Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
|---|
| detection of cowdria ruminantium by means of a dna probe, pcs20 in infected bont ticks, amblyomma hebraeum, the major vector of heartwater in southern africa. | a dna probe, pcs20, previously described for use in detection of cowdria ruminantium infections in amblyomma variegatum (the principal vector of heartwater) hybridized with c. ruminantium dna in organs of laboratory-infected a. hebraeum adult ticks (the major southern african vector of heartwater). the probe hybridized with c. ruminantium dna in 46/49 midguts from male ticks and 26/29 from females, thus indicating infection. corresponding salivary glands were less heavily infected, but infection ... | 1993 | 8432329 |
| ixodid ticks (acari: ixodidae) and livestock production: effect of varying acaricide treatments on ticks and productivity in east coast fever-immunized weaner and dairy cattle. | in a pilot trial to evaluate cost-effective methods of acaricide application, east coast fever-immunized weaner and dairy cattle were subjected to varying tick control regimens. all experimental cattle were maintained under the same extensive system of management. their monthly tick load, packed cell volumes, incidence of blood protozoans, weight changes, and daily milk production were noted. apart from rhipicephalus appendiculatus neumann, other tick species found in the study site were r. pulc ... | 1993 | 8510109 |
| saliva-activated transmission (sat) of thogoto virus: dynamics of sat factor activity in the salivary glands of rhipicephalus appendiculatus, amblyomma variegatum, and boophilus microplus ticks. | thogoto (tho) virus is transmitted from infected to uninfected ticks when co-feeding on uninfected guinea-pigs, even though the guinea-pigs do not develop a detectable viraemia. this form of non-viraemic transmission is potentiated by a factor(s) secreted by the saliva of ticks and hence has been termed saliva-activated transmission (sat). the synthesis of the sat factor by the salivary glands of three ixodid tick species was determined by placing uninfected nymphal ticks on guinea-pigs that wer ... | 1992 | 1326431 |
| laboratory studies on the life cycle of amblyomma marmoreum (acari: ixodidae) on two different hosts. | a comparative study was made of the life cycle of the tortoise tick, amblyomma marmoreum koch, on tortoises and guinea pigs under laboratory conditions. at 25 degrees c and 85% rh with natural day length, duration of off-host stages (preoviposition, oviposition, incubation, and premolt) was similar for ticks fed on both hosts. delay in preoviposition (up to 90 d) was observed in some gravid females. larvae, nymphs, and adults had longer feeding periods on tortoises than on guinea pigs. adult fem ... | 1992 | 1404252 |
| 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 |
| synganglial morphology and neurosecretory centers of adult amblyomma americanum (l.) (acari: ixodidae). | lone star ticks, amblyomma americanum (l.), were processed by standard histological means for paraffin embedding, sectioning, and staining by the paraldehyde-fuchsin technique. the synganglion is highly condensed around the esophagus and possesses paired optic, cheliceral, palpal, pedal i-iv nerves, and opisthosomal nerves and a single unpaired esophageal nerve. although optic nerves were observed leading from the eyes to the protocerebrum, distinct optic ganglia were not seen in any of the prep ... | 1992 | 1460618 |
| parasites of cottontail rabbits of southern illinois. | fifteen species of parasites including haemaphysalis leporispalustris, ixodes dentatus, amblyomma americanum, cediopsylla simplex, odontopsyllus multispinosus, cuterebra sp., obeliscoides cuniculi, trichostrongylus calcaratus, trichostrongylus affinis, longistriata noviberiae, dermatoxys veligera, trichuris sp., mosgovoyia sp., taenia pisiformis, and hasstilesia tricolor as well as coccidia oocysts were collected from 96 cottontail rabbits (sylvilagus floridanus) confined to a pen in southern il ... | 1992 | 1491303 |
| tick (acari: ixodidae) attachment cement and salivary gland cells contain similar immunoreactive polypeptides. | a specific antiserum (12c) raised to a 90-kda immunogenic component of salivary glands of the tick rhipicephalus appendiculatus recognized similar 90-kda polypeptides from salivary glands of the american dog tick, dermacentor variabilis, and the lone star tick, amblyomma americanum, as well as 70-kda polypeptides in the cement of d. variabilis, a. americanum, and r. sanguineus (brown dog tick). the reduction in size of the polypeptide for these ticks suggests that it is modified in some way duri ... | 1992 | 1495047 |
| feeding efficiency of larval hyalomma truncatum (acari: ixodidae) on hosts previously exposed to ticks. | the effect of guinea pig response to feeding larval hyalomma truncatum koch ticks was studied by measuring the percentage of ticks engorging and molting, their engorged weight, and hemoglobin content. four guinea pigs were infested with 100, 200, 400, and 1,000 larvae, respectively, on three occasions at 21-d intervals, followed by a fourth infestation with 500 larvae. during the second, third, and fourth infestations, significantly fewer ticks engorged on each guinea pig than during the first i ... | 1992 | 1495048 |
