identification of hemolytic activity in saliva of the lone star tick (acari:ixodidae).hemolytic activity was identified in the saliva of amblyomma americanum (l.) when red blood cells from sheep were incubated with tick saliva in the presence of phosphatidylcholine and sodium deoxycholate. the hemolytic activity was destroyed by boiling or treating with trypsin. the hemolytic activity in tick saliva was calcium-dependent, and inhibited by a phospholipase a2 inhibitor oleyloxyethyl phosphorylcholine. phosphatidylserine could replace phosphatidylcholine in the hemolytic assays but ...19979103758
pyriproxyfen effects on newly engorged larvae and nymphs of the lone star tick (acari:ixodidae).newly engorged larvae and nymphs of the lone star tick, amblyomma americanum (l.), were exposed to 9 treatments of pyriproxyfen in glass vials consisting of dosages of 4, 8, and 16 micrograms/cm2 for 7 d, 14 d, and continuous exposure periods at each concentration. treatment of newly engorged larvae resulted in decreased molting, altered postmolt defecation, and nymphal survival with results being dose and exposure dependent. molting inhibition ranged from 35.9 to 68.4%. successfully molted nymp ...19979103764
evidence for attachment pheromones in the cayenne tick (acari:ixodidae).evidence is presented for the existence of male-produced attachment pheromones in the tick amblyomma cajennense (f). unfed males and females attached significantly faster to shaved sides on bovine hosts where preattached males were present than did adult ticks released in control areas. attached ticks did not form clusters around the preattached males as described for other species of amblyomma. they attached in areas under bags where they had been released, but were not necessarily close to the ...19979103768
the possible role of two common three-host ticks, rhipicephalus appendiculatus and amblyomma hebraeum, in the transmission of bovine leukosis virus.the possible role of rhipicephalus appendiculatus and amblyomma hebraeum in the mechanical and transstadial transmission of bovine leukosis virus (blv) was investigated. blv-free laboratory strains of r. appendiculatus and a. hebraeum nymphal ticks (n = 400) were fed on a blv-infected and a negative control bovine. at various intervals after engorgement the ticks were homogenised and injected subcutaneously into blv-negative sheep. adult r. appendiculatus and a. hebraeum, which had fed as nymphs ...19969120860
development and use of specific polymerase reaction for the detection of an organism resembling ehrlichia sp. in white-tailed deer.the role of white-tailed deer (odocoileus virginianus) in the epidemiology of ehrlichia chaffeensis and the agent of human granulocytic ehrlichiosis (hge) is not fully understood, and diagnostic procedures may be complicated by the recent detection of 16s rdna sequence from an ehrlichia sp.-like organism in wild deer. a specific forward primer (dga) and an ehrlichia spp. reverse primer (ga1ur) were constructed to amplify this new, distinct ehrlichia sp.-like 16s rdna. the dga primer, a forward p ...19979131554
a novel neuropeptide-endocrine interaction controlling ecdysteroid production in ixodid ticks.ixodid (hard) ticks are blood-feeding arthropods that require a blood meal to complete each stage of development. however, the hormonal events coordinating aspects of feeding and development are only poorly understood. we have delineated a new neuropeptide-endocrine interaction in the adult tick, amblyomma hebraeum, that stimulates the synthesis of the moulting hormones, the ecdysteroids. in adult female ticks, ecdysteroid synthesis could be demonstrated in integumental tissue incubated in vitro ...19979149427
enema infusion technique inappropriate for evaluating viral competence of determine whether anal infusion of virus simulates the natural route of infection rather than intracoelomic injection, we compared the course of venezuelan equine encephalitis (vee) virus infection in amblyomma cajennense (f.) ticks that had been exposed to virus by enema infusion with that in ticks fed on a viremic host or exposed by intracoelomic inoculation. although virus was detected in virtually all ticks 14 d after exposure, orally exposed ticks contained significantly less virus (10(1 ...19979151493
some factors affecting infestation of white-tailed deer by blacklegged ticks and winter ticks (acari:ixodidae) in southeastern missouri.a total of 5,669 ticks of 4 species was collected from 515 hunter killed, white-tailed deer. odocoileus virginianus (zimmerman), in southeastern missouri from 1993 through 1995. the american dog tick, dermacentor variabilis (say) (4 adults), the lone star tick, amblyomma americanum (l.) (57 adults, 2 nymphs), the blacklegged tick, ixodes scapularis (say) (3,120 adults), and the winter tick, dermacentor albipictus (packard) (2.059 adults, 436 nymphs, 1 larva) were collected. patterns of adult d. ...19979151505
genetic markers for the identification of two tick species, amblyomma dissimile and amblyomma rotundatum.genetic markers are described for 2 species of reptile and amphibian ticks, amblyomma dissimile and amblyomma rotundatum, by allozyme electrophoresis. fixed allelic differences in 4 out of the 8 examined loci allowed the unequivocal separation of both of these species. a strong correlation was found between these genetic markers and the relative size of the spurs in coxae iv but not with the punctuation pattern of the scutum. moreover, no overlap was found in the distribution of relative spur si ...19979194816
assay for phenoloxidase activity in amblyomma americanum, dermacentor variabilis, and ixodes scapularis.phenoloxidase activity in amblyomma americanum, dermacentor variabilis, and ixodes scapularis was assayed. no phenoloxidase activity was detected compared to high activity through time in larvae of the greater wax moth (galleria mellonella). we conclude that activated prophenoloxidase does not act as an opsonin in ixodid ticks tested to date.19979194851
attempted transmission of human granulocytotropic ehrlichia (hge) by amblyomma americanum and amblyomma maculatum.transstadial transmission of human granulocytotrophic ehrlichia (hge) was attempted in dogs using amblyomma americanum (l.) and a. maculatum koch, two species that, as adults, feed readily on human beings. larvae and nymphs were acquisition-fed on a dog that was parasitemic with hge. two months later, following digestion of the blood meal and subsequent molting to nymphal or adult stage, these ticks were fed to repletion on hge-naive dogs. none of the dogs developed clinical evidence of ehrlichi ...19979195722
isolation of ehrlichia chaffeensis from wild white-tailed deer (odocoileus virginianus) confirms their role as natural reservoir hosts.field and experimental studies have implicated white-tailed deer (odocoileus virginianus) as probable reservoir hosts for ehrlichia chaffeensis, the causative agent of human monocytic ehrlichiosis, but natural infection in deer has not been confirmed through isolation of e. chaffeensis. thirty-five white-tailed deer collected from three amblyomma americanum-infested populations in georgia were examined for evidence of e. chaffeensis infection by serologic, molecular, cell culture, and xenodiagno ...19979196173
