| ticks (acari: ixodidae) collected from small and medium-sized kansas mammals. | seven species of hard-bodied ticks were collected from 20 species of small and medium-sized mammals in kansas; amblyomma americanum l., dermacentor variabilis (say), haemaphysalis leporispalustris (packard), ixodes cookei packard, i. kingi bishopp, i. sculptus neumann, and i. texanus banks. dermacentor variabilis was found statewide, a. americanum only in the eastern one-third of the state, and the ixodes spp. and h. leporispalustris were widely scattered. the most common tick found was d. varia ... | 1994 | 8057327 |
| parasitic arthropods of sympatric opossums, cotton rats, and cotton mice from merritt island, florida. | six species of parasitic arthropods were collected from 12 opossums (didelphis virginiana), 8 species were obtained from 28 cotton rats (sigmodon hispidus), and 4 species were collected from 10 cotton mice (peromyscus gossypinus) from merritt island, brevard county, florida. the flea polygenis gwyni was the only parasite that infested all 3 host species, and it was present in very high densities (mean intensity = 73.7) on the opossums. the american dog tick, dermacentor variabilis, and the tropi ... | 1993 | 8459341 |
| a comparison of field tick infestation on n'dama, zebu and n'dama x zebu crossbred cattle. | tick burdens, estimated from cumulative tick counts, were determined on n'dama, zebu and f1 n'dama x zebu crossbred cattle. n'dama showed significantly fewer ticks than the zebu and f1 cattle (p < 0.001). a previous trypanosomosis infection did not affect tick burdens on the three genotypes. amblyomma variegatum had a prevalence of 84.8% and hyalomma spp. 15.2%, with the ratio similar on all cattle breeds. trypanosomosis infection increased the serological prevalence of anaplasma marginale in ze ... | 1993 | 8493760 |
| [ticks and hemoparasitoses in livestock in senegal. v. the northern guinea area]. | the authors report the results of a study on ticks and hemoparasitoses among cattle, sheep and goats in the north-guinean zone. during a period of 15 months, ticks were systematically removed from 40 cattle, 40 sheep and 40 goats in order to assess the population dynamics and to determine more accurately the preferential sites of settlement of the following different species collected from these animals: amblyomma variegatum, boophilus geigyi, hyalomma truncatum, h. marginatum rufipes, rhipiceph ... | 1993 | 8073170 |
| computer-controlled olfactometer system for studying behavioral responses of ticks to carbon dioxide. | an olfactometer system that consisted of a laptop computer, a carbon dioxide analyzer, and an apparatus to control gas flows was designed to study ixodid tick behavioral responses to varying carbon dioxide (co2) concentrations. the system provided a method to regulate and measure stimulatory co2 concentrations (1-99 ppm) above ambient co2 background levels. adult amblyomma americanum (l.) and dermacentor variabilis (say) demonstrated behavioral responses to co2 concentrations as low as 9 ppm abo ... | 1993 | 8510116 |
| recent acquisitions on tick and tick-borne disease resistance in n'dama (bos taurus) and gobra zebu (bos indicus) cattle. | the use of disease resistant breeds is recognised as an economically realistic alternative to acaricide application and drug administration in tick and tick-borne disease control schemes. although resistance is mainly associated with zebu (bos indicus) breeds, studies carried out in the gambia show a higher resistance to ticks and tick-borne diseases in n'dama (bos taurus) than in gobra (b. indicus) cattle. tick resistance in n'dama breed appears to be effective against those species with long h ... | 1995 | 8532370 |
| the relationship between cowdria and ehrlichia: change in the behaviour of ehrlichial agents passaged through amblyomma hebraeum. | following an earlier report that an ehrlichia-like agent isolated from an adult hyalomma truncatum female became more pathogenic and elicited a disease in sheep indistinguishable from heartwater after having been passaged through amblyomma hebraeum, a similar phenomenon is herewith recorded. an ehrlichial agent demonstrated in the blood smear of a serologically positive, naturally infected lamb, changed in behaviour and assumed the characteristics of cowdria after passage through a. hebraeum. cr ... | 1993 | 8134623 |
| cowdria ruminantium identified in amblyomma gemma using a dna probe pcs20. | amblyomma gemma ticks were collected from wild animals on a 20,000 acre game ranch in a heartwater endemic area in kenya, close to nairobi. a. variegatum is the main vector of heartwater in kenya. e.a. lewis, 1947, in a one sentence report has implicated a. gemma to be a vector of heartwater without giving any details. adult a. gemma were collected from giraffe giraffa camelopardalis, hartebeest alcephalus busephalus, eland taurotragus oryx and ostrich struthio camelus during cropping exercises. ... | 1993 | 8134629 |
| physiological and nutritional responses of steers infested with varying densities of amblyomma americanum (acari: ixodidae). | the effects of varying densities of lone star tick, amblyomma americanum (l.), on measured physiological parameters of beef cattle in a controlled environment was determined. steers were infested with either 0, 20, 60, or 120 pairs of adult ticks. heart rate, respiration, rectal temperature, fecal and urine excretions, and water and feed consumption were monitored daily. blood samples were taken every 3rd d to measure cortisol, total proteins, urea nitrogen, and glucose levels. hematocrits were ... | 1995 | 8537543 |
| prostaglandin biosynthesis and subcellular localization of prostaglandin h synthase activity in the lone star tick, amblyomma americanum. | we report on prostaglandin (pg) biosynthesis in the lone star tick, amblyomma americanum. in vitro preparations of whole female ticks and internal tissues were competent to biosynthesize four pgs: pga2/pgb2, pgd2, pge2, pgf2 alpha. pga2/pgb2 was the major product under optimal conditions. pg biosynthesis by whole tick and internal tissues were sensitive to incubation conditions including, protein concentration, time, temperature, ph, and presence of a co-factor cocktail composed of reduced gluta ... | 1995 | 8541884 |
| development and transmission of cowdria ruminantium by amblyomma males transferred from infected to susceptible sheep. | male amblyomma sp. were tested as vectors of cowdria ruminantium, causative agent of heartwater disease. the males were allowed to feed on sheep experimentally infected with c. ruminantium and then were transferred to susceptible sheep to test for transmission of the rickettsia. the experiments were done in two trials. in the first trial, a. hebraeum were exposed to the palm river stock of c. ruminantium, while in the second trial the kiswani stock of cowdria was tested with a. variegatum. ticks ... | 1993 | 8134630 |
| prevalence of rickettsia-like organisms and spotted fever group rickettsiae in ticks (acari: ixodidae) from zimbabwe. | the prevalence of rickettsia-like organisms in ticks from zimbabwe was determined using the hemolymph test. amblyomma hebraeum had the highest prevalence of rickettsia-like organisms. other species with rickettsia-like organisms included amblyomma sparsum, amblyomma variegatum, hyalomma marginatum rufipes, ripicephalus simus, haemaphysalis leachi, amblyomma rhinocerotis, and hyalomma truncatum. ticks with no demonstrable rickettsia-like organisms infection were boophilus decoloratus, haemaphysal ... | 1995 | 8551500 |
