carried out to determine the susceptibility of mammalian cells to infection with different species of theileria in vitro. sporozoites of theileria parva (parva), theileria parva (lawrencei) and theileria taurotragi were isolated from rhipicephalus appendiculatus ticks by grinding infected ticks in medium, filtering the suspension and concentrating by centrifugation. the sporozoites were used in attempts to infect in vitro peripheral blood leucocytes harvested from 16 different m ... | 1983 | 6406967 |
| transmission of theileria parva by a population of rhipicephalus appendiculatus under simulated natural conditions. | a 2 hectare paddock on the muguga estate, kiambu district of kenya (altitude 2100 m) free of theileria parva-infected ticks was seeded by applying rhipicephalus appendiculatus nymphs to cattle infected with theileria parva (kiambu 4). it was estimated that over 50 000 engorged nymphs fell onto the pasture from 4 cattle with high parasitaemias during the cold season (june). samples of these ticks were placed in plastic cylinders under the vegetation in the paddock and sexual stages of t. parva we ... | 1983 | 6406968 |
| some factors controlling the stimulation of sporogony of theileria parva in its tick vector rhipicephalus appendiculatus. | | 1984 | 6423558 |
| blast transformation of adherent macrophages infected in vitro with sporozoites of theileria parva. | rhipicephalus appendiculatus ticks were fed on cows with parasitemia from theileria parva infection (east coast fever). homogenates of salivary glands with infective sporozoites were added to cultures of (i) monocyte-derived adherent macrophages from normal bovine peripheral blood and (ii) macrophages from spleen and bone marrow. it was shown by light, phase-contrast, and electron microscopies and by tests for lysosomal enzymes, phagocytosis of carbon particles, and cell markers (fibronectin and ... | 1984 | 6428284 |
| chemotherapy of east coast fever: parvaquone treatment of clinical disease induced by isolates of theileria parva. | two experiments were carried out in which parvaquone was used to treat experimentally-induced acute clinical east coast fever infections. in the first experiment, infections with theileria parva parva (kiambu 5) were induced by applying infected rhipicephalus appendiculatus ticks or by inoculation of triturated infected-tick stabilate. the character of the disease was similar with both methods of infection and following a single treatment with parvaquone at 20 mg kg-1, 5 of 7 cattle in each grou ... | 1984 | 6437050 |
| survival of rhipicephalus appendiculatus (acarina: ixodidae) and persistence of theileria parva (apicomplexa: theileriidae) in the field. | | 1984 | 6439668 |
| a rapid method to select rhipicephalus appendiculatus salivary glands infected with theileria parva. | | 1984 | 6439849 |
| the effect of sulphaquinoxaline on the feeding and breeding performance of the tick rhipicephalus appendiculatus neumann (acarina: ixodidae). | | 1984 | 6512646 |
| bovine homocytotropic antibody in the sera of cattle resistant to infestation with rhipicephalus appendiculatus. | the homologous skin sensitizing activity of serum from tick-naive cattle (bos taurus) and from cattle resistant to the tick rhipicephalus appendiculatus was tested by attempting to induce passive cutaneous anaphylaxis (pca) in tick-naive calves. the serum from tick-resistant cattle induced pca, whereas that from tick-naive cattle failed to do so. the pca was more marked at 72 hours than at 24 hours after administration of the serum. treatment of the serum by heat at 56 degrees c for 2 hours or b ... | 1984 | 6516209 |
| cutaneous responses of cattle to extracts from rhipicephalus appendiculatus larvae. | a component of an extract from rhipicephalus appendiculatus larval ticks induced an immediate hypersensitivity reaction in sensitized cattle when intra-dermally inoculated. generally, the magnitude of the cutaneous reaction depended upon the duration of exposure of the cattle to tick infestation. the skin reaction was absent in steers not previously fed on by ticks. field trials, using the extract in the narok district of kenya (masailand), showed that the skin swelling thus induced was biggest ... | 1984 | 6541396 |
| the effects of 20-hydroxyecdysone and juvenile hormone iii on tick cells. | two cell lines isolated from rhipicephalus appendiculatus ( rae 25) and anocentor (= dermacentor) nitens (ane 58) responded to the invertebrate hormones 20-hydroxyecdysone (20-he) and juvenile hormone iii (jh iii) in vitro. in the presence of 0.2 or 2 nmolar 20-he, the cells of the continuous line rae 25 attached to the culture substrate at a rate of 9% per hr for the first 8 hr, as did cells in growth medium. twenty or 200 nmolar of 20-he reduced the rate of cell attachment to 6% per hr, and in ... | 1983 | 6674457 |