| tick sweep: modification of the tick drag-flag method for sampling nymphs of the deer tick (acari: ixodidae). | we describe a version of the standard tick drag-flag modified for use in close-growing and tangled vegetation, as well as under ornamental shrubbery and fallen branches. two major features of the sweep are: (1) it allows the user to remain upright with the flag parallel to the ground, thus sampling effectively beneath low and fallen branches and around shrubs, as well as capturing host-seeking ticks in advance of the operator; and (2) the use of a flannel rubberized-laminate fabric (crib sheet) ... | 1992 | 1495058 |
| field evaluation of two formulations of cyfluthrin for control of ixodes dammini and amblyomma americanum (acari: ixodidae). | liquid or granular cyfluthrin was applied in the spring and fall to different test plots at a rate of 0.41 (ai) kg/ha to control ixodes dammini spielman, clifford, piesman & corwin and amblyomma americanum (l.). spring application of liquid cyfluthrin showed the most significant decreases of both species. i. dammini nymphs were reduced 97% at 10 d, 100% at 2 mo, and 100% at 1 yr; and a. americanum adults and nymphs were reduced 91-93% at 10 d and 100% at 2 mo posttreatment. granular cyfluthrin a ... | 1992 | 1495073 |
| attempted transmission of borrelia burgdorferi (spirochaetales: spirochaetaceae) (jdi strain) by ixodes scapularis (acari: ixodidae), dermacentor variabilis, and amblyomma americanum. | laboratory-reared ixodes scapularis say, amblyomma americanum (l.), and dermacentor variabilis (say) were fed on new zealand white rabbits experimentally infected with borrelia burgdorferi (jdi strain). at repletion, spirochetes could be detected by dark-field microscopy only in i. scapularis. acquisition rates were 18 and 21%. when previously exposed nymphs of each species were fed on susceptible rabbits, i. scapularis was the only tick of the three species that transmitted b. burgdorferi. when ... | 1992 | 1495078 |
| 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 |
| 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 |
| borrelia sp. in ticks recovered from white-tailed deer in alabama. | six hundred sixty-five hunter-killed white-tailed deer (odocoileus virginianus) from 18 counties in alabama (usa) were examined for ticks. most of the collections were made at state-operated wildlife management areas. four species of ticks (n = 4,527) were recovered: the lone star tick amblyomma americanum (n = 482); the gulf coast tick a. maculatum (n = 11); the winter tick dermacentor albipictus (n = 1,242); and the black-legged tick ixodes scapularis (n = 2,792). fifty-six percent of the tick ... | 1992 | 1512879 |
| monthly incidence of theileria cervi and seroconversion to babesia odocoilei in white-tailed deer (odocoileus virginianus) in texas. | monthly monitoring of fawns collected from an area in texas endemic for theileria cervi and babesia odocoilei showed that transmission of t. cervi occurred during july and august, a time period consistent with the occurrence of amblyomma americanum. seroconversion to b. odocoilei occurred during october to december and possibly continued through january and february. the time of seroconversion was more suggestive of transmission of b. odocoilei by ixodes scapularis than by amblyomma americanum. | 1992 | 1512881 |
| ectoparasites of the blackbuck antelope (antilope cervicapra). | fifty-two free-ranging blackbuck antelope (antilope cervicapra) from texas were examined for ectoparasites. two species of sucking lice (anoplura), one species of chewing louse (mallophaga), one species of louse fly (diptera), and three species of ticks (acari) were found. this is the first report of the anoplurans linognathus cervicaprae and l. pithodes from the western hemisphere. the southern deer ked (lipoptena mazamae), the winter tick (dermacentor albipictus), and the rabbit tick (haemaphy ... | 1992 | 1512888 |
| 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 |
| comparative infections of epizootic and enzootic strains of venezuelan equine encephalomyelitis virus in amblyomma cajennense (acari: ixodidae). | to compare the potential for an enzootic or an epizootic strain of venezuelan equine encephalomyelitis (vee) virus to infect amblyomma cajennense (f.), larval ticks were fed on guinea pigs (strain 13) inoculated with an enzootic viral strain of variant i-e (68u201) or on guinea pigs inoculated with an epizootic strain of variant i-a (trinidad donkey). peak viremias were 10(5.2) plaque-forming units (pfu)/ml and 10(7.3) pfu/ml in guinea pigs infected with enzootic and epizootic viral strains, res ... | 1992 | 1404262 |
| comparative study of tick burdens in gudali and wakwa cattle under natural infestation in the subhumid highlands of wakwa, cameroon. preliminary observations. | the relative resistance to different cattle ticks of gudali and wakwa cattle with different levels of brahman breeding, grazed on natural pastures in the subhumid tropics of wakwa, cameroon, was assessed using pasture tick infestations. the basic design consisted of 5 young bulls of each breed from different sire herds. tick populations were observed in gudali and wakwa bulls over a period of four weeks when the climate was thought to be highly favourable for the free-living stages of ticks. cou ... | 1992 | 1339999 |