| field evaluation of deet and a piperidine repellent (ai3-37220) against amblyomma americanum (acari: ixodidae). | repellent efficacy of deet (n,n-diethyl-3-methylbenzamide) and a piperidine, ai3-37220, was evaluated topically on human volunteers against lone star tick, amblyomma americanum (l.), nymphs and adults in the field. ai3-37220, at 0.5 mg/cm2, provided > 90% repellency against adult and nymphal ticks over a 6-h test period and showed significantly better repellent efficacy than deet. deet, at the same concentration, provided 85% repellency at 0 h and deteriorated to 55% repellency at 6 h. | 1995 | 8551512 |
| serologic diagnosis of human monocytic ehrlichiosis by immunoblot analysis. | human monocytic ehrlichiosis is caused by ehrlichia chaffeensis, an intracellular bacterium probably transmitted by the tick amblyomma americanum in the united states. despite its lack of specificity in discriminating among infections by closely related ehrlichia spp., immunofluorescence assay (ifa) is the most frequently used serological diagnostic method. to improve the specificity of the serological diagnosis, we compared antigenic profile of e. canis and e. chaffeensis antigen with homologou ... | 1994 | 8556515 |
| ventilation in the adults of amblyomma hebraeum and a. marmoreum (acarina, ixodidae), vectors of heartwater in southern africa. | the objective of this study was to establish the major features of respiratory gas exchange in unfed adults of the ticks amblyomma hebraeum and a. marmoreum, both vectors of heartwater in southern africa. carbon dioxide emission of ticks was measured at 25 degrees c using flow-through respirometry in order to determine standard metabolic rate (smr) and the temporal pattern of gaseous emission. for both species, smr was extremely low and approximately 100 fold less than that predicted for an inse ... | 1993 | 8134650 |
| hemocytic rickettsia-like organisms in ticks: serologic reactivity with antisera to ehrlichiae and detection of dna of agent of human granulocytic ehrlichiosis by pcr. | ixodid ticks were collected from connecticut, massachusetts, missouri, pennsylvania, rhode island, and british columbia (canada) during 1991 to 1994 to determine the prevalence of infection with hemocytic (blood cell), rickettsia-like organisms. hemolymph obtained from these ticks was analyzed by direct and indirect fluorescent antibody (fa) staining methods with dog, horse, or human sera containing antibodies to ehrlichia canis, ehrlichia equi, or rickettsia rickettsii. of the 693 nymphal and a ... | 1995 | 8567911 |
| identification of an uncultivable borrelia species in the hard tick amblyomma americanum: possible agent of a lyme disease-like illness. | bites from the hard tick amblyomma americanum are associated with a lyme disease-like illness in the southern united states. to identify possible etiologic agents for this disorder, a. americanum ticks were collected in missouri, texas, new jersey, and new york and examined microscopically. uncultivable spirochetes were present in approximately 2% of the ticks. borrelia genus-specific oligonucleotides for the flagellin and 16s rrna genes were used for amplification of dna. products were obtained ... | 1996 | 8568302 |
| progress towards a program for the eradication of amblyomma variegatum from the caribbean. | amblyomma variegatum (fabricius), the tropical bont tick, is now widely distributed in the caribbean. eighteen islands countries are now or were recently infested with the tick. to stop the spread of this tick to other non-infested islands and to the mainland areas of south, central and north america, a regional eradication program has been proposed and endorsed by the respective governments on each of the amblyomma variegatum infested islands, including the french government and caricom member ... | 1993 | 8134654 |
| identification of vertebrate volatiles stimulating olfactory receptors on tarsus i of the tick amblyomma variegatum fabricius (ixodidae). i. receptors within the haller's organ capsule. | gas chromatography-coupled electrophysiological recordings (gc-el) from olfactory sensilla within the capsule of haller's organ of the tick amblyomma variegatum indicate the presence of a number of stimulants in rabbit and bovine odours, and in steer skin wash. some of these stimulants were fully identified by gas chromatography-mass spectrometry analysis and by matching electrophysiological activity of synthetic analogues as: 1) hexanal, 2-heptenal, nonanal, furfural, benzaldehyde, and 2-hydrox ... | 1994 | 8151519 |
| ixodid ticks from panthers and bobcats in florida. | ixodid ticks were present in all 189 samples examined from 53 florida panthers (felis concolor coryi, 104 collections) and 85 bobcats (felis rufus floridana) in florida (usa) between 1974 and 1991. we identified 3,251 ticks from panthers and 918 from bobcats. specimens of dermacentor variabilis, ixodes scapularis, i. affinis, amblyomma maculatum, and a. americanum were present on 49, 39, 17, seven, and two of the 53 florida panthers, respectively, and comprised 36%, 55%, 7%, 1%, and < 1% of the ... | 1995 | 8592378 |
| propagation of the tick amblyomma variegatum in the caribbean. | the tropical bont tick, amblyomma variegatum, is an african tick species which infests livestock and wildlife. it was probably introduced in the central eastern islands of the caribbean during the 18th or 19th century, with cattle shipped from senegal. in africa and the caribbean, this tick is a vector of heartwater (a rickettsial disease of ruminants) and is associated with acute dermatophilosis (a bacterial skin disease of animals). until 1948, only guadeloupe and the neighbouring islands of m ... | 1995 | 8593414 |
| parasites of domestic and wild animals in south africa. xxxiii. ixodid ticks on scrub hares in the north-eastern regions of northern and eastern transvaal and of kwazulu-natal. | ixodid ticks were collected from scrub hares (lepus saxatilis) at three localities. nine tick species were recovered from 24 hares examined at pafuri, kruger national park, northern transvaal. the most abundant and prevalent species were hyalomma truncatum, rhipicephalus kochi and a rhipicephalus species (near r. pravus). twelve tick species were collected from 120 scrub hares examined around skukuza, kruger national park, eastern transvaal. the immature stages of hyalomma truncatum were most ab ... | 1995 | 8600436 |
| dietary modification of host blood lipids affect reproduction in the lone star tick, amblyomma americanum(l.). | the feeding and reproductive performance of female lone star ticks (amblyomma americanum (l.)) infesting guinea pigs on diets containing 15% fish oil (fo) or safflower oil (so) were investigated. replete ticks fed on fo-fed guinea pigs weighed approximately 30% less than those on the so-fed guinea pigs. the lower engorged weight resulted in a similar decrease in the mass and number of eggs laid and number of larvae hatching. no effect of host dietary treatment was observed upon the reproductive ... | 1996 | 8604084 |
| epidemiological studies on dermatophilosis in the caribbean. | dermatophilosis is one of the most important diseases of domestic ruminants in the caribbean islands where the clinical disease has been shown to be associated with the presence of the tick amblyomma variegatum. seroepidemiological studies were conducted to clarify the epidemiology of the disease in the region with a particular attention paid to the role of a. variegatum. a bank of 1300 cattle sera from the lesser antilles was screened by elisa for the presence of antibodies to dermatophilus con ... | 1993 | 8161379 |