epidemiological aspects of the brazilian spotted fever: seasonal activity of ticks collected in an endemic area in são paulo, brazil.ticks were collected from vegetation and animals at monthly intervals during one year (1993-1994) in an endemic area of brazilian spotted fever in the country of pedreira, state of são paulo. six species of ticks were identified amblyomma cajennense, amblyomma cooperi, amblyomma triste, anocentor nitens, rhipicephalus sanguineus and boophilus microplus. only the first species was sufficiently numerous to permit a quantitative study with seasonal activity, although the distribution and source of ...19979197151
acquisition of protective immunity in geochelone pardalis against amblyomma marmoreum (acari:ixodidae) nymphal ticks.significant increases in serum globulins (alpha 1, alpha 2, beta and gamma) were observed in mountain leopard tortoises (geochelone pardalis) after they had been immunized with nymphal homogenates of amblyomma marmoreum. there was a concomitant significant increase in the numbers of leukocytes (lymphocytes, basophils, monocytes and eosinophils). resistance to nymphal-challenge infestations was manifested by reduced feeding time, lower engorgement masses, and significantly fewer (p < 0.0001) numb ...19979204497
development and evaluation of a recombinant antigen, monoclonal antibody-based competitive elisa for heartwater serodiagnosis.cowdria ruminantium is the etiologic agent of heartwater, a tick-transmitted foreign animal disease with considerable potential for entrance into the usa. a competitive enzyme-linked immunosorbent assay (celisa) was developed to detect serologic responses to c. ruminantium infection. the celisa utilized a recombinant form of the c. ruminantium major antigenic protein (map-1) as the antigen and an anti-map-1 monoclonal antibody as the competing indicator reagent. experimental antisera to c. rumin ...19979211230
a specific prostaglandin e2 receptor and its role in modulating salivary secretion in the female tick, amblyomma americanum (l.).prostaglandins of the 2-series (e.g. pge2) are typically synthesized from arachidonic acid (aa) after aa is released from cellular phospholipids after activation of an intracellular phospholipase a2 (pla2). treatment of isolated salivary glands with pla2 inhibitor oleyloxyethyl phosphorylcholine (opc) or prostaglandin synthetase inhibitors reduced dopamine-induced fluid secretion and cyclic amp (camp) levels in isolated salivary glands. pge2 and its analog, 17-phenyl trinor pge2, partly reversed ...19979219365
ability of the lyme disease spirochete borrelia burgdorferi to infect rodents and three species of human-biting ticks (blacklegged tick, american dog tick, lone star tick) (acari:ixodidae).the infectivity of a diverse collection of borrelia burgdorferi strains from north america for mice was determined as a prelude to vector competence experiments with the 3 primary human-biting tick species in the eastern united states (ixodes scapularis say, dermacentor variabilis (say), amblyomma americanum (l.)]. of the 34 b. burgdorferi strains inoculated into mice, 29 were infectious; the exceptions were 5 isolates from texas. vector competence experiments were conducted with 2 strains from ...19979220680
ticks (acari: ixodida) uncommonly found biting humans in north carolina.collection records are presented that document human-biting by otobius megnini, amblyomma maculatum, haemaphysalis leporispalustris, ixodes cookei, ixodes dentatus, and rhipicephalus sanguineus in north carolina. these species are either extremely rare in north carolina or they are normally considered non-human feeders. the record of otobius megnini represents the first collection of this species in north carolina in over 50 years. it is proposed that immature rhipicephalus sanguineus feed on hu ...19979221733
the effects of the bont tick, amblyomma hebraeum, on milk production of sanga and sanga x brahman cattle.the effects of adults on the bont tick, amblyomma hebraeum on the milk production of sanga and sanga x zebu (brahman) cattle were measured over a period of 11 weeks in the low veld of zimbabwe in the summer of 1986. four groups of lactating cows, consisting of two breeds, each divided into a high and low tick treatment, were exposed to very low or high challenges of ticks and their milk production measured by weighing their calves before and after suckling. the liveweight gains (lwg) of the calv ...19979226643
identification of an ixodes ricinus salivary gland fraction through its ability to stimulate cd4 t cells present in balb/c mice lymph nodes draining the tick fixation site.balb/c mice infested with larvae or nymphs of ixodes ricinus develop in their lymph nodes a t cell-specific immune response triggered by salivary gland soluble antigens (sga). sga are apparently conserved in the 3 biological stages of i. ricinus ticks and are species specific. sga derived from partially fed females i. ricinus stimulate lymph node t cells from mice infested with i. ricinus larvae or nymphs. in contrast, lymph node cells from mice infested with amblyomma hebraeum nymphs do not res ...19979226956
short report: geographic distribution of different genetic types of ehrlichia chaffeensis.the 120-kd protein gene of ehrlichia chaffeensis was used to characterize ehrlichial dna from seven pools of adult amblyomma americanum ticks. ticks from missouri, kentucky, and north carolina contained e. chaffeensis dna of the arkansas strain genotype. ticks from north carolina also contained ehrlichiae of the sapulpa strain genotype, originally identified in oklahoma.19979230803
crimean-congo haemorrhagic fever virus infection in the western province of saudi 1990, an outbreak of suspected viral haemorrhagic fever involving 7 individuals occurred in mecca in the western province of saudi arabia. congo-crimean haemorrhagic fever (cchf), not previously known to be present in saudi arabia, was incriminated. a study of the epidemiology of this virus was therefore carried out in mecca, and in nearby jeddah and taif in 1991-1993; 13 species of ixodid ticks (5 hyalomma spp., 5 rhipicephalus spp., 2 amblyomma spp., 1 boophilus sp.) were collected from liv ...19979231193
helminths and arthropods of black and white rhinoceroses in southern africa.helminths and arthropods were collected and quantified from two black rhinoceroses (diceros bicornis bicornis) and one white rhinoceros (ceratotherium simum), and ticks from an additional four black and two white rhinoceroses in southern africa. the helminths of a black rhinoceros from the republic of south africa and one from namibia were quantitatively measured and recorded for each compartment of the alimentary tract. probstmayria vivipara was the most abundant parasite in each animal. a rece ...19979249695
contribution to the knowledge of ixodidae ticks of wild mammals of somalia.this study was based on material collected in 1983-1984 from wild mammals of the middle scebeli. low scebeli and bay regions of somalia. a total of 292 specimens (156 males, 65 females, 70 nymphase, 1 larva) from 13 host species were examined. the following species of ixodidae were identified. amblyomma variegatum (fabricius, 1794); haemaphysalis calcarata neumann, 1902; haemaphysalis spinulosa neumann, 1906; rhipicephalus armatus pocock, 1900; rhipicephalus pravus donitz, 1910; rhipicephalus pu ...19969257347
