| na, k-atpase in the salivary gland of the ixodid tick amblyomma hebraeum (koch) and its relation to the process of fluid secretion. | total and ouabain-sensitive atpase activities were determined in the salivary glands of ticks throughout the feeding cycle. activities were very low in unfed specimens. in the glands of feeding females, the activities rose until a maximum was reached for both atpase components at approximately 200 mg. the activities remain low in males throughout the feeding period. these findings are discussed in relation to the fluid secretory process of the salivary glands. | 1976 | 133818 |
| parasites of domestic and wild animals in south africa. xiii. the seasonal incidence of adult ticks (acarina: ixodidae) on cattle in the northern transvaal. | ticks were collected over a period of 13 months, at approximately fortnightly intervals, from 6 africaner oxen kept on the farm nylsvley in the naboomspruit district. the 8 species of ixodidae collected were, in order of abundance, rhipicephalus appendiculatus, r. evertsi evertsi, hyalomma marginatum rufipes, h. truncatum, amblyomma hebraeum, r. simus, boophilus decoloratus and ixodes cavipalpus. the relative abundance of adult ticks of these species, their predilection feeding sites and seasona ... | 1979 | 460821 |
| a bioassay method for the pheromone(s) of the bont tick amblyomma hebraeum koch. | a bioassay was developed which enabled the detection of the pheromones of the bont tick (amblyomma hebraeum koch) within 2 hours with a reproducibility of 82 +/- 13%. dried, solvent-extracted ticks were glued onto the shaved backs of rabbits. those ticks to which pheromone extract was subsequently applied strongly attracted females of the same species. in a 2-way choice test a cork disc impregnated with pheromone extract was even more attractive to female ticks than a treated dried tick. | 1979 | 460823 |
| studies on the ecology of the tick amblyomma hebraeum koch in the eastern cape province of south africa. ii. survival and development. | quantitative data are given on the survival and rate of development of amblyomma hebraeum koch in relation to temperature and humidity, in laboratory and field conditions. by comparison with other ixodid species the developmental periods of a. hebraeum are extremely long. development is most rapid at 30 c, and the duration of the developmental periods increases exponentially with decreasing temperature. oviposition occurs successfully at 15 and 30 c, egg incubation at 20 to 30 c, and larval and ... | 1977 | 577931 |
| repeated feeding of amblyomma herbraeum (acarina: ixodidae) immatures on laboratory hosts. host effects on tick yield, engorged weight and engorgement period. | rabbits and sheep are unable to acquire a resistance to larvae and nymphs of amblyomma hebraeum. after repeated infestation of hosts there is no progressive decline in either the tick yield or the engorged weight of fed ticks. seasonal fluctuations in engorged weights do occur however, with the weight declining in early to midwinter and increasing in early to midsummer. changes in hose physiology as a result of low temperature acclimatization appear to be responsible for the fluctuations. tick y ... | 1978 | 722460 |
| effects of 60co irradiation on amblyomma hebraeum koch, 1844 (acarina: ixodidae). | the effects of 60co irradiation on amblyomma hebraeum koch, 1844 were studied by mating normal females to males irradiated to attain dosages of 0, 2, 4, 6 and 8 kilorad. the males of all 5 groups were observed mating 7 days after being placed on the host. the higher the irradiation dosage received by the males, progressively longer were the feeding periods of the females mated with them and fewer completed their engorgement. furthermore, the mass of the females when engorged was lower, fewer lai ... | 1978 | 750959 |
| resistance to toxaphene by the bont tick, amblyomma hebraeum (koch). | a series of in vitro and in vivo trials confirmed resistance by the three-host bont tick, amblyomma hebraeum (koch), to toxaphene in the cape, natal and transvaal provinces of the republic of south africa, and in swaziland and transkei. resistance was present in 80 of 97 field strains examined. lindane and ddt resistance was present in the one field strain tested. the results of comparative in vivo hand spraying and plunge dipping trials confirmed those of the larval in vitro tests, thus validat ... | 1977 | 874951 |
| aggregation response of nymphs to pheromone(s) produced by males of the tick amblyomma hebraeum (koch). | | 1976 | 1250397 |
| acquired immunity to larvae of amblyomma marmoreum and a.hebraeum by tortoises, guinea-pigs and guinea-fowl. | a study of acquired resistance in guinea-pigs, guinea-fowl and tortoises to larvae of the ticks amblyomma hebraeum koch and a.marmoreum koch (acari: ixodidae) showed that repeated infestations of the laboratory host resulted in a 29.3-49.4% reduction respectively in weight of engorged larvae. no resistance was induced in guinea-fowl, the natural host for larvae of both species. a small decline in the mean weight of engorged larvae was observed for both species of ticks after three successive inf ... | 1992 | 1421505 |
| adult amblyomma hebraeum burdens and heartwater endemic stability in cattle. | several conclusions of importance to studies on the epidemiology of heartwater were drawn from an investigation in which the numbers of adult amblyomma hebraeum ticks, to which a closed herd of hereford cattle were exposed over a period of 6 1/2 years, were manipulated. with a tick cowdria ruminantium infection rate of 3-5%, an endemically stable situation was created by dipping the herd only when an average of 10 adult male and female a. hebraeum ticks were counted on 10 animals. when the avera ... | 1992 | 1513597 |
| the identification of a shared immunogen present in the salivary glands and gut of ixodid and argasid ticks. | the identification of a 70-kda immunogen present in salivary gland extracts of several ixodid species, namely hyalomma truncatum (sweating-sickness-inducing (ss+) and non-inducing (ss-) strains), hyalomma marginatum rufipes and rhipicephalus evertsi evertsi, is reported. the immunogen was identified by western blots using a monoclonal antibody of the igm isotype directed against a 70-kda immunogen present in the salivary glands of (ss-) female h. truncatum ticks. cross-reactivity with the gut of ... | 1992 | 1446571 |
| comparison of the attachment rates of males of the ticks amblyomma hebraeum and a. variegatum to cattle, sheep and rabbits in the absence of aggregation-attachment pheromone. | losses in domestic ruminants caused by heartwater (cowdria ruminantium infection) in zimbabwe and mozambique are greater when the vector is amblyomma hebraeum than when the vector is a. variegatum. it has been suggested that the epidemiology of the disease may be influenced by the rates at which unfed adults of these two tick species attach to uninfested hosts (i.e. in the absence of the male-produced aggregation-attachment pheromone [aap]). in this study we confined unfed males of a. hebraeum a ... | 1992 | 1446569 |
