| reactivation of rickettsia rickettsii in dermacentor andersoni ticks: an ultrastructural analysis. | virulent rickettsia in dermacentor andersoni lose their pathogenicity and virulence for guinea pigs when subjected to physiological stresses, such as starvation (overwintering), of its tick vector. however, incubation of infected ticks at an elevated temperature (37 degrees c) for 24 to 48 h or feeding for a time (usually greater than 10 h) induces r. rickettsii to revert to a virulent state, a phenomenon defined as "reactivation." electron microscopy reveals that the microcapsular and slime lay ... | 1982 | 6811439 |
| seasonal activity and colorado tick fever virus infection rates in rocky mountain wood ticks, dermacentor andersoni (acari: ixodidae), in north-central colorado, usa. | | 1983 | 6827573 |
| influence of parasitemia level at feeding on development of anaplasma marginale theiler in dermacentor andersoni stiles. | four splenectomized dairy calves were inoculated with a virginia isolate of anaplasma marginale theiler and served as an infective source (donor) for laboratory-reared dermacentor andersoni stiles nymphs. two donor calves developed higher parasitemias during tick feeding than did the 2 other donor calves. one month after molting, adult ticks were incubated at 37 c for 2.5 days to stimulate development of colonies of a marginale, and homogenates of gut were made from ticks fed on each donor calf. ... | 1983 | 6869951 |
| artificial feeding of adult and nymphal dermacentor andersoni (acari: ixodidae) during studies on bovine anaplasmosis. | | 1983 | 6876089 |
| in vitro feeding of dermacentor andersoni (stiles): effects of histamine and other mediators. | female dermacentor andersoni were induced to feed on defibrinated bovine blood through fixed mouse skin membranes. their feeding behaviour was recorded electronically, the tick being incorporated into the circuit and acting as a variable resistor during the periods of sucking, salivation and rest. recordings of the feeding behaviour of these ticks were similar to those of ticks feeding on rabbits. known concentrations of histamine, serotonin, dopamine, prostaglandin e1 and prostaglandin f2a were ... | 1983 | 6877868 |
| influence of dermacentor andersoni infestation on lymphocyte responsiveness to mitogens. | | 1982 | 6985018 |
| demonstration of anaplasma marginale theiler in ticks by tick transmission, animal inoculation, and fluorescent antibody studies. | cattle were inoculated with a virginia isolate of anaplasma marginale theiler and served as an infective source for laboratory-reared dermacentor andersoni stiles and d variabilis (say) nymphs. transstadial transmission of a marginale was demonstrated by feeding the newly molted adult ticks of both species on susceptible cattle and by inoculation of gut and salivary gland homogenates collected from adult ticks at postattachment days 5 and 7. oral secretions collected from the same group of ticks ... | 1980 | 6989298 |
| observations on the behaviour of dermacentor andersoni larvae infesting normal and tick resistant guinea-pigs. | in three separate experiments the behaviour of dermacentor andersoni larvae on normal and tick-resistant guinea-pigs was studied at intervals throughout 5-day infestation periods. fewer larvae survived on resistant hosts and their mean sizes were less than those of larvae on normal hosts, the differences becoming more obvious as time progressed. when measured at 32 degrees c, the peristaltic rates of midgut diverticula of the larvae surviving on resistant hosts were consistently lower than those ... | 1982 | 7070838 |
| morphologic characteristics of colonies of anaplasma marginale theiler in midgut epithelial cells of dermacentor andersoni stiles. | colonies of anaplasma marginale theiler were studied in midgut epithelial cells of adult dermacentor andersoni stiles that were infected as nymphs. colonies were categorized by light microscopy into 5 morphologic types that appear to represent stages in a developmental sequence. the mean diameter of the colony types ranged from 5.64 micrometer to type 1 colonies to 10.49 micrometers of type 5 colonies. representatives of each colony type were selected by light microscopy and were sectioned for e ... | 1982 | 7073078 |
| influence of increased temperature on anaplasma marginale theiler in the gut of dermacentor andersoni stiles. | three splenectomized dairy calves were inoculated with a virginia isolate of anaplasma marginale theiler and served as an infective source for laboratory-reared dermacentor andersoni stiles nymphs. one month after molting, groups of adult ticks were incubated at 37 c for 0, 1.5, 2.5, and 7 days. gut homogenates were made from ticks representing each incubation period. twenty-four susceptible, splenectomized dairy calves were each inoculated iv with a gut homogenate extracted from 50 adult ticks ... | 1982 | 7091815 |
| survey for evidence of colorado tick fever virus outside of the known endemic area in california. | a virus very similar or identical to colorado tick fever (ctf) virus was recovered from the blood clot of one of 104 black-tailed jack rabbits (lepus californicus) examined during a survey for various zoonotic agents in mammals and ticks from the university of california, hopland field station, mendocino county, california, 1974--79. this is the first reported isolation of a ctf-like virus from l. californicus, and only the second time such a virus has been found in northwestern california. mend ... | 1982 | 7102919 |
| quinone inhibition of sex pheromone activity in the ticks dermacentor andersoni stiles and dermacentor variabilis (say). | disruption of sex pheromone activity in female rocky mountain wood ticks, dermacentor andersoni stiles, and american dog ticks, dermacentor variabilis (say), was achieved by treatment with the quinones para-benzoquinone and menadione. the most effective treatments were those administered by inoculation to unfed, mature, adult females prior to feeding. inoculation of p-benzoquinone was also effective when administered to feeding ticks, from 2 to 5 days after they had attached, though not to the s ... | 1982 | 7131198 |
| guanine biosynthesis in the ticks (acari) dermacentor andersoni (ixodidae) and argas (persicargas) arboreus (argasidae): fate of labelled guanine precursors. | | 1982 | 7143379 |
| immune responsiveness of the bovine host to repeated low-level infestations with dermacentor andersoni. | | 1982 | 7149833 |
| dermacentor variabilis and dermacentor andersoni: genital sex pheromones. | | 1982 | 7151942 |
| the induction of host resistance to tick infestation with a salivary gland antigen. | salivary gland antigen, sga, derived from partially engorged female dermacentor andersoni was shown to be capable of inducing resistance to tick infestation in guinea pigs never previously exposed to ticks. immunization regimens involved the administration of sga by different routes and with or without the use of adjuvants. induced resistance was expressed by significantly fewer larvae engorging, and the weight of larvae which did engorge was reduced. salivary gland antigen has been shown to int ... | 1981 | 7212171 |