| 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 |
| oral secretion elicited by effectors of signal transduction pathways in the salivary glands of amblyomma americanum (acari: ixodidae). | the abilities of various effectors of signal pathways in tick salivary glands to stimulate oral secretions in partially fed amblyomma americanum (l.) female ticks were compared. pilocarpine stimulated secretion the most rapidly following tick stimulation, but its effectiveness declined with time and subsequent injections. secretion rates induced by dopamine and theophylline increased with time of collection and additional injections and were as effective as pilocarpine after 60 min. activators o ... | 1992 | 1552527 |
| distribution, density, and lyme disease spirochete infection in ixodes dammini (acari: ixodidae) on white-tailed deer in maryland. | a statewide survey of ticks parasitizing white-tailed deer was carried out in maryland during november 1989 to assess the status of the deer tick, ixodes dammini spielman, clifford, piesman & corwin, the major vector of lyme disease in the northeastern united states. ticks were collected from deer carcasses brought in by hunters at 23 check stations (one per county). a total of 3,437 i. dammini were collected from 538 of 1,281 deer (42%), together with 2,013 dermacentor albipictus (packard) and ... | 1992 | 1552529 |
| quantitative evaluation of sampling methods for ixodes dammini and amblyomma americanum (acari: ixodidae). | three tick-sampling methods (dry ice-baited tick traps, cloth drags, and ambulatory human host) were evaluated to determine which technique yielded the greatest capture of host-seeking stages of ixodes dammini spielman, clifford, piesman & corwin and amblyomma americanum (l.). the most reliable method, catching more stages and significantly more numbers of i. dammini and a. americanum; was dry ice-baited tick traps. there were no significant differences between the drag and human-host methods fo ... | 1992 | 1625293 |
| inability of ixodes cookei and amblyomma americanum nymphs (acari: ixodidae) to transmit borrelia burgdorferi. | the vector competency of ixodes cookei packard and amblyomma americanum (l.) for borrelia burgdorferi was studied using syrian hamsters. ixodes dammini spielman, clifford, piesman & corwin were used as controls. darkfield and immunofluorescent examinations of midgut diverticula revealed b. burgdorferi spirochetes in 32 of 36 (88.9%) i. dammini larvae, 5 of 36 (13.9%) i. cookei larvae, and 7 of 36 (19.4%) a. americanum larvae within 48 h after feeding on infected syrian hamsters. b. burgdorferi w ... | 1992 | 1625302 |
| the role of amblyomma variegatum in the transmission of heartwater with special reference to guadeloupe. | heartwater has been diagnosed in guadeloupe, marie-galante, and antigua; it induces important losses among goats and european or cross-bred cattle when local zebu creole are highly resistant to infection. amblyomma variegatum is the vector of the disease in the caribbean. the tick strain of martinique, occurring in that island that has apparently been disease-free since 1948, has not lost its ability to experimentally transmit the disease. in guadeloupe 97% of nymphs and nearly 100% of adults fe ... | 1992 | 1626882 |
| amblyomma americanum (l.): protein kinase c-independent fluid secretion by isolated salivary glands. | protein kinase c activity was partially purified from tick salivary glands by fast protein liquid chromatography anion-exchange chromatography. enzyme activity was stimulated by ca2+, phosphatidylserine, and diacylglycerol with the highest activity observed in the presence of all three modulators. enzyme activity was inhibited by a synthetic pseudosubstrate peptide with an amino acid sequence resembling the protein kinase c substrate phosphorylation site. the protein kinase c activator, 1-oleoyl ... | 1992 | 1582485 |
| amblyomma americanum: characterization of salivary prostaglandins e2 and f2 alpha by rp-hplc/bioassay and gas chromatography-mass spectrometry. | secretagogue-induced saliva of the tick, amblyomma americanum (l.) was fractionated by reversed-phase-high-performance liquid chromatography (rp-hplc) and bioassayed in smooth muscle preparations. material with retention times of authentic prostaglandin e2 (pge2) and prostaglandin f2 alpha (pgf2 alpha) were found to cause contraction of preparations of rat colon and rat stomach strips. gas chromatography-mass spectra of selected ions of both hplc-purified fractions confirmed the existence of pge ... | 1992 | 1730268 |
| 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 |
| influence of exposure period and management methods on the effectiveness of chickens as predators of ticks infesting cattle. | experiments undertaken on rusinga island, kenya, indicated that rhipicephalus appendiculatus (neumann) was the predominant tick consumed on tick-infested cattle by chickens, followed by amblyomma variegatum (fabricius), boophilus decoloratus (koch) and rhipicephalus evertsi evertsi (neumann). the number of ticks consumed by chickens released with cattle in a 3 h release period was not significantly different from ticks consumed in a 4 h release period. in a free management system, chickens 1-3 m ... | 1992 | 1413461 |