| a case of gynandromorphism in amblyomma hebraeum (acari: ixodidae). | a gynandromorph specimen of amblyomma hebraeum was found on a goat on which adult ticks were bred in the laboratory. | 1992 | 1552517 |
| a comparison of the attraction of nymphs and adults of the ticks amblyomma hebraeum and a. variegatum to carbon dioxide and the male-produced aggregation-attachment pheromone. | the attraction of nymphs of the ticks amblyomma hebraeum and a. variegatum to co2 alone and co2 together with the male-produced aggregation-attachment pheromone (aap) was investigated. matching experiments on the attraction of the adults of the two species were run for comparison. nymphs of a. hebraeum were strongly attracted to sources of co2 and co2/aap at distances of 10 and 15 m. at distances of 20 and 25 m significantly more nymphs were attracted to co2/aap than to co2 alone. adults of a. h ... | 1992 | 1563302 |
| an indirect mechanism by which a protein from the male gonad hastens salivary gland degeneration in the female ixodid tick, amblyomma hebraeum. | in the adult female tick, amblyomma hebraeum koch (acari: ixodidae), salivary gland degeneration is triggered by an ecdysteroid, provided the female is above a critical weight (approximately 300-400 mg). in mated females, salivary gland degeneration is virtually complete within 4 days of detachment from the host. in virgin females, salivary gland degeneration is delayed by 4 days. this delay can be reversed by the injection of a male reproductive tract homogenate directly into the hemocoel. in t ... | 1992 | 1446071 |
| perception of breath components by the tropical bont tick, amblyomma variegatum fabricius (ixodidae). ii. sulfide-receptors. | wall-pore sensilla in the capsule of haller's organ on foreleg tarsi of the tick, amblyomma variegatum, show multicellular responses upon stimulation with human and bovine breath. filtering breath through charcoal removes the stimulant for some of these receptors. analysis by gas chromatography coupled with olfactory sensillum electrophysiological recordings indicates that an ethanol extract of the breath components trapped on charcoal contains a major stimulant eluting at the same retention tim ... | 1992 | 1432848 |
| immunization of rabbits against nymphs of amblyomma hebraeum and a. marmoreum (acari: ixodidae). | himalayan rabbits immunized with homogenates prepared from nymphs of amblyomma hebraeum koch and a. marmoreum koch ticks developed humoral and probably also cell-mediated immunity to their respective homogenates. beta and gamma globulin levels and numbers of eosinophils and neutrophils increased significantly in inoculated rabbits. the recipient animals developed resistance to homospecific nymphal infestations. cross resistance between the two species was not evaluated. nymphs of both species th ... | 1992 | 1404253 |
| transient infections of goats with a novel spotted fever group rickettsia from zimbabwe. | a novel spotted fever group rickettsia has recently been isolated from amblyomma hebraeum ticks in zimbabwe. in a survey of 172 goat sera collected throughout zimbabwe the highest prevalence of antibodies reactive with this rickettsia was in the south of the country, the area where a hebraeum is most commonly found. nine goats were infected using male and female a hebraeum taken from a tick line shown to be infected with the novel rickettsia. by week 3 after infection, seroconversion occurred in ... | 1991 | 1780580 |
| perception of breath components by the tropical bont tick, amblyomma variegatum fabricius (ixodidae). i. co2-excited and co2-inhibited receptors. | wall-pore olfactory sensilla located in the capsule of haller's organ on the tarsus of amblyomma variegatum ticks bear cells responding to vertebrate breath: one of these sensilla contains a co2-excited receptor and a second sensillum has a co2-inhibited receptor. each of these antagonistic co2-receptors, which display typical phasic-tonic responses, monitors a different co2-concentration range. the co2-inhibited receptor is very sensitive to small concentration changes between 0 and ca. 0.2%, b ... | 1992 | 1331433 |
| parasites of domestic and wild animals in south africa. xxx. ectoparasites of kudus in the eastern transvaal lowveld and the eastern cape province. | sets of four kudus were shot and examined for arthropod parasites at approximately monthly intervals from april 1981 to march 1983 in the southern part of the kruger national park, eastern transvaal lowveld. these animals harboured 10 ixodid tick species of which boophilus decoloratus followed by amblyomma hebraeum were the most abundant. the seasonal abundances of these ticks and of amblyomma marmoreum, rhipicephalus appendiculatus, rhipicephalus evertsi evertsi and rhipicephalus zambeziensis w ... | 1992 | 1297956 |
| responses of the ticks amblyomma hebraeum and a. variegatum to known or potential components of the aggregation-attachment pheromone. iv. attachment stimulation of nymphs. | ten known or potential components of the aggregation-attachment pheromone (aap) of the ticks amblyomma hebraeum and a. variegatum, as well as a mixture of these components and extracts of prefed males of the two species, were tested as attachment stimulants for nymphs. unfed nymphs were confined in linen bags on the ears of rabbits that had been treated with the test compounds, mixture or extracts; the numbers attached were recorded after 24 h. in a. hebraeum, attachment was induced by four comp ... | 1992 | 1286610 |
| responses of the ticks amblyomma hebraeum and a. variegatum to known or potential components of the aggregation-attachment pheromone. iii. aggregation. | ten known or potential components of the aggregation-attachment pheromone (aap) of the ticks amblyomma hebraeum and a. variegatum, as well as mixtures of these components, extracts of prefed males and live prefed males, were tested as aggregation stimulants. in field assays, laboratory-reared unfed male and female ticks were released 20 cm downwind of co2/pheromone release sites; the numbers of ticks that aggregated at the release sites were recorded after 30 min. in a. variegatum, aggregation w ... | 1992 | 1286609 |
| arsenic resistance in species of multi-host ticks in the republic of south africa and swaziland. | a survey was made in the republic of south africa and swaziland to determine the incidence of arsenic resistance in multi-host ixodid ticks. arsenic resistant strains were found in the following species:- rihipicephalus appendiculatus, rhipicephalus evertsi, rhipicephalus capensis, amblyomma hebraeum and a species of hyalomma, tentatively identified as hyalomma rufipes. strains of haemaphysalis leachi, haemaphysalis silacea and ixodes pilosus were also tested. | 1975 | 1223285 |
| acquisition of resistance to the bont tick amblyomma hebraeum (acarina: ixodidae) by goats. | goats acquired resistance to larvae of amblyomma hebraeum following three repeated infestations. resistance was associated with immediate type i hypersensitivity reactions following intradermal skin tests using crude egg extracts. in a separate experiment, the inoculation of tick-naive goats with extracts of the larvae of a. hebraeum failed to induce observable effects on feeding larvae despite the development of anti-larval antibodies. | 1991 | 1909066 |
