Publications

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
influence of dermacentor andersoni infestation on lymphocyte responsiveness to mitogens.		1982	6985018
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
demonstration of anaplasma marginale in hemolymph of dermacentor andersoni by animal inoculation and by fluorescent-antibody technique.	hemolymph was collected from adult dermacentor andersoni stiles that had been infected with anaplasma marginale theiler as nymphs. before hemolymph was collected, the adult ticks were either incubated and unfed at 37 c for 2.5 days or fed for 6 days on sheep. hemolymph collected from groups of 100 ticks was inoculated into susceptible splenectomized calves. smears of hemolymph from the same groups of ticks were prepared for examination by fluorescent antibody technique. hemolymph from incubated ...	1983	6346968
development of colonies of anaplasma marginale in the gut of incubated dermacentor andersoni.		1983	6625314
radiorespirometric determination of contribution of pentose phosphate cycle to metabolism of glucose in dermacentor andersoni.		1983	6631086
demonstration of colonies of anaplasma marginale in the midgut of rhipicephalus simus.	rhipicephalus simus nymphs were allowed to feed on a cow experimentally infected with the bw-strain of anaplasma marginale from republic of south africa, and they were studied as adults. colonies were demonstrated by light microscopy in midgut epithelial cells of adult ticks that were unfed (as adults), incubated, or prefed for 72 hours on a cow. the colonies occurred in 5 different morphologic types (1 to 5) that were similar to those described previously for a virginia isolate of a marginale i ...	1983	6660614
tularaemia transmitted by ticks (dermacentor andersoni) in saskatchewan.	common wood ticks (dermacentor andersoni) collected from saskatchewan landing provincial park, saskatchewan in the spring of 1982 transmitted a lethal tularaemia infection to four of six rabbits. francisella tularensis organisms were isolated from tissues taken from the dead rabbits and identified from subcultures using an indirect immunofluorescent antibody assay. one human associated with the animals developed symptoms of tularaemia and, after successful therapy, had a significant increase in ...	1983	6667429
pheromone-induced aggregation of ixodid ticks before host contact.	the presence of a pre-feeding aggregation pheromone was demonstrated in the species dermacentor variabilis, dermacentor andersoni, dermacentor parumapertus, amblyomma americanum and haemaphysalis leporispalustris by assay within a petri dish. however, amblyomma maculatum and amblyomma cajennense did not aggregate in the sector containing discs of presumed pheromone within the hour period. d. andersoni and a. americanum recognized each other's pheromone and a. americanum recognized that of h. lep ...	1983	6683667
biochemical and immunochemical analysis of rickettsia rickettsii strains of various degrees of virulence.	six strains of rickettsia rickettsii from montana and north carolina were examined in an effort to identify rickettsial constituents associated with virulence. fever responses, scrotal reactions, and mortalities of male guinea pigs inoculated intraperitoneally with 1,000 pfu of rickettsial strains revealed that the two montana patient strains ( sheila smith and norgaard ) and one montana strain ( sawtooth female 2) from the wood tick, dermacentor andersoni, could be placed in the group of highes ...	1984	6427110
demonstration of the inclusion appendage of anaplasma marginale in nymphal dermacentor andersoni.	dermacentor andersoni nymphs were placed in stockinettes and allowed to feed on a splenectomized calf with experimentally induced anaplasmosis when the parasitemia was 3%-5%. nymphs were selected on each of the 6 days of feeding and every 5 days from repletion through molting to the adult stage (25 days postrepletion); they were killed and midgut tissues were processed and examined by light and electron microscopies. no stages of a marginale were seen in tissues of feeding ticks. visualization o ...	1984	6497136
some aspects of organic acid metabolism in dermacentor andersoni female.		1984	6512290
significant changes in epidermal langerhans cells of guinea-pigs infested with ticks (dermacentor andersoni).	resistance to tick feeding has previously been shown to be an acquired, immunologically mediated phenomenon in guinea-pigs, associated with cutaneous basophil hypersensitivity to tick antigens. in this study, langerhans cells (lc) in the epidermis of guinea-pigs were monitored during tick infestations of susceptible and resistant animals. a specific adenosine triphosphatase (atpase) staining technique was used to identify epidermal lc. the numbers of lc decreased significantly around the sites o ...	1984	6228517
