Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| serum basophil-stimulating activity in the guinea-pig during induction of basophilic responses to ovalbumin and tick feeding. | we have described functional and biochemical characteristics of a distinct t-cell dependent guinea-pig basophil-stimulating factor (bsf), measured using a sensitive 7-day bone marrow culture assay, standardized with high-activity bsf present in serum-free splenic cell-conditioned medium (cm). in the present studies, the in vivo relevance of bsf was explored during protocols of induction of peripheral blood or tissue basophil responses to ovalbumin (oa) injection or amblyomma americanum tick feed ... | 1986 | 3733145 |
| [isolation of a new orbivirus kindia (palyam group) from ticks amblyomma variegatum in the republic of guinea]. | a new arbovirus named "kindia" has been isolated from ticks amblyomma variegatum in guinea (west africa), district kindia. this virus is classified into palyam group of orbiviruses, due to its physico-chemical, biological and antigenic properties. | 1986 | 3731365 |
| parasites of domestic and wild animals in south africa. xviii. the crowned guinea fowl (numida meleagris), an important host of immature ixodid ticks. | the tick burdens of 10 crowned guinea fowl (numida meleagris), shot at approximately 3-monthly intervals in the mountain zebra national park, and of 21 crowned guinea fowl from the andries vosloo kudu reserve, the majority of which were shot at monthly intervals, were determined. no adult ticks were recovered from any of the guinea fowl. the birds in the mountain zebra national park harboured 4 species of ixodid ticks of which amblyomma marmoreum was the most abundant and most prevalent. three b ... | 1986 | 3725331 |
| amblyomma americanum: physiochemical isolation of a protein derived from the tick salivary gland that is capable of inducing immune resistance in guinea pigs. | crude salivary gland derived proteins from amblyomma americanum ticks were analyzed by physiochemical (gel filtration and ion exchange chromatography) and immunochemical guinea pig igg1 (anti-tick immunoaffinity column) techniques for the presence of antigens responsible for the induction of host immune resistance responses. gel filtration (g-75 sephadex) and ion exchange (diethyl aminoethyl cellulose) chromatography of crude salivary gland antigen yielded multiple fractions, but only one fracti ... | 1986 | 3720900 |
| metabolism of ecdysteroids in the female tick amblyomma hebraeum (ixodoidea, ixodidae): accumulation of free ecdysone and 20-hydroxyecdysone in the eggs. | [3h]-20-hydroxyecdysone ([3h]-20e) injected into amblyomma hebraeum females 7 days before the beginning of oviposition, viz. at the beginning of vitellogenesis, was converted to 3 polar peaks of unknown nature called 1, 2 and 3, and to apolar conjugates ap1, ap2 and ap3. ap2 have the same retention times as the esters of 20e with long chain fatty acids described in ornithodoros moubata (diehl et al. 1985). however, principally unmetabolized 20e was incorporated into the ovaries, and 16% of the i ... | 1987 | 3693624 |
| computer simulation of area-wide management strategies for the lone star tick, amblyomma americanum (acari: ixodidae). | 1987 | 3669024 | |
| protection of cattle against heartwater in botswana: comparative efficacy of different methods against natural and blood-derived challenges. | five groups of tswana-cross castrated male cattle between 20 and 30 months of age (a total of 158 animals) were transported from a ranch in a heartwater-free area of south botswana to a feedlot near gaborone in the east of botswana where heartwater is endemic. on arrival, one group was vaccinated intravenously with the onderstepoort sheep blood heartwater vaccine, one group was vaccinated intravenously with the new onderstepoort tick-derived heartwater vaccine and a third group was vaccinated su ... | 1987 | 3604029 |
| tick infestations on livestock in the yemen arab republic and their potential as vectors of livestock diseases. | a survey of ticks on cattle, camels, sheep, goats and donkeys in four different geographical locations of the yemen arab republic (yar) was carried out to provide more information on the possible risk of tick-borne diseases to imported exotic cattle included in the yar's plans for livestock development. the most abundant ticks were hyalomma spp. particularly on camels. ticks found on cattle included hyalomma spp., amblyomma variegatum, boophilus annulatus and rhipicephalus spp. in general with t ... | 1987 | 3603710 |
| the development of amblyomma americanum and dermacentor variabilis (acari: ixodidae) fed on rabbits immunized with tick hemolymph. | the possibility of interfering with the normal function of tick hemolymph using antihemolymph antibodies taken in with the bloodmeal, was investigated. cell free hemolymph from replete amblyomma americanum and dermacentor variabilis ticks was used to immunize rabbits. immunized rabbits developed high antihemolymph antibody titers (ca. 10(5)) and had no ill side effects. rabbits were simultaneously infested with larvae, nymphs, and adult ticks. the biological performance of ticks fed on immunized ... | 1987 | 3588587 |