| evidence for an assembly pheromone(s) produced by males of the bont tick, amblyomma hebraeum (acarina: ixodidae). | | 1977 | 903938 |
| the influence of adrenergic agonists and their antagonists on isolated salivary glands of ixodid ticks. | various drugs elicit fluid secretion by isolated salivary glands of two species of ixodid ticks (dermacentor andersoni stiles and amblyomma hebraeum koch). among catecholamines, the following order of potency was observed: dopamine, epinine, noradrenaline = adrenaline and isoprenaline. the following drugs, in order of potency, were also agonists on this preparation: ergonovine, ergotamine, 6-hydroxydopamine, apomorphine, phenylephrine, norphenylephrine, beta-phenylethylamine, tyramine, d, l-dopa ... | 1977 | 891618 |
| transmission of a spotted fever group rickettsia by amblyomma hebraeum (acari: ixodidae). | amblyomma hebraeum, a cattle tick common in southern africa, was demonstrated to be capable of maintaining an infection with an unclassified spotted fever group rickettsia both transtadially and transovarially. all feeding stages of the tick transmitted the infection to rabbits. the rickettsia was isolated and found to be serotypically distinct from three strains of rickettsia conorii by microimmunofluorescence. rabbit serum titers were found to be higher with indirect fluorescent antibody (ifa) ... | 1991 | 1941925 |
| ecology of the tick amblyomma hebraeum koch in the eastern cape province of south africa. i. distribution and seasonal activity. | in the eastern cape province of south africa larvae of amblyomma hebraeum koch occur in well-drained, shaded habitats, with a ground cover of grass. the life cycle is normally of 3 years duration. peak larval activity occurs in the summer of the 1st year, peak nymphal activity in the spring of the 2nd year, and peak adult activity in the summer of the 3rd year. larval activity shows no direct correlation with macroclimate. adult activity is correlated with, in the following order of signficance, ... | 1977 | 886412 |
| role of cattle in the epidemiology of tick-bite fever in zimbabwe. | almost 100% of 52 cattle tested from the southern areas of zimbabwe were found to have antibodies reactive with rickettsia conorii compared with less than 30% of 120 cattle from the north. steers artificially infected with r. conorii isolated from amblyomma hebraeum were found to show no hematological or biochemical signs of disease but did seroconvert. clinical signs of infection were restricted to regional lymphadenopathy and dermal erythema, edema, and tenderness at the inoculation site. rick ... | 1991 | 2007631 |
| seasonal abundance of ticks associated with indigenous goats on a northern transvaal farm. | the 3 most abundant tick species on indigenous goats on a northern transvaal farm were found to be rhipicephalus evertsi evertsi, rhipicephalus appendiculatus and amblyomma hebraeum. three other tick species were present in small numbers. the economical and ecological importance of the ticks found on the goats, mainly in rural areas where chemical control of ticks is practically non-existant, is discussed. the high number of goats in the study area and the shift towards alternative methods of ti ... | 1991 | 2051439 |
| drag-sampling of free-living ixodid ticks in the kruger national park. | free-living ticks were collected by means of drag-sampling in 32 of the 35 landscape zones of the kruger national park during a period of 1 calendar month. of the 18,199 specimens collected, 99.53% were larvae, 0.05% nymphs and 0.42% adults. fourteen species were collected. amblyomma hebraeum followed by boophilus decoloratus, predominated, both in distribution and abundance. large variations were encountered between drags. there was no correlation between the numbers of larvae collected and tim ... | 1991 | 2052317 |
| proteins and free amino acids in the salivary secretion and haemolymph of the tick amblyomma hebraeum. | electrophoretic and chromatographic separations of the salivary secretion of amblyomma hebraeum showed a less complex protein pattern than that of ornithodoros savignyi. a hyaluronidase active component was isolated. the haemolymph protein pattern showed a major protein fraction with a mobility slightly faster than that of bovine serum albumin. | 1978 | 754123 |
| resistance to certain organophosphorus ixodicides in the bont tick, amblyomma hebraeum koch, in the republic of south africa and swaziland. | a series of in vitro trails confirmed resistance in the three-host tick, amblyomma hebraeum koch, to the organophosphorus ixodicides, dioxathion, chlorfenvinphos, quintiofos, bromophos-ethyl and a dioxathion/chlorfenvinphos combination. the results of a routine survey showed that a resistance factor of greater than 100x was present in the offspring of ticks in six of 115 field isolates tested. these six isolates were confined to the lowveld areas of the province of natal, republic of south afric ... | 1978 | 752082 |
| the activity of insect juvenile hormone mimics in larval amblyomma hebraeum koch (acarina: metastriata: ixodidae). | a total of 14 insect juvenile hormone mimics was tested for activity in amblyomma hebraeum by exposing newly engorged larvae to filter paper impregnated with hormone mimics. the most active compounds used in this assay were hs 103 (6-ethyl-3-pyridyl geranyl ether; ec50=0,0018 mg/cm2), zr 512 (ethyl 3,7,11-trimethyldodeca-2,4-dienoate; ec50=0,0022 mg/cm2), hs 2 (6-methyl-3-pyridyl geranyl ether; ec50=0,0035 mg/cm2), zr 615 (n-ethyl 3,7,11-trimethyldodeca-2,4-dieneamide; ec50=0,0035 mg/cm2), zr 77 ... | 1978 | 704043 |
| efficacy of ivermectin delivered from an intraruminal sustained-release bolus against natural infestations of five african tick species on cattle. | the efficacy of ivermectin delivered by an orally administered prototype sustained-release bolus over approximately 90 days was evaluated against natural infestations of five african tick species. twenty cattle, allocated by restricted randomization based on counts of standard boophilus decoloratus, were allocated to two groups and were either given an ivermectin bolus or designated as non-medicated controls. all cattle grazed a single pasture of native grasses for 20-40 days before treatment an ... | 1990 | 2267728 |
| actions of some transmitters and their antagonists on salivary secretion in a tick. | cholinomimetics (pilocarpine, carbachol, physostigmine, acetylcholine, acetyl-beta-methylcholine) and sympathomimetics (dopamine, epinephrine), when injected into the hemolymph, provoked salivary fluid secretion in the female ixodid tick amblyomma hebraeum koch. atropine, but not tubocurarine or toxiferine, abolished pilocarpine-induced secretion without reducing the response to dopamine. reserpine and guanethidine likewise selectively attenuated pilocarpine-induced secretion. following extirpat ... | 1978 | 677342 |