| observations on cattle ticks in huila province (angola). | in huila province of angola, 3864 ticks were collected during a parasitological survey carried out in the rainy season from october 1990 to april 1991. the samples were collected from cattle gathered for the annual vaccination campaign against contagious bovine pleuropneumonia, anthrax and blackleg in 18 veterinary stations of six municipalities. after tick classification, the following proportions of ticks were obtained: rhipicephalus evertsi mimeticus (27.1%), amblyomma pomposum (26.4%), booph ... | 1994 | 8171837 |
| in vitro feeding of instars of the ixodid tick amblyomma variegatum on skin membranes and its application to the transmission of theileria mutans and cowdria ruminatium. | an in vitro feeding method using rabbit or cattle skin membranes, applied successfully to all stages (larvae, nymphae and adults) of the ioxodid tick, amblyomma variegatum, is described. the feeding apparatus consisted of a blood container with a membrane placed on top of a tick containment unit. a carbon dioxide atmosphere of between 5 and 10% and a temperature of 37 degrees c were used as stimulants for the attachment of the ticks. high co2 concentrations in the atmosphere improved the feeding ... | 1993 | 8233589 |
| ticks parasitizing humans in georgia and south carolina. | from 1990 through 1995, 913 ticks removed from 460 human patients in georgia or south carolina were identified and recorded. the majority of these specimens (758, 83.0%) were lone star ticks, amblyomma americanum. one hundred and four (11.4%) american dog ticks dermacentor variabilis, 36 (3.9%) blacklegged ticks ixodes scapularis, 9 (1.0%) gulf coast ticks amblyomma maculatum, and 6 (0.7%) brown dog ticks rhipicephalus sanguineus were also recovered. all active stages (larvae, nymphs, and adults ... | 1996 | 8636862 |
| progress in research on tick-borne diseases: theileriosis and heartwater. | the rapid population growth in subsaharan africa necessitates a great increase in animal production in the more humid zones. vector-borne diseases occurring in these zones will assume more importance, but are difficult to control. they include theileriosis and heartwater. recent developments in research on these diseases are presented. indigenous animal populations in endemic areas, subjected to natural selection, are far less susceptible than exotic stock. heartwater, caused by the rickettsia c ... | 1993 | 8372422 |
| establishment of the foreign partheonogenetic tick amblyomma rotundatum (acari: ixodidae) in florida. | the parthenogenetic tick amblyomma rotundatum, a central and south american species, has become established in southern florida. the date of introduction is unknown, but it is suspected to be either during the 1930s, when 1 of its natural hosts, the giant or marine toad, bufo marinus, was introduced to southern florida as a potential biological control of pest beetles in sugar cane fields, or between 1955 and 1964 when specimens of b. marinus were accidentally or deliberately released in the gre ... | 1993 | 8410557 |
| systemic treatment of white-tailed deer with ivermectin-medicated bait to control free-living populations of lone star ticks (acari:ixodidae). | whole-kernel corn was treated with 10 mg ivermectin per 0.45 kg corn and fed at rate of approximately .45 kg/deer per day to white-tailed deer confined in the treatment pasture, whereas deer in an adjacent control pasture received a similar ration of untreated corn. treatments were dispensed from february through september of 1992 and 1993, and free-living populations of lone star ticks. amblyomma americanum (l.), were monitored in both pastures using dry-ice traps to quantify nymphs and adults ... | 1996 | 8667385 |
| an immunoblotting diagnostic assay for heartwater based on the immunodominant 32-kilodalton protein of cowdria ruminantium detects false positives in field sera. | heartwater, a major constraint to improved livestock production in zimbabwe, threatens to invade areas which have been previously unaffected. to monitor its spread in zimbabwe, an immunoblotting diagnostic assay based on the responses of animals to the immunodominant, conserved 32-kda protein of cowdria ruminantium was evaluated. in this assay, no false reactions were detected with sera known to be positive and negative, but sera from some cattle, sheep, and goats from heartwater-free areas of z ... | 1993 | 8253974 |
| acquisition of resistance to the tick amblyomma variegatum in boran cattle, bos indicus and the effects of trypanosoma congolense and babesia bigemina on host resistance. | resistance was induced in cattle to the tick amblyomma variegatum by five consecutive infestations with nymphs and adults. using the principal component analysis (pca), it was found that percentage of adults engorged, percentage of adults which died, percentage of nymphs which engorged, percentage of nymphs which moulted and percentage of nymphs which died, were the main indicators of resistance against a. variegatum. the percentages of nymphs which engorged or moulted after the third infestatio ... | 1996 | 8686177 |
| molecular cloning of delta 9 fatty acid desaturase from the protozoan tetrahymena thermophila and its mrna expression during thermal membrane adaptation. | in response to a decrease in its growth temperature, the protozoan tetrahymena is known to increase the level of unsaturated fatty acids in its membrane phospholipids so as to maintain the correct physical state (fluidity) of the membranes. in this organism, synthesis of unsaturated fatty acids is initiated by delta 9 acyl-coa desaturase. our previous studies have shown that, during cold adaptation, the activity of microsomal palmitoyl- and stearoyl-coa desaturase increases, reaching a maximal l ... | 1996 | 8694777 |
| salivary gland changes and host antibody responses associated with feeding of male lone star ticks (acari:ixodidae). | the goal of this study was to demonstrate that male lone star ticks, amblyomma americanum (l.), actively feed on rabbits during attachment and that the host is capable of mounting an immune response against male salivary gland proteins. during attachment, it was shown that male ticks salivary glands hypertrophy. an enzyme-linked immunosorbent assay was used to detect rabbit serum proteins in the midgut of previously attached male ticks. sds-polyacrylamide gel electrophoresis showed that the prot ... | 1996 | 8699458 |
| cold-hardiness of a laboratory colony of lone star ticks (acari: ixodidae). | the cold-hardiness of a lone star tick, amblyomma americanum (l.), laboratory colony was characterized. fed and unfed larvae, fed and unfed nymphs, and unfed adults did not survive exposure to -17 degrees c for 7 d. after an 8-d exposure to -10 degrees c, adults tolerated cold better than immatures and unfed specimens fared better than fed ticks. exposing unfed 6-wk-old (postmolt) adult males and females to -15 degrees c for increasing intervals up to 2 h suggests that males were more tolerant t ... | 1996 | 8699473 |
| resistance and cross-resistance in rabbits to adults of three species of african ticks (acari: ixodidae). | resistance to rhipicephalus appendiculatus, amblyomma variegatum and amblyomma hebraeum was investigated in the laboratory by infesting rabbits with adults of each of the three species followed by homospecific or heterospecific secondary infestations. significantly lower female engorged weights and egg mass weights were taken as evidence of protective immunity. following a single infestation with adults, rabbits developed homospecific protective immunity (resistance) to only r. appendiculatus an ... | 1996 | 8706589 |