morphology of colonies of anaplasma marginale in nymphal dermacentor andersoni.	colonies of anaplasma marginale theiler were studied in midgut epithelial cells of nymphal dermacentor andersoni stiles that had become infected by feeding on splenectomized calves with anaplasmosis. colonies of a marginale were not observed in nymphal ticks killed during the 6-day feeding period, but were present in sections of midgut epithelial cells of ticks killed as early as 5 days after repletion. colonies of a marginale also were present in ticks examined throughout development to the adu ...	1984	24049913
presence of common antigens, including major surface protein epitopes, between the cattle (intraerythrocytic) and tick stages of anaplasma marginale.	epitopes of major surface proteins of the intraerythrocytic cattle stage of anaplasma marginale were demonstrated in the midgut stage of the organism within the infective tick host dermacentor andersoni. these proteins were common to all a. marginale isolates tested and at all stages of parasitemia. sera from cattle immunized with the tick midgut stage of a. marginale immunoprecipitated multiple-erythrocyte-stage proteins, as demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophore ...	1985	2415457
acquisition and expression of resistance by bos indicus and bos indicus x bos taurus calves to amblyomma americanum infestation.	purebred and crossbred bos indicus calves were infested 1, 2, or 3 times with 10 female and 5 male amblyomma americanum. resistance was acquired by both the purebred and the crossbred calves after 1 infestation and resulted in statistically significant decreases in the percentages of females that engorged, the mean weights of engorged females, and the mean weights of egg masses. comparisons between breeds of the percent of female ticks that engorged during the first and second infestations indic ...	1985	3998956
discriminant analysis of vegetational and topographical factors associated with the focal distribution of rocky mountain wood ticks, dermacentor andersoni (acari: ixodidae), on cattle range.		1985	4009628
transmission of anaplasma marginale by adult dermacentor andersoni during feeding on calves.	laboratory-reared dermacentor andersoni ticks experimentally infected as nymphs with anaplasma marginale were allowed to feed as adults from 1 to 9 days on susceptible, splenectomized calves to determine when, during feeding, the hematozoan was transmitted from ticks to cattle. in experiment 1, ticks were allowed to feed on calves for 1, 2, 3, 4, 5, or 6 days and anaplasmosis did not result. the same calves were used for experiment 2, and ticks were allowed to feed for 1, 3, 6, 7, 8, or 9 days a ...	1985	4026042
resistance to ixodid tick infestation induced by administration of tick-tissue culture cells.	primary tissue culture cells of developing larvae of amblyomma americanum were administered to guinea-pigs never previously exposed to ixodid ticks. guinea-pigs were given 1 x 10(6) primary culture cells on days 0, 7 and 21 by subcutaneous injection and challenged with male and female a. americanum on day 35. a significant degree of induced host tick resistance was expressed by reduced engorgement weight of females, reduced oviposition by those females which did obtain a blood meal, and by death ...	1985	4083961
effects of tick infestation on the plaque-forming cell response to a thymic dependent antigen.	strain-2 guinea-pigs were given two five-day infestations with dermacentor andersoni larvae. each exposure consisted of 100 larvae, and the first and second infestations were separated by a seven-day tick-free period. tick-exposed animals were given an intravenous injection with sheep red blood cells (srbc) at selected times during and after infestation: (a) the last, fifth day, of a first exposure, (b) the second day of a second infestation, (c) the fifth day of a second infestation and (d) fou ...	1985	3913388
epidemiologic aspects of bovine anaplasmosis in semiarid range conditions of south central idaho.	the prevalance of anaplasma marginale-infected cows, as determined by use of the modified rapid card agglutination (mrca) test, was measured during a 4-year period (1980-1983). the prevalence of a marginale-infected cows, defined as positive reactors on the mrca test, remained constant (31%-37%). the apparent incidence of a marginale transmission to susceptible cows was approximately 7% from 1980 to 1981, 8% from 1981 to 1982, and no transmission from 1982 to 1983. the occasional mrca-positive c ...	1986	3963555