| a contribution to the anatomy and histology of the female reproductive system of amblyomma cajennense (acarina: ixodidae). | the genital system of the tick amblyomma cajennense is composed of several parts: a single tubular ovary where a great number of ova develop except for a longitudinal groove on its dorsal surface, with feeding the ova develop multiplying the size and weight of the ovary, as they reach maturity they are ovulated into the lumen. two oviducts are connected to the ovary on each side, these thicken at a certain region forming the knee shaped ampulla. this significant region is where great numbers of ... | 1992 | 1500779 |
| 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 |
| 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 |
| experimental transmission of cowdria ruminantium (rickettsiales) by the american reptile tick amblyomma dissimile koch, 1844. | a senegalese isolate of the rickettsia cowdria ruminantium was transmitted transstadially by nymphs of the american reptile tick amblyomma dissimile. only eight nymphs, fed as larvae on a saanen goat reacting to heartwater, were required to transmit fatal heartwater to another susceptible goat. since a. dissimile usually feeds on snakes, iguanas and lizards in central america, the tick is not considered to play a significant role in the transmission of heartwater between ruminants. however, the ... | 1992 | 1395974 |
| 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 |
| 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 |
| 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 |
| [attempt to attract amblyomma variegatum (acarina:ixodina) on cattle previously treated with aggregation-fixation pheromones and a pyrethrinoid acaricide]. | the application of synthetic pheromonal aggregation-attachment compounds or male tick extracts on certain sites of the body of bull calves reared on infested pastures did not induce any attraction of free adults on these sites. previously attached males were more attractive than synthetic pheromones or natural extracts. very small amounts of flumethrin poured directly on testicles or on the dewalp induced a large decrease in the infestation of these sites. | 1992 | 1298024 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| interspecific differences in the movements of female ticks on reptiles. | movements of females of two reptile ticks, amblyomma limbatum and aponomma hydrosauri were studied to determine whether the behaviour of the species on hosts was similar or different. experiments were conducted to determine if the movement of females on hosts prior to mating was influenced by the delayed attachment of conspecific males. a field experiment was also undertaken to determine whether data obtained during laboratory experiments reflected the behaviour of females on hosts in the field. ... | 1992 | 1587690 |
| laboratory and field observations on anti-tick properties of the plant gynandropsis gynandra (l.) brig. | a shrubby plant, abundant in east kenya, gynandropsis gynandra (l.) brig., was shown to exhibit repellent and acaricidal properties to larvae, nymphs and adult rhipicephalus appendiculatus and amblyomma variegatum ticks. all stages of ticks avoided the leaves of the plant and a high percentage of the ticks which were continuously exposed to its leaves died; surviving ticks were weak and inactive but regained activity when exposed to fresh air. the effectiveness of the plant's leaves as a repelle ... | 1992 | 1615623 |
| 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 |
| [asymptomatic carrier state in creole goats and cattle after recovery from cowdria infection in guadeloupe]. | creole goats and cattle in guadeloupe can be carriers of cowdriosis (heartwater: cowdria ruminantium) after recovery for a period as long as 11 months in goats and 2 months in cattle. the carrier status was demonstrated by feeding amblyomma variegatum nymphs on recovered animals and the resulting adult ticks on susceptible goats. cowdria ruminantium was not detected permanently during the carrier status. | 1992 | 1301623 |
| 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 |
| venezuelan equine encephalomyelitis virus infection in and transmission by the tick amblyomma cajennense (arachnida: ixodidae). | to assess a possible role of ticks as the maintenance host for epizootic strains of venezuelan equine encephalomyelitis (vee) virus, laboratory experiments were conducted to determine if ticks could become infected, maintain, and transmit the virus. larval and nymphal amblyomma cajennense (f.) and larval dermacentor nitens neumann ticks were exposed to epizootic vee virus (trinidad donkey strain) by allowing them to feed on viremic guinea pigs (strain 13). in a. cajennense, transstadial transmis ... | 1991 | 1875367 |
| effect of ivermectin on the volume of blood ingested by two species of ticks (acari: ixodidae) feeding on cattle. | females of the lone star tick, amblyomma americanum (l.), and the american dog tick, dermacentor variabilis (say), were fed on ivermectin (ivomec)-treated and untreated bovines to determine the effect of the acaricide on volume of blood ingested and to compare the weight differences between the treatment and control groups at various time intervals after attachment. adult females from each genus were collected from bos tarus hosts and subjected to hematin assays on three collection dates to esti ... | 1991 | 1875376 |