| ultrastructure of anaplasma marginale theiler in dermacentor andersoni stiles and dermacentor variabilis (say). | cattle were inoculated with a virginia isolate of anaplasma marginale theiler and served as an infective source for laboratory-reared dermacentor andersoni stiles and d variabilis (say) nymphs. anaplasma marginale was demonstrated by electron microscopy in gut tissues of replete nymphal ticks and in unfed, incubated, and feeding adult ticks that were exposed to the organism as nymphs when they fed on an infected cow. the a marginale organism in replete nymphs and adult feeding ticks were morphol ... | 1980 | 7212430 |
| transmission of anaplasma marginale theiler by dermacentor andersoni stiles and dermacentor variabilis (say). | cattle were inoculated with a virginia isolate of anaplasma marginale theiler and served as an infective source for laboratory-reared dermacentor andersoni stiles and d variabilis (say) nymphs. following a molt and subsequent feeding of adult ticks on susceptible cows, transstadial transmission of a marginale occurred from cattle with parasitemias ranging from undetectable (in a carrier cow) to a peak of 27% (in an acutely ill cow). homogenates of gut tissue from unfed, incubated, and feeding ad ... | 1981 | 7224310 |
| bilateral gynandromorphism in dermacentor andersoni (acari: ixodidae): morphologic and cytogenetic analysis. | | 1981 | 7288835 |
| resistance and cross-resistance of guinea pigs to dermacentor andersoni stiles, d. variabilis (say), amblyomma americanum (linnaeus), and ixodes scapularis say. | the ability of guinea pigs to acquire resistance to dermacentor andersoni and amblyomma americanum was determined by repeatedly infesting separate sets of guinea pigs with tick larvae. resistance was measured in terms of reduced numbers successfully engorging and reduced weight of those ticks that engorged. an 83% reduction in numbers of larvae engorging and a 64.5% reduction in the weight of engorged larvae were seen between the first and second infestations with d. andersoni. guinea pigs exhib ... | 1981 | 7328454 |
| chemoprophylaxis of vector-borne anaplasmosis with sustained-release boluses. | sustained-release oxytetracycline boluses (20%) delivering 145 to 150 mg/bolus/day were administered to complement-fixation test-negative cattle at dosages of 2.0, 2.5, and 3.0 mg/kg of body weight. subsequent challenge exposure of cattle with dermacentor andersoni stiles infected with anaplasma marginale theiler indicated that treatment with the dosage of 2.5 mg/kg prevented clinical anaplasmosis and that treatment with the dosage of 3.0 mg/kg prevented disease infection. | 1981 | 7340579 |
| the role of cottontail rabbits (sylvilagus spp.) in the ecology of rickettsia rickettsii in the united states. | rocky mountain (sylvilagus nuttallii) and eastern (s. floridanus) cottontails were examined for their susceptibility to virulent and avirulent strains of the spotted fever agent, rickettsia rickettsii. both species of rabbits responded to inoculation of yolk sac suspensions containing 500 egg ld50 of either virulent or avirulent rickettsiae, with rickettsemias detectable as early as 3 days after inoculation and lasting up to 7 days. when fed upon by infected ticks, only one of three rocky mounta ... | 1980 | 7406116 |
| dermacentor andersoni: salivary gland proteins suppressing t-lymphocyte responses to concanavalin a in vitro. | salivary glands obtained from feeding adult female dermacentor andersoni (acari:ixodidae) were fractionated using differential centrifugation, detergents, centrifugal concentrators incorporating filter membranes with various molecular weight cutoffs, and preparative sds-page. a lymphocyte proliferation assay was used to evaluate the effects of salivary gland fractions on cona-induced blastogenesis of normal murine splenocytes. lipid, soluble, and detergent-soluble fractions were found to signifi ... | 1995 | 7498423 |
| evidence of common and genus-specific epitopes on ornithodoros spp. tick (acari: argasidae) salivary proteins. | new zealand white rabbits were repeatedly infested with ornithodoros turicata (duges), ornithodoros talaje (guérin-méneville), and ornithodoros coriaceus (koch) at 2-wk intervals. blood samples were taken from each animal 10 d after each infestation and the titer of anti-tick antibody was determined by enzyme-linked immunosorbent assay. subsequent cross-reactivity studies demonstrated that the antitick antisera nonspecifically bound to salivary gland extract proteins prepared from several other ... | 1995 | 7544412 |
| mosquito sensitivity to a scorpion neurotoxin expressed using an infectious sindbis virus vector. | the scorpion, androctonus australis hector, produces an insect-specific toxin (aahit) encoded by the scotox gene. to assess the toxicity of aahit for mosquitoes, we have taken a novel approach to express the scotox gene in vivo. we have engineered a double subgenomic sindbis (dssin) virus that contains the scotox gene in the viral genome and intrathoracically inoculated the virus (te/3'2j/scotox) into mosquitoes (aedes aegypti, ae. triseriatus and culex pipiens), houseflies (musca domestica) and ... | 1995 | 7551198 |
| tick paralysis in two llamas. | an 18-month-old sexually intact male llama and a 7-month-old female llama were examined because of weakness, lethargy, and recumbency. both had signs of ascending motor paralysis with minimal or no afferent sensory loss. tick paralysis was diagnosed on the basis of complete clinical recovery following removal of a single, attached and engorged female tick (dermacentor andersoni) from each llama. the male llama recovered within a few hours after removal of the tick, but recovery in the female lla ... | 1995 | 7591950 |
| effects of dermacentor andersoni (acari: ixodidae) salivary gland extracts on bos indicus and b. taurus lymphocytes and macrophages: in vitro cytokine elaboration and lymphocyte blastogenesis. | cattle and laboratory animal species-acquired resistance to tick infestation has an immunological basis involving antigen presenting cells, b-lymphocytes, t-lymphocytes, and cytokines. tick infestation has been shown to impair guinea pig antibody responses to a thymic-dependent antigen and in vitro responsiveness of lymphocytes to t-cell mitogens. tick salivary gland extracts inhibited in vitro proliferative responses of normal murine lymphocytes to the t-cell mitogen concanavalin a (con a) and ... | 1995 | 7616525 |