cloning and sequence of a gene for the homologue of the stearoyl coa desaturase from salivary glands of the tick amblyomma americanum.a 1488 base pair cdna clone has been isolated from a cdna library made from salivary glands from 3-day feeding adult female ticks. the sequence of this cdna suggests it is the gene for the tick homologue of the stearoyl coa desaturase. this gene is expressed in eggs and all feeding stages of the adult examined, but appears to be transcribed to an 8 kb mrna as well as a 1.5 kb mrna. because ticks have the ability to synthesize monounsaturated fatty acids and demonstrate a large increase in saliva ...19979272444
isolation and characterization of americanin, a specific inhibitor of thrombin, from the salivary glands of the lone star tick amblyomma americanum (l.).a thrombin (ec inhibitor (americanin) was isolated from the salivary glands of the lone star tick amblyomma americanum (l.) using reversed-phase chromatography and anion-exchange chromatography. americanin did not inhibit any other protease tested, including factor xa, plasmin, trypsin, chymotrypsin, elastase, papain, pepsin, and carboxypeptidase. the inhibition of thrombin by americanin decreased dramatically with dilution of the reaction mixture including thrombin, its substrate, and ...19979287955
seroepidemiology of rickettsia typhi, spotted fever group rickettsiae, and coxiella burnetti infection in pregnant women from urban tanzania.immunofluorescent antibody (ifa) testing was performed on sera drawn from 150 pregnant women in the port city of dar es salaam, tanzania. prevalence of antibodies to rickettsia typhi was 28%, higher than in any of the 12 other african countries in which serosurveys using ifa testing have been performed. seroprevalence of antibodies to spotted fever group rickettsiae antigens was 25.3%, comparable with that found in other sub-saharan countries endemic for amblyomma ticks. only 4.7% of women were ...19979288814
different organisms associated with heartwater as shown by analysis of 16s ribosomal rna gene sequences.cowdria ruminantium is a rickettsial parasite which causes heartwater, a economically important disease of domestic and wild ruminants in tropical and subtropical africa and parts of the caribbean. because existing diagnostic methods are unreliable, we investigated the small-subunit ribosomal rna (srrna) gene from heartwater-infected material to characterise the organisms present and to develop specific oligonucleotide probes for polymerase chain reaction (pcr) based diagnosis. dna was obtained ...19979299697
on the mechanism of water vapour sorption from unsaturated atmospheres by ticksthe nascent salivary secretion of 41 partly dehydrated and unfed adult female amblyomma variegatum, 5&shy;8 months post-ecdysis, during water vapour uptake at 93.5 % relative humidity and 20 &deg;c, had an osmolality of between 298.6 and 769.7 mosmol kg-1 (mean &plusmn; s.d. 470.3&plusmn;85.8 mosmol kg-1). this range would allow water vapour uptake at relative humidities of approximately 98&shy;99 %, but it would not suffice for lower relative humidities down to 80&shy;85 %, the critical equilib ...19979319391
a novel phospholipase a2 activity in saliva of the lone star tick, amblyomma americanum (l.).saliva from female lone star ticks, amblyomma americanum, contained a novel phospholipase a2 (pla2) activity that hydrolyzed 14c-arachidonate from 14c-arachidonyl phosphatidylcholine. the tick saliva pla2 (ts-pla2) was active over a broad ph range (4.5-11.5) with two distinct ph optima of ph 5.5 and 9.5. though extracellular pla2s are reported to be activated by millimolar ca2+, ts-pla2 was sensitive to submicromolar ca2+ and was half-maximally activated by 3.5 microm ca2+. tick saliva contains ...19979326887
rickettsiae-infected ticks in an endemic area of spotted fever in the state of minas gerais, brazil.a study on tick-borne rickettsiosis was developed in the county of santa cruz do escalvado, state of minas gerais, brazil, where a clinical case of the disease, confirmed by necropsy, had been reported. of the 1,254 ticks collected, 1,061 belonged to the amblyomma genus, 57 to the rhipicephalus sanguineus species, 81 to boophilus microplus, and 46 to anocentor nitens. the hemolymph test associated with giménez staining showed that 18 of the 221 a. cajennense specimens, 1 of the 16 r. sanguineus, ...19979361740
artificial feeding of amblyomma cajennense (fabricius, 1787) (acari:ixodidae) through silicone artificial feeding system was used where citrated bovine blood was offered to male and female amblyomma cajennense. vestiges of blood, sweat, hair and exfoliated skin were used as phago-stimulants placed on the surface of the silicone membrane. the ticks were collected, as engorged nymphs, from naturally infested equines, with the ecdysis occurring in the laboratory. four hundred ticks were used, 50% being female, at three to four weeks post-ecdysis. vestiges of blood on the silicone membrane ...19979361751
natural history of ehrlichia chaffeensis (rickettsiales: ehrlichieae) in the piedmont physiographic province of georgia.the roles of wild mammals and ticks in the epidemiology of ehrlichia chaffeensis at a suspected endemic site were investigated using serologic testing, culture, and polymerase chain reaction (pcr) supported by restriction endonuclease analysis and dna sequencing. antibodies reactive to e. chaffeensis (> or = 1:64) were detected in 92% of white-tailed deer (odocoileus virginianus), 21% of raccoons (procyon lotor), and 8% of opossums (didelphis virginianus), but not in 8 other species of mammals. ...19979379294
crimean-congo hemorrhagic fever in ticks (acari: ixodidae) and ruminants: field observations of an epizootic in bandia, senegal (1989-1992).from 1989 to 1992, a longitudinal study of the relationships between different tick species and domestic ungulates in the transmission and amplification of crimean-congo hemorrhagic fever (cchf) virus was undertaken in the bandia area in senegal where the presence of the virus had been reported previously. an epizootic occurred in 1991-1992 and 22 strains of cchf virus were isolated from hyalomma marginatum rufipes koch, amblyomma variegatum (f.), rhipicephalus guilhoni morel & vassiliades, and ...19979379454
seasonal prevalence of ticks and tick-transmitted haemoparasites in traditionally managed n'dama cattle with reference to strategic tick control in the gambia.a survey of tick spatial and seasonal distribution in traditional managed n'dama cattle over 1 year old was carried out in the gambia over 16 months. presence of anaplasma marginale and babesia spp. in the blood smears and their antibodies in the serum of same animals were also examined. tick species, in decreasing order of abundance, were: boophilus geigy, rhipicephalus senegalensis, b.decoloratus, hyalaomma truncatum, h.marginatum rufipes and amblyomma variegatum. all tick species peaked durin ...19979430113
first isolation and cultivation of borrelia burgdorferi sensu lato from missouri.five borrelia burgdorferi sensu lato isolates from missouri are described. this represents the first report and characterization of such isolates from that state. the isolates were obtained from either ixodes dentatus or amblyomma americanum ticks that had been feeding on cottontail rabbits (sylvilagus floridanus) from a farm in bollinger county, mo., where a human case of lyme disease had been reported. all isolates were screened immunologically by indirect immunofluorescence by using monoclona ...19989431909