dot-elisa assessment of guinea pig antibody responses to repeated dermacentor andersoni infestations.	acquired resistance to ixodid tick infestation is expressed by cattle and laboratory animals. humoral factors appear to be involved in host acquired resistance to tick bite; however, specific immune responses have yet to be fully characterized. this study examined tick resistance expressed by hartley guinea pigs upon repeated infestation with dermacentor andersoni, and describes longitudinal development of antigen specific immunoglobulin over approximately 180 days. guinea pigs were infested eit ...	1986	3712171
longevity of colonies of anaplasma marginale in midgut epithelial cells of dermacentor andersoni.	colonies of anaplasma marginale in midgut epithelial cells of experimentally infected dermacentor andersoni were studied in adult ticks 1, 3, and 6 months old. longevity of the parasite in ticks was assessed by evaluating its infectivity for splenectomized calves; calves were exposed by feeding ticks and by inoculation of tick gut homogenates. longevity was also evaluated by determining size, type, and density of colonies in male and female ticks. the effect of incubation (2.5 days at 37 c) on c ...	1986	3752671
percutaneous infection of nymphal dermacentor andersoni with anaplasma marginale.	newly replete nymphal dermacentor andersoni (principals) were percutaneously exposed to anaplasma marginale by injection of either intact or lysed infected bovine erythrocytes. control nymphs were fed on calves with anaplasmosis. the subsequently molted adults were examined for infection by light microscopy, and companion ticks were tested for infectivity by allowing them to feed on susceptible calves. when they fed as adults, both control ticks and percutaneously inoculated principals transmitt ...	1986	3752672
transmission of anaplasma marginale theiler by males of dermacentor andersoni stiles fed on an idaho field-infected, chronic carrier cow.	the role of ticks and carrier cattle in epizootics of bovine anaplasmosis was further clarified by demonstrating unequivocally, for the first time, that male ticks fed on a chronic carrier cow naturally infected with anaplasma marginale can transmit this parasite intrastadially and biologically when subsequently fed on susceptible cattle. these data indicate that field epizootics of acute anaplasmosis may be initiated by males of tick vector species that feed on carrier cattle and subsequently t ...	1986	3777655
the effect of avermectins on feeding, salivary fluid secretion, and fecundity in some ixodid ticks.	we tested the effects of the potent acaricides, avermectin b1a (avm) and 22,23-dihydroavermectin b1 (ivermectin; ivm) when injected directly into partially fed and fully engorged female ticks. when injected into small ticks (amblyomma hebraeum koch), neither drug (up to 100 micrograms/kg b.w.) inhibited subsequent engorgement nor affected oviposition latency, weight of total egg mass laid nor viability of laid eggs. at higher concentrations (1000 and 5000 micrograms/kg b.w.), avm and ivm were ma ...	1986	3451859
biochemical studies on tick embryogenesis: lipovitellin and protease activity in dermacentor andersoni (acari: ixodidae).		1986	3525840
ectoparasites of black-tailed prairie dogs (cynomys ludovicianus) from south dakota.	during the summers of 1982 and 1983, black-tailed prairie dogs (cynomys ludovicianus) were examined for parasites. those collected and their respective prevalence included linognathoides cynomyis (46.3%), opisocrostis hirsutus (53.7%), opisocrostis tuberculatus cynomuris (2.4%), androlaelaps fahrenholzi (12.2%), ixodes sculptus (2.4%) and dermacentor andersoni (4.9%). the collection data indicated that l. cynomyis, o. hirsutus and a. fahrenholzi were at low population densities during this perio ...	1987	3586214
attempted transmission to cattle of anaplasma marginale from overwintered dermacentor andersoni ticks.	since the 1983 summer outbreak of anaplasmosis in southern saskatchewan, the role of the tick, dermacentor andersoni as an overwintering reservoir for anaplasma marginale has been questioned. the purpose of this study was to determine if spring-collected ticks carried virulent a. marginale. sixteen splenectomized calves were assigned randomly to two groups of 14 principals and two controls. adult d. andersoni, collected in april from areas having high transmission rates of a. marginale, were con ...	1987	3651893
absence of assembly pheromones in the hard ticks dermacentor variabilis and dermacentor andersoni (acari: ixodidae).		1987	3694628