| molecular and biological characterization of a newly isolated anaplasma marginale strain. | anaplasma marginale, a rickettsial hemoparasite of cattle and other ruminants, results in significant economic losses worldwide. distinct strains of a. marginale have been identified based on differences in tick transmissibility, molecular size of surface proteins and dna restriction fragments, and reactivity to a panel of monoclonal antibodies. these different strains vary considerably in their virulence, antigenic composition, and ability to protect against heterologous challenge. in this pape ... | 1994 | 7858023 |
| dna typing of rickettsiae in naturally infected ticks using a polymerase chain reaction/restriction fragment length polymorphism system. | we used the polymerase chain reaction/restriction fragment length polymorphism (pcr/rflp) rickettsial typing system of regnery and others to rapidly identify rickettsiae in naturally infected ticks. unlike previously described methods, our pcr assays type rickettsiae directly from tick tissues without first isolating the organisms. we collected 226 adult dermacentor andersoni ticks in the bitterroot mountains of western montana and analyzed them for possible rickettsial infection by hemolymph te ... | 1994 | 7906924 |
| persistence of tick-derived anaplasma marginale in cultured bovine turbinate and endothelial cells. | anaplasma marginale from salivary glands of dermacentor andersoni was used to inoculate monolayers of bovine turbinate and endothelial cells. monolayers were passaged at 2 or 4 week intervals and monitored with light and electron microscopy and with an a. marginale-specific dna probe. intracellular inclusions were observed in turbinate cells after 2-4 weeks. the number of inclusion-bearing cells increased over 1-2 weeks and gradually disappeared. a radiolabeled fragment from within the msp1 beta ... | 1993 | 8134656 |
| acquired resistance of guinea pigs to dermacentor andersoni mediated by humoral factors. | humoral and cell-mediated immune resistance to tick infestation has been documented in many host-parasite relationships. this study examines passive transfer of resistance to dermacentor andersoni expressed by recipients of serum pools derived from guinea pigs that had acquired resistance through experimental infestation. recipients of sera from high titer adult-infested animals expressed resistance evidenced by reduced engorgement weights, histological changes at tick attachment sites, and tick ... | 1993 | 8277384 |
| detection of anaplasma marginale (rickettsiales: anaplasmataceae) in hemolymph of dermacentor andersoni (acari: ixodidae) with the polymerase chain reaction. | the polymerase chain reaction (pcr) was used to detect anaplasma marginale in hemolymph collected from live dermacentor andersoni stiles ticks. hemolymph was collected from severed legs of male and female ticks exposed to a. marginale as either nymphs or adults. heat treatment was found to be the optimum method of hemolymph preparation for pcr. hemolymph samples were collected and pooled from adult ticks exposed as nymphs on days 0-10 of feeding on a susceptible calf. for male and female ticks e ... | 1993 | 8360902 |
| detection of anaplasma marginale (rickettsiales: anaplasmataceae) in secretagogue-induced oral secretions of dermacentor andersoni (acari: ixodidae) with the polymerase chain reaction. | the polymerase chain reaction (pcr) was used to detect anaplasma marginale in secretagogue-induced oral secretions of male and female dermacentor andersoni stiles exposed as nymphs or adults by feeding on infected calves. a 409-bp dna fragment derived from the a. marginale (florida isolate) msp1 beta gene was amplified with oligonucleotide primers bap-2 (5'-gtatggcacgtagtcttgggatca-3') and al34s (5'-cagcagcagcaagaccttca-3'). the target dna was amplified in oral secretions of female ticks exposed ... | 1993 | 8360903 |
| impact of persistent anaplasma marginale rickettsemia on tick infection and transmission. | anaplasma marginale, an intraerythrocytic rickettsia of cattle, is transmitted biologically by ticks. because of the brevity of acute a. marginale infection, transmission may rely on the tick's ability to acquire the organism from persistently infected cattle with low rickettsemia levels. by using a nucleic acid probe to quantitate low-level infection, we found that rickettsemia levels in persistently infected cattle fluctuated at approximately 5-week intervals during a 24-week period, from < 10 ... | 1993 | 8370734 |
| development of anaplasma marginale in salivary glands of male dermacentor andersoni. | development of the rickettsia, anaplasma marginale, in salivary glands of male dermacentor andersoni exposed as nymphs or adult ticks, was studied indirectly by inoculation of susceptible calves with homogenates and directly by examination, using light microscopy and a dna probe; some unfed ticks were incubated before tissues were collected. salivary gland homogenates made from ticks in every treatment group caused anaplasmosis when injected into susceptible calves; prepatent periods decreased a ... | 1993 | 8427453 |
| ecology of porcupines (erethizon dorsatum) and colorado tick fever virus in rocky mountain national park, 1975-1977. | the involvement of porcupines, erethizon dorsatum (l.), in the ecology of colorado tick fever (ctf) virus in rocky mountain national park was investigated from 1975 to 1977. porcupine dens and feeding activity were found mostly on rocky knolls or on south-facing slopes within open stands of the montane coniferous forest, and 20 adult porcupines were trapped or captured by hand at those locations. an average of 24.6 +/- 5.4 adult dermacentor andersoni stiles ticks were found per animal (annual ra ... | 1993 | 8433332 |
| preliminary studies on the effect of anaplasma marginale antibodies ingested by dermacentor andersoni ticks (acari:ixodidae) with their blood meal on infections in salivary glands. | the effect of anaplasma marginale antibodies ingested with the tick blood meal was tested on infected male ticks that were allowed to feed on cattle immunized with the erythrocytic stage of a. marginale. the experiments were done in two trials. trial 1 was done using splenectomized calves (two calves per treated and control groups) while ticks in trial 2 were fed on intact yearling cattle (four cattle per treated and control groups). the cattle were immunized with purified outer membrane protein ... | 1996 | 8674360 |
| antibody against an anaplasma marginale msp5 epitope common to tick and erythrocyte stages identifies persistently infected cattle. | a protein epitope of major surface protein 5 (msp5), defined by monoclonal antibody (mab) anaf16c1, is conserved among anaplasma species (e. s. visser, t. c. mcguire, g. h. palmer, w. c. davis, v. shkap, e. pipano, and d. p. knowles, jr., infect. immun. 60:5139-5144, 1992) and is expressed in the salivary glands of infected ticks. a competitive inhibition elisa (celisa) for the detection of bovine anti-msp5 antibodies was developed by using purified recombinant msp5 fusion protein and mab anaf16 ... | 1996 | 8862589 |