biases associated with several sampling methods used to estimate abundance of ixodes scapularis and amblyomma americanum (acari: ixodidae).several tick sampling methods were evaluated for ixodes scapularis say and amblyomma americanum (i.) in oak-dominated mixed hard-wood, pitch pine-dominated, and mixed hardwood and pine forests in coastal new jersey. walking surveys were more efficient for collecting i. scapularis adults than dragging by a factor of > 2:1. in contrast, drag sampling yielded nearly twice as many a. americanum adults compared with walking surveys. i. scapularis subadults were rarely collected during walking surveys ...19979439115
ecdysteroid regulation of salivary gland degeneration in the ixodid tick, amblyomma hebraeum: a reconciliation of in vivo and in vitro observations.salivary gland degeneration in the female tick amblyomma hebraeum koch is triggered by an ecdysteroid (es) hormone. under both in vivo and in vitro conditions, degeneration requires 4 days for completion. in partially fed females that have fed beyond a "critical weight," the commitment period for salivary gland degeneration occurs between 24 and 48 h after removal from the host. although tissue degeneration begins within 24 h postengorgement, es titer as measured by radioimmunoassay (ria) does n ...19989473365
new distribution records of amblyomma americanum (l.) (acari: ixodidae) in new york state.amblyomma americanum, commonly called the lone star tick, has been widely-distributed in the southeastern united states for many years. distribution of this species apparently did not extend to new york state until the 1970s, after which the northern distribution in new york was limited to long island (suffolk and nassau counties), where it has become locally abundant. since then, there has been just one published record from new york state, in westchester county, just north of new york city. fr ...19979491364
isolation of a functional ecdysteroid receptor homologue from the ixodid tick amblyomma americanum (l.).ecdysteroids are assumed to be the major steroid hormones in arthropods. however, with the exception of insects and crustaceans, very little is known about ecdysteroid action in other arthropods. to determine if ecdysteriods play a functional role in the ixodid tick, amblyomma americanum (l.), we isolated cdnas encoding three presumed ecdysteroid receptor isoforms (aamecra1, aamecra2, and aamecra3) that have common dna and ligand binding domains linked to distinct amino termini. the dna and liga ...19979501418
human ehrlichioses: newly recognized infections transmitted by ticks.human ehrlichioses are tick-borne infections caused by bacteria in the genus ehrlichia. human monocytic ehrlichiosis is caused by ehrlichia chaffeensis and human granulocytic ehrlichiosis is caused by an agent similar to ehrlichia equi. e. chaffeensis infects mononuclear phagocytes and is transmitted by lone star ticks (amblyomma americanum) found in the south central and eastern united states. the agent of human granulocytic ehrlichiosis infects mostly neutrophils, it transmitted by ixodes spec ...19989509259
ticks infesting sheep and goats in the sudan.very little work has been carried out on ticks infesting small ruminants in the sudan. of some 70 tick species recorded in the sudan, 34 species of different genera were collected from sheep and goats, two belonging to the genus amblyomma, seven to the genus hyalomma, 22 to the genus rhipicephalus and three to the genus boophilus. nevertheless, their distribution, the seasonal abundance and population dynamics are poorly studied. particularly, the peculiar distribution of a. lepidum and a. varie ...19979530698
erythema migrans-like rash illness at a camp in north carolina: a new tick-borne disease?borrelia burgdorferi, the causative agent of lyme disease, has never been isolated from a patient thought to have acquired lyme disease in any southeastern state.19979531233
phylogenetic placement of rickettsiae from the ticks amblyomma americanum and ixodes scapularis.a rickettsial isolate (isolate moaa) belonging to the spotted fever group (sfg) was obtained from the lone star tick amblyomma americanum. we used pcr to characterize the genes for the rickettsial outer membrane proteins rompa and rompb. we sequenced the pcr products (domains i of both the rompa gene and the rompb gene) of moaa and wb-8-2, another rickettsial isolate from a. americanum. to place moaa and wb-8-2 and two other nonpathogenic isolates (rickettsia rickettsii hip2 and rickettsia monta ...19989574696
effect of controlling natural field-tick infestation on the growth of n'dama and gobra zebu cattle in the gambia.the effect of tick infestations on liveweight gain (lwg) was assessed by comparison of weight changes in flumethrin-treated n'dama and gobra zebu cattle (16-20 months old) with respective control groups submitted to natural tick challenge over 1 year. flumethrin was applied monthly, fortnightly or weekly. preventive treatments against anaplasmosis, babesiosis and trypanosomosis were given. mortality rate was recorded and post-mortem examinations carried out. in both treated and control animals, ...19989604263
efficacy of tags impregnated with pheromone and acaricide for control of amblyomma variegatum.the efficacy of tags impregnated with pheromone and acaricide for control of amblyomma variegatum on cattle in guadeloupe was determined for a 13-week trial. comparisons were made between untreated cattle and cattle with tags containing either pheromones alone (o-nitrophenol, methyl salicylate, 2,6-dichlorophenol and phenylacetaldehyde), pheromones plus acaricide (cyfluthrin or deltamethrin), or acaricide alone. tags were fastened to cattle both on collars on the neck and with adhesive to tail h ...19989622367
dynamics of free-living ixodid ticks on a game ranch in the central province, ixodid ticks were collected at monthly intervals from january to december 1996 by dragsampling the vegetation of mtendere game ranch in the chisamba district of the central province, zambia. ticks belonging to 11 species were recovered. rhipicephalus appendiculatus was most abundant, comprising 90% of the total number collected. all life stages of this tick showed a definite seasonal pattern of activity. the adults were present mainly during the rainy season (february and march), the ...19989629590
development, reproductive capacity and survival of amblyomma variegatum and boophilus decoloratus in relation to host resistance and climatic factors under field determine the developmental periods, fecundity and survival of amblyomma variegatum and boophilus decoloratus and the effect of host resistance, a study was carried out in the field at abernossa ranch in ethiopia using three breeds of cattle: arssi, boran and boran x friesian crossbreed. the investigation took place between october 1991 and september 1992. the developmental periods of both tick species were recorded. the hatching periods of larvae, engorgement, larvo-nymphal and nympho-adult ...19989637226
first records of amblyomma americanum, ixodes (ixodes) dentatus, and ixodes (ceratixodes) uriae (acari: ixodidae) from maine.the first records of 3 ixodid tick species collected in the state of maine are reported. a total of 23 records of the lone star tick, amblyomma americanum (l., 1758), in 11 counties from hosts with no history of travel outside the state demonstrates that this tick is now a resident of maine. ixodes dentatus marx, 1899 is recorded from waldo and lincoln counties, and ixodes uriae white, 1852 is recorded from matinicus rock in knox county. this is the first report of i. uriae from the eastern unit ...19989645873