| role of genital sex pheromones in amblyomma americanum and a. maculatum (acari: ixodidae). | amblyomma americanum and a. maculatum were studied to determine if genital sex pheromones were present, as reported in dermacentor species. chemical analysis of methanol extracts of the anterior reproductive tracts (source of the genital sex pheromone) of a. americanum and a. maculatum confirmed the presence of the same fatty acids that act as components of the genital sex pheromone in dermacentor variabilis and d. andersoni. in both amblyomma species, removal of the anterior reproductive-tract ... | 1991 | 1860418 |
| [sites of fixation of amblyomma variegatum ticks on their hosts in guadeloupe (french west indies)]. | the examination of 458 domestic and wild hosts of the tick a. variegatum allowed to collect 8,581 larvae, 646 nymphs, 685 adults in 9 different animal species and to determine their preferential attachment sites. in another survey on 15 goats and 5 cattle, 12,345 larvae, 2,111 nymphs and 4,625 adults were counted on the anatomic sites. immature ticks feed preferentially on the head, neck and limbs of birds, the limbs of mongoose and the limbs and ears of dogs, goats and cattle. adults feed only ... | 1991 | 1843828 |
| 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 |
| predation on livestock ticks by chickens. | chickens were shown to be natural predators of ticks. rhipicephalus appendiculatus were recovered in large numbers from the crops and gizzards of chickens which had scavenged for 30 min-1 h among tick-infested cattle. other ticks recovered were amblyomma variegatum and boophilus decoloratus. the numbers of ticks recovered ranged from 3 to 331, with an average of 81 per chicken. cattle facilitated the predation of ticks by certain behavioural actions. chickens also picked up both engorged and une ... | 1991 | 1858289 |
| 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 |
| ixodid and argasid ticks. keys to their identification. | ticks of the ixodidae family are important ectoparasites of humans and animals. of the 80 or so species found in the united states, about 20 are of veterinary importance. ticks are second only to mosquitoes as carriers of human pathogens. the ixodid (or hard) ticks are the most common and are represented by the genera ixodes, haemaphysalis, boophilus, rhipicephalus, amblyomma, and dermacentor. accurate identification of the species of ixodid ticks within an area is a prerequisite to control and ... | 1991 | 2014622 |
| histopathology of attachment sites of amblyomma variegatum and rhipicephalus appendiculatus on zebu cattle of varying resistance to ticks. | mature, unimproved east african zebu cattle (bos indicus) naturally exposed to ticks from birth were ranked for resistance to ticks by repeated whole-body counts of infesting ticks. four cattle of high resistance, four of low resistance and two of intermediate resistance were artificially infested with nymphs of amblyomma variegatum and rhipicephalus appendiculatus. two friesian cattle (bos taurus) with less exposure to ticks were similarly infested. biopsies of tick attachment sites were examin ... | 1991 | 1858290 |
| dissemination, replication, and trans-stadial persistence of dugbe virus (nairovirus, bunyaviridae) in the tick vector amblyomma variegatum. | the dissemination and replication of dugbe (dug) virus and its tissue tropisms in the tick vector amblyomma variegatum were examined by immunohistochemical analysis using specific antibody, in situ hybridization with a viral-complementary riboprobe, and infectivity assays of dissected tissues. dugbe virus was localized in both unfed and feeding adults inoculated as nymphs or orally infected by capillary feeding, and in nymphs infected by capillary feeding. in non-feeding ticks, the main sites of ... | 1991 | 1867347 |
| tick infestations on zebu cattle in western kenya: individual host variation. | monthly collections were made of all ticks from 25 mature east african zebu cattle and 5 yearlings for 13 mo on rusinga island, lake victoria, kenya, from september 1986 to september 1987. the most common species were rhipicephalus appendiculatus neumann and amblyomma variegatum f.; boophilus decoloratus koch and rhipicephalus evertsi evertsi neumann also were present in fewer numbers. cattle were ranked according to their degree of resistance to each of the four species and to each stage in the ... | 1991 | 2033602 |
| exotic ectoparasites of ostriches recently imported into the united states. | eleven species of ectoparasitic arthropods were collected and identified from ostriches (struthio camelus) recently imported into the united states from africa and europe. four of these species are reported from ostriches for the first time. the parasites included adult hippoboscid flies (struthiobosca struthionis) and 10 species of adult ixodid ticks (amblyomma gemma, a. lepidum, a. variegatum, haemaphysalis punctata, hyalomma albiparmatum, h. luscitanicum, h. marginatum rufipes, h. truncatum, ... | 1991 | 2023323 |
| 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 |