| developmental studies of anaplasma marginale (rickettsiales:anaplasmataceae) in male dermacentor andersoni (acari:ixodidae) infected as adults by using nonradioactive in situ hybridization and microscopy. | the development of anaplasma marginale theiler was studied in ticks using a nonradioactive in situ hybridization method developed in our laboratory. male rocky mountain wood ticks, dermacentor andersoni stiles, were infected intrastadially by allowing them to feed for 7 d on an infected calf (acquisition feeding). the ticks were then removed and held in a humidity chamber for 5 d before being fed on a 2nd susceptible call for 10 d (transmission feeding). two groups of 10 ticks were collected dai ... | 1996 | 8961639 |
| rickettsia peacockii sp. nov., a new species infecting wood ticks, dermacentor andersoni, in western montana. | rickettsia peacockii, a new species of spotted fever group rickettsiae, was identified from rocky mountain wood ticks (dermacentor andersoni) collected in the sapphire mountain range on the eastern side of bitterroot valley, montana. dna from r. peacockii skalkahot (t = type strain) in naturally infected tick tissue was amplified by a pcr assay with primer sets derived from eubacterial 16s ribosomal dna (rdna), rickettsial citrate synthase, and 190-kda surface antigen (rompa) genes. partial 16s ... | 1997 | 9103635 |
| vector competence of ixodes scapularis, i. spinipalpis, and dermacentor andersoni (acari:ixodidae) in transmitting borrelia burgdorferi, the etiologic agent of lyme disease. | this report describes the vector competence of 3 ixodid tick species, ixodes scapularis (say), i. spinipalpis (nuttall), and dermacentor andersoni (stiles), for borrelia burgdorferi in colorado. the study was based on preliminary field work performed in 6 colorado counties, where rodents and ticks were collected and assayed for the presence of b. burgdorferi. four of the 6 counties produced 52 rodent and 39 i. spinipalpis isolates of b. burgdorferi. two b. burgdorferi isolates were tested under ... | 1997 | 9103755 |
| detection of colorado tick fever virus by using reverse transcriptase pcr and application of the technique in laboratory diagnosis. | colorado tick fever (ctf) virus elicits an acute illness in humans, producing nonspecific flu-like symptoms and a biphasic fever in approximately 50% of patients. the disease is transmitted by the adult rocky mountain wood tick (dermacentor andersoni), and therefore incidence is limited by the habitat and life cycle of that vector. the early symptoms of infection are difficult to distinguish from those of several other agents, especially rickettsia rickettsii. serologic testing is usually unable ... | 1997 | 9114408 |
| characterization of an endosymbiont infecting wood ticks, dermacentor andersoni, as a member of the genus francisella. | a microorganism (dermacantor andersoni symbiont [das]) infecting rocky mountain wood ticks (d. andersoni) collected in the bitterroot mountains of western montana was characterized as an endosymbiont belonging to the genus francisella. previously described as wolbachia like, the organism's dna was amplified from both naturally infected tick ovarial tissues and vero cell cultures by pcr assay with primer sets derived from eubacterial 16s ribosomal dna (rdna) and francisella membrane protein genes ... | 1997 | 9327558 |
| african swine fever virus infection in the argasid host, ornithodoros porcinus porcinus. | the pathogenesis of african swine fever virus (asfv) infection in ornithodoros porcinus porcinus was examined in nymphal ticks infected with the asfv isolate chiredzi/83/1. at times postinfection (p.i.) ranging from 6 h to 290 days, ticks or dissected tick tissues were titrated for virus and examined ultrastructurally for evidence of virus replication. the asfv infection rate in ticks was 100% in these experiments, and virus infection was not associated with a significant increase in tick mortal ... | 1998 | 9499019 |
| detection of cattle naturally infected with anaplasma marginale in a region of endemicity by nested pcr and a competitive enzyme-linked immunosorbent assay using recombinant major surface protein 5. | a competitive enzyme-linked immunosorbent assay using recombinant major surface protein 5 (rmsp5-celisa) of anaplasma marginale was validated in a naturally infected cattle herd in an area of eastern oregon where a. marginale is endemic. the true positive and negative a. marginale infection status of 235 randomly selected cattle was determined by using a nested pcr (npcr) coupled with msp5 sequence analysis and hybridization. judgment of the reliability of the npcr and hybridization for detectio ... | 1998 | 9508311 |
| granulocytic ehrlichiosis in tick-immune guinea pigs. | we investigated whether ixodes scapularis-mediated host immunity interrupts transmission of the agent of human granulocytic ehrlichiosis (aohge) to guinea pigs. ticks infected with aohge readily transmitted aohge to tick-immune guinea pigs, despite incomplete tick engorgement and host attachment. although tick immunity can prevent lyme borreliosis, protection is not afforded against granulocytic ehrlichiosis. | 1998 | 9529119 |
| tick-borne diseases of sheep and goats caused by babesia, theileria or anaplasma spp. | a review is given on the babesia, theileria, and anaplasma species infecting sheep and goats. b. ovis is the most important disease agent. it is transmitted by rhipicephalus bursa, r. turanicus, hyalomma anatolicum excavatum, and probably by r. evertsi evertsi b. ovis is widely spread in southern europe, the middle east, and central asia. its geographical distribution in south and east asia and in africa is widely unknown. b. motasi obviously represents several nosodemes in separate regions. it ... | 1997 | 9530692 |
| taxonomic relationships among spotted fever group rickettsiae as revealed by antigenic analysis with monoclonal antibodies. | the spotted fever group (sfg) is made up of more than 20 different rickettsial species and strains. study of the taxonomic relationships among the group has been attempted by phenotypic, genotypic, and phylogenetic analyses. in this study, we determined taxonomic relationships among the sfg rickettsiae by comparative analysis of immunogenic epitopes reactive against a panel of monoclonal antibodies. a total of 98 monoclonal antibodies, which were directed against epitopes on the major immunodomi ... | 1998 | 9542904 |
| 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 ... | 1998 | 9574696 |
| in vitro susceptibilities of 27 rickettsiae to 13 antimicrobials. | the mics of 13 antibiotics (doxycycline, thiamphenicol, rifampin, amoxicillin, gentamicin, co-trimoxazole, ciprofloxacin, pefloxacin, ofloxacin, erythromycin, josamycin, clarithromycin, and pristinamycin) were determined for 27 available rickettsial species or strains. we used two in vitro cell culture methods described previously: the plaque assay and the microplaque colorimetric assay. our results confirm the susceptibilities of rickettsiae to doxycycline, thiamphenicol, and fluoroquinolones. ... | 1998 | 9660979 |