delivery of ivermectin by injectable microspheres.a bioabsorbable, injectable microsphere formulation containing ivermectin in poly-(lactide-co-glycolide) copolymer (pla/pga) was developed to provide long-lasting delivery of the drug for control of livestock pests. a solvent-evaporation technique was used to produce the spherical beads containing approximately 30% ivermectin and ranging in size from 25-250 microns. the pattern of delivery of the drug into the blood stream of spanish goats was characterized for a 50:50 pla/pga, a 90:10 pla/pga c ...19989650514
comparative evaluation of 16s, map1 and pcs20 probes for the detection of cowdria and ehrlichia species in ticks.we have developed a panel of 16s ribosomal rna gene probes for heartwater epidemiology; five of these detect different cowdria genotypes (ball3, senegal, omatjenne, crystal springs, and mara 87/7); one detects all five of these genotypes; one detects any group iii ehrlichia species other than cowdria; one detects any group ii ehrlichia species. we have used these probes on pcr-amplified rickettsial 16s rrna genes from over 200 amblyomma ticks. control ticks were laboratory-reared and either unin ...19989668452
pcr detection of cowdria ruminantium infection in ticks and animals from heartwater-endemic regions of zimbabwe.the development of a pcr assay for the detection of cowdria ruminantium infection in ticks has been previously described. here we report a further evaluation of this assay by comparison with a dna probe and with the mouse inoculation assay (mia). application of the pcr assay in determining the prevalence of infection in ruminants and ticks from heartwater-endemic areas of zimbabwe is also described. one hundred uninfected and 120 infected amblyomma hebraeum ticks were analyzed by pcr, dna probe ...19989668453
the caricom/fao/iica caribbean amblyomma program.the objective of the caribbean amblyomma program is to eradicate the tropical bont tick (tbt), amblyomma variegatum, from the caribbean. field activities directed to eradication of the tbt were initiated in may 1995 commencing in northern caribbean islands. plans have been finalized for the remaining islands to the south to start eradication activities in early 1997. the components of the program include tick control and surveillance, adaptive research, training, communications, and extension. d ...19989668484
successes and failures in the tropical bont tick eradication campaigns in the french antilles.the amblyomma variegatum eradication campaigns, based on three phases and a 5-year program, as in other islands of the caribbean, started in the french antilles in april 1994 with various financial inputs. the progress of the campaigns in the two islands of guadeloupe and martinique contrast sharply. owing to a shortage and inadequacy of results with regard to the initial objectives, particularly in organization, communication efforts, cattle identification, and application of acaricides on live ...19989668485
entomopathogenic nematodes as a potential biological control method for ticks.entomopathogenic nematodes have been used for biological control of certain insect pests. in these studies the nematodes were tested as a possible biological control agent for engorged female ticks. five species of infective juveniles (ijs) were tested initially for their ability to penetrate and kill ticks, including steinernema glaseri (sg), s. riobravus (sr), s. carpocapsae (dt), s. feltiae (sf) and heterorhabiditis bacteriophora (hp88). infective juveniles (ijs) of srs and sfs appeared to be ...19989668486
a trial to control or eradicate amblyomma hebraeum ticks and heartwater on three ranches in zimbabwe. 19989668492
attempts to feed amblyomma variegatum ticks on artificial membranes.feeding jars were used to feed nymphs of amblyomma variegatum on blood of goats or cattle. sterile blood was collected daily or weekly (kept at 4 degrees c or frozen until use), with addition either of heparin alone or of heparin and antibiotics/fungicide or of heparin, adenosine triphosphate and glutathione. membranes were made of a thin (0.12-0.32 mm) film of silicone mastic. blood in the jars was replaced twice a day, and reached a temperature of 39 degrees c in a waterbath before it became a ...19989668493
repeatability of the level of infestation by amblyomma variegatum ticks on creole cattle. 19989668494
seasonal variation of ticks on cattle in burkina faso.cattle of the sahel zebu peuhl breed from traditionally managed livestock herds in a representative area of north soudanese savana (with 400-900 mm of rainfall/year from may to september) located in the central land of burkina faso, were monitored over 12 months for tick and blood parasite. two species of ticks were found: amblyomma variegatum and hyalomma marginatum rufipes. h. m. rufipes was found on cattle all year round with a highest infestation rate in june characterized by means of 10 +/- ...19989668496
distribution, abundance, and seasonal activities of ticks collected from rodents and vegetation in south carolina.ixodid ticks were collected from live-trapped rodents and by flagging vegetation at sites in the piedmont, sandhills, coastal plain, and coastal zone of south carolina from may 1994 through december 1995. a total of 1,514 ticks was recovered from 237 live-trapped rodents. host-attached species included ixodes minor neumann (n = 818), dermacentor variabilis (say) (n = 346), amblyomma maculatum koch (n = 209), ixodes affinis neumann (n = 89), and ixodes scapularis say (n = 52). species of questing ...19989673934
prostaglandin e2 in the salivary glands of the female tick, amblyomma americanum (l.): calcium mobilization and exocytosis.a cholera toxin-sensitive, prostaglandin e2 (pge2) specific receptor has been identified in the plasma membrane fraction of tick salivary glands. in the present study, we report that stimulation of dispersed salivary glands of the lone star tick amblyomma americanum (l.) with 1 nm to 10 microm pge2 increased the intracellular concentration of inositol trisphosphate (ip3) in a dose-dependent manner. incubation of dispersed tissue with 1 nm to 10 microm pge2 also stimulated release of 45ca2+ from ...19989684330
investigating the epidemiology of heartwater (cowdria ruminantium infection) by means of a transmission dynamics model.a mathematical model of the transmission dynamics of cowdria ruminantium by the ixodid tick amblyomma hebraeum in the bovine host is developed and used to investigate the epidemiology of heartwater across a range of vector challenge. the processes described are supported by empirical data. the pattern of outcome measures (incidence, case-fatality and proportion of infected hosts) predicted agrees with those described anecdotally from field experience and empirical observation, and demonstrates t ...19989695100
host specificity of amblyomma cajennense (fabricius, 1787) (acari: ixodidae) with comments on the drop-off rhythm.the parasitic specificity of larval, nymph and adult amblyomma cajennense on six different host species: oryctolagus cuniculus, rattus norvegicus, gallus gallus domesticus, anas platyrhynchus, coturnix coturnix and streptopelia decorata is described. in terms of the numbers of larvae and nymphs recovered, o. cuniculus was the best host species. the modal day for drop-off of larvae and nymphs was day three for the mammal hosts, but variable in the birds. we conclude that adult a. cajennense have ...19989698869