| some helminth and arthropod parasites of the grey duiker, sylvicapra grimmia. | sixteen grey duikers were culled on the farm riekert 's laager in the central transvaal at irregular intervals from may 1979-march 1981. one trematode species, 3 cestode species and 16 nematode species were recovered from these animals. of these the following are new helminth records for this antelope: cooperia hungi , cooperia neitzi , cooperia pectinata , trichostrongylus axei, trichostrongylus colubriformis, trichostrongylus falculatus , trichostrongylus instabilis , impalaia tuberculata , ne ... | 1983 | 6676685 |
| the development of theileria=cytauxzoon taurotragi (martin and brocklesby, 1960) from eland in its tick vector rhipicephalus appendiculatus. | the sexual cycle of theileria taurotragi was identified in the gut lumen of replete rhipicephalus appendiculatur nymphs maintained at 28 degrees c which had fed on eland with rising parasitaemias. macro- and micro-gametes developed from ring-form piroplasms within 24 h after repletion. the microgamonts were elongate with 2 or more lateral projections. the nuclei of the microgamonts divided into 4 and the microgamonts differentiated into 4 thread-like microgametes each with a central nucleus. rou ... | 1980 | 6775268 |
| identification of theileria infections in the salivary glands of hyalomma anatolicum anatoli cum and rhipicephalus appendiculatus using isoenzyme electrophoresis. | lysates prepared from the salivary glands of uninfected hyalomma anatolicum anatolicum and rhipicephalus appendiculatus and from ticks of these species infected with 2 strains of theileria annulata and 1 strain of t. parva respectively have been examined for enzyme polymorphism using thin layer starch gel electrophoresis. representative enzymes from 3 of the major metabolic pathways, the tricarboxylic acid cycle, the glycolytic pathway and the pentose phosphate pathway were investigated. only 1 ... | 1981 | 6785914 |
| the effect of irradiation on the susceptibility of rhipicephalus appendiculatus ticks to theileria parva infection. | irradiation doses of 800 rad. or less had no detectable effect on the subsequent development of unfed nymphal rhipicephalus appendiculatus ticks. doses of 1600 rad. or above impaired feeding and moulting and delayed the subsequent development of unfed nymphs. at 6400 rad. no ticks completed their moult. unfed nymphal r. appendiculatus irradiated at 0, 400, 800 and 1600 rad. were applied to 3 cattle infected with t. parva (kiambu 4). the theileria infections in the salivary glands of the resultan ... | 1981 | 6787541 |
| artificial infection of rhipicephalus appendiculatus with theileria parva by percutaneous injection. | rhipicephalus appendiculatus nymphs were inoculated with fresh or cryopreserved blood containing theileria parva piroplasms, or with cell culture grown stages of t parva. the use of fresh blood was successful. cryopreserved blood containing dimethylsulphoxide (dmso), killed most nymphs after inoculation: dmso could be removed by slow dialysis, without destroying the infectivity of the blood. attempts to infect ticks by inoculating cell culture grown stages of t parva failed, even when large numb ... | 1980 | 6789418 |
| the initial stages of infection of cattle cells with theileria parva sporozoites in vitro. | large numbers of theileria parva sporozoites were separated from rhipicephalus appendiculatus adult ticks by filtration and were then concentrated by centrifugation. the sporozoites were incubated at 37 degrees c with leucocytes from 6 cattle of bos indicus and b. taurus types. giemsa-stained smears and living preparations under interference contrast microscopy were used to follow the course of the infection of the leucocytes with sporozoites. sporozoites were seen to attach rapidly to about 25% ... | 1981 | 6791118 |
| epidemiology of east coast fever: some effects of temperature on the development of theileria parva in the tick vector, rhipicephalus appendiculatus. | the moulting behaviour of nymphal rhipicephalus appendiculatus from the laboratory colony and 3 field strains from kenya was greatly influenced by constant temperatures between 18 and 37 degrees c but was not significantly different for the 4 tick strains. six batches of r. appendiculatus (muguga laboratory) nymphs which had engorged on cattle parasitaemic with 4 stocks of theileria parva (kiambu 4, kiambu 5, muguga and mbita 4) isolated in kenya were incubated at constant temperatures between 1 ... | 1981 | 6791119 |
| observations on the transmission of theileria mutans in south africa. | four isolates of theileria mutans obtained from geographically distant parts of south africa by subinoculation of infected blood were found to be readily transmitted by the bont tick amblyomma hebraeum. all attempts to transmit these isolates with rhipicephalus appendiculatus were unsuccessful. possible explanations for differences between these results and those reported by earlier workers in this country are discussed. | 1981 | 6792579 |