| development of a non-radioactive dna probe and in situ hybridization for detection of anaplasma marginale in ticks and cattle. | a non-radioactive dna probe was developed for detection of anaplasma marginale in ticks and cattle. the probe was labeled with digoxigenin 11-dutp by polymerase chain reaction. the probe was tested on bovine blood and was found to be a sensitive and specific detection method for a. marginale in cattle. the dna probe was then adapted for in situ hybridization (ish) of a. marginale in dermacentor andersoni and d. variabilis ticks infected either as nymphs or adults. one-half of each tick was studi ... | 1998 | 9668458 |
| characterization of an immunosuppressant protein from dermacentor andersoni (acari: ixodidae) salivary glands. | a 36-kda soluble protein was found in the salivary glands of female dermacentor andersoni (stiles) ticks that suppressed the in vitro proliferative response of murine splenocytes to concanavalin a (con a). incubating the purified protein with splenocytes reduced the incorporation of thymidine into the dna of proliferating t-lymphocytes by more than 90% compared with cells exposed to con a and buffer alone. the n-terminal amino acid sequence of the immunosuppressant protein was determined to be n ... | 1998 | 9701936 |
| tick-borne relapsing fever in british columbia, canada: first isolation of borrelia hermsii. | the spirochete that causes tick-borne relapsing fever, borrelia hermsii, was isolated in pure culture during 1995 and 1996 from three acutely ill human patients infected in southern british columbia, canada. the geographic area of exposure is a known focus of this disease dating back to 1930 when the first case was recognized in a human. analyses of plasmid dna, protein profiles, and reactivity with a species-specific monoclonal antibody identified the new isolates of spirochetes as b. hermsii, ... | 1998 | 9817862 |
| persistence of anaplasma ovis infection and conservation of the msp-2 and msp-3 multigene families within the genus anaplasma. | goats which have recovered from acute anaplasma ovis infection remain seropositive, although infected erythrocytes cannot be detected by microscopic examination. persistence of a. ovis 17 to 21 months following experimental infection was demonstrated by pcr detection of the msp-5 gene. quantitative analysis of persistent rickettsemia over time showed that all levels were below the limit of microscopic detection and ranged from a low of 10(2) organisms/ml to peaks of 10(6) organisms/ml. two patte ... | 1998 | 9826393 |
| comparison of surface proteins of anaplasma marginale grown in tick cell culture, tick salivary glands, and cattle. | anaplasma marginale, a tick-borne rickettsial pathogen of cattle, infects bovine erythrocytes, resulting in mild to severe hemolytic disease that causes economic losses in domestic livestock worldwide. recently, the virginia isolate of a. marginale was propagated in a continuous tick cell line, ide8, derived from embryonic ixodes scapularis. development of a. marginale in cell culture was morphologically similar to that described previously in ticks. in order to evaluate the potential of the cel ... | 1999 | 9864202 |
| lethal effect of rickettsia rickettsii on its tick vector (dermacentor andersoni). | rickettsia rickettsii, the causative agent of rocky mountain spotted fever, was lethal for the majority of experimentally and transovarially infected rocky mountain wood ticks (dermacentor andersoni). overall, 94.1% of nymphs infected as larvae by feeding on rickettsemic guinea pigs died during the molt into adults and 88. 3% of adult female ticks infected as nymphs died prior to feeding. in contrast, only 2.8% of uninfected larvae failed to develop into adults over two generations. infected fem ... | 1999 | 9925615 |
| body lice as tools for diagnosis and surveillance of reemerging diseases. | body lice are vectors of three bacteria which cause human disease: rickettsia prowazekii, the agent of epidemic typhus; bartonella quintana, the agent of trench fever; and borrelia recurrentis, the agent of relapsing fever. a recrudescence of body lice is being observed as the numbers of individuals living under social conditions which predispose individuals to infestation have increased. because this phenomenon may lead to the reemergence of infections transmitted by body lice, we aimed to asse ... | 1999 | 9986818 |
| comparison of ehrlichia muris strains isolated from wild mice and ticks and serologic survey of humans and animals with e. muris as antigen. | in metropolitan tokyo, the ehrlichia muris seropositivity rate of 24 wild mice was 63% in hinohara village, but in the surrounding areas, it was 0 to 5%. this finding suggests that the reservoir of e. muris is focal. among the 15 seropositive mice, ehrlichiae were isolated from 9 apodemus speciosus mice and 1 a. argenteus mouse, respectively. five ehrlichial isolates were obtained from 10 ticks (haemaphysalis flava) collected in asuke town, aichi prefecture, where the e. muris type strain had be ... | 1999 | 10074536 |
| restriction of major surface protein 2 (msp2) variants during tick transmission of the ehrlichia anaplasma marginale. | anaplasma marginale is an ehrlichial pathogen of cattle that establishes lifelong persistent infection. persistence is characterized by rickettsemic cycles in which new a. marginale variant types, defined by the sequence of the expressed msp2 transcripts, emerge. the polymorphic msp2 transcripts encode structurally distinct msp2 proteins and result in an antigenically diverse and continually changing a. marginale population within the blood. in this manuscript, we used sequence analysis of msp2 ... | 1999 | 10077656 |
| detection and identification of ehrlichia, borrelia burgdorferi sensu lato, and bartonella species in dutch ixodes ricinus ticks. | a sensitive and specific pcr hybridization assay was developed for the simultaneous detection and identification of ehrlichia and borrelia burgdorferi sensu lato. in separate assays the 16s rrna gene of ehrlichia species and the 23s-5s rrna spacer region of b. burgdorferi sensu lato were amplified and labeled by pcr. these pcr products were used in a reverse line blot hybridization assay in which oligonucleotide probes are covalently linked to a membrane in parallel lines. hybridization of the s ... | 1999 | 10364588 |
| invasion and intracellular development of the human granulocytic ehrlichiosis agent in tick cell culture. | human granulocytotropic ehrlichias are tick-borne bacterial pathogens that cause an acute, life-threatening illness, human granulocytic ehrlichiosis (hge). ehrlichias within neutrophil granulocytes that invade tick bite sites are likely ingested by the vector, to be transmitted to another mammalian host during the tick's next blood meal. thus, the cycle of replication and development in the vector is prerequisite to mammalian infection, and yet these events have not been described. we report tic ... | 1999 | 10405394 |
