| distribution and prevalence of spotted fever group rickettsiae in ticks from south carolina, with an epidemiological survey of persons bitten by infected ticks. | live ticks removed from human hosts were tested for the presence of spotted fever group rickettsiae from 1974 through 1976. spotted fever group rickettsiae were detected in dermacentor variabilis, amblyomma americanum, amblyomma maculatum, and ixodes scapularis. persons from whom positive ticks were removed in 1974 and 1975 were questioned about ensuing illness. eleven of 51 persons from whom rickettsia-positive d. variabilis were removed reported some unexplained combination of symptoms compati ... | 1978 | 103448 |
| rocky mountain spotted fever in connecticut: human cases, spotted-fever group rickettsiae in ticks, and antibodies in mammals. | three parameters were used in 1976 and 1977 to assess the status of rocky mountain spotted fever (rmsf) in connecticut--compilation and review of clinical data on suspected human cases for the 13-year period 1965--1977, examination of tick tissues for spotted fever-group rickettsiae by the hemolymph test and direct immunofluorescence, and analyses of mammalian sera for antibodies against rickettsia rickettsii. there were six presumptive rmsf cases which probably originated in connecticut. four o ... | 1979 | 111543 |
| the effect of the temperature regime on dermacentor variabilis (say) populations in eastern north america. | | 1979 | 474059 |
| dermacentor variabilis (say) larval activity in wisconsin. | | 1979 | 474060 |
| tick paralysis in a grey fox. | one hundred seventeen dermacentor variabilis were removed from the head and back of a grey fox (urocyon cinereoargenteus) showing paresis and diminished motor reflexes of the hind limbs. rapid and total recovery led to a diagnosis of tick paralysis. | 1979 | 480518 |
| resistance to tick-borne francisella tularensis by tick-sensitized rabbits: allergic klendusity. | mammals become hypersensitive to ticks that feed upon them. that hypersensitivity was thought responsible for an observation that a large number of francisella tularensis-infected dermacentor variabilis failed to infect a rabbit previously exposed to ticks of that species. in a series of tests of that hypothesis, rabbits sensitized to ticks were often significantly more resistant than control animals to tick-borne tularemia. the conditions that determine the klendusity are thought to be variable ... | 1979 | 484770 |
| further observations on the behavior of adult males of dermacentor variabilis (a cari: ixodidae) with respect to attached females. | | 1979 | 537012 |
| distribution of the american dog tick, dermacentor variabilis (say), and its small-mammal hosts in relation to vegetation types in a study area in nova scotia. | | 1979 | 540270 |
| feeding performance, survival and appearance of dermacentor variabilis nymphs (acari: ixodidae), as influenced by host resistance. | | 1977 | 609084 |
| seasonal dynamics of american dog tick, dermacentor variabilis (say), populations in southwestern nova scotia. | | 1978 | 630475 |
| influence of various conditioning photoperiods on the subsequent feeding activity of dermacentor variabilis nymphs (acari: ixodidae). | | 1978 | 633304 |
| ecto- and endoparasites of the black bear in northern wisconsin. | parasites collected from free-ranging black bears, ursus americanus, in northern wisconsin included dermacentor variabilis, d. albipictus, ixodes scapularis, demodex sp., trichodectes pinguis euarctidos, baylisascaris transfuga and dirofilaria ursi. mange, possibly caused by the demodex sp., also was observed. dental caries were common and periodontal disease was observed in one animal. | 1978 | 633522 |
| ultrastructure of the foveal glands of the ticks, dermacentor andersoni stiles and d. variabilis (say). | the foveal glands of dermacentor variabilis appear to consist of 2 cell types. the outer cells (type i) are active, with large areas of abundant finely granular material, apparently precursors of the mature secretory granules. the inner cells (type ii) are apparently storage cells. they are highly vacuolated and contain coarsely granular material as well as presumably mature secretory granules. the foveal glands of d. andersoni contain only type ii cells with extensive accumulations of presumabl ... | 1978 | 660384 |
| effects of two juvenile hormone analogs and beta-ecdysone on nymphal development, spermatogenesis, and embryogenesis in dermacentor variabilis (say) (acari: ixodidae). | | 1978 | 660393 |
| chemosterilization of dermacentor variabilis say (acari: ixodidae). i. effects of metepa on the cytology and fertility of males treated as unfed adults. | the effects of metepa on the cytology and fertility of male dermacentor variabilis treated as unfed adults are determined. evidence of cellular damage is found in testicular areas where actively dividing cells and some enlarging spermatocytes are found. the amount of cellular damage correlates positively to the concentration of the chemosterilant and results in decreases numbers of spermatids. in crosses of treated males to untreated females, resulting egg masses hatch normally; however, the per ... | 1978 | 682072 |