| resistance of brahman and simmentaler cattle to southern african ticks. | field collections of ticks from two breeds of cattle in the north western transvaal showed the common tick species to be rhipicephalus appendiculatus, amblyomma hebraeum, rhipicephalus evertsi evertsi and hyalomma marginatum rufipes. the number of these ticks was higher on simmentaler than on brahman cattle. correlation was found between the number of ticks on the cattle and their serum gamma globulin levels indicating an increase in the production of antibodies. similar correlation was also fou ... | 1990 | 2339000 |
| morphology of the spermatid and spermatozoon of amblyomma hebraeum koch (acarina; ixodidae). | spermatids and spermatozoa of amblyomma hebraeum were examined by scanning and transmission electron microscopy as well as by freeze-etch and freeze-fracture techniques. the external surface of the spermatid is smooth except for a rim of two parallel grooves near the anterior apex. this rim probably marks the level at which a cap detaches, permitting extrusion of the inner cord during spermatozoon maturation. both ends of the spermatid are closed, the anterior part being slightly thicker than th ... | 1978 | 654427 |
| chemoreceptor organs used in detection of pheromone(s) of the tick amblyomma hebraeum (acarina: ixodidae). | | 1977 | 609070 |
| tick infestations and tick-borne diseases in zimbabwe rhodesia. | the distribution of tick species in zimbabwe rhodesia is significantly influenced by land utilization practices. the most commonly occurring species in the over-grazed tribal areas is boophilus decoloratus. by contrast, well-managed commercial farms and ranches support a wide range of tick species, the most important of which is rhipicephalus appendiculatus. until recently tick-borne diseases of cattle were efficiently controlled through dipping. the low incidence of disease was an important fac ... | 1979 | 553966 |
| the use of time-series analysis to forecast bont tick (amblyomma hebraeum) infestations in zimbabwe. | studying the dynamics of tick infestations on cattle is an essential step in developing optimal strategies for tick control. successful strategic tick control requires accurate predictions of when tick infestations will reach predetermined threshold levels. in the case of amblyomma hebraeum, earlier work has shown that there is no consistent pattern of seasonal activity. this means that a statistical model for predicting a. hebraeum infestations cannot reliably use climatic factors as the only i ... | 1992 | 1526202 |
| the role of males of the bont tick (amblyomma hebraeum) in the transmission of cowdria ruminantium (heartwater). | the role of males of the bont tick (amblyomma hebraeum) in the transmission of cowdria ruminantium (heartwater) was investigated. transstadial (nymph to adult) and intrastadial transmission were demonstrated. males transferred from live or dead hosts to live hosts were shown to transmit c. ruminantium repeatedly. it was concluded that male transmission is of importance in the epidemiology of heartwater. | 1989 | 2588467 |
| [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 |
| effects of the avermectin analogue mk-243 on vitellogenesis and reproduction in the ixodid tick, amblyomma hebraeum. | a dose-dependent reduction in weight of total egg mass and a slightly increased oviposition latency were observed following injection of the avermectin analogue mk-243 (4"-epi-methylamino-4"-deoxyavermectin b1) directly into the haemocoel of engorged female amblyomma hebraeum koch (acari: ixodidae). egg laying was almost completely inhibited at 100 micrograms/kg body weight. mk-243 markedly inhibited ovary development and vitellogenesis. ticks treated with 100 micrograms mk-243/kg also had one-t ... | 1992 | 1526201 |
| description of aegyptianella botuliformis n. sp. (rickettsiales: anaplasmataceae) from the helmeted guineafowl, numida meleagris. | aegyptianella botuliformis n. sp. (rickettsiales: anaplasmataceae) isolated from helmeted guineafowls numida meleagris from the kruger national park is described. the rickettsia occurs within a membrane-bound vacuole in the cytoplasm of erythrocytes with up to 8 organisms in a mature inclusion. the initial body resembles that of aegyptianella pullorum. the tightly packed, sausage-shaped intermediate forms are a distinctive morphological feature, seen as irregular, pleomorphic forms under light m ... | 1992 | 1513599 |
| a freeze etching study on the distribution of nuclear pores during spermatogenesis in ticks. | in this study the freeze-fracturing and freeze-etching techniques was used to study pore distribution during spermatogenesis in ticks. three species of ixodid ticks were studied: hyalomma dromedarii, h. marginatum and amblyomma hebraeum. in all three species of the ticks examined, the nuclei of the early stages of male germ cells showed varying degrees of aggregation into pore-rich and pore-poor areas. spermatocytes demonstrated significant pore clustering in pore-rich areas, leaving areas almos ... | 1992 | 1500776 |
| ultrastructure of symbiont-like microorganisms associated with the sperm of ixodid ticks. | the endospermatophores found in the seminal receptacles of three species of ixodid ticks: hyalomma marginatum, h. dromedarii and amblyomma hebraeum were examined. the seminal receptacles showed the presence of symbiont-like microorganisms in association with the sperm cells. these yeast-like microorganisms represent extracellular symbionts, produced by the male and introduced in the genital system of the female through copulation. the symbionts frequently occur freely in large agglomerations sur ... | 1992 | 1500765 |
| olfactory responses of adult amblyomma hebraeum and a. variegatum (acari: ixodidae) to attractant chemicals in laboratory tests. | unfed adults of the african ticks, amblyomma hebraeum koch and a. variegatum (fabricius), important vectors of human and animal diseases, were exposed to volatile compounds in an olfactometer in efforts to identify both tick-produced or synthetic chemicals capable of eliciting an attraction response. a formula, relative efficacy of attraction, was devised for comparison of responses between species and sexes to a particular test stimulus, or within a homogeneous population to different stimuli. ... | 1992 | 1526203 |
| acaricide susceptibility of amblyomma variegatum (acari:ixodidae) from puerto rico and guadeloupe. | base-line data on acaricide susceptibility of larvae and of larvae and nymphs of the tropical bont tick, amblyomma variegatum (fabricius), from puerto rico and guadeloupe were collected on 14 and six compounds, respectively. nymphs 7-8 weeks old from puerto rico and guadeloupe, and larvae 3-4 weeks old from guadeloupe, were exposed for 24 or 48 h to residues of acetone dilutions of technical-grade or commercial formulations of acaricides on disposable glass pipettes. effectiveness of the acarici ... | 1991 | 1773678 |