| q fever. | q fever is a zoonosis with a worldwide distribution with the exception of new zealand. the disease is caused by coxiella burnetii, a strictly intracellular, gram-negative bacterium. many species of mammals, birds, and ticks are reservoirs of c. burnetii in nature. c. burnetii infection is most often latent in animals, with persistent shedding of bacteria into the environment. however, in females intermittent high-level shedding occurs at the time of parturition, with millions of bacteria being r ... | 1999 | 10515901 |
| tick paralysis: 33 human cases in washington state, 1946-1996. | tick paralysis is a preventable cause of illness and death that, when diagnosed promptly, requires simple, low-cost intervention (tick removal). we reviewed information on cases of tick paralysis that were reported to the washington state department of health (seattle) during 1946-1996. thirty-three cases of tick paralysis were identified, including 2 in children who died. most of the patients were female (76%), and most cases (82%) occurred in children aged <8 years. nearly all cases with infor ... | 1999 | 10585792 |
| immunity reduces reservoir host competence of peromyscus leucopus for ehrlichia phagocytophila. | infection with ehrlichia phagocytophila in white-footed mice is transient and followed by a strong immune response. we investigated whether the presence of acquired immunity against e. phagocytophila precludes white-footed mice from further maintenance of this agent in nature. mice were infected with e. phagocytophila via tick bite and challenged either 12 or 16 weeks later by ixodes scapularis nymphs infected with the same agent. xenodiagnostic larvae fed upon each mouse simultaneously with cha ... | 2000 | 10678968 |
| a state-by-state survey of ticks recorded from humans in the united states. | based on tick specimens accessioned into the u.s. national tick collection, the species of ticks recorded as ectoparasites of humans are documented and compared for 49 u.s. states. a total of 44 tick species was recorded as parasites of humans, consisting of 11 species of soft ticks (argasidae) and 33 species of hard ticks (ixodidae). four of the hard tick species are not native to the u.s. and were removed from travelers returning from foreign destinations. therefore, we record 40 of the 84 spe ... | 2000 | 10925803 |
| influence of soluble proteins from the salivary glands of ixodid ticks on the in-vitro proliferative responses of lymphocytes from balb/c and c3h/hen mice. | in the u.s.a., borrelia burgdorferi, the causative agent of lyme borreliosis, is transmitted to humans by the ticks ixodes scapularis and i. pacificus. tick modulation of host immunity is an important factor in tick transmission of such pathogens. the proliferative responses of lymphocytes from balb/c and c3h/hen mice exposed to the salivary-gland soluble proteins (sgsp) of i. scapularis, i. pacificus or dermacentor andersoni were therefore compared in vitro. this produced the present report, th ... | 2000 | 10983564 |
| antigenic variation of anaplasma marginale by expression of msp2 mosaics. | anaplasma marginale is a tick-borne pathogen, one of several closely related ehrlichial organisms that cause disease in animals and humans. these ehrlichia species have complex life cycles that require, in addition to replication and development within the tick vector, evasion of the immune system in order to persist in the mammalian reservoir host. this complexity requires efficient use of the small ehrlichial genome. a. marginale and related ehrlichiae express immunoprotective, variable outer ... | 2000 | 11035716 |
| evaluation of pcr-based methods for discrimination of francisella species and subspecies and development of a specific pcr that distinguishes the two major subspecies of francisella tularensis. | previous studies have demonstrated that the four subspecies of the human pathogen francisella tularensis, despite showing marked variations in their virulence for mammals and originating from different regions in the northern hemisphere, display a very close phylogenetic relationship. this property has hampered the development of generally applicable typing methods. to overcome this problem, we evaluated the use of pcr for discrimination of the subspecies using various forms of long arbitrary pr ... | 2000 | 11060087 |
| isolation of a spotted fever group rickettsia, rickettsia peacockii, in a rocky mountain wood tick, dermacentor andersoni, cell line. | an embryonic cell line (dae100) of the rocky mountain wood tick, dermacentor andersoni, was observed by microscopy to be chronically infected with a rickettsialike organism. the organism was identified as a spotted fever group (sfg) rickettsia by pcr amplification and sequencing of portions of the 16s rrna, citrate synthase, rickettsia genus-specific 17-kda antigen, and sfg-specific 190-kda outer membrane protein a (rompa) genes. sequence analysis of a partial rompa gene pcr fragment and indirec ... | 2001 | 11157215 |
| strain composition of the ehrlichia anaplasma marginale within persistently infected cattle, a mammalian reservoir for tick transmission. | tick-borne ehrlichial pathogens of animals and humans require a mammalian reservoir of infection from which ticks acquire the organism for subsequent transmission. in the present study, we examined the strain structure of anaplasma marginale, a genogroup ii ehrlichial pathogen, in both an acute outbreak and in persistently infected cattle that serve as a reservoir for tick transmission. using the msp1alpha genotype as a stable strain marker, only a single genotype was detected in a disease outbr ... | 2001 | 11158120 |
| neuropathogenic properties of argas (persicargas) walkerae larval homogenates. | several tick species have been demonstrated, described, or suspected to cause paralysis in their host during the repletion process, presumably by impairing neurotransmission. the resulting polyneuropathy gradually spreads to the upper limbs causing incoordination and ends in respiratory failure. this form of paralysis is commonly confused with guillain-barrè syndrome, botulism and myasthenia gravis and although the clinical symptoms of these diseases are similar, it is not clear whether the path ... | 2001 | 11223384 |
| what's eating you? dermacentor andersoni. | | 2001 | 11236219 |
| quantitative analyses of variations in the injury of endothelial cells elicited by 11 isolates of rickettsia rickettsii. | eleven isolates of spotted fever group rickettsiae from the blood of patients or ixodid ticks from north and south america were characterized. all isolates were identified as rickettsia rickettsii using restriction fragment length polymorphism analysis of a 532-bp rompa gene fragment obtained by pcr. the ability of the r. rickettsii isolates to elicit cytopathic effects and parameters of oxidative injury were examined in cultured human ea.hy 926 endothelial cells. cytopathic effects were determi ... | 2001 | 11427428 |