| ultrastructural features of cowdria ruminantium in midgut epithelial cells and salivary glands of nymphal amblyomma hebraeum. | colonies of cowdria ruminantium were studied in midgut epithelial cells and salivary gland acini of nymphal amblyomma hebraeum that were infected experimentally as larvae. colonies were found in both tissues and studied with light and electron microscopy. colonies observed within gut cells frequently contained 2 types of the organism: electron-dense and reticulated forms. the morphology of colonies from salivary glands, as seen with light microscopy, varied from compact, densely-staining, small ... | 1987 | 3587934 |
| effects of season and area on ectoparasites of white-tailed deer (odocoileus virginianus) in mississippi. | nine species of ectoparasites (4 acari, 2 mallophaga, 1 anoplura, 1 diptera, and 1 siphonaptera) were recovered from 126 white-tailed deer collected in northern, central, and southern mississippi. intensity and prevalence of adults of ixodes scapularis and larvae, nymphs, and adults of amblyomma americanum varied significantly over collection periods, but not between host sexes. lipoptena mazamae occurred on deer from only one study area. although individual deer were heavily parasitized by tric ... | 1987 | 3586204 |
| computer simulation of population dynamics of the lone star tick, amblyomma americanum (acari: ixodidae). | 1987 | 3585931 | |
| effects of gamma radiation on spermatogenesis and fertility of male amblyomma americanum (acari: ixodidae). | amblyomma americanum males were treated with 0.5, 1, 2, 3, 4, 8, and 16 krad of gamma radiation. testes of ticks treated with 2, 3, 4, 8, and 16 krad were smaller than those of ticks irradiated at lower levels and controls. no recognizable alteration in timing of spermatogenesis was noted among the different radiation groups, but severe breakdown and depletion of germinal cells was noted at 4, 8, and 16 krad. percent hatch of larvae from crosses of irradiated males and untreated females decrease ... | 1987 | 3585625 |
| comparison of rates of infection by the lyme disease spirochete in selected populations of ixodes dammini and amblyomma americanum (acari: ixodidae). | at a major endemic focus in new jersey, 50% of 290 adult ixodes dammini collected in the fall of 1984 were infected with the lyme disease spirochete (borrelia burgdorferi), which was statistically higher than the rate found in the 202 adult ticks (39.6%) examined during the spring. neither sex nor site of collection within the focus significantly affected the infection rate. the observed infection rates were similar to those reported in endemic areas of new york and connecticut. borrelia burgdor ... | 1986 | 3577494 |
| 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 |
| a seed tick infestation of the conjunctiva: amblyomma americanum larva. | ticks commonly infest humans but rarely bite the eyes. they are vectors of disease; therefore, rapid and complete removal is important. their attachment can be so secure that removal is difficult or hazardous. we excised a larval form of amblyomma americanum from a woodsman's conjunctiva. | 1987 | 3566026 |
| demonstration of colonies of cowdria ruminantium in midgut epithelial cells of amblyomma variegatum. | the development of colonies of cowdria ruminantium was studied in midgut epithelial cells of adult amblyomma variegatum that had become infected by feeding as nymphs on cattle with experimentally induced heart-water disease. colonies were not observed in gut tissues obtained from nymphs during the feeding period, but were present in midgut epithelial cells of ticks obtained at 15 days after they were replete through molting to the adult stage. colonies were small (1 to 10 micron) initially, but ... | 1987 | 3551699 |
| spirochetes in ticks and antibodies to borrelia burgdorferi in white-tailed deer from connecticut, new york state, and north carolina. | ticks were screened for spirochetes and serum samples from white-tailed deer (odocoileus virginianus) were assayed for antibodies to borrelia burgdorferi during 1983-1984. using fluorescein isothiocyanate-labeled rabbit antibodies produced to b. burgdorferi, the etiologic agent of lyme disease, spirochetes were detected in ixodes dammini (10.5% of 1,193) and dermacentor albipictus (0.6% of 157) adults from connecticut, i. dammini nymphs (49.1% of 108) and adults (64.7% of 99) from armonk, new yo ... | 1986 | 3520030 |