| parasites of domestic and wild animals in south africa. xxv. ixodid ticks on sheep in the north-eastern orange free state and in the eastern cape province. | the tick burdens of 115 merino sheep, slaughtered over a period of 15 consecutive months on a farm in the north-eastern orange free state, were determined. a total of 7 ixodid and 1 argasid tick species were recovered and the seasonal abundances of boophilus decoloratus, hyalomma marginatum rufipes, margaropus winthemi and rhipicephalus evertsi evertsi were determined. one hundred and forty-nine merino sheep were slaughtered over periods varying from 10 to 25 months on 3 farms in eastern provinc ... | 1991 | 1923373 |
| 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 |
| 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 |
| 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 |
| 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 |
| comparative studies on the vector capacity of the different stages of amblyomma variegatum fabricius and hyalomma rufipes koch for congo virus, after intracoelomic inoculation. | groups of nymphs and adults of hyalomma rufipes and larvae, nymphs and adults of amblyomma variegatum were infected by intracoelomic inoculation with congo virus at concentrations of 10(3.5)ld50 (group a), 10(1.5)ld50 (group b) and 10(0.5)ld50 (group c). the infection rates for the different groups were: groups a, 92-100% for all stages of ticks, except for adult h. rufipes which had 87%; group b, 56.8, 68.1 and 50.7% for larvae, nymphs and adults of a. variegatum, respectively, and 96.3 and 84. ... | 1991 | 1907050 |
| distribution and incidence of ectoparasites on small mammals in a rainforest belt of southern nigeria. | a total of 174 small mammalian hosts were trapped in ekpoma, bendel state, nigeria from october, 1986 to september, 1987 and examined for ectoparasites. 108 infested hosts had 10 species of ectoparasites comprising three species of mites (laelaps (echinolaelaps) muricola, laelaps (e.) gigantea and laelaps (e.) echidninus); two species of ticks (amblyomma variegatum and ixodes sp.); two species of fleas (xenopsylla cheopis and x. braziliensis); and on especies each of sucking lice (polyplax spinu ... | 1991 | 1928798 |
| 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 |
| tick (acari: ixodidae) infestations on zebu cattle in western kenya: seasonal dynamics of four species of ticks on traditionally managed cattle. | a study was conducted on the population dynamics of four tick species infesting livestock on rusinga island. infestations of rhipicephalus appendiculatus neumann, rhipicephalus evertsi evertsi neumann, amblyomma variegatum (f.)., and boophilus decoloratus (koch) were monitored on east african shorthorn zebu cattle at monthly intervals for 2 yr. these cattle were of unimproved stock under traditional husbandry without any tick control practices. most ticks were on cattle between september and mar ... | 1991 | 1941930 |
| a review of the ixodid ticks (acari, ixodidae) occurring in southern africa. | eighty-three species of ixodid ticks, as well as several entities that have yet to be described, occur in the republic of south africa plus the 4 independent states lying within its borders (bophuthatswana, venda, transkei and ciskei) and in namibia, botswana, lesotho and swaziland. they belong to the following genera: amblyomma (8 spp.); aponomma (3 spp.); boophilus (2 spp.); cosmiomma (1 sp.); dermacentor (1 sp.); haemaphysalis (10 spp.); hyalomma (2 spp., one of them with 2 subspp.); ixodes ( ... | 1991 | 1881661 |
| 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 |
| increased population densities of amblyomma americanum (acari: ixodidae) on long island, new york. | lone star ticks, amblyomma americanum comprised a significantly greater proportion of total ticks flagged on eastern long island and fire island, new york, in 1986 and 1990 than in samples reported by other authors from the 1940s (when a. americanum was not collected by flagging or from hosts) and the 1970s. therefore, population densities of a. americanum apparently have increased in recent years on southeastern long island, where this species now is distributed widely. | 1991 | 2040963 |
| further investigations on the action of ecdysteroids on the salivary glands of the female tick amblyomma americanum. | two phytecdysteroids (abutasterone, makisterone a) and five synthetic ecdysteroid analogues, all at 1 microgram/ml, were tested on salivary glands from the female tick, amblyomma americanum l. (acari:ixodidae), held in organ culture for four days. all of these substances caused a significant reduction in fluid secretory competence of salivary glands in vitro. this constitutes further evidence that the structural requirements for causing salivary-gland degeneration in ticks are similar to those g ... | 1991 | 2044433 |
| 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 |
| a comparison of the reproductive parameters of females of two reptile tick species. | in comparisons of females of two reptile tick species aponomma hydrosauri and amblyomma limbatum, ap. hydrosauri was initially larger, and after mating on the host engorged faster and remained attached for a shorter time before completing engorgement and detaching. amb. limbatum had a longer period of engorgement, and achieved a greater engorged weight. engorged amb. limbatum females laid significantly more eggs than equivalent sized ap. hydrosauri. although the two species are ecologically simi ... | 1991 | 1787031 |