detection of a spotted fever group rickettsia in amblyomma cajennense (acari: ixodidae) in south texas.thai tick typhus rickettsia (strain tt-118), a spotted fever group rickettsia of indeterminant pathogenicity, was isolated from a mixed pool of larval ixodes and rhipicephalus ticks collected from thailand in 1962. here we report the surprising finding of a spotted fever group rickettsia with closest sequence homology to the thai tick typhus rickettsia in amblyomma cajennense (f.) ticks from south texas. sequence analysis was performed on segments of 3 genes that differentiate rickettsial specie ...19989701930
population dynamics of immature amblyomma maculatum (acari: ixodidae) and other ectoparasites on meadowlarks and northern bobwhite quail resident to the coastal prairie of texas.a survey of ectoparasites from 219 meadowlarks conducted during 2 consecutive fall-winter periods in a coastal prairie found immature amblyomma maculatum koch to be the most abundant parasite. peak larval infestations occurred in december with 80-100% of collected birds infested and with a monthly mean of up to 34 larvae per bird. peak nymphal infestations occurred in february or march with 95-100% of birds infested and with a monthly mean of up to 11 nymphs per bird. seasonal dynamics of these ...19989701932
illustrated key to nymphs of the tick genus amblyomma (acari: ixodidae) found in the united states.a dichotomous identification key, with important characters illustrated by scanning electron micrographs, is provided for nymphs of the 9 species of the genus amblyomma occurring in the united states. species included are a. americanum (l.), a. cajennense (f.), a. dissimile koch, a. imitator kohls, a. inornatum (banks), a. longirostre (koch), a maculatum koch, a. rotundatum koch, and a. tuberculatum marx. notes on the geographical distributions, medical and veterinary importance, and nymphal sta ...19989701933
phospholipase a2 activity in salivary glands and saliva of the lone star tick (acari: ixodidae) during tick feeding.phospholipase a2 (pla2) activity levels in tick [amblyomma americanum (l.)] salivary glands and saliva were examined during tick feeding by using 14c-phosphatidylcholine as the substrate. saliva produced by stimulating female ticks to salivate with dopamine contains pla2 (ts-pla2) activity. the ts-pla2 activity level in saliva did not change significantly during tick feeding except for a decrease in the last rapid feeding phase (> 200 mg) and in replete ticks. phospholipase a2 activity was highe ...19989701935
interaction of entomopathogenic nematodes (steinernematidae) with selected species of ixodid ticks (acari: ixodidae).entomopathogenic nematodes, currently used for biological control of various insect pests, were tested for their ability to penetrate and kill replete females of several species of ticks including dermacentor variabilis (say), rhipicephalus sanguineus (latreille), amblyomma maculatum koch, and a. cajennense (f.). these species were found to be susceptible to the entomopathogenic nematodes, steinernema feltiae (filipjev) or s. riobravus (cabanillas & poinar), shown in previous studies in our labo ...19989701938
isolation of two functional retinoid x receptor subtypes from the ixodid tick, amblyomma americanum (l.).retinoid x receptors (rxr) play a central role in a variety of nuclear signaling pathways in both vertebrates and invertebrates. vertebrate rxrs are encoded by a multigene family whereas the insect rxr homologue, ultraspiracle (usp), is encoded by a single gene. to determine if acarines possess an rxr homologue similar to insect usps, we isolated cdnas encoding two distinct rxr genes, aamrxr1 and aamrxr2, from the ixodid tick, amblyomma americanum (l.). the dna binding domains share 95 and 87% i ...19989705073
demonstration of a carrier state for cowdria ruminantium in wild ruminants from africa.four wild african ruminants, eland (taurotragus oryx), giraffe (giraffa camelopardalis), kudu (tragephalus strepsiceros strepsiceros), and blue wildebeest (connochaetes taurinus), were experimentally infected with the rickettsia cowdria ruminantium, the tickborne agent causing heartwater in domestic ruminants. the infections were established, and c. ruminantium was transmitted to naive small ruminants by the vector amblyomma hebraeum when transmission attempts were made at days 128 (eland and wi ...19989706566
the travels of a lone star tick.a lone-star tick, amblyomma americanum, was found as a pedunculated lesion on the back of the arm of an 84 year old man in northern ireland. this was acquired on a visit to the usa. the tick is found mainly in texas and the ozark mountains of missouri, with scattered foci in other parts of southern usa. it is the vector of rocky mountain spotted fever. as worldwide travel becomes increasingly common, exotic parasites make occasional appearances in northern europe.19989708212
outbreak of rickettsia africae infections in participants of an adventure race in south africa.african tick-bite fever, caused by rickettsia africae and transmitted by amblyomma ticks, is an emerging rickettsiosis in southern africa. because of increased tourism to this area, several cases in tourists have been reported recently. we report 13 cases of r. africae infection diagnosed in france that occurred in competitors returning from an adventure race in south africa and compare our data with previously reported findings. most of our patients presented with fever, headache, multiple inoc ...19989709882
antibody to a cdna-derived calreticulin protein from amblyomma americanum as a biomarker of tick exposure in humans.the antibody responses of human and animal hosts were studied to determine the utility of antibody against recombinant tick calreticulin (rtc), a cdna-derived protein isolated from salivary glands of amblyomma americanum l., as a biologic marker of tick exposure. rabbits fed upon by either a. americanum or dermacentor variabilis say developed significant anti-rtc antibody responses, as measured by both elisa and immunoblot assay. in contrast, gerbils exposed to aedes aegypti did not develop anti ...19989715947
physician-diagnosed erythema migrans and erythema migrans-like rashes following lone star tick differentiate cases of physician-diagnosed erythema migrans and erythema migrans-like rashes associated with lone star tick (amblyomma americanum) bites.19989722725
a review of heartwater and the threat of introduction of cowdria ruminantium and amblyomma spp. ticks to the american mainland.heartwater, caused by the rickettsial agent cowdria ruminantium, is one of the most devastating livestock diseases in sub-saharan africa. in addition to domestic cattle, sheep, and goats, a variety of nondomestic species can acquire subclinical and clinical infections. recent epidemiologic findings that demonstrate a long-term host carrier state in domestic and wild ruminants, intrastadial transmission by the tick vectors (amblyomma spp.), vertical transmission of the agent from cows to their ca ...19989732023