| theileria orientalis occurs in central africa. | an outbreak of bovine theileriosis in burundi was investigated and the occurrence of theileria orientalis in central africa was confirmed for the first time. its identity was established on morphological and serological grounds. the parasite was associated with clinical signs and further complicates the disease picture of bovine theileriosis in africa. amblyomma variegatum is suspected as being the local vector. | 1986 | 3517994 |
| 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 |
| [oviposition and longevity of amblyomma variegatum fabricius, 1794 (ixodoidea : ixodidae) ticks in the people's republic of the congo]. | 1987 | 3453516 | |
| [trial of flumethrine for amblyomma variegatum tick control on a cattle ranch in guadeloupe]. | 1987 | 3453502 | |
| 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 |
| field tests of the response of female amblyomma variegatum (acari:ixodidae) to the synthetic aggregation-attachment pheromone and its components. | fifty percent of an amblyomma variegatum female population were able to find upwind-positioned targets containing the synthetic aggregation-attachment pheromone of this species or the pheromone component o-nitrophenol alone. the ticks were not attracted to the other components of the pheromone: methyl-salicylate and pelargonic acid. the mean time required for the ticks to reach a target at 1 m from the starting point was 3 min and 20 s. | 1986 | 3451866 |
| ecology and phenology of ticks in zambia: seasonal dynamics on cattle. | a study of the seasonality and infestation rates of ticks was carried out in 11 cattle herds in different ecological habitats in zambia between 1980 and 1982. wherever possible supplementary data were obtained from opportunistic collections from cattle and other hosts. analysis of over 1000 tick collections from cattle indicated that infestation rates of the most important species, amblyomma variegatum and rhipicephalus appendiculatus vary in different ecological habitats: (i) in western provinc ... | 1986 | 3451861 |
| the effect of avermectins on feeding, salivary fluid secretion, and fecundity in some ixodid ticks. | we tested the effects of the potent acaricides, avermectin b1a (avm) and 22,23-dihydroavermectin b1 (ivermectin; ivm) when injected directly into partially fed and fully engorged female ticks. when injected into small ticks (amblyomma hebraeum koch), neither drug (up to 100 micrograms/kg b.w.) inhibited subsequent engorgement nor affected oviposition latency, weight of total egg mass laid nor viability of laid eggs. at higher concentrations (1000 and 5000 micrograms/kg b.w.), avm and ivm were ma ... | 1986 | 3451859 |
| the effect of dipping on parasitic and free-living populations of amblyomma hebraeum on a farm and on an adjacent nature reserve. | domestic stock on a farm 30 km north of grahamstown were treated with an acaricide at regular intervals over a period of several years. this resulted in a marked reduction in all stages of development of amblyomma hebraeum on kudu (tragelaphus strepsiceros), scrub hares (lepus saxatilis) and helmeted guinea fowl (numida meleagris) which were on the farm compared with the burdens of similar animals in an adjacent nature reserve. the populations of free-living larvae of a. hebraeum on this farm an ... | 1987 | 3448583 |
| 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 |
| rearing and infection techniques for amblyomma species to be used in heartwater transmission experiments. | techniques for the rearing of amblyomma species to be used in heartwater (cowdria ruminantium) transmission experiments are discussed. these involve the breeding and maintenance of infected and non-infected strains of ticks. they include the feeding of ticks on sheep, rabbits, mice, tortoises and guinea fowl. | 1987 | 3448576 |
| 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 reservoir status of goats recovered from heartwater. | experiments were conducted with creole goats and amblyomma variegatum ticks in guadeloupe to investigate whether it is possible to transmit cowdria ruminantium to susceptible hosts with nymphs fed in the larval stage on recovered goats. of 88 batches of larvae fed after the return of the goats' temperature to normal, or after challenge or immunosuppression, only the 9 batches of larvae fed during the febrile reaction, 2 batches applied 2 and 3 days respectively after recovery, and a single batch ... | 1987 | 3448574 |
| 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 |
| epidemiology of heartwater in guadeloupe and in the caribbean. | at present, heartwater in the caribbean is known with certainty only on guadeloupe, marie galante and antigua; the first 2 islands are widely infected. the most important factors responsible for particular aspects of heartwater in guadeloupe are: cowdria ruminantium of high virulence. a very resistant cattle population (creole), not normally clinically affected. a fairly susceptible goat population (creole) (22% goats born in endemic areas die after experimental inoculation) which, fortunately, ... | 1987 | 3448572 |