| a self-medicating applicator for control of ticks on deer. | a self-medicating applicator for killing ticks on deer and domestic ungulates by passive transfer of acaricides during feeding is described. the applicator consists of a barrel divided into a food bin (above) and a sealed self-contained acaricide reservoir (below) with a vertical, centrally-located ceramic column that extends from the reservoir into the food bin. acaricide is drawn up the column from the sealed reservoir by absorption. animals attracted to the food in the device acquire the acar ... | 1996 | 8744707 |
| efficacy of pheromone-acaricide-impregnated tail-tag decoys for controlling the bont tick, amblyomma hebraeum (acari: ixodidae), on cattle in zimbabwe. | a large-scale field test using pheromone-acaricide-impregnated plastic tail-tag decoys demonstrated excellent efficacy of these devices for control of the bont tick, amblyomma hebraeum, on cattle in zimbabwe. the tail tags were impregnated with a mixture containing o-nitrophenol, methyl salicylate, 2,6-dichlorophenol and phenylacetaldehyde and one of three different acaricides (cyfluthrin, flumethrin or alphacypermethrin). o-nitrophenol and methyl salicylate are components of the a. hebraeum att ... | 1996 | 8746132 |
| the seasonal occurrence of ticks (acari: ixodidae) on sheep and in the field in the judean area of israel. | a 2 year survey of ixodid ticks in the judean area of israel between 1983 and 1985 showed that sheep were parasitized by the following species: rhipicephalus sanguineus group (30.6%), rhipicephalus bursa (25.3%), haemaphysalis cretica (20.5%), haemaphysalis otophila (20.1%) and hyalomma anatolicum excavatum (3.1%). three other species, hyalomma marginatum rufipes, boophilus annulatus and amblyomma lepidum were also present but in very low numbers. a total of 50,816 specimens (78.1% adult ticks) ... | 1996 | 8746133 |
| amblyomma americanum: a potential vector of human ehrlichiosis. | polymerase chain reaction primers specific for ehrlichia chaffeensis were used to amplify dna from extracts of pooled ticks. amplification was performed on extracts from 140 pools (1,579 total ticks) consisting of three tick genera collected from five states. the characteristic 389-basepair product was observed after amplification of extracts from seven different pools of adult amblyomma americanum (117 pools, 1,462 ticks), but not from pools of nymphs. no specific product was observed after amp ... | 1993 | 8357086 |
| tropical bont tick eradication campaign in the french antilles. current status. | the amblyomma variegatum eradication campaign was officially started in april 1994 in martinique and in guadeloupe, including its dependencies of marie galante, desirade and st martin. a budget of $10.5 and $5.9 million for guadeloupe and martinique, respectively, was initially (1991) calculated and considered necessary to achieve the program. however, eec, the most important donor, estimated that 75% only of this proposal was acceptable, on which it agrees to support a maximum of 50%. the balan ... | 1996 | 8784487 |
| factors of variation of amblyomma variegatum infestation on creole cattle in guadeloupe. | the level of infestation of "creole" beef cattle of guadeloupe by the tick amblyomma variegatum was recorded during a long-term survey in an experimental farm: 61 steers and 83 cows were distributed in different lots according to sex and management. they grazed continuously either on irrigated digitaria decumbens pastures or on dry native savannahs. tick numbers as well as animal weights were registered monthly. climatic data were also recorded. different acaricide treatments were tested during ... | 1996 | 8784527 |
| development of a computer model of the population dynamics of amblyomma variegatum and simulations of eradication strategies for use in the caribbean. | control or eradication efforts should cover wide areas because of long-range migration potential of immature ticks attached to birds, such as cattle egrets. careful follow-up inspections are also imperative. simulation 1 shows how rapidly the population numbers may expand from small numbers, either introduced or missed. simulation 4 indicates extending the treatment cycle beyond the residual effectiveness of the acaricide to save labor or funds would be false economy. the result could be to main ... | 1996 | 8784528 |
| 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 |
| differential recognition of saliva antigens from the ixodid tick amblyomma hebraeum (acari: ixodidae) by sera from infested and immunized rabbits. | we determined the protein composition and antigenic content of saliva from amblyomma hebraeum female ticks of different weight classes. the mean protein concentration of saliva of small partially fed ticks (< 100 mg) was 333 +/- 83 micrograms/ml and that of large partially fed ticks (150-420 mg) was 59 +/- 14 micrograms/ml. the reduction in concentration mostly was caused by the significantly higher fluid volume per minute secreted by large ticks. polypeptide analysis of saliva indicated the pre ... | 1993 | 8433335 |
| effects of temperature on fecundity and viral replication in amblyomma cajennense (arachnida: ixodidae) infected with venezuelan equine encephalomyelitis virus. | to assess how temperature affects fecundity and venezuelan equine encephalomyelitis (vee) viral replication in vee-infected amblyomma cajennense (f.), adult ticks were inoculated intracoelomically with either vee virus (i-a variant) or diluent. ticks were held at 19, 26, or 33 degrees c and tested for vee virus over 20 d. up to 10 pairs of ticks (1 female:1 male) from each temperature group were allowed to feed on guinea pigs on day 8 after inoculation. maximum titers did not differ significantl ... | 1993 | 8433340 |
| control of amblyomma variegatum and dermatophilosis on local and exotic breeds of cattle in ghana. | the occurrence of dermatophilosis on cattle in the tropics is closely associated with infestation by amblyomma variegatum ticks. animals that are more susceptible to the disease also tend to carry higher tick burdens. longitudinal studies carried out on the accra plains suggest that n'dama cattle acquire an enhanced degree of resistance to these ticks following initial exposure. lesions on zebu-type ghana sanga cattle tend to be confined to the predilection feeding sites of adult a. variegatum e ... | 1996 | 8809991 |
| 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 |
| prospects for biological control of livestock ticks, rhipicephalus appendiculatus and amblyomma variegatum, using the entomogenous fungi beauveria bassiana and metarhizium anisopliae. | both beauveria bassiana and metarhizium anisopliae induced approximately 30% mortalities in adult rhipicephalus appendiculatus feeding on rabbits while m. anisopliae induced a mortality of 37% in adult amblyomma variegatum. both fungal species induced reductions in engorgement weights, fecundity, and egg hatchability in adult a. variegatum. m. anisopliae reduced fecundity by 94% in a. variegatum. furthermore, b. bassiana reduced egg hatchability to 0%, while 11% of the infected females failed to ... | 1996 | 8812559 |
| seroconversion to cowdria ruminantium of malawi zebu calves, reared under different tick control strategies. | the seroconversion by indirect elisa to cowdria ruminantium over the first year of life of sixty-six malawi zebu calves born into groups which were dipped 17 times per year was compared to seroconversion of 32 calves born into non-dipped groups. amblyomma variegatum tick counts and clinical disease in each group of cattle were monitored throughout the study period. no cases of heartwater were seen in either group of calves over the first 22 months of life. only one case of heartwater was observe ... | 1993 | 8134628 |