isolation and characterization of salivary antigens from the female tick, dermacentor andersoni.	the salivary glands of ixodid ticks are complex organs which are known to contain the antigens responsible for tick resistance in animals. we have identified a large number of proteins from salivary gland extracts (sge), at least some of which are immunologically recognized by tick resistant animals and which are therefore presumed to be secreted salivary components. during the 6 to 10 day feeding process, a number of these antigens alter in concentration according to individual kinetics, and so ...	1987	3299226
infectivity of three anaplasma marginale isolates for dermacentor andersoni.	three isolates of anaplasma marginale--virginia (vam), illinois (iam), and florida (fam)--were compared for infectivity for dermacentor andersoni. the isolates were selected, in part, because of a tail-like appendage that has been demonstrated in the vam and iam, but not in the fam. ticks were exposed to the isolates as nymphs either naturally by feeding on a calf with anaplasmosis or artificially by percutaneous inoculation with infected bovine erythrocytes. they were examined for infectivity a ...	1987	3826850
the population dynamics of two vertically transmitted infections.	the transmission of keystone virus in the mosquito aedes atlanticus and of rickettsia rickettsii in the tick dermacentor andersoni is modeled and analyzed. both of these infections can be transmitted vertically from an infective parent to newborn offspring as well as horizontally via direct or indirect contacts with infected individuals. the vertical transmission mechanism plays a major role in the maintenance of these infections and its effects are analyzed in detail. this same mechanism can ac ...	1988	3148206
hybridization of dna probes to a. marginale isolates from different sources and detection in dermacentor andersoni ticks.	dna from the washington, south-idaho, virginia and florida isolates of anaplasma marginale was hybridized to probes specific for anaplasma centrale and a. marginale. the a. centrale probes ac-2 and ac-4 hybridized to identical bands on all of these isolates. the hybridization patterns suggests that the virginia, florida and the south african isolates are similar. a number of bands were obtained with the washington isolate which differed from those obtained with the other isolates. probe ac-2 cou ...	1988	3217095
preliminary studies of the development of anaplasma marginale in salivary glands of adult, feeding dermacentor andersoni ticks.	on each day of feeding on susceptible calves, salivary glands obtained from groups of adult ticks that transmitted anaplasma marginale were examined for a marginale colonies by use of light microscopy and transmission electron microscopy. on day 8 of feeding, salivary glands were examined, using fluorescein-labeled antibody and methyl green-pyronine stain. use of fluorescein-labeled antibody consistently revealed small numbers of fluorescent foci in salivary gland acinar cells obtained from tick ...	1988	2458688
experimental infection of six species of ixodid ticks with dugbe virus (family bunyaviridae, genus nairovirus).	the vector potential of each of 6 species of colonized north american and african ixodid ticks was assessed by intracoelomic inoculation with dugbe virus (ibar 1792, 14th passage in suckling mouse brain) and viral titers were monitored after selected incubation periods. persistence of dugbe virus for greater than or equal to 53 days in 5 species (dermacentor andersoni, d. variabilis, amblyomma americanum, rhipicephalus appendiculatus, and r. sanguineus) indicates that infection occurred. viral t ...	1989	2496609
intermediate site of development of anaplasma marginale in feeding adult dermacentor andersoni ticks that were infected as nymphs.	the development of anaplasma marginale in midgut epithelial cells was studied in feeding, transmitting adult dermacentor andersoni ticks. laboratory-reared ticks experimentally infected as nymphs were allowed to feed from 1 to 9 days on susceptible calves. gut tissues from ticks were collected on each day they fed (total, 9 days) and were processed for light and transmission electron microscopy. colonies of a marginale were abundant during the first 6 days of feeding, after which numbers decreas ...	1990	2301812