| cowdria ruminantium: stability and preservation of the organism. | blood collected in either sodium heparin or disodium edetate vacutainers from febrile goats infected with 4 isolates of cowdria ruminantium and cryopreserved with 10% dimethyl sulphoxide at -70 degrees c and -196 degrees c was an effective stabilate to initiate heartwater infections in goats. a homogenized pool of whole amblyomma variegatum ticks in snyder's buffer, maintained at -196 degrees c, was used to infect a goat with c. ruminantium. liver and spleen collected from swiss mice infected wi ... | 1987 | 3448560 |
| morphology and development of cowdria ruminantium in amblyomma ticks. | the morphology and development of cowdria ruminantium have been studied in amblyomma hebraeum and a. variegatum. colonies of c. ruminantium have so far been demonstrated microscopically in gut, salivary gland cells, haemocytes and malphighian tubules of infected amblyomma ticks. colonies in gut cells were seen in both unfed and feeding ticks but colonies in salivary gland acini were observed only in nymphs that had fed for 4 days. although the predominant type seen in both tick stages was the re ... | 1987 | 3448559 |
| evidence for regurgitation by amblyomma americanum. | western blot analysis of amblyomma americanum-derived midgut extracts using tick-resistant rabbit and guinea pig antisera demonstrated several unique polypeptides ranging from 7 to 355 kda. these polypeptides were not observed in similar blots of salivary gland extracts or serum from the respective host animals. the data from this study suggest that female a. americanum ticks regurgitate gut material during feeding. such a finding explains the ability of immunization with gut-derived preparation ... | 1988 | 3420794 |
| kinetic properties of toxic protease inhibitors isolated from tick eggs. | 1. egg-toxins from rhipicephalus evertsi evertsi, boophilus microplus, boophilus decoloratus and hyalomma truncatum were found to be inhibitors of trypsin and in two cases also of chymotrypsin. 2. fast tight-binding and slow-binding inhibition were observed. 3. immunological identity of the toxins were assessed with ouchterlony immunodiffusion and elisa. 4. the protease content of b. decoloratus and amblyomma hebraeum tick eggs were determined by a linked enzyme assay. 5. the predictive value of ... | 1988 | 3391338 |
| ticks parasitising the indian buffalo (bubalus bubalis) and their possible role in disease transmission. | a total of 13 ixodid tick species, boophilus microplus, haemaphysalis bispinosa, haemaphysalis cornupunctata, haemaphysalis himalaya, heamaphysalis montgomeryi, hyalomma anatolicum anatolicum, hyalomma dromedarii, hyalomma marginatum isaaci, hyalomma (hyalommina) brevipunctata, hyalomma (hyalommina) hussaini, nosomma monstrosum, rhipicephalus haemaphysaloides, and r. turanicus were collected off 424 buffaloes from the northwestern states of india. ten tick species, amblyomma testudinarium, b. mi ... | 1988 | 3369083 |
| seasonal changes in feeding on cattle and reproduction by amblyomma americanum (acari: ixodidae) under field conditions. | 1988 | 3357171 | |
| 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 |
| 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 |
| abnormal development of amblyomma variegatum (acarina: ixodidae). | 1988 | 3351871 | |
| hosts and population dynamics of amblyomma variegatum (acari: ixodidae) on guadeloupe, french west indies. | 1988 | 3351867 | |
| the natural control of heartwater vectors. | socio-economic factors and environmental considerations have increasingly encouraged the search for methods of tick control other than acaricidal treatment. biological control management regimes have, so far, not proved to be sound replacements for acaricides. the major natural control methods employed successfully at present are host resistance and pasture management. the former has been extensively studied and utilized in a one-host-tick situation, and its potential specificity for the amblyom ... | 1987 | 3329337 |
| 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 |
| 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 |
| danger of introducing heartwater onto the american mainland: potential role of indigenous and exotic amblyomma ticks. | the existence of heartwater on 3 islands of the central lesser antilles and the presence of an efficient vector originating from africa, amblyomma variegatum, on most of the islands of this region constitute a serious threat for livestock on the american mainland. the disease can be introduced there either by infected animals or infected ticks. the most likely way is probably the transportation of domestic animals which are heavily infested by ticks. due to the low rate of infection of ticks in ... | 1987 | 3329328 |
| 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 |