| an assessment of host resistance to ticks on cross-bred cattle in burundi. | groups of cattle of four different cross-breeds (ankole x friesian, ankole x brown-swiss, ankole x guernsey, ankole x sahiwal) plus a group of pure ankole cattle were immunized against tick-borne diseases: east coast fever, using a theileria parva trivalent vaccine, and anaplasmosis, babesiosis and, subsequently, heartwater. with the exception of two small subgroups of ankole and ankole x sahiwal which were treated by weekly spraying using delnav, all the groups were exposed to natural field cha ... | 1996 | 8834737 |
| a case of tick bite from amblyomma testudinarium on the glans penis. | a tick which bit the glans penis of a 40-year-old japanese man was surgically excised together with the skin where the bite occurred. it was identified as amblyomma testudinarium through the taxonomical investigation of its morphological characteristics. to our best knowledge, our patient is the sixth tick bite from this species of tick recorded in the chugoku district of japan. | 1996 | 8839244 |
| effects of pyriproxyfen on engorged females and newly oviposited eggs of the lone star tick (acari:ixodidae). | engorged females and 1- to 3-d-old eggs of the lone star tick, amblyomma americanum (l), were exposed to 9 treatments of pyriproxyfen (4, 8, and 16 micrograms/cm2) in glass vials at exposure periods of 7 d, 14 d, and continuous at each dosage level. treatment of newly engorged females did not affect the number of females ovipositing, but the number of eggs oviposited decreased as dosage and exposure time increased. complete inhibition of egg hatch occurred at all treatment levels except that of ... | 1996 | 8840677 |
| the life-cycle of amblyomma variegatum (acari: ixodidae): a literature synthesis with a view to modelling. | all available information on the life-cycle of amblyomma variegatum is collated. data for each parameter are analysed to derive mathematical descriptions, which may now be used to construct a model of the life-cycle of this tick. areas for future research are identified. these include the collection of data for most parameters around threshold conditions to clarify discrepancies reported in the literature and to better quantify the relationships described, examination of the effects of photoperi ... | 1995 | 8847166 |
| cowdriosis in senegal: some epidemiological aspects. | the results of a study on the abundance of amblyomma variegatum in different ecological zones and of cowdria ruminantium infection rates in nymphal and adult ticks of the north guinean zones are given. joint research is also conducted on the evaluation of seroprevalence. in this study, it appears that the vector is most important in the north guinean zone, followed by the south sudan and the coastal niayes zones. elsewhere, the tick populations are not significant or absent. the infection rate i ... | 1993 | 8134635 |
| survival and water-balance characteristics of unfed adult amblyomma cajennense (acari: ixodidae). | off-host survival, water balance, and cold tolerance of unfed adult, cayenne ticks, amblyomma cajennense (f.), were examined to evaluate species characteristics important to zoogeography and off-host ecology. survivorship decreased when males and females were subjected to progressively drier constant environmental conditions. average maximum survival was 641.2 and 682.5 d at 85% rh and 23 degrees c (2.98 mm hg) for males and females, respectively. mean survival in both sexes was progressively le ... | 1996 | 8906907 |
| ectoparasites (acari, mallophaga, anoplura, diptera) of white-tailed deer, odocoileus virginianus, from southern florida. | during a 7-yr period (1984-1990), 300 white-tailed deer, odocoileus virginianus (zimmermann), from 7 localities in collier, dade, and monroe counties in southern florida were examined for ectoparasites. eight species were identified: 4 ticks [ixodes scapularis say, i. affinis neumann, amblyomma maculatum (koch), and dermacentor variabilis (say)], 1 chigger mite [eutrombicula splendens (ewing)], 1 ked (lipoptena mazamae rondani), 1 chewing louse [tricholipeurus lipeuroides (megnin)], and 1 suckin ... | 1996 | 8906911 |
| seasonal activity and relative abundance of amblyomma americanum in mississippi. | ecological investigations of the lone star tick, amblyomma americanum (l.), were conducted in 3 adjacent 60-m2 plots, located in noxubee national wildlife refuge, noxubee county, mississippi. ticks were collected weekly from july 1992 to july 1993 by flagging randomly selected lanes. during the year, larval ticks were collected first in early july, with peak numbers in september, and they were collected no later than late october. nymphal ticks were collected from mid-march to late october, with ... | 1996 | 8906916 |
| the tick vectors of cowdriosis in angola. | amongst the amblyomma species presently known to be capable of transmitting cowdria ruminantium six have been recorded in angola. a. pomposum is the most important and widely distributed. of secondary importance are a. variegatum, which prevails in cabinda and moxico provinces, and a. astrion which occurs in the littoral and transition strips and on camabatela plateau. a. sparsum and a. tholloni which are specific parasites of wild hosts are considered accidental vectors. a. hebraeum was introdu ... | 1993 | 8134639 |
| tick avoidance behaviors associated with a decreased risk of anti-tick salivary gland protein antibody seropositivity in military personnel exposed to amblyomma americanum in arkansas. | during april through september 1990, 399 military personnel who originated from either fort chaffee, arkansas (n = 236) or fort wainwright, alaska (n = 163) were studied during maneuvers in tick-infested areas at fort chaffee. study subjects completed a questionnaire and had pre- and post-maneuvers serum specimens analyzed for antibodies to several rickettsial and ehrlichial agents and to amblyomma americanum (lone star tick) salivary gland proteins (anti-tick saliva antibodies [atsa], a biologi ... | 1996 | 8916798 |
| human ehrlichiosis--maryland, 1994. | ehrlichiosis is an emerging tickborne infectious disease caused by obligate intracellular, gram-negative rickettsia that infect leukocytes. human monocytic ehrlichiosis (hme) is caused by ehrlichia chaffeensis and is believed to be transmitted by amblyomma americanum (the lone star tick). most hme cases have been reported in southeastern and south-central states. during may-july 1994, five cases of serologically confirmed hme were identified among residents of maryland. all five persons lived ne ... | 1996 | 8926996 |
| cellular responses in experimental chronic and acute dermatophilosis infections of sheep. | the cellular infiltrate into the dermis in dermatophilosis lesions is composed of a range of cell types. the aim of this study was to establish if the composition of the cellular infiltrate in chronic lesions was different from that in healing lesions. experimental dermatophilus congolensis infections of sheep were used to study the sequential changes in cell types during the course of chronic and acute infections. infestations of adult amblyomma variegatum ticks were used to produce chronic les ... | 1993 | 8134642 |