immunization of rabbits with amblyomma hebraeum nymphal homogenates and implications for the host amplification system.immunochemical mechanisms involved in tick rejection by a host are not well documented. the role of serum globulins, and that played by the amplification system's humoral products (thrombin from the coagulation, plasmin from the fibrinolytic, and kallikrein from the kinin systems) in tick-resistant animal hosts have not yet been demonstrated. it is known, however, that factors c1, c3 and c5 of the complement system play a role in tick rejection, and that factors c3a and c5a are anaphylatoxins ca ...19989741053
ixodid tick infestations of wild birds and mammals on a game ranch in central province, zambia.ticks were collected at irregular intervals from december 1995 to november 1996 from wildlife on mtendere game ranch in the chisamba district of central province, zambia. total collections were made from two species of ground-nesting birds and 20 species of small and large mammals. thirteen species/subspecies of ixodid ticks were recovered. rhipicephalus appendiculatus was the most abundant, followed by boophilus decoloratus and rhipicephalus evertsi evertsi. small numbers of immature ticks of o ...19989741055
establishment of the tortoise tick amblyomma marmoreum (acari: ixodidae) on a reptile-breeding facility in florida.the tortoise tick amblyomma marmoreum koch was found to be established on a reptile facility in central florida. over a 5-mo period, 443 ticks were collected from tortoises, dogs, and vegetation. collections from hosts were primarily from 3 species of exotic tortoises, including leopard tortoises, aldabra tortoises, and yellow-footed tortoises. the total numbers of ticks present, the presence of all life stages, and the slow development of this species indicate that this is not a recent infestat ...19989775582
kinetics and cross-species comparisons of host antibody responses to lone star ticks and american dog ticks (acari: ixodidae).understanding of the animal antibody response to tick salivary gland proteins is necessary to identify candidate antibodies that may have use as species- and feeding-duration-specific biomarkers of tick exposure in humans. the kinetics of the humoral immune response of rabbits to challenge feeding by 2 tick species [amblyomma americanum (l.) and dermacentor variabilis (say)] was characterized by both enzyme-linked immunosorbent assay and immunoblot. western blot analysis revealed that rabbits pr ...19989775620
geographic distribution of ticks (acari: ixodidae) in michigan, with emphasis on ixodes scapularis and borrelia burgdorferi.a 12-yr (1985-1996) passive survey in michigan based upon tick submissions from citizens yielded 4,755 ticks of 21 species, 16 of which were probably indigenous in the state. three species of dermacentor [most common, d. variabilis say and d. albipictus (packard)]; 2 species of amblyomma [most common, a. americanum (l.)]; and 12 species of ixodes (most common, i. cookei packard and i. scapularis say), as well as haemaphysalis leporispalustris (packard), rhipicephalus sanguineus latreille, and th ...19989775623
ehrlichia chaffeensis in missouri ticks.a nested polymerase chain reaction specific for ehrlichia chaffeensis was used to attempt to amplify dna from extracts of 100 individual ticks collected from 13 counties in central missouri. seventeen of 59 amblyomma americanum and six of 41 dermacentor variabilis ticks exhibited the characteristic 389-basepair product. this supports the hypothesis that these tick species may be vectors of human monocytic ehrlichiosis.19989790445
natural coinfection of a white-tailed deer (odocoileus virginianus) population with three ehrlichia spp.the ticks amblyomma americanum and ixodes scapularis, strongly implicated vectors of ehrlichia chaffeensis and the human granulocytic ehrlichiosis (hge) agent, respectively, commonly are found on white-tailed deer (odocoileus virginianus). as deer can be infected with e. chaffeensis, the hge agent, and another ehrlichia-like organism, a deer population parasitized by both tick species in coastal georgia was tested for evidence of ehrlichia spp. infection using serologic, molecular, and culture t ...19989794627
the distribution of heartwater in the highveld of zimbabwe, 1980-1997.heartwater, the tick-borne disease caused by the rickettsia cowdria ruminantium has historically been confined to the southern and western lowvelds of zimbabwe. since 1986, however, cases of heartwater have been diagnosed with increasing frequency in the central and eastern regions of the previously heartwater-free highveld plateau. during the same period, collections of the two major tick vectors of heartwater in zimbabwe, amblyomma hebraeum and amblyomma variegatum, were made for the first tim ...19989809322
parasites of domestic and wild animals in south africa. xxxv. ixodid ticks and bot fly larvae in the bontebok national park.ixodid ticks were collected during february of each year from 1983-1992 from bontebok and grey rhebok in the bontebok national park, western cape province. when available other mammals as well as ground-nesting birds and leopard tortoises were examined. eleven tick species were recovered. rhipicephalus nitens followed by rhipicephalus glabroscutatum and an ixodes sp. (near i. pilosus) were the most abundant, while amblyomma marmoreum infested the widest host range. the larvae of three bot files ...19989809325
comment on "a possible explanation of the apparent breed-related resistance in cattle to bont tick (amblyomma hebraeum) infestations" by m.i. meltzer, veterinary parasitology 67 (1996) 275-279. 19989823067
a molecular and serologic survey of ehrlichia canis, e. chaffeensis, and e. ewingii in dogs and ticks from oklahoma.polymerase chain reaction and southern hybridization were used to survey for the presence of ehrlichia canis, ehrlichia chaffeensis, and ehrlichia ewingii in blood samples of 65 dogs that harbored ticks from northcentral and northeastern oklahoma. dog blood samples were also examined for antibodies against e. canis and e. chaffeensis, using an immunofluorescent antibody test. ten of 65 dogs (15.4%) examined were positive for ehrlichia spp. by pcr. four (6.2%) were positive for e. ewingii, 2 (3.1 ...19989831955
encephalitozoon-like microsporidia in the ticks amblyomma cajennense and anocentor nitens (acari: ixodidae).a encephalitozoon-like microsporidia was found in epithelial cells of the midgut and the salivary glands of amblyomma cajennense (f.) and anocentor nitens (neumann) that had fed on rabbits. ultrastructural studies demonstrated that all stages of the life cycle of the parasite occur in parasitophorous vacuoles and contain only 1 nucleus. the sporonts detach from the limiting membrane of the vacuole and divide by binary fission to produce the sporoblasts, each presenting a thickened electron-dense ...19989835698
experimental transmission of hepatozoon americanum vincent-johnson et al., 1997 to dogs by the gulf coast tick, amblyomma maculatum koch.experimental transmission of hepatozoon americanum to dogs was attempted with four ixodid ticks, viz., rhipicephalus sanguineus, amblyomma americanum, amblyomma maculatum and dermacentor variabilis. ticks that dogs ingested included some that were laboratory-reared and experimentally fed as nymphs on a dog with naturally occurring hepatozoonosis; other ticks were collected as replete or partially engorged larvae, nymphs and adults from dogs that had hepatozoonosis and natural infestations of tic ...19989877066