| 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 |
| the tick vectors of cowdria ruminantium (ixodoidea, ixodidae, genus amblyomma) and their distribution. | twelve species of amblyomma are presently known to be capable of transmitting cowdria ruminantium. of these a. variegatum is the most important and widely distributed vector in africa. it has also extended its range considerably outside this continent, eastward to the yemen arab republic and to the islands of madagascar, réunion and mauritius, and westward to the cape verde islands and to some of the west indian islands. a. hebraeum is probably the only field vector in most parts of southern afr ... | 1987 | 3329325 |
| natural transmission of heartwater. | heartwater has been transmitted experimentally by 12 amblyomma species. their importance depends on the extent of their distribution, adaptation to domestic stock and their efficacy as vectors. except for one report of transovarial transmission, transmission is transstadial. ticks may obtain the infection while feeding on reacting animals, subclinically infected hosts or perhaps on immune animals after reinfection. there is a marked increase in the infectivity of infected ticks during feeding bu ... | 1987 | 3329324 |
| the application of the indirect fluorescent antibody test in research on heartwater. | the preparation of the antigen, details of the reagents, the titration of the antispecies conjugates and the execution of the indirect fluorescent antibody test are described. the sensitivity and specificity of the test and its applicability to the detection of antibodies to cowdria ruminantium are recorded. the test is both highly specific and sensitive and can be applied to a wide range of studies on heartwater, including epidemiology, determination of the c. ruminantium infection rate of ambl ... | 1987 | 3329322 |
| 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 |
| 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 |
| 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 |
| heartwater. the development and life cycle of cowdria ruminantium in the vertebrate host, ticks and cultured endothelial cells. | various aspects of the development and life cycle of cowdria ruminantium are discussed. c. ruminantium is transmitted transstadially by certain amblyomma species. apparently organisms initially develop in the gut epithelial cells of ticks and subsequent stages of c. ruminantium invade and develop in the salivary gland acini cells of the vector. stages at which transmission to the final host are attained appear to be coordinated with the feeding cycle of the ticks and the vertebrate host is infec ... | 1987 | 3329309 |
| 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 |
| role of small mammals in population dynamics and dissemination of amblyomma americanum and dermacentor variabilis (acari: ixodidae) at land between the lakes, tennessee. | 1987 | 3295243 | |
| characterization of tick antigens inducing host immune resistance. ii. description of rabbit-acquired immunity to amblyomma americanum ticks and identification of potential tick antigens by western blot analysis. | feeding by adult amblyomma americanum ticks induced a level of immunity in rabbits to subsequent tick feeding that resulted in a significant decrease in tick feeding success and fecundity. histological analysis of tick feeding sites in hosts expressing resistance revealed a predominant eosinophil response, with weak basophil and neutrophil infiltrates. while the basophil was never the dominant granulocyte at the tick feeding sites in resistant hosts, this cell exhibited the greatest increase in ... | 1988 | 3291384 |
| [effect of natural infestation by amblyomma variegatum ticks on the growth of creole cattle and goats]. | 1988 | 3253862 | |
| remote recognition of amblyomma variegatum habitats in guadeloupe using landsat-tm imagery. | 1988 | 3232619 | |
| 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 |
| 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 |
| effects of photoperiod on nymphal diapause in amblyomma americanum (acari: ixodidae). | 1988 | 3204627 | |
| medium-sized mammal hosts of amblyomma americanum and dermacentor variabilis (acari: ixodidae) at land between the lakes, tennessee, and effects of integrated tick management on host infestations. | 1988 | 3204625 | |
| 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 |
| feeding performance of amblyomma variegatum (acarina: ixodidae) fed repeatedly on rabbits. | rabbits infested with different stages of amblyomma variegatum fabricius, 1794 became resistant to subsequent infestations by the same tick. resistance was manifested by a reduction of 73.6% in the mean engorged weight of female ticks by the 3rd infestation. by the 5th infestation, only 70% of the nymphs engorged and their mean engorged weight was 57.7% of that of nymphs fed on tick-naive control rabbits. in the case of larvae, there was a 22.8% reduction in their mean engorged weight by the 6th ... | 1988 | 3197579 |