| the epidemiology and control of camel dermatophilosis. | camel dermatophilosis was only recently described. it appears however that it is more widespread than originally thought. in kenya it has generally been found in the main semi-arid camel rearing areas of samburu and laikipia districts although it has not yet been found in the arid areas of turkana district. in an investigation of ticks on 200 camels, no amblyomma variegatum ticks were found although many other ticks were present. a. variegatum is suspected to transmit dermatophilosis in many dom ... | 1993 | 8134647 |
| the systemic effect of adult and immature amblyomma variegatum ticks on the pathogenesis of dermatophilosis. | the systemic effect of adult and nymphal amblyomma variegatum on the pathogenesis of experimental infections of dermatophilus congolensis was investigated. three groups of four sheep were used with all 12 sheep being infected with identical titrated doses of d. congolensis one group of sheep was simultaneously infested with adult a. variegatum the second with nymphal a. variegatum and the third group were the controls, with no exposure to ticks. assessment of the resulting infections indicate th ... | 1993 | 8134648 |
| the effect of tick control on the prevalence of dermatophilosis on indigenous cattle in ghana. | the effectiveness of three tick control regimes on the occurrence of amblyomma variegatum and dermatophilosis on cattle on the coastal plains of ghana were compared. animals at one kraal were sprayed with amitraz at predilection feeding sites of ticks every second week using a high concentration minimum volume technique. animals at two other kraals were treated with a deltamethrin based pour-on acaricide; at one kraal it was applied once every month while at the other kraal it was used at strate ... | 1993 | 8134649 |
| isolation of the causative agent of heartwater (cowdria ruminantium) from three amblyomma species in eight districts of kenya. | thirteen isolates of cowdria ruminantium were made from eight different districts of kenya by four different isolation methods. feeding adult amblyomma species ticks derived from nymphs collected in the field and the inoculation of homogenates prepared from adult field ticks had the highest success rate. the reattachment of adult ticks collected in the field was successful on only one of five attempts, and the subinoculation of blood from suspected heartwater carriers was unsuccessful. seven of ... | 1997 | 9004475 |
| the relationship between tick (amblyomma hebraeum) infestation and immunity to heartwater (cowdria ruminantium infection) in calves in zimbabwe. | the occurrence of endemic stability for heartwater (cowdria ruminantium infection) is a controversial issue, because the means by which young cattle and other neonatal ruminants become infected and acquire immunity to the disease have never been adequately explained. we conducted a study in a heartwater-endemic area in southeastern zimbabwe to investigate the relationships between calf immunity to c. ruminatium, infestations of the tick vector amblyomma hebraeum and dam, colostral and calf antib ... | 1995 | 8533273 |
| some properties of the ecdysteroid receptor in the salivary gland of the ixodid tick, amblyomma hebraeum. | salivary gland degeneration in ixodid ticks is triggered by an ecdysteroid hormone. we used [3h]ponasterone a (poa) as a specific ligand to detect the ecdysteroid receptor in the salivary glands of large, partially fed female ticks (amblyomma hebraeum koch; acari: ixodidae). binding of [3h]poa was thermolabile and sensitive to pronase, but not to dnase or rnase, indicating that the ligand binds to a protein. scatchard analysis of [3h]poa binding strongly suggested the presence of an ecdysteroid ... | 1995 | 8536946 |
| the life-cycle of the bont tick amblyomma hebraeum in vitro. | the life-cycle of the hard tick amblyomma hebraeum was completed in vitro by feeding all life-stages of the tick through silicone membranes on bovine blood from an abattoir. ticks were placed in a simple feeder membranes on bovine blood from an abattoir. ticks were placed in a simple feeder consisting of a honey jar containing the blood with a glass tube insert (o.d. 42 mm) across the end of which the membrane was stretched. this feeding unit was held in a water bath (38 degrees c). larvae and n ... | 1995 | 8550288 |
| clinical disorders observed in anteaters (myrmecophagidae, edentata) in captivity. | the major health problems found in 103 captive lesser anteaters (tamandua tetradactyla) and giant anteaters (myrmecophaga tridactyla), family myrmecophagidae, are presented and correlated with management. the most common of 200 recorded clinical disorders involved the digestive system (26%), nutritional deficiency (20%), injury (15.5%), respiratory system (10%), skin (7%) and circulatory system (4.5%), but 13% of the cases were inconclusive. parasites were identified in 48.5% of faecal samples, ... | 1995 | 8560755 |
| temporal association of amblyomma americanum with the presence of ehrlichia chaffeensis reactive antibodies in white-tailed deer. | from 1981 through 1993, tick infestations and serum antibodies reactive to ehrlichia chaffeensis, the causative agent of human ehrlichiosis, were monitored among white-tailed deer (odocoileus virginianus) at whitehall experimental forest, clarke county, georgia (usa). neither ticks nor e. chaffeensis antibodies were detected during the first two years of the study. infestations of the lone star tick (amblyomma americanum), a suspected vector of e. chaffeensis, first were noted on deer in 1983. p ... | 1995 | 8583627 |
| prevalence of antibodies to coxiella burnetti, rickettsia conorii, and rickettsia typhi in seven african countries. | the prevalences of antibodies reactive with coxiella burnetti, rickettsia conorii, and rickettsia typhi were determined by indirect fluorescent antibody testing of sera from seven african countries. the seroprevalences of antibodies reactive with c. burnetti and r. conorii in countries from north africa were similar to those reported from southern europe. in countries of sub-saharan africa, the seroprevalence of antibodies reactive with c. burnetti varied greatly; the generally higher figures fo ... | 1995 | 8589132 |
| ehrlichia-like 16s rdna sequence from wild white-tailed deer (odocoileus virginianus). | the reservoir hosts of ehrlichia chaffeensis, etiologic agent of human ehrlichiosis are unknown. initially, white-tailed deer (wtd) were serologically implicated as possible reservoirs of e. chaffeensis. subsequent studies showed that wtd were susceptible to infection with e. chaffeensis and that deer-to-deer transmission by a tick vector, amblyomma americanum, is possible under experimental conditions. to determine if wild wtd were infected with e. chaffeensis, whole blood was collected from 10 ... | 1996 | 8627501 |
| parasites of domestic and wild animals in south africa. xxxiv. arthropod parasites of nyalas in north-eastern kwazulu-natal. | seventy-three nyalas (tragelaphus angasii) in the umfolozi, mkuzi and ndumu game reserves in northeastern kwazulu-natal were examined for arthropod parasites during 1983 and 1984. in addition, six animals were examined during 1994. ten ixodid tick species, two louse species and a louse fly species were recovered. the nyalas were good hosts of all stages of development of boophilus decoloratus, rhipicephalus appendiculatus and rhipicephalus muehlensi and the immature stages of amblyomma hebraeum ... | 1995 | 8628570 |
| amblyomma variegatum (acari: ixodidae): mechanism and control of arbovirus secretion in tick saliva. | saliva is considered to be the conduit by which pathogens are transmitted from blood-sucking arthropod vectors to their vertebrate hosts, but supporting evidence for this is fragmentary. to determine if thogoto (tho) virus, a tick-borne member of the influenza virus family, is transmitted via tick saliva, and whether virus replication is a prerequisite for such transmission, two experimental conditions were compared: (1) "biological transmission" and (2) "mechanical transmission." in (1), tho vi ... | 1996 | 8631383 |