development and infectivity of anaplasma marginale in dermacentor andersoni nymphs.	the development of anaplasma marginale was studied in dermacentor andersoni nymphs after they had fed on a calf with ascending anaplasma infection. gut tissues were collected on day 4 of tick feeding, from newly replete (fed) nymphs and on postfeeding days (pfd) 5, 10, 15, 20, and were processed for light and electron microscopy to determine density of a marginale colonies. homogenates of gut tissues were prepared from nymphs collected on the same days and inoculated into susceptible, splenectom ...	1990	2386330
ivermectin is not an agonist at a gaba receptor in tick salivary glands.	the avermectins, broad-spectrum anti-parasitic agents which are effective against ticks, act principally by stimulating gamma-aminobutyric acid (gaba) receptors directly or indirectly. gaba is known to potentiate dopamine-induced fluid secretion in the salivary glands of female ixodid ticks. we thus tested whether 10 microm ivermectin would have an effect similar to gaba in the isolated salivary gland preparation of dermacentor andersoni. ivermectin was not an agonist at this gaba receptor.	1991	1660804
horizontal movement of adult ixodes dammini (acari: ixodidae) attracted to co2-baited traps.	the ability of male and female deer ticks, ixodes dammini spielman, clifford, piesman, & corwin, to move horizontally was evaluated by performing a mark-recapture study. in each of two experiments, 120 ticks were marked with fluorescent powder and released at predetermined distances from a co2-baited trap. the mean recruitment distance was 1.8 m after 6 d of trap operation. this distance is appreciably lower than those calculated from previous studies of several other species of ixodid ticks, in ...	1991	1941943
factors v and vii anticoagulant activities in the salivary glands of feeding dermacentor andersoni ticks.	the salivary glands of dermacentor andersoni ticks possess anticoagulant activities that can alter the clotting time of rabbit whole blood. salivary gland extracts from female ticks inhibit both the intrinsic and extrinsic coagulation systems, and maximal activities against both pathways occur when the ticks attain about 250 mg feeding weight. these anticoagulants are directed against both coagulation factors v and vii, but they do not affect factors ii or x. despite this salivary anticoagulant ...	1991	1992089
nonspecific activation of complement factor 5 by isolated dermacentor andersoni salivary antigens.	salivary gland extracts from feeding dermacentor andersoni ticks contain an activity that activated both rabbit and human complement to produce inflammatory cell chemotactic activity. purified salivary antigens (sga), isolated from the glands of female ticks with anti-saliva immunoglobulins from tick-resistant rabbits, also induced chemotactin generation. it has been demonstrated previously that the intradermal injection of such sga into normal animals induces nonspecific inflammatory reactions ...	1991	2010863
rocky mountain spotted fever.	rocky mountain spotted fever is an endemic tickborne disease found throughout the united states and other regions of the world. exposure may result in a spectrum of disease from subclinical infection to severe or fatal multiorgan collapse. the disease is maintained in nature in ixodid tick vectors and their hosts. the most important ticks in the united states are dermacentor variabilis and dermacentor andersoni. small mammals are the natural reservoirs in the wild. dogs become infected when a ti ...	1991	2014623
tick information sheet. the rocky mountain wood tick. dermacentor andersoni.		1991	2014625
differential effects of photoperiod on development and reproduction in "montane" and "prairie" strains of the rocky mountain wood tick (acari: ixodidae).	progeny of dermacentor andersoni stiles adults collected from one "montane" and two "prairie" sites in southern alberta, canada, were exposed to combinations of 9:15, 11:13 and 13:11 (l:d) daily photoperiods during various stages of their life cycle. time required for developmental and reproductive events was recorded. significant differences in mean molting times of fed larvae were observed, yet the differences were small, and mean times were not attributed to photoperiodic regime. fed nymphal ...	1991	2033610
modulation of host-immune responses by ticks (acari: ixodidae): effect of salivary gland extracts on host macrophages and lymphocyte cytokine production.	ixodid tick infestation induces host acquired resistance, which involves immunoglobulin cell-mediated and complement-dependent effector pathways. ticks have developed countermeasures to modulate host antiarthropod responses. ixodid-mediated host immunomodulation results in vitro in reduced responsiveness to t-lymphocyte mitogens for cells obtained from infested hosts and impaired antibody responses to a thymic dependent antigen. salivary gland extracts from days 0-9 of engorgement from unmated, ...	1992	1404261