| hyperosmotic oral fluid secretion during active water vapour absorption and during desiccation-induced storage-excretion by the unfed female tick amblyomma americanum. | 1991 | 2061709 | |
| isolation of borrelia burgdorferi from arthropods collected in texas. | the texas department of health laboratory cultured arthropods from november 1988 through december 1989 in an attempt to isolate borrelia burgdorferi, the etiologic agent of lyme disease. spirochetes were isolated from eight of 1,093 pools of arthropods cultured. the spirochetal isolates were from several tick and one flea species, including amblyomma americanum, a. maculatum, ixodes scapularis, and ctenocephalides felis. these 8 isolates reacted specifically when treated with monoclonal antibodi ... | 1991 | 2063950 |
| [seasonal dynamics of tick infestations in cattle (ixodoidea) in cattle sold in the area of yaoundé, cameroon]. | among the tick species identified in cameroon, eight were found in cattle in yaoundé: amblyomma variegatum, boophilus annulatus, b. decoloratus, haemaphysalis aciculifer, hyalomma nitidum, rhipicephalus longus, rh. lunulatus, rh. sulcatus. three species, hm. aciculifer, h. nitidum and rh. lunulatus, were identified for the first time in yaoundé. rhipicephalus and hyalomma were abundant during the rainy season. boophilus was abundant throughout the year, with a maximum concentration at the end of ... | 1991 | 1824137 |
| studies on ticks of veterinary importance in nigeria: intrinsic factors influencing oviposition and egg-hatch of amblyomma variegatum under natural conditions. | during the peak of rains of 1983, 1984 and 1985 in the forest zone of nigeria, female amblyomma variegatum engorged to various weights were subjected to different experiments for the purpose of observing the intrinsic factors which influence oviposition and egg-hatch under natural conditions. two types of oviposition patterns were observed. new terms were introduced to quantify the relationships between the daily weight loss and daily number of eggs oviposited by a tick. these terms are "actual ... | 1991 | 1916533 |
| manifestations of immunity in sheep repeatedly infested with amblyomma americanum ticks. | three sheep were infested 4 times with 100 amblyomma americanum tick pairs and kept indoors until the natural termination of the infestations. characteristics of the tick populations that show efficiency of feeding, fertility, and offspring development, and elisa antibodies to tick salivary gland extracts were studied at each infestation. on average, female ticks fed on tick-naive sheep detached at 12.1 +/- 0.2 (mean +/- standard error) days, weighed 492 +/- 16.8 mg, engorged 40.7 mg per day, an ... | 1991 | 1919917 |
| antigens of amblyomma americanum ticks recognized by repeatedly infested sheep. | sera were taken from 3 sheep that had been infested 5 times with amblyomma americanum and that exhibited manifestations of humoral depression to homologous antigens and anti-tick resistance. proteins extracted from the intestine or salivary glands of unfed ticks or salivary glands from partially (3-day) fed ticks were analyzed by polyacrylamide gel electrophoresis (page) and sodium dodecyl sulfate-page. antigens recognized by the sheep in the same materials before and after each infestation were ... | 1991 | 1919918 |
| predators of the tick amblyomma variegatum (acari: ixodidae) in guadeloupe, french west indies. | some vertebrate species in guadeloupe are predators of free or parasitic stages of amblyomma variegatum (fabricius). among birds, 1.9% of the 421 identified animals found in the stomachs of grackles (quiscalus lugubris), 1.6% of the 364 animals found in the stomachs of free-ranging chickens, and 0.3% of the 4642 animals found in the stomach of cattle egrets (bubulcus ibis) were a. variegatum ticks. the most efficient predator of ticks was the tropical fire ant, solenopsis geminata, which was obs ... | 1991 | 1773677 |
| 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 |
| 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 |
| selective breeding for photoperiodically induced developmental diapause in laboratory strains of amblyomma americanum (acari: ixodidae). | offspring of amblyomma americanum (l.) reared for four generations in a 12:12 (l:d) photoperiod in the laboratory were held in 10:14 (l:d) conditions and bred to select for developmental diapause (dia) or nondiapause (non) characteristics for two additional generations. sequential generations of fed dia nymphs had mean molting times (days from detachment to ecdysis) that were 8.0% (dia1) and 35.7% (dia2) greater than parental ticks, and maximal development time was extended by 20% in dia2 ticks ... | 1991 | 1941917 |
| mechanisms of host-tick contact with special reference to amblyomma americanum (acari: ixodidae) in beef cattle forage areas. | at least five groups of parameters regulate contact between ticks and host animals. group 1 (seasonal effects) and group 2 (daily effects) comprise abiotic parameters and include daylength, temperature, relative humidity, and interactions thereof. groups 3, 4, and 5 consist of biotic parameters. these pertain to biological processes in ticks (group 3), such as hunger responses and spatial patterns in aphagous tick populations; biological processes in host animals (group 4), such as patterns of h ... | 1991 | 1941920 |