| 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 |
| 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 |
| 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 |
| susceptibility of amblyomma americanum to natural and experimental infections with theileria cervi. | one hundred fifty amblyomma americanum were examined between march and september 1986 from cookson hills wildlife refuge in eastern oklahoma (usa). of these ticks, 11% (17 of 150) were infected with theileria cervi. field-collected nymphal ticks had an 8% (3 of 37) prevalence of infection averaging 1.0 infected acini/nymph. female ticks had a 16% prevalence of infection averaging 1.6 infected acini/female; t. cervi was not observed in salivary glands of field-collected male ticks. when laborator ... | 1988 | 3193564 |
| ability to ixodes scapularis, dermacentor variabilis, and amblyomma americanum (acari: ixodidae) to acquire, maintain, and transmit lyme disease spirochetes (borrelia burgdorferi). | 1988 | 3193425 | |
| ticks parasitizing humans in a lyme disease endemic area of southern new york state. | a total of 126 tick specimens were submitted by tick bite victims to the westchester county department of health, white plains, new york, and to the new york medical college, medical entomology laboratory, armonk, new york, during 1985. these included 96 (76.2%) ixodes dammini, 26 (20.6%) dermacentor variabilis, and two (1.6%) amblyomma americanum. i. dammini parasitism was reported during all months of the year except december and february and involved all life stages. only d. variabilis adults ... | 1988 | 3189288 |
| 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 |
| 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 |
| the ultrastructure of sporogony in theileria cervi (bettencourt et al., 1907) in salivary glands of female amblyomma americanum (l.) ticks. | the process of sporogony of theileria cervi in salivary glands of unfed and feeding amblyomma americanum females that were infected as nymphs was studied by light and electron microscopy (sem and tem). sporogony was observed only in granular acini type iii and in cells classified as complex granular. infected acini in salivary glands of both unfed and feeding ticks were enlarged. some stages of parasite development were evident with light microscopy and sem, but the specific events of sporogony ... | 1987 | 3125313 |
| failure to detect infection in fallow deer (cervus dama) exposed to theileria cervi from white-tailed deer. | a frozen stabilate was produced from theileria cervi sporozoites in salivary glands of adult amblyomma americanum. the stabilate was inoculated into three fallow deer (cervus dama) and two white-tailed deer (odocoileus virginianus). following inoculation, the white-tailed deer developed parasitemias as determined by blood smear examination at 11 and 13 days postexposure. repeat examination of blood from the three fallow deer for 30 days postexposure failed to reveal observable piro-plasms. these ... | 1987 | 3119873 |
| geographic distribution of bhanja virus. | a review on the geographic distribution, vectors and hosts of bhanja virus (bunyaviridae) is based on reports about: isolations of the virus; antibody surveys. bhanja virus has been isolated in 15 countries of asia, africa and europe, and antibodies against it have been detected in 15 additional countries. vector range includes ticks of the family ixodidae (subfam. amblyomminae; not subfam. ixodinae): 13 species of 6 genera (haemaphysalis, dermacentor, hyalomma, amblyomma, rhipicephalus and boop ... | 1987 | 3108117 |
| epidemiology of theileriosis in calves in an endemic area of kenya. | thirty-one calves born into five maasai zebu cattle herds over a period of 1 month in the trans-mara division of kenya, endemic for theileriosis, were recruited for an intensive study of theileriosis. no calves up to 6 months of age died but all developed theileria infections as judged by slide examination and serology. parasitosis by t. mutans schizonts in lymph node smears was usually higher than that of t. parva. the t. mutans schizonts usually occurred at an earlier age but persisted at a pa ... | 1986 | 3085323 |
| prevalence of piroplasmosis in equines in the colombian province of cordoba. | eighty-two equine sera from 13 farms in northern colombia were examined for antibodies to babesia caballi and b. equi using the complement fixation (cf) and the indirect fluorescent antibody (ifa) test. seroreactors to both piroplasms were present on all farms. the ifa test indicated a prevalence of 90% for b. caballi and 94% for b. equi. the cf test detected antibodies to b. caballi in 41% and to b. equi in 65% of the animals. the prevalence of seroreactors in different age groups revealed a si ... | 1988 | 3041656 |