persistence of anaplasma marginale (rickettsiales: anaplasmataceae) in male dermacentor andersoni (acari: ixodidae) transferred successively from infected to susceptible calves.	the persistence of anaplasma marginale theiler in male dermacentor andersoni stiles ticks exposed to the organism as adults was studied as the ticks were successively transferred to five susceptible calves. all calves fed upon by these ticks rapidly developed clinical anaplasmosis; incubation periods of infection ranged from 19 to 26 d and did not change significantly with successive feedings. development of a. marginale in tick midgut and salivary glands was followed daily during tick feeding ( ...	1992	1495076
detection of rickettsia rickettsii in saliva, hemolymph and triturated tissues of infected dermacentor andersoni ticks by polymerase chain reaction.	the technique of polymerase chain reaction (pcr) is potentially superior to existing methods for detecting rickettsial infections in ticks. for this reason, we developed assays for identifying rickettsial infections in ticks by pcr. our assays amplified a 500 bp fragment from the gene encoding the romp b protein of rickettsia rickettsii. the selected primers amplified fragments of the predicted size from all spotted fever group rickettsiae (r. rickettsii, r. parkeri, r. conorii, r. sibirica) tes ...	1992	1528203
development of anaplasma ovis (rickettsiales: anaplasmataceae) in male dermacentor andersoni (acari: ixodidae) transferred from infected to susceptible sheep.	the development of anaplasma ovis was studied in dermacentor andersoni males transferred from infected to susceptible sheep. laboratory-reared male d. andersoni were allowed to feed for 6 d on a sheep with ascending a. ovis parasitemia. the ticks were removed and held at room temperature in a humidity chamber for 6 d, after which they were allowed to feed on five susceptible sheep for 1, 3, 5, 7, or 9 d. gut and salivary glands were collected from ticks during the 21-d experiment and examined wi ...	1992	1552534
development of anaplasma marginale in male dermacentor andersoni transferred from parasitemic to susceptible cattle.	the development and transmission of anaplasma marginale was studied in dermacentor andersoni males. laboratory-reared male d andersoni were allowed to feed for 7 days on a calf with ascending a marginale parasitemia. the ticks were then held in a humidity chamber for 7 days before being placed on 2 susceptible calves. anaplasmosis developed in the calves after incubation periods of 24 and 26 days. gut and salivary glands were collected from ticks on each day of the 23-day experiment and examined ...	1992	1586018
recent advances in the biology of anaplasma spp. in dermacentor andersoni ticks.		1992	1626880
an incidental case of tick paralysis in a holstein calf exposed to dermacentor andersoni.		1992	17423967
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
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
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
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
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
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
effect of prior exposure to noninfected ticks on susceptibility of mice to lyme disease spirochetes.	to determine whether prior exposure to nearctic ixodes vector ticks protects native reservoir mice from tick-borne infection by lyme disease spirochetes, we compared their infectivities for white-footed mice and laboratory mice that had been repeatedly infested by noninfected deer ticks. nymphal ticks readily engorged on tick-exposed laboratory mice, but their feeding success on white-footed mice progressively declined. tick-borne spirochetes readily infected previously tick-infested mice. thus, ...	1998	9797328
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
successive tick infestations selectively promote a t-helper 2 cytokine profile in mice.	several studies have revealed that t lymphocytes and cytokines play a crucial role in determining the outcome of parasitic infections in terms of protective immunity. in this study we found that rhipicephalus sanguineus tick saliva stimulates transforming growth factor-beta (tgf-beta), and reduces interleukin-12 (il-12) secretion by cells from normal c3h/hej mice. moreover, murine lymph node cells harvested 6 days after the fourth infestation with ticks presented an 82.4% decrease in their proli ...	1999	10233725
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