| 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 |
| parasite burdens and host susceptibility of zebu and n'dama cattle in village herds in gambia. | helminth and tick burdens of n'dama cattle kept in village herds were compared with parasite burdens in zebu cattle introduced into the same herds. the animals were monitored regularly for tick and helminth burdens, and blood samples were examined for differential white cell counts. the zebu were found to have significantly higher numbers of endo- and ectoparasites. the n'dama had significantly higher levels of circulating eosinophils than the zebu during peak parasite burdens. no difference in ... | 1991 | 1788936 |
| etiologic agent of lyme disease, borrelia burgdorferi, detected in ticks (acari: ixodidae) collected at a focus in alabama. | the study was conducted at sites of known transmission of borrelia burgdorferi in east central alabama. the objectives were to determine species of ticks present at these sites, their host associations, and species of ticks and small mammals naturally infected with b. burgdorferi. a total of 451 hosts were examined for ticks, including cotton mice, peromyscus gossypinus (le conte); cotton rats, sigmodon hispidus say & ord; southern short-tailed shrews, blarina carolinensis (bachman); house mice, ... | 1991 | 1941933 |
| borrelia burgdorferi in ticks (acari: ixodidae) from coastal virginia. | ixodid ticks removed from hosts and from vegetation during march-november 1987 at sites in coastal virginia and north carolina were examined for borrelia burgdorferi. b. burgdorferi was evident in nine (22%) ixodes cookei packard removed from rice rats (oryzomys palustris), a white-footed mouse (peromyscus leucopus), and raccoons (procyon lotor); four (6%) amblyomma americanum (l.) removed from raccoons; and two (3%) dermacentor variabilis (say) removed from a raccoon and a rice rat. b. burgdorf ... | 1991 | 1941936 |
| horizontal movement of adult ixodes dammini (acari: ixodidae) attracted to co2-baited traps. | the ability of male and female deer ticks, ixodes dammini spielman, clifford, piesman, & corwin, to move horizontally was evaluated by performing a mark-recapture study. in each of two experiments, 120 ticks were marked with fluorescent powder and released at predetermined distances from a co2-baited trap. the mean recruitment distance was 1.8 m after 6 d of trap operation. this distance is appreciably lower than those calculated from previous studies of several other species of ixodid ticks, in ... | 1991 | 1941943 |
| the occurrence of streptothricosis and its association with amblyomma variegatum ticks in st. lucia. | cattle, horses, sheep and goats in all areas of st. lucia were examined to ascertain the prevalence and distribution of streptothricosis on the island and to investigate its association with the occurrence of amblyomma variegatum ticks. although the disease was found to occur throughout st. lucia it was more prevalent and generally of a more severe form in areas where a. variegatum ticks are present. a tick control programme in the north of the island appeared to have resulted in a dramatic redu ... | 1991 | 1789020 |
| ehrlichiosis in children. | tick-borne rickettsiae of the genus ehrlichia have recently been recognized as a cause of human illness in the united states. in the years 1986-1988, 10 cases of ehrlichiosis were diagnosed in children in oklahoma. fever and headache were universal: myalgias, nausea, vomiting, and anorexia were also common. rash was observed in six patients but was a prominent finding in only one. leukopenia, lymphopenia, and thrombocytopenia were common laboratory abnormalities. six patients were treated with t ... | 1991 | 1987531 |
| ticks (ixodidae) parasitizing humans in four provinces of north-western argentina. | in four provinces of north-western argentina (catamarca, jujuy, salta and tucumán), between march 1976 and march 1990, 514 ticks were found on humans. they were identified as rhipicephalus sanguineus group (1 male), boophilus microplus (6 male, 1 female), amblyomma parvum (9 male, 13 female), a. cajannense (35 male, 30 female, 81 nymphs), a. neumanni (33 male, 41 female, 144 nymphs) and amblyomma spp. (10 nymphs, 110 larvae). most of the ticks were from the phytogeographical region of chaco, one ... | 1991 | 1809248 |
| tick information sheet. the lone star tick. amblyomma americanum. | 1991 | 2014616 | |
| crimean-congo haemorrhagic fever virus replication in adult hyalomma truncatum and amblyomma variegatum ticks. | the kinetics of the replication of the crimean-congo haemorrhagic fever virus (cchfv) was studied in intra-anally inoculated adult hyalomma truncatum and amblyomma variegatum ticks. the virus was re-isolated by suckling mouse inoculation and revealed by antigen capture with ground ticks and indirect immunofluorescence of haemolymph. the virus was detected in ticks in the first hours post-inoculation (p.i.) and its replication was observed from 36 h p.i. onwards. virus titre reached a maximum wit ... | 1991 | 1803413 |