| 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 |
| morphogenetic diapause in amblyomma variegatum (acari: ixodidae). | in southern africa, amblyomma variegatum fabricius is characterized by a strict seasonal activity. experiments were carried out to determine whether a diapause mechanism regulates this seasonality. engorged a.variegatum females were exposed to controlled laboratory conditions or natural field conditions at different times of the year. females exposed in a natural environment in september-october (short day) had significantly longer pre-oviposition periods than females exposed from november to ma ... | 1988 | 2980187 |
| comparison of the isozyme phenotypes of the morphologically similar ticks amblyomma cajennense and a. imitator (acari: ixodidae) from south texas. | a survey of amblyomma koch tick populations in southern texas revealed that a. imitator kohls was restricted to the two most southern counties, but that a. cajennense (fabricius) ranged at least as far north as kingsville, tex. females of the two species could be distinguished by the presence of chitinous tubercles on the festoons of a. cajennense and the presence of projections over both sides of the apron of the genital aperture in a. imitator. males were distinguished by size, ornamentation, ... | 1989 | 2926774 |
| effect of age on cholinesterase activity and protein of unfed larval ticks. | the cholinesterase (ache) activity and total protein in homogenates of unfed larvae of amblyomma americanum (l.), a. cajennense (fabricius), a. maculatum koch, anocentor nitens neumann, and boophilus microplus (canestrini) were determined weekly in ticks 1-6 wk of age. there was a considerable variation in total protein, ache, and the ratio of ache to protein as the ticks aged. however, ache activities were constant or increased with age and total protein levels were constant or decreased. no di ... | 1989 | 2918444 |
| 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 |
| pheromones and other semiochemicals of the acari. | in contrast to the exceptional diversity of semiochemical-regulated behavior in the insects, chemical communication in the acari is restricted to a few limited roles. these include clustering, mate-finding processes, host- and food-finding processes, and dispersal. no evidence of pheromones regulating oviposition, necrophoric behavior, recognition of hive mates, or many other processes found in numerous insect groups has been reported in the acari. perhaps the most noteworthy feature of acarine ... | 1985 | 2857547 |
| 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 |
| [ticks of the family ixodidae in guinea and the isolation of arboviruses from them. ii. results of virologic and serologic research]. | 55697 ixodidae ticks of 35 species, belonging to 7 genera, were collected in guinea in 1981-1983. virological study of 29410 ticks was performed by intracerebral infection of newborn white mice. 49 viral strains were isolated. authors identified 38 strains of the 8 following arboviruses: dugbe, bhanja, cgl-congo (ecologically connected with ticks), blue tongue virus of sheep and abadine (association with ticks was found for the first time), kindia and forekarya (the new viruses). serological scr ... | 1989 | 2811754 |
| amblyomma marmoreum on tortoises of southern province, zambia. | reptiles from southern province, zambia were captured and inspected for ticks. seven of 18 tortoises (geochelone pardalis) were infested by small numbers of adults and nymphs of amblyomma marmoreum. under such circumstances, the tick had little apparent effect on the host. none of the 13 specimens representing four species of snakes examined were infested with ticks. | 1989 | 2810567 |
| comparison of flagging, walking, trapping, and collecting from hosts as sampling methods for northern deer ticks, ixodes dammini, and lone-star ticks, amblyomma americanum (acari:ixodidae). | ticks were sampled by flagging, collecting from the investigator's clothing (walking samples), trapping with dry-ice bait, and collecting from mammal hosts on fire island, ny, u.s.a. the habitat distribution of adult deer ticks, ixodes dammini, was the same in simultaneous collections from the investigator's clothing and from muslin flags. walking and flagging samples can both be biased by differences between investigators, so the same person should do comparative samples whenever possible. walk ... | 1989 | 2806016 |
| reduction of the amblyomma americanum (acari: ixodidae) population at fort a.p. hill, virginia, by aerial application of diazinon granules: correlation of percentage control with received dose. | habitat (280 ha) of lone star tick, amblyomma americanum (l.), was aerially treated with 14% diazinon granules. concentration of acaricide reaching the forest floor ranged from 0.02 to 1.25 kg (ai)/ha. greater than 85% control was achieved at study plots receiving the highest dose. a positive correlation was shown between dose received at the forest floor and percentage of control of adults (r = 0.91) and nymphs (r = 0.86). | 1989 | 2795622 |