| isolation of cowdria ruminantium by means of percoll density gradient centrifugation and detection by an enzyme-linked immunosorbent assay. | the isolation of cowdria ruminantium by means of percoll density gradient centrifugation permits the recovery of partially purified viable populations of the organism possessing distinctly different densities. these conclusions are based upon results of analyses of density fractions by intravenous inoculation into sheep, protein determination, electron microscopy and enzyme-linked immunosorbent assay. morphological differences were observed in the density fractions obtained from infected brain t ... | 1986 | 3014417 |
| field sampling of unfed adults of amblyomma hebraeum koch. | no methods have previously been available for the field sampling of unfed adults of amblyomma hebraeum. we released 2000 unfed adults into a 5-m2 area in mopane woodland in southeastern zimbabwe. the ticks sought shelter beneath the debris on the soil surface but emerged and became active in host seeking when stimulated. effective stimuli were the odours of cattle and sheep and high concentrations of carbon dioxide from dry ice. the ticks did not respond to low concentrations of carbon dioxide, ... | 1987 | 3135161 |
| resistance of indigenous african cattle to the tick amblyomma hebraeum. | field collections of amblyomma hebraeum koch adults from six breeds of cattle were conducted on two farms in the northern transvaal. the density of a. hebraeum adults was highest on simmentaler cows, followed by santa gertrudis, africaner, bonsmara, brahman and nguni. indigenous breeds, namely nguni, bonsmara and africaner, have the highest level of resistance to a. hebraeum. the relationship between tick abundance and the high level of resistance found in the indigenous breeds is discussed. | 1991 | 1773680 |
| aggregation pheromones of the bont tick amblyomma hebraeum: identification of candidates for bioassay. | volatiles emitted by male amblyomma hebraeum while feeding on a rabbit were quantitatively sampled by the dynamic solvent effect and analysed by capillary gas-liquid chromatography and mass spectrometry. changes in emissions of 2-methyl propanoic acid, benzaldehyde and 2-nitrophenol paralleled reported increases in the attractiveness of males to conspecific ticks after 4-5 days of feeding. these compounds are therefore candidates for the bioassay of pheromonal activity. | 1988 | 3194113 |
| 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 |
| parasites of domestic and wild animals in south africa. xxix. ixodid ticks on hares in the cape province and on hares and red rock rabbits in the orange free state. | one hundred and seventeen scrub hares, lepus saxatilis, were examined for ixodid ticks in various regions of the cape province. they were infested with 18 tick species and the seasonal abundances of the immature stages of amblyomma hebraeum, amblyomma marmoreum, hyalomma marginatum rufipes, rhipicephalus appendiculatus and rhipicephalus glabroscutatum and all stages of rhipicephalus oculatus and the adults of a rhipicephalus sp. (near r. oculatus) were determined. seventy-two scrub hares on 3 fa ... | 1991 | 1780126 |
| comparison of known and suspected pheromonal constituents in males of african ticks, amblyomma hebraeum koch and amblyomma variegatum (fabricius). | three low molecular weight compounds were found in hexane:diethyl ether extracts of fed males of the african ticks, amblyomma variegatum (tropical bont tick) and a. hebraeum (bont tick), namely, o-nitrophenol, methyl salicylate and 2,6-dichlorophenol. these same compounds were also fond in a rinse of fed a. variegatum males, but were absent or present in only trace amounts in a rinse of fed a. hebraeum males, o-nitrophenol and methyl salicylate were present in much higher concentrations (i.e., a ... | 1991 | 1786745 |
| seasonal occurrence of the bont tick (amblyomma hebraeum) in the southern lowveld of zimbabwe. | the seasonal occurrence of the bont tick amblyomma hebraeum was recorded over 2 years on 20 brahman cattle held in a 240-ha paddock at mbizi in southeastern zimbabwe. the cattle were infested with all life cycle stages throughout the study period, and no clearly defined seasonal patterns were recorded. males remained attached for up to about 6 months, and consequently accumulated on the cattle and outnumbered females considerably. the cattle did not acquire resistance to a. hebraeum and the abun ... | 1991 | 1786747 |
| the presence of cowdria ruminantium antigen in various tissues of amblyomma hebraeum imagines as detected by an enzyme-linked immunosorbent assay. | investigation into the presence of c. ruminantium antigen, using an enzyme-linked immunosorbent assay (elisa) in various tick tissues and haemolymph of adult amblyomma hebraeum ticks revealed that the organism invades a number of body parts and can be demonstrated in a. hebraeum. in females, the gut, salivary glands, hypodermis and synganglion and in males, the salivary glands and gut showed the highest concentration. | 1988 | 3217097 |
| control of induced infestations of adult amblyomma hebraeum with sustained release ivermectin. | the efficacy of ivermectin, administered in a sustained release formulation by intraruminal pumps at approximate daily dose rates of 20, 40 and 60 micrograms/kg, was evaluated in 16 cattle against induced infestations of 3 strains of adult amblyomma hebraeum. engorged female ticks were mass-measured and incubated, and reproductive data recorded. there was an increase in mortality of male and female ticks compared to that of controls with increasing daily dose of ivermectin, and a decrease in the ... | 1987 | 3295646 |
| resistance of restrained bos taurus dairy bull calves to the bont tick amblyomma hebraeum (acarina: ixodidae). | three infestations of restrained jersey and friesland bull calves with adult amblyomma hebraeum did not affect the rate of engorgement of female ticks and resulted in an insignificant decline in the mean engorgement weight of female ticks recovered from the friesland group. repeated infestations significantly affected the egg-laying capacity of engorged female ticks recovered from both groups of hosts. the friesland calves manifested an enhanced resistance to the larvae and nymphs of amblyomma h ... | 1991 | 1882498 |
| purification of cowdria ruminantium by lectin cellular affinity chromatography. | this review covers the isolation of cowdria ruminantium by lectin cellular affinity chromatography from different amblyomma hebraeum sources. cellular affinity chromatography has been reviewed with special attention being given to the application of this technique in the isolation of rickettsiae. | 1987 | 3329313 |
| heartwater. the artificial transmission of cowdria ruminantium in domestic ruminants and mice. | the artificial transmission of cowdria ruminantium with infected blood, organ homogenates, peritoneal macrophages, tick stabilate and tissue culture cells is discussed. organ homogenates prepared from the myocardium, spleen, kidneys and liver of diseased animals are commonly used to infect mice. the efficacy of organ homogenates as a source of c. ruminantium depends on factors such as the route of inoculation and the heartwater isolate used. heartwater is artificially transmitted with infected t ... | 1987 | 3329318 |