| expression of anaplasma marginale major surface protein 2 variants in persistently infected ticks. | anaplasma marginale, an intraerythrocytic ehrlichial pathogen of cattle, establishes persistent infections in both vertebrate (cattle) and invertebrate (tick) hosts. the ability of a. marginale to persist in cattle has been shown to be due, in part, to major surface protein 2 (msp2) variants which are hypothesized to emerge in response to the bovine immune response. msp2 antigenic variation has not been studied in persistently infected ticks. in this study we analyzed msp2 in a. marginale popula ... | 2001 | 11447197 |
| dermacentor andersoni: effects of repeated infestations on lymphocyte proliferation, cytokine production, and adhesion-molecule expression by balb/c mice. | the effects of repeated infestations with dermacentor andersoni nymphs on the lymphocyte functions of balb/c mice were investigated. the in-vitro proliferation responses to concanavalin-a or salivary-gland molecules, the production of cytokines, and the expression of two adhesion molecules-leucocyte function-associated antigen-1 (lfa-1) and very late activation-4 (vla-4)-were all studied. in addition, the ability of salivary-gland extract or saliva from d. andersoni to modulate expression of lym ... | 2001 | 11454252 |
| health protocol for translocation of free-ranging elk. | when considering an elk (cervus elaphus) restoration program, wildlife managers must evaluate the positive and negative elements of translocation. we prepared this protocol to give an overview of health considerations associated with translocation of elk, with an emphasis on movement of free-ranging elk from western north america to the southeastern usa. we evaluated infectious agents and ectoparasites reported in elk from two perspectives. first, we made a qualitative estimate of the ability of ... | 2001 | 11504216 |
| transcriptional analysis of p30 major outer membrane multigene family of ehrlichia canis in dogs, ticks, and cell culture at different temperatures. | ehrlichia canis, an obligatory intracellular bacterium of monocytes and macrophages, causes canine monocytic ehrlichiosis. e. canis immunodominant 30-kda major outer membrane proteins are encoded by a polymorphic multigene family consisting of more than 20 paralogs. in the present study, we analyzed the mrna expression of 14 paralogs in experimentally infected dogs and rhipicephalus sanguineus ticks by reverse transcription-pcr using gene-specific primers followed by southern blotting. eleven ou ... | 2001 | 11553557 |
| specific expression of anaplasma marginale major surface protein 2 salivary gland variants occurs in the midgut and is an early event during tick transmission. | infectivity of anaplasma spp. develops when infected ticks feed on a mammalian host (transmission feed). specific anaplasma marginale major surface protein 2 (msp2) variants are selected for within the tick and are expressed within the salivary glands. the aims of this study were to determine when and where msp2 variant selection occurs in the tick, how msp2 expression is regulated in salivary glands of transmission-feeding ticks, and whether the number of a. marginale organisms per salivary gla ... | 2002 | 11748171 |
| colorado tick fever. | colorado tick fever, also known as mountain fever and mountain tick fever, is a well-described, viral, tick-borne disease common to the rocky mountain region of the united states and canada. the rocky mountain wood tick, dermacentor andersoni, is the primary vector. the triad of high fever, severe myalgia, and headache is typical, but not specific. although a self-limited disease in most cases, severe complications may occur. pcr techniques have been developed that allow the diagnosis to be esta ... | 2002 | 11982311 |
| infection of tick cells and bovine erythrocytes with one genotype of the intracellular ehrlichia anaplasma marginale excludes infection with other genotypes. | anaplasma marginale, a tick-borne rickettsial pathogen of cattle, is endemic in several areas of the united states. many geographic isolates of a. marginale that occur in the united states are characterized by the major surface protein 1a, which varies in sequence and molecular weight due to different numbers of tandem repeats of 28 or 29 amino acids. recent studies (g. h. palmer, f. r. rurangirwa, and t. f. mcelwain, j. clin. microbiol. 39:631-635, 2001) of an a. marginale-infected herd of catt ... | 2002 | 11986275 |
| tularemia. | francisella tularensis is the etiological agent of tularemia, a serious and occasionally fatal disease of humans and animals. in humans, ulceroglandular tularemia is the most common form of the disease and is usually a consequence of a bite from an arthropod vector which has previously fed on an infected animal. the pneumonic form of the disease occurs rarely but is the likely form of the disease should this bacterium be used as a bioterrorism agent. the diagnosis of disease is not straightforwa ... | 2002 | 12364373 |
| expression of anaplasma marginale major surface protein 2 operon-associated proteins during mammalian and arthropod infection. | the antigenically variant major surface protein 2 (msp2) of anaplasma marginale is expressed from a 3.5-kb operon that contains, in a 5'-to-3' direction, four open reading frames, opag3, opag2, opag1, and msp2. this operon structure was shown to be conserved among genotypically and phenotypically distinct a. marginale, a. ovis, and a. centrale strains. the individual opag amino acid sequences are highly conserved among a. marginale strains, with identities ranging from 95 to 99%. opag2 and opag3 ... | 2002 | 12379676 |
| antigenic classification of rickettsia felis by using monoclonal and polyclonal antibodies. | rickettsia felis is a flea-transmitted rickettsia. there is a discrepancy between its reported phylogenic and phenotypic identifications. following the first report of r. felis, it was considered by tests with serologic reagents to be closely related to another recognized flea-transmitted rickettia, r. typhi. subsequently, it appeared to be more closely related to spotted fever group (sfg) rickettsiae by genetic analysis. in the present work, r. felis was studied by microimmunofluorescence (mif) ... | 2003 | 12626446 |
| bartonella henselae in ixodes ricinus ticks (acari: ixodida) removed from humans, belluno province, italy. | the potential role of ticks as vectors of bartonella species has recently been suggested. in this study, we investigated the presence of bartonella species in 271 ticks removed from humans in belluno province, italy. by using primers derived from the 60-kda heat shock protein gene sequences, bartonella dna was amplified and sequenced from four ixodes ricinus ticks (1.48%). to confirm this finding, we performed amplification and partial sequencing of the pap31 protein and the cell division protei ... | 2003 | 12643827 |