| comparison of resistance in three breeds of cattle against african ixodid ticks. | tick resistance in three breeds of cattle, two indigenous breeds (arssi and boran) and one boran x friesian cross-bread, were compared following natural tick infestations at abernossa ranch in ethiopia. the local arssi breed was found to have the highest tick resistance, followed by the boran breed, whereas the boran x friesian was the least resistant. over a period of 12 months, from october 1991 to september 1992, a total of 32,897 ticks composed of four genera were collected from the animals. ... | 1996 | 8665816 |
| investigation of tick-borne viruses as pathogens of humans in south africa and evidence of dugbe virus infection in a patient with prolonged thrombocytopenia. | in the course of investigating suspected cases of viral haemorrhagic fever in south africa patients were encountered who had been bitten by ticks, but who lacked evidence of infection with crimean-congo haemorrhagic fever (cchf) virus or non-viral tick-borne agents. cattle sera were tested by enzyme-linked immunoassay to determine whether tick-borne viruses other than cchf occur in the country. the prevalence of antibody in cattle sera was 905/2116 (42.8%) for cchf virus, 70/1358 (5.2%) for dugb ... | 1996 | 8666081 |
| catabolism of dopamine and 5-hydroxytryptamine by monoamine oxidase in the ixodid tick, amblyomma hebraeum. | the purpose of this study was to assess biogenic amine catabolism in amblyomma hebraeum koch (an african cattle tick). we assayed haemolymph and saliva for a variety of biogenic amines (usually following injection of substrate into the haemolymph) in partially fed females using hplc coupled to electrochemical detection. dopamine (da) and 5-hydroxytryptamine (5-ht) were rapidly converted to dihydroxyphenylacetic acid (dopac) and 5-hydroxyindoleacetic acid (5-hiaa) respectively, indicating that mo ... | 1996 | 8673075 |
| demonstration of vertical transmission of cowdria ruminantium, the causative agent of heartwater, from cows to their calves. | one of the most important questions about the epidemiology of heartwater in the field is how cowdria ruminatium is transmitted within vertebrate host populations. in this study vertical transmission of c. ruminantium from cows to their calves was demonstrated. twelve mixed-breed calves, born to dams living in a heartwater-endemic area of zimbabwe, were tested post-natally for the presence of c. ruminantium. vertical transmission was demonstrated to occur under natural field conditions using test ... | 1996 | 8750689 |
| the association between amblyomma variegatum and dermatophilosis: epidemiology and immunology. | a close association was found between infestation with amblyomma variegatum and the occurrence of dermatophilosis on cattle on the coastal plains of ghana. animals belonging to breeds traditionally regarded as more susceptible to the disease also tended to carry higher tick burdens. the basis of the association between infestation with this tick and the occurrence of dermatophilosis would appear to involve tick-induced immunosuppression. | 1996 | 8809987 |
| amblyomma tick feeding in relation to host health. | the tick amblyomma variegatum has been shown by field and controlled laboratory experiments to have a direct causal relationship with severe clinical dermatophilosis. the tick does not transmit the pathogen in the usual sense, either biologically or mechanically. the tick suppresses the immune system of the host, for unknown reasons, and this appears to enable the existing dermatophilosis to become a severe disease. there are other factors involved with the progression of dermatophilosis to clin ... | 1996 | 8809988 |
| the pathogenesis of dermatophilosis. | pathogen, host and environmental factors must be considered in order to understand the pathogenesis of dermatophilosis. a frequently cited sequence of events involves physical damage to the skin, bacterial multiplication in the epidermis, repeated cycles of invasion by hyphae, infiltration by neutrophils and exudate, regeneration of epidermis and reinvasion. this paper is concerned with pathogen driven mechanisms involved in the origin and development of dermatophilus congolensis infections. pri ... | 1996 | 8809989 |
| heartwater in ghana: implications for control of ticks. | heartwater, an often fatal rickettsial disease of domestic ruminants transmitted by amblyomma variegatum ticks, ranks with the a. variegatum-associated skin disease dermatophilosis as a major constraint to the upgrading of livestock productivity in ghana. an epidemiological survey, using new diagnostic tests, is being carried out to determine the incidence and distribution of heartwater and other tickborne diseases in ghanaian cattle, sheep and goats. preliminary results from a longitudinal surv ... | 1996 | 8809994 |
| phylogeny of ticks (ixodida) inferred from nuclear ribosomal dna. | phylogenetic relationships of 9 species of ticks were inferred from nucleotide sequences of the d1 domain of large subunit ribosomal dna (rdna), the v4 region of small subunit rdna and sequences immediately adjacent to these regions. six of the 7 subfamilies in the argasidae and ixodidae were represented: ornithodorinae and argasinae from the argasidae (soft ticks); and ixodinae, amblyomminae, haemaphysalinae and rhipicephalinae from the ixodidae (hard ticks). a mite, phytoseiulus persimilis, fr ... | 1996 | 8818731 |
| the efficacy of amitraz against cattle ticks in tanzania. | the efficacy of amitraz on cattle ticks was assessed by susceptibility tests, spraying and dipping trials. tests on the susceptibility of three tick species, rhipicephalus appendiculatus, amblyomma variegatum and boophilus decoloratus to amitraz (technical grade-purity 98.6% w/w) showed all 15 tick strains tested to be highly susceptible, with lc50 ranging between 0.001% and 0.03%, and lc99, between 0.01% and 0.07%. spraying trials were carried out on calves infested with r. appendiculatus, a. v ... | 1996 | 8856759 |
| site-specific geographic association between amblyomma americanum (acari: ixodidae) infestations and ehrlichia chaffeensis-reactive (rickettsiales: ehrlichieae) antibodies in white-tailed deer. | serum samples from white-tailed deer, odocoileus virginianus zimmermann, collected from 1982 through 1992 from the southeastern united states were tested for antibodies reactive to ehrlichia chaffeensis anderson, dawson, jones, & wilson, the causative agent of human ehrlichiosis. results were compared between areas based on known infestations of the lone star tick, amblyomma americanum l., a suspected vector of e. chaffeensis. one hundred and twenty-five of 300 (41.7%) deer tested positive (> or ... | 1996 | 8906920 |
| infestations of the bont tick amblyomma hebraeum (acari: ixodidae) on different breeds of cattle in zimbabwe. | infestations of adults and nymphs of amblyomma hebraeum were counted on brahman (br), brahman x simmental (bs), sanga (sa) and hereford (he) steers exposed to infested pastures at mbizi in southern zimbabwe in 1986-1987. herefords were always the most heavily infested, while the sanga tended to carry the fewest ticks with the brahman and brahman x simmental groups being in between. the ratios of the engorged females on the four breeds were 2.3:1.4:1.4:1.0 for he:br:bs:sa. the ratios of the stand ... | 1996 | 8952073 |