| the ecology of the african vectors of heartwater, with particular reference to amblyomma hebraeum and amblyomma variegatum. | the hosts, sites of attachment, life cycle, habitat requirements and seasonal abundance of amblyomma astrion, amblyomma cohaerens, amblyomma gemma, amblyomma hebraeum, amblyomma lepidum, amblyomma marmoreum, amblyomma pomposum, amblyomma sparsum, amblyomma tholloni and amblyomma variegatum, the 10 potential vectors of heartwater in africa, are listed. factors influencing the distribution and abundance of the ticks as well as interactions with other species and the role of predators and pathogens ... | 1987 | 3329326 |
| some avian and mammalian hosts of amblyomma hebraeum and amblyomma marmoreum (acari: ixodidae). | large numbers of birds, wild mammals and domestic stock from a variety of localities within the republic of south africa were examined for infestation with the ixodid ticks amblyomma hebraeum and amblyomma marmoreum. every warthog (phacochoerus aethiopicus), burchell's zebra (equus burchelli), impala (aepyceros melampus) and kudu (tragelaphus strepsiceros) from the kruger national park in the north-eastern transvaal lowveld was infested with a. hebraeum. in the eastern cape province every helmet ... | 1987 | 3329327 |
| specificity and effects of host resistance on the african tick rhipicephalus zambeziensis (acarina: ixodidae). | repeated infestations of the rabbit with adult rhipicephalus zambeziensis ticks resulted in a ten-fold reduction in engorgement weight of adult ticks and a significant decline in engorgement weight of nymphs. there was no evidence of cross-resistance against the south african bont tick, amblyomma hebraeum. immunization of rabbits with crude extracts of whole-tick protein significantly influenced engorgement weights and oviposition rates of adult r. zambeziensis. histological studies of tissues f ... | 1991 | 1893799 |
| chemical control of the heartwater vectors. | this paper reviews available literature on the efficacy of acaricides against amblyomma hebraeum and other tick species, and presents information on tests done with registered chemicals in the laboratory. little published information is available on the efficacy of chemicals specifically against a. hebraeum. a host of formulations are registered for use as acaricides on cattle, sheep, and goats in south africa and thus, by implication, against this species. resistance has only been described to ... | 1987 | 3329335 |
| pheromone/acaricide mixtures in the control of the tick amblyomma hebraeum: effects of acaricides on attraction and attachment. | unfed adults and nymphs of the bont tick amblyomma hebraeum koch are attracted to hosts on which fed males, emitting an aggregation-attachment pheromone (aap), are attached. pheromone/acaricide mixtures have the potential to selectively attract and kill these ticks. we have investigated the effects of three acaricides, amitraz (an amidine), flumethrin (a synthetic pyrethroid) and chlorfenvinphos (an organophosphate), combined with aap, on the attraction and attachment of the unfed adults. attrac ... | 1991 | 1893800 |
| parasites of domestic and wild animals in south africa. xxvii. ticks on helmeted guineafowls in the eastern cape province and eastern transvaal lowveld. | seventy-six helmeted guineafowls (numida meleagris) were shot in the andries vosloo kudu reserve and on an adjacent farm in the eastern cape province during the period may 1985 to january 1987 and their tick burdens determined. a total of 10 ixodid tick species were recovered, of which amblyomma hebraeum, amblyomma marmoreum and haemaphysalis silacea were the most abundant. the seasonal abundances of these 3 species and of hyalomma marginatum rufipes were ascertained. a marked difference between ... | 1991 | 1923375 |
| ultrastructural morphology of cowdria ruminantium in midgut epithelial cells of adult amblyomma hebraeum female ticks. | amblyomma hebraeum male and female ticks, experimentally infected as larvae with the ball 3 stock of cowdria ruminantium, were fed on a heartwater susceptible sheep. the initial attachment of the males was required as a pre-requisite for female attachment. reticulate bodies were the predominant morphologic form of cowdria observed in gut epithelial cells after 1-3 days of feeding. single intermediate bodies and no elementary bodies were observed. organisms were found within a membrane-bound vacu ... | 1991 | 1923381 |
| isolation of spotted fever group rickettsias from triturated ticks using a modification of the centrifugation-shell vial technique. | a modification of the centrifugation-shell vial technique was used to isolate spotted fever group (sfg) rickettsias from triturated ticks which had previously been stored at -80 degrees c for up to 7 months. sfg rickettsias were successfully isolated in vero cells from all 7 haemolymph positive ticks (amblyomma hebraeum) used in the experiment. attempts were also made to use these tick triturates to establish sfg rickettsial infections in tissue culture. vero cells were used for 5 of the tick tr ... | 1991 | 1949146 |
| problems with the interpretation of epidemiological data in heartwater: a study on 23 farms. | in an epidemiological study undertaken on 23 farms where heartwater occurs endemically, it was found that on an overall average, antibodies to cowdria ruminantium were detected in 64.3% of the cattle, 6 adult amblyomma hebraeum ticks were counted per animal and 7.0% of ticks were infected with the heartwater agent. it was found that the seropositivity of the animals was determined largely by the tick loads to which they were subjected and that the influence of the tick c. ruminantium infection r ... | 1987 | 3448573 |
| biochemical studies on the eggs of amblyomma hebraeum. | the isolation, characterization and kinetic properties of a toxic and non-toxic anti-protease from the eggs of a. hebraeum are compared with similar data obtained for eggs of other tick species. the biochemistry of various physiological processes in tick eggs is reviewed. | 1987 | 3448575 |
| the use of flumethrin 1% pour-on for the control of amblyomma spp. in various southern african countries. | efficacy trials with flumethrin 1% pour-on were conducted in 9 different areas in 3 southern and central african countries against amblyomma hebraeum and a. variegatum on cattle. a dose volume of 10 ml/100 kg body mass applied at bi-weekly intervals provided excellent control of both tick species on their predilection sites, irrespective of locally and seasonally high tick pressure. the trial results demonstrate clearly that this new concept of tick control can be effectively applied in commerci ... | 1987 | 3448582 |
| the impact of pure infestations of rhipicephalus appendiculatus and amblyomma hebraeum on the productivity of cattle and implications for tick control strategies in africa. | this paper reviews studies carried out by an fao project in zimbabwe, on the effects of the ticks rhipicephalus appendiculatus and amblyomma hebraeum on the productivity of cattle. larvae and nymphs of the two species had no detectable effect on liveweight gain (lwg). the losses in lwg caused by each adult female that completed feeding were approximately 4 g for r. appendiculatus and 10 g for a. hebraeum. losses in milk production caused by both species amounted to approximately 7 g for every fe ... | 1990 | 2126617 |