| pictorial key to the adults of hard ticks, family ixodidae (ixodida: ixodoidea), east of the mississippi river. | six genera and 27 species of hard ticks (ixodidae) currently are recognized in the united states east of the mississippi river as follows: amblyomma (4 species), boophilus (1), dermacentor (3), haemaphysalis (2), ixodes (16), and rhipicephalus (1). we present a diagrammatic couplet key to the adults of the six genera and 27 species of ixodidae found in the eastern portion of the united states. | 1989 | 2795615 |
| pericarditis associated with tick-borne q fever. | a case of pericarditis associated with q fever is described. transmission was probably via an arthropod vector, which was most likely the kangaroo tick amblyomma triguttatum. complete recovery occurred in association with the use of non-steroidal anti-inflammatory agents only. this is a rare presentation of q fever implicating transmission by a novel vector. | 1989 | 2775046 |
| delayed-type hypersensitivity test for assessing tick-immune status of cattle in zambia. | delayed-type hypersensitivity skin reactions were used to assess the tick resistance status of tonga calves in zambia. the antigen used in the tests was a homogenate of unfed nymphal rhipicephalus appendiculatus which had been shown to give protective immunity in guinea pigs to adult female r appendiculatus. there was a significant negative correlation between the intensity of the reactions and the total number of ticks (amblyomma variegatum, r appendiculatus, hyalomma truncatum, boophilus decol ... | 1989 | 2773195 |
| dugbe virus replication in nymph and adult amblyomma variegatum. | 1989 | 2772415 | |
| female mediation of feeding time on cattle in adult lone star ticks (acari: ixodidae). | the extended feeding time response on cattle of adult lone star ticks, amblyomma americanum (l.), during november through december is facultative and is mediated by the female. mean feeding time (11.8 d) in female ticks taken from the field and held at 14:10 (l:d) photoperiod and 25 degrees c for greater than or equal to 15 d was significantly shorter (p = 0.05) than for females taken directly from the field and fed on cattle (14.6 d). mean feeding times of females from the field paired to males ... | 1989 | 2769719 |
| polyfluoro 1,3-diketones as systemic insecticides. | a series of aryl polyfluoro 1,3-diketones were examined for systemic ectoparasiticidal activity in cattle. the compounds demonstrated efficacy against several economically important species of insects and acarina. at dosages of 5 mg/kg x1 or 0.35 mg/kg per day intraruminally, activity was observed against blowfly larvae (phormia regina), adult stable fly (stomoxys calcitrans), and lone star tick (amblyomma americanum). in vivo activity was not directly related to in vitro activity, showing a str ... | 1989 | 2769686 |
| monitoring of naturally acquired and artificially induced immunity to amblyomma variegatum and rhipicephalus appendiculatus ticks under field and laboratory conditions. | the ability of rabbits, goats and cattle to acquire immunity to the ixodid ticks amblyomma variegatum and rhipicephalus appendiculatus was studied under laboratory and field conditions. rabbits were successfully immunized with crude salivary gland extract (sge) and midgut extract (me) obtained from flat or partly fed female r. appendiculatus ticks. the lowest numbers of larvae were produced by females fed on rabbits immunized with unfed midgut extract. similar reductions in larval production cou ... | 1989 | 2766896 |
| amblyomma variegatum ticks and the occurrence of bovine streptothricosis in antigua. | the association between the occurrence of amblyomma variegatum ticks and streptothricosis was studied on the caribbean island of antigua. the prevalence of streptothricosis was higher on animals having a. variegatum ticks compared to that of animals not infested with a. variegatum ticks. there was a steady increase in the prevalence of severe lesions as the level of infestation with adult a. variegatum ticks increased. however the distribution of skin lesions could not be related to the predilec ... | 1989 | 2763757 |
| acquired resistance to ixodid ticks induced by tick cement antigen. | antisera from guinea pigs made resistant to infestation with an ixodid tick of east and central africa, rhipicephalus appendiculatus, were used to identify the tick antigens they recognized by immunoblotting. most of the antigens were found in tick salivary glands and in tick attachment cement. antisera from r. appendiculatus-resistant guinea pigs also recognized some salivary-gland antigens in ticks of other species (r. pulchellus, r. evertsi, amblyomma variegatum and a. gemma). antibodies agai ... | 1989 | 2758939 |