| increasing the paralyzing ability of a laboratory colony of dermacentor andersoni stiles. | field-collected rocky mountain wood ticks dermacentor andersoni stiles from british columbia caused limited paralysis in hamsters at high doses, but not at lower doses, while ticks collected from alberta failed to cause paralysis. this prompted development of a laboratory strain of ticks with a more consistent ability to cause paralysis. progeny of ticks that paralyzed a cow near walhachin, british columbia were reared and assayed for paralyzing ability. a high-virulence colony was selected for ... | 2003 | 12693847 |
| recombinant vp7-based enzyme-linked immunosorbent assay for detection of immunoglobulin g antibodies to colorado tick fever virus. | vp6, vp7, vp9, vp10, vp11, and vp12 of colorado tick fever virus (ctf virus), a virus member of the genus coltivirus, family reoviridae, were expressed in bacteria with the pgex-4t-2 vector. a partial sequence of vp7 (designated pvp7) was chosen to elaborate an enzyme-linked immunosorbent assay (elisa) for detecting anti-ctf virus immunoglobulin g (igg) antibodies in humans. this was based on two observations: (i) among all expressed proteins, pvp7 showed the highest immunoreactivity to an anti- ... | 2003 | 12734255 |
| characterization of a recombinant immunomodulatory protein from the salivary glands of dermacentor andersoni. | the gene encoding a 36-kda (p36) immunomodulatory protein present in saliva of dermacentor andersoni was cloned in prokaryotic and eukaryotic expression vectors. a polymerase chain reaction (pcr)-generated cdna lacking signal peptide was cloned into the escherichia coli expression vector pet28 and a similar sequence was cloned into pib/v5-his-topo expression vector for stable transfection of insect cells, high 5 trade mark. the 26-kda molecular mass of p36 expressed by bacteria is in agreement w ... | 2003 | 12791102 |
| transmission of anaplasma marginale by boophilus microplus: retention of vector competence in the absence of vector-pathogen interaction. | whether arthropod vectors retain competence for transmission of infectious agents in the long-term absence of vector-pathogen interaction is unknown. we addressed this question by quantifying the vector competence of two tick vectors, with mutually exclusive tropical- versus temperate-region distributions, for genetically distinct tropical- and temperate-region strains of the cattle pathogen anaplasma marginale. the tropical cattle tick boophilus microplus, which has been eradicated from the con ... | 2003 | 12904396 |
| development of colorado tick fever virus in the rocky mountain wood tick, dermacentor andersoni. | | 1959 | 13626953 |
| identification of rickettsia rickettsii in the wood tick, dermacentor andersoni, by means of fluorescent antibody. | | 1960 | 13688983 |
| isolation of a virus closely related to powassan virus from dermacentor andersoni collected along north cache la poudre river, colo. | | 1960 | 13838002 |
| morphology and functioning of the mouthparts of dermacentor andersoni stiles. | | 1960 | 13851716 |
| nonpathogenic rickettsias related to the spotted fever group isolated from ticks, dermacentor variabilis and dermacentor andersoni from eastern montana. | | 1963 | 14053295 |
| anaplasma marginale theiler observed in the gut and excreta of dermacentor andersoni stiles (dermacentor venustus marx). | | 1964 | 14204828 |
| difference of sites of attachment of dermacentor andersoni stiles to cattle in southeastern alberta and in south central british columbia, in relation to possible existence of genetically different strains of ticks. | | 1965 | 14328661 |
| antigens and alternatives for control of anaplasma marginale infection in cattle. | anaplasmosis, a tick-borne cattle disease caused by the rickettsia anaplasma marginale, is endemic in tropical and subtropical areas of the world. the disease causes considerable economic loss to both the dairy and beef industries worldwide. analyses of 16s rrna, groesl, and surface proteins have resulted in the recent reclassification of the order rickettsiales. the genus anaplasma, of which a. marginale is the type species, now also includes a. bovis, a. platys, and a. phagocytophilum, which w ... | 2003 | 14557295 |
| simultaneous variation of the immunodominant outer membrane proteins, msp2 and msp3, during anaplasma marginale persistence in vivo. | vector-borne bacterial pathogens persist in the mammalian host by varying surface antigens to evade the existing immune response. to test whether the model of surface coat switching and immune evasion can be extended to a vector-borne bacterial pathogen with multiple immunodominant surface proteins, we examined anaplasma marginale, a rickettsia with two highly immunogenic outer membrane proteins, major surface protein 2 (msp2) and msp3. the simultaneous clearance of variants of the two most immu ... | 2003 | 14573687 |
| transstadial transfer of west nile virus by three species of ixodid ticks (acari: ixodidae). | larvae and/or nymphs of four species of ixodid ticks, ixodes scapularis say, amblyomma americanum (l.), dermacentor andersoni stiles, and dermacentor variabilis say, were fed to completion on laboratory hamsters or mice which had been inoculated with a west nile (wn) virus isolate from culex pipiens l. captured in connecticut usa. maximum titers in mice and hamsters were approximately 5 and two logs, respectively, lower than recorded (10 logs) in a naturally infected american crow, corvus brachy ... | 2003 | 14680122 |
| rickettsia species infecting amblyomma cooperi ticks from an area in the state of são paulo, brazil, where brazilian spotted fever is endemic. | owing to the potential role of the tick amblyomma cooperi in the enzootic cycle of rickettsia rickettsii, the etiologic agent of brazilian spotted fever (bsf), this study evaluated infection by rickettsia species in a. cooperi ticks collected from an area in brazil where bsf is endemic. among a total of 40 a. cooperi adult ticks collected in an area of bsf endemicity in the state of são paulo, pcr analysis detected dna of rickettsia bellii in 16 ticks (40%), and 3 other ticks (7.5%) were positiv ... | 2004 | 14715737 |
| an immune responsive factor d-like serine proteinase homologue identified from the american dog tick, dermacentor variabilis. | a dermacentor variabilis cdna encoding a clip-domain serine proteinase homologue with glycine replacing the catalytic serine was identified from tick haemocytes. the d. variabilis product was most similar to tachypleus tridentatus haemocyte antimicrobial factor d and shared significant homologies with a number of immune-responsive gene products of arthropods, including insect prophenoloxidase-activating cofactors. northern blotting analyses confirmed that the tick serine proteinase homologue exp ... | 2004 | 14728664 |