| organ culture of ixodid-tick salivary glands. | this work describes an organ-culture method for isolated salivary glands of the ixodid tick amblyomma hebraeum koch. the support medium is a tc 199-1% agarose gel with no hormonal or undefined supplements. i used a fluid-transport assay for measuring viability of salivary glands. when cultured at 26 degrees c, female glands secreted fluid at 65% on day 2, 59% on day 4 and 42% on day 6 post-culture compared to glands tested on day 0. fluid secretory rates in culture were higher than rates of glan ... | 1990 | 2226073 |
| a comparison of live and destructive sampling methods of determining the size of a parasitic tick populations. | the accuracy of a general and a specific method of collecting and counting ixodid ticks on live hosts was compared with that of a destructive technique which can only be applied to dead animals. destructive sampling provided considerably more accurate results than either of the live sampling methods when applied to domestic goats (capra hircus) and a duiker (sylvicapra grimmia). the smaller the life stage and the tick species the less likely it is that it will be recovered by either of the live ... | 1987 | 3453335 |
| foot abscess in goats in relation to the seasonal abundance of adult amblyomma hebraeum and adult rhipicephalus glabroscutatum (acari: ixodidae). | the seasonal prevalence of foot abscess affecting angora and boer goats in valley bushveld in the eastern cape province of south africa was significantly related to the seasonal abundance of adult amblyomma hebraeum and adult rhipicephalus glabroscutatum. angora goats harboured more ticks than boer goats and also had a greater number of abscessed feet. larger numbers of ticks and abscesses were recorded on hind feet than on fore feet. there was no significant correlation between rainfall and the ... | 1987 | 3508202 |
| 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 |
| effect of 20-hydroxyecdysone on the salivary glands of the male tick, amblyomma hebraeum. | female ticks (acari: ixodidae) feed only once in the adult stage, dying after laying a large batch of eggs. during the early post-engorgement stage, haemolymph ecdysteroid titre rises, which is probably responsible for autolysis of the salivary glands that takes place at this time. males, on the other hand, can re-attach and feed numerous times during the adult stage. males were fed on rabbits for either 7 or 14 days. haemolymph was collected either the day of removal from the host or 4 days lat ... | 1990 | 2226074 |
| increased pathogenicity of an ehrlichia-like agent after passage through amblyomma hebraeum: a preliminary report. | after being passaged through 3 generations of amblyomma hebraeum, an ehrlichia-like agent isolated from an adult hyalomma truncatum female became more pathogenic and elicited a disease in sheep indistinguishable from heartwater. cross-immunity between this agent and several stocks of cowdria ruminantium and high levels of antibody elicited by the agent against 2 stocks of c. ruminantium in the indirect fluorescent antibody test, confirmed its close relationship to cowdria. | 1990 | 2293132 |
| infection rates with cowdria ruminantium of nymphs and adults of the bont tick amblyomma hebraeum collected in the field in zimbabwe. | cowdria ruminantium (heatwater) infection rates of field populations of the bont tick, amblyomma hebraeum, were determined at two locations in the southern lowveld of zimbabwe. at mbizi quarantine station, unfed adult males and females, and nymphs were collected at intervals over a 2-year period using traps. at lemco ranch, engorged nymphs were collected on three occasions from weaner calves and allowed to moult to adults. the unfed ticks were fed in small pools on heartwater-susceptible sheep, ... | 1990 | 2399648 |
| the carrier status of sheep, cattle and african buffalo recovered from heartwater. | sheep, cattle and the african buffalo (syncerus caffer) were shown to remain carriers of heart-water (caused by cowdria ruminantium) for long periods after recovery; 223, 246 and 161 days, respectively. transmission was achieved using adults of the southern african bont tick (amblyomma hebraeum) that had fed as nymphs on recovered animals. our findings differ from those of other workers who attempted transmission using nymphs that had fed as larvae on recovered animals or with blood from recover ... | 1989 | 2617830 |
| resistance of nguni, bonsmara and hereford cattle to ticks in a bushveld region of south africa. | counts of engorged female ticks on naturally infested cattle over a 2 year period, showed that indigenous nguni cattle harboured significantly fewer amblyomma hebraeum, boophilus decoloratus and hyalomma spp. during periods of peak abundance than either bonsmara or hereford cattle. fewer abscesses, associated with tick bite, were also present in the nguni cattle. individual tick resistance indices, determined after artificial tick infestation in the field, could not be correlated with hair lengt ... | 1989 | 2626263 |
| the host status of the striped mouse, rhabdomys pumilio, in relation to the tick vectors of heartwater in south africa. | striped mice, rhabdomys pumilio, were trapped over a 17 month period in the thomas baines nature reserve in the eastern cape province of south africa. captured mice were placed in cages, over water, and naturally detaching ticks were collected. only 5 larvae and 1 nymph of amblyomma hebraeum were recovered from the mice. these represented less than 0.1% of the total number of ticks recovered. no amblyomma marmoreum were recovered. as the vegetation and large mammals and tortoises in the thomas b ... | 1989 | 2626267 |
| spectral sensitivity, absolute threshold, and visual field of two tick species, hyalomma dromedarii and amblyomma variegatum. | 1. the spectral sensitivity in the wavelength range of 340-750 nm was determined by both a behavioral approach based on spontaneous positive phototaxis and the electroretinogram (erg). 2. concerning phototaxis the camel tick, hyalomma dromedarii, showed two sensitivity maxima, one in the uv range (ca. 380 nm) and another in the blue-green range (ca. 500 nm). at higher intensities the relative sensitivity was more pronounced in the uv and at lower intensities more pronounced in the blue-green (re ... | 1989 | 2746548 |
| the effect of the bont tick (amblyomma hebraeum) on the weight gain of africander steers. | the effects of the bont tick amblyomma hebraeum on the productivity of cattle need to be quantified in order to design economically optimal control programs. liveweight gains (lwgs) of three groups of africander steers, maintained in the same pasture and exposed to zero, medium or high numbers of larvae, nymphs and adults of the tick, were measured. larvae and nymphs had no significant effect on lwg but adults had a large, statistically significant effect (p less than 0.05). the tick-free group ... | 1989 | 2815542 |