| rocky mountain spotted fever (tick-borne typhus) in south carolina: an educational program and tick/rickettsial survey in 1973 and 1974. | because the incidence of spotted fever is increasing in south carolina, campaigns were carried out in 1973 and 1974 to provide the public and medical practitioners, through pamphlets and news media, with information about spotted fever and the ticks which transmit the causative agent, rickettsia rickettsii. people were also invited to save and submit live ticks removed from vegetation, animals and humans, for examination by the hemolymph test. a total of 1,186 ticks consisting of 987 dermacentor ... | 1975 | 811127 |
| rocky mountain spotted fever in mississippi: survey for spotted fever antibodies in dogs and for spotted fever group reckettsiae in dog ticks. | during epidemiologic studies of rocky mountain spotted fever in mississippi in 1973, dogs were surveyed for antibodies tp spotted fever group antigens and for tick parasites infected with rickettsiae of the spotted fever group. fifty-three (46%) of 116 serum samples had complement-fixing antibody titers greater than or equal to 1:8 as compared to only one (5%) of 21 samples from a group of dogs obtained from metropolitan chicage. fifty-two per cent of the dogs tested from mississippi had microag ... | 1976 | 814809 |
| the distribution in oregon of ixodes pacificus, dermacentor andersoni, and dermacentor occidentalis with a note on dermacentor variabilis (acarina: ixodidae). | | 1977 | 845890 |
| changing patterns in the incidence of rocky mountain spotted fever on long island (1971-1976). | clinical data from 124 rocky mountain spotted fever (rmsf) cases submitted by long island physicians and hospitals were compiled for the six-year period 1971-1976. this information was subsequently compared to two parameters: first, the geographic distribution of human cases and rickettsia-infected dermacentor variabilis (say), and, secondly, the human population dynamics in long island towns since 1950. despite an overall decline in the rate of suburbanization and population growth, cases of rm ... | 1977 | 920726 |
| distribution of suspected tick vectors and reported cases of rocky mountain spotted fever in california. | evidence is presented for an area of human risk to rocky mountain spotted fever (rmsf) in california extending beyond the range of its classic tick vector, dermacentor andersoni. geographic, seasonal, and host distributions of dermacentor variabilis and dermacentor occidentalis suggest these species as potential vectors of rmsf in california outside the range of dermacentor andersoni. | 1976 | 961695 |
| human babesiosis on nantucket island: transmission by nymphal ixodes ticks. | in order to identify potential vectors of human babesiosis (babesia microli) in southern massachusetts, i attempted to transmit the infection via nymphal ticks of that species found to be most abundant on reservoir hosts (peromyscus leucopus) in nature. mice were collected at frequent intervals throughout a year in a known enzootic focus on nantucket island, and ticks were removed by hand. ticks of only two species were present; larvae and nymphs of ixodes scapularis were about 10 times as numer ... | 1976 | 1008124 |
| neurosecretory system of the american dog tick, dermacentor variabilis (acari: ixodidae). ii. distribution of secretory cell types, axonal pathways and putative neurohemal-neuroendocrine associations; comparative histological and anatomical implications. | histological observations using specialized techniques reveal neurosecretory cells in 18 centers throughout the rind (cortex) of the central nerve mass or synganglion of dermacentor variabilis. many cells contribute to complicated networks of neurosecretory pathways and tracts in pre- and post-esophageal portions of the synganglion. the four types of neurohemal-neuroendocrine associations found in dermacentor resemble structures found in soft ticks (argasidae) and in other arachnida, but are mor ... | 1975 | 1117459 |
| parasites of black bears of the lake superior region. | parasites collected from free-ranging black bears, ursus americanus pallas, 1780, from northeastern minnesota or northern michigan include the dog tick, dermacentor variabilis (say, 1821), the winter tick, d. albipictus (packard, 1869), a louse, trichodectes pinguis euarctidoes hopkins, 1954, an ascarid worm, baylisascaris transfuga (rudolphi, 1819), a filarial worm, dirofilaria ursi yamaguti, 1941, taeniid tapeworms, and unidentified fleas. the broad fish tapeworm, diphyllobothrium latum (linna ... | 1975 | 1142551 |
| evaluation of co2-baited traps for survey of amblyomma maculatum koch and dermacentor variabilis say (acarina: ixodidae). | | 1975 | 1159725 |
| the regulation of adult american dog tick, dermacentor variabilis say, seasonal activity and breeding potential (ixodidae: acarina). | | 1975 | 1179959 |
| recent records of ticks, ixodes cookei packard and dermacentor variabilis (say) (acarina: ixodoidea) in southwestern ontario. | | 1975 | 1193021 |
| relationships of immature dermacentor variabilis (say) (acari: ixodidae) with the white-footed mouse, peromyscus leucopus, in southwestern wisconsin. | | 1975 | 1195285 |
| the effect of mean winter temperature around 0 degrees c on the population size of the american dog tick, dermacentor variabilis, say. (acarina: ixodidae). | | 1975 | 1211069 |
| parasitic arthropods of sympatric meadow voles and white