| proceedings of a workshop on the control of amblyomma variegatum and associated diseases. accra, ghana, 4 november 1994. | | 1996 | 8966770 |
| impact on salivary gland degeneration by putative ecdysteroid antagonists and agonists in the ixodid tick amblyomma hebraeum | ecdysteroids cause salivary gland degeneration in female ixodid ticks. we tested the effects of the following compounds on salivary gland degeneration in the ixodid tick amblyomma hebraeum koch: hhcs (22s,23s-homocastasterone), ssbr (22s,23s-homobrassinolide), stgm (2alpha,3alpha(oh)2-delta22-stigmasten-6-one), rh 5849, and rh 5992. the first three are brassinosteroids (putative ecdysone antagonists) and the last two are nonsteroidal mimics of ecdysone in a variety of insects. in vitro, hhcs (up ... | 1996 | 8980038 |
| african tick-bite fever. an imported spotless rickettsiosis. | to characterize the clinical presentation and course of african tick-bite fever, a recently rediscovered rickettsiosis caused by rickettsia africae (a new species within the spotted fever group of rickettsiae), to establish its relationship with amblyomma tick species, and to discuss its role in the etiology of fever in patients who are returning from the tropics. | 1997 | 8996049 |
| cloning and sequence of a gene for a homologue of the c subunit of the v-atpase from the salivary gland of the tick amblyomma americanum (l). | a 1084 base pair partial cdna showing similarity to the c subunit of the vacuolar atpase (v-atpase) was isolated on a clone from a cdna library made from salivary glands from 3-day-old feeding adult amblyomma americanum (l.) female ticks. the 5' end was completed using primer extension and the two pieces joined to form a complete cdna of 1373 bp. this mrna is expressed in embryos and the salivary glands of unfed adults and adult females at all stages of feeding. specific inhibitors of the v-atpa ... | 1997 | 9013257 |
| a possible explanation of the apparent breed-related resistance in cattle to bont tick (amblyomma hebraeum) infestations. | adult male amblyomma hebraeum tick infestations and the weights of 20 brahman steers and 38 mashona heifers were measured at different periods at the veterinary quarantine area at mbizi, zimbabwe. the experiment for the brahmans lasted 108 weeks and that for the mashona for 113 weeks. the brahman steers weighed a maximum average of 478.4 kg (se 7.9 kg), which was significantly different to the mashona heifers maximum average of 391.4 kg (se 5.6 kg) (p < 0.001). the brahmans had a maximum average ... | 1996 | 9017875 |
| survival of six species of african ticks in relation to saturation deficits. | the survival of unfed males and females of six species of african ticks was monitored at five different saturation deficits at constant temperature (25 degrees c). the survivorship curves for each species comprised a pre-mortality period, prior to when ticks started to die and a mortality period corresponding to a rapid increase in the mortality rate. longevity was defined as pre-mortality plus mortality. a negative correlation between the longevity of the ticks and the saturation deficits was f ... | 1996 | 9022266 |
| tick-raccoon associations and the potential for lyme disease spirochete transmission in the coastal plain of north carolina. | raccoons (procyon lotor) were live-trapped and examined for ticks from july 1990 to july 1993 in the coastal plain of north carolina on marine corps base, camp lejeune, north carolina (usa). five species of ixodid ticks were found on 351 (78%) of 449 raccoons. amblyomma americanum was the most abundant tick found on raccoons. dermacentor variabilis, ixodes texanus, and ixodes scapularis were frequently collected, while ixodes cookei were rarely collected from raccoons. tick burdens were not affe ... | 1997 | 9027688 |
| primary isolation of spotted fever group rickettsiae from amblyomma cooperi collected from hydrochaeris hydrochaeris in brazil. | this paper reports the first isolation of a spotted fever group rickettsia from an amblyomma cooperi ixodid collected from a capybara (hydrochaeris hydrochaeris) in an endemic area of spotted fever in the county of pedreira, state of são paulo, brazil. isolation was performed in vero cell culture and submitted to immunofluorescence, using antibody from rickettsia rickettsii-positive human serum. | 1996 | 9040845 |
| identification and characterization of anticoagulant activities in the saliva of the lone star tick, amblyomma americanum (l.). | anticoagulant activities against both the extrinsic and intrinsic coagulation pathways were identified in the saliva of partially fed female lone star ticks, amblyomma americanum (l.). the activities of factor xa and thrombin in the common pathway of the coagulation cascade were inhibited by tick saliva. the greatest anticoagulant activities were found in the saliva of ticks weighing more than 200 mg. the anticoagulant activities in tick saliva could be detected without preincubation of tick sal ... | 1997 | 9057694 |
| serological survey of heartwater relative to the distribution of the vector amblyomma variegatum and other tick species in north cameroon. | a study was carried out on the spatial and temporal distribution of amblyomma variegatum and other ticks infesting sheep and goats in northern cameroon. a serological survey of heartwater (cowdriosis) using a competitive elisa was concurrently carried out in the same flocks. a. variegatum was found to be the most predominant species accounting for 48.3% of all the ticks collected. other species identified included rhipicephalus sulcatus, r. lunulatus, r. turanicus, boophilus decoloratus, b. annu ... | 1997 | 9066062 |
| field sampling of the tick amblyomma variegatum (acari: ixodidae) on pastures in guadeloupe; attraction of co2 and/or tick pheromones and conditions of use. | field experiments were conducted in guadeloupe to evaluate the attraction of different chemicals on a guadeloupean strain of amblyomma variegatum. such tick sampling techniques may help to assess the size of the tick population on pastures before, during and after an attempted tick eradication campaign. co2 was absolutely necessary to activate ticks, including the larvae. in addition to activation, our data suggested that co2 itself is attractive for ticks. the reactivity of the ticks varied gre ... | 1997 | 9080680 |
| the impact of ixodiphagus hookeri, a tick parasitoid, on amblyomma variegatum (acari: ixodidae) in a field trial in kenya. | in an experiment to investigate the effect of the tick parasitoid, ixodiphagus hookeri, on tick numbers on cattle, 150000 parasitoids were released over a period of 1 year in a field where ten cattle infested with multiple tick species were kept. amblyomma variegatum was reduced from 44 to two ticks per animal while rhipicephalus appendiculatus increased over the time of parasitoid release. during the time of release 51% of the nymphs of a. variegatum collected from the animals were parasitized. ... | 1997 | 9080682 |
| prostaglandin biosynthesis by salivary glands isolated from the lone star tick, amblyomma americanum. | salivary glands separated from internal tissues of the lone star tick, amblyomma americanum, are competent to synthesize prostaglandins (pgs). using an in vitro pg biosynthesis assay four major pgs, namely, pga2/pgb2, pgd2, pge2, and pgf2 alpha were synthesized. under standard assay conditions pga2/pgb2 was the predominant product. salivary tissues as well as non-salivary internal tissues were capable of pg biosynthesis. we observed that storing ticks at -80 degrees c for 3 months resulted in re ... | 1997 | 9090120 |