| pheromone-mediation of host-selection in bont ticks (amblyomma hebraeum koch). | the bont tick, amblyomma hebraeum, is the principal vector to southern african ruminants of heartwater (cowdria ruminantium infection). the role of feeding male ticks, which emit an aggregation-attachment pheromone, in attracting unfed ticks to cattle was investigated. calves infested with feeding male ticks were more attractive to unfed adult ticks than were uninfested calves. the presence of the pheromone on previously infested cattle apparently allows unfed ticks to discriminate between hosts ... | 1989 | 2911745 |
| ticks on livestock in st. lucia. | cattle, sheep, goats and horses were examined for ticks. over 95% of holstein cross-breeds, 28% of sheep (local mixed breeds) and 18% of goats (local mixed breeds) examined from 18 august to 4 september 1983 were infested with the southern cattle tick, boophilus microplus canestrini. about 90 and 17% of the horses examined were infested with the tropical horse tick, anocentor nitens neumann, and the tropical bont tick, amblyomma variegatum fabricius, respectively. the tropical bont tick was foun ... | 1985 | 4090245 |
| field sampling of unfed nymphs of amblyomma hebraeum. | unfed nymphs of amblyomma hebraeum koch, 1844 shelter under debris on the soil surface and become active in host-seeking when stimulated with carbon dioxide. the active nymphs are not attracted to sources of carbon dioxide and hence cannot be effectively sampled using static carbon dioxide traps. however, these nymphs will cling to flannelette and can be sampled by flagging. larger numbers are recovered if the soil surface is sampled using a vacuum device. | 1988 | 3137010 |
| eradication efforts against tropical bont tick, amblyomma variegatum, in the virgin islands. | | 1969 | 5766830 |
| comparative feeding behaviour and food preferences of oxpeckers (buphagus erythrorhynchus and b. africanus) in captivity. | the feeding methods, activities and behaviour of red-billed and yellow-billed oxpeckers in captivity were compared. both species were found to be very similar with regard to feeding. the differences observed were a greater dependence on ectoparasites such as flies and larger ticks (amblyomma hebraeum) and a higher food intake for the yellow-billed oxpecker. these differences are the result of the larger size, limited choice of host animals and closer host/oxpecker relationship of the yellow-bill ... | 1988 | 3194119 |
| properties of na, k-atpase from the salivary glands of the ixodid tick amblyomma hebraeum. | | 1980 | 6253039 |
| ability of adults of amblyomma hebraeum (acarina: ixodidae) to feed repeatedly on sheep and cattle. | adult amblyomma hebraeum ticks were exposed at 14-day intervals on five sheep on 46 occasions and on three cattle on 15 occasions to determine the effects of repeated feeding. the engorged weight and percentage of ticks which fed successfully on sheep declined significantly at first but subsequently they increased. on cattle there was no progressive decline in engorged weight, although the percentage which fed successfully declined significantly and was lower than that for sheep. this decline wa ... | 1988 | 3201710 |
| the treatment of ticks on tortoises using amitraz. | amitraz at a concentration of 2 ml litre-1 of water successfully induced detachment of amblyomma marmoreum and amblyomma hebraeum ticks from the mountain tortoise, geochelone pardalis. detached ticks died without reattaching. at the strength used, amitraz had no apparent adverse effects on the tortoises. | 1988 | 3210221 |
| a bioassay technique for the pheromone emitted by amblyomma hebraeum males. | attachment of amblyomma hebraeum females, either around feeding males or in areas in which extracts of fed males had previously been placed, was studied. the percentage attachment of female ticks around feeding males was significantly higher than that inside extract-treated areas. it was also found that the percentage attachment around the males increases with time, but there is little or no increase in attachment with time inside the treated areas. the amount of pheromone released by 1 feeding ... | 1983 | 6634086 |
| purification of cowdria ruminantium by density gradient centrifugation. | the isolation of cowdria ruminantium by differential and isopycnic density gradient centrifugation is reviewed with special reference to the suitability of percoll as density gradient medium. infected sheep brain, amblyomma hebraeum nymphae and various mouse organs were used as starting material. by these methods, partially purified viable populations of the organism with distinctly different densities were obtained. the conclusions are based upon results of analyses of density fractions by inoc ... | 1987 | 3329312 |
| biochemical studies on the salivary glands and haemolymph of amblyomma hebraeum. | the functional significance of some components of salivary glands and of their secretion and of haemolymph of amblyomma hebraeum and other tick species is reviewed with respect to host responses at the attachment site, the survival of specific pathogens in the vector, the transmission of pathogens and immunological responses of the host to tick infestation. | 1987 | 3329330 |
| [experimental transmission of the yellow fever virus by the tick amblyomma variegatum (f.) (author's transl)]. | experimental transmission of the yellow fever virus by the tick amblyomma variegatum (f.) (the tropical bont tick) is demonstrated for the first time. the tick transmitted the virus from one monkey to another. trans-stasial passage from nymph to adult stage was also demonstrated. the possible role of amblyomma variegatum as a vector and a potential reservoir of yellow fever is discussed. | 1982 | 7105284 |
| the developmental success of amblyomma hebraeum and amblyomma marmoreum on the leopard tortoise, geochelone pardalis. | the success of natural infestations of various life history stages of amblyomma hebraeum and amblyomma marmoreum on the leopard tortoise, geochelone pardalis, was compared. success was measured by the time taken for ticks to detach, as well as the percentage of ticks engorging and subsequently either moulting to the next life history stage or laying viable eggs. larvae of a. hebraeum were the only developmental stage not recovered. nymphae and female a. hebraeum were less successful in moulting ... | 1988 | 3353093 |
| the use of domestic chickens as laboratory hosts of the larvae of the bont tick, amblyomma hebraeum. | a comparison of attachment, engorgement and moulting success of amblyomma hebraeum larvae fed on domestic chickens and himalayan giant white rabbits indicates that chickens are better hosts than the rabbits. moreover the time needed for detachment of all engorged larvae is significantly less for chickens than for the rabbits. no evidence of induced immunity was found in chickens on re-infestation with larvae of a. hebraeum. | 1988 | 3353104 |