dna binding properties of the ecdysteroid receptor in the salivary gland of the female ixodid tick, amblyomma hebraeum.salivary gland degeneration in the female tick, amblyomma hebraeum koch (acari: ixodidae) is controlled by an ecdysteroid hormone. in an earlier study (mao, h., mcblain, w.a., kaufman, w.r., 1995. some properties of the ecdysteroid receptor in the salivary gland of the ixodid tick, amblyomma hebraeum. gen. comp. endocrinol. 99, 340-348), we demonstrated that a protein component of a salivary gland extract binds to ponasterone a (pon a) with high affinity (kd-1 nm), suggesting a tick ecdysteroid ...19989887511
[two cases of spotted fever group rickettsiosis contracted in southern parts of africa].a 40-year-old japanese male stayed in zimbabwe and developed a fever above 38 degrees c during which he noted a typical eschar in the lumbar region and also regional inguinal lymphadenopathy. although not conspicuous, erythematous eruptions accompanied by itching were observed on the face, trunk and lower extremities. after returning to japan and visiting our hospital, he was suspected of rickettsiosis and put on minocycline which gradually led to the improvement of the symptoms. immunofluoresce ...19989916419
population genetic structure of a three-host tick, amblyomma dissimile, in eastern venezuela.patterns of genetic variation for the tick amblyomma dissimile were analyzed from a total of 200 ticks collected on 12 toads (bufo marinus), 14 snakes (boa constrictor), and 8 lizards (iguana iguana) at 11 localities. the analyses were performed on electrophoretic data from 8 isozyme loci. mean heterozygosity per locus was 6% (+/-3.1) per population. differences in allelic frequencies among ticks from different individual hosts were the major source of genetic variability in this study. host spe ...19989920303
distributions of the vectors of heartwater, amblyomma hebraeum and amblyomma variegatum (acari: ixodidae), in zimbabwe.the tick vectors of heartwater (cowdria ruminantium infection) in zimbabwe, amblyomma hebraeum and amblyomma variegatum, historically were believed to be confined to the low-lying regions of the south and north-west of the country. however, country-wide surveys performed in 1975-1980 and 1988-1991 demonstrated that both species were also established in western parts of the highveld plateau and had started to encroach on the predominantly heartwater-free central and eastern highveld regions. to d ...199810030008
profile of the ecdysteroid hormone and its receptor in the salivary gland of the adult female tick, amblyomma hebraeum.we examined the hemolymph ecdysteroid titer (by radioimmunoassay) and profile of the ecdysteroid receptor (ecr/usp; by [3h]ponasterone a binding, gel mobility shift assay, western blot) in the salivary gland of the ixodid tick, amblyomma hebraeum koch (acari: ixodidae) throughout the tick feeding period and first 6 days post-engorgement. throughout the slow phase of feeding, the hemolymph ecdysteroid titer was approximately 18 pg/microliter. the titer peaked at approximately 52 pg/microliter dur ...199910070743
molecular cloning of camp-dependent protein kinase catalytic subunit isoforms from the lone star tick, amblyomma americanum (l.).the salivary glands of ixodid ticks are central to tick feeding and to survival during off-host periods. they produce and secrete a number of molecules critical to maintaining the complex host-vector interface and to maintaining osmotic balance. we have previously shown that a cyclic amp-dependent protein kinase (capk) is involved in the mechanism of salivary gland secretion. we have now cloned cdnas encoding three isoforms of the catalytic subunit (capk-c) of the capk from amblyomma americanum, ...199910070744
naturally occurring hepatozoonosis in coyotes from oklahoma.nine of 16 free-ranging coyotes (canis latrans) from central oklahoma (usa) had naturally acquired infections of hepatozoon americanum. infections were confirmed by recognition of tissue stages closely resembling h. americanum in skeletal and cardiac muscle. at the time coyotes were collected they were infested with a variety of ticks, including adult gulf coast ticks (amblyomma maculatum). we propose that the high prevalence of h. americanum in this small sample of free-ranging coyotes and the ...199910073352
novel ehrlichia organism (rickettsiales: ehrlichieae) in white-tailed deer associated with lone star tick (acari: ixodidae) parasitism.polymerase chain reaction (pcr) evidence of a novel ehrlichia organism was found recently in wild white-tailed deer, odocoileus virginianus zimmermann, and lone star ticks, amblyomma americanum l., from the southeastern united states. to evaluate whether lone star tick parasitism was associated with the presence of this novel ehrlichia organism in deer, 2 retrospective studies were conducted using specific nested pcr to test archived deer serum samples. the 1st study of 150 serum samples collect ...199910083757
phylogeny of the hard ticks (ixodidae) inferred from 18s rrna indicates that the genus aponomma is paraphyletic.we examined the phylogeny of ticks (acari:parasitiformes:ixodida) and their closest known mite relatives (acari:parasitiformes:mesostigmata and holothyrida) using 18s rrna sequences. in our analyses, we included sequences from 36 taxa. sequences for 13 hard ticks (family ixodidae), 5 soft ticks (family argasidae), and 2 mesostigmatid mites were obtained from the genbank database and we generated sequences for 15 hard ticks and 1 holothyrid mite. ten of these tick species were endemic to australi ...199910191073
molecular cloning and characterization of the ehrlichia chaffeensis variable-length pcr target: an antigen-expressing gene that exhibits interstrain variation.a clone expressing an immunoreactive protein with an apparent molecular mass of 44 kda was selected from an ehrlichia chaffeensis arkansas genomic library by probing with anti-e. chaffeensis hyperimmune mouse ascitic fluid. nucleotide sequencing revealed an open reading frame (orf) capable of encoding a 198-amino-acid polypeptide. the orf contained four imperfect, direct, tandem 90-bp repeats. the nucleotide and deduced amino acid sequences did not show close homologies to entries in the molecul ...199910203503
[experimental transmission of crimean-congo hemorrhagic fever virus: role of 3 vector species in the maintenance and transmission cycles in senegal].in this article, we published the role of three species of ticks amblyomma variegatum (fabricius, 1974), hyalomma marginatum rufipes (koch, 1844) and hyalomma truncatum (koch, 1844) in the maintenance and transmission of the cchf virus. the imagos of these species were infected by intracoelomic route. vertical transmission (transtasial and transovarial) and horizontal transmission for different stases were studied by isolation on newborn mice, polymerase chain reaction, indirect immunofluorescen ...199910229934
responses of three species of adult ticks (acari: ixodidae) to chemicals in the coats of principal and minor laboratory bioassays, host-seeking adult blacklegged ticks, ixodes scapularis say, lone star ticks, amblyomma americanum (l.), and american dog ticks, dermacentor variabilis (say), were exposed to substances from the pelage of dogs and white-tailed deer, odocoileus virginianus (zimmermann). male a. americanum exhibited an arrestant response to all samples of deer tarsal gland substances tested, whereas female a. americanum, female i. scapularis, and male and female d. variabilis responded to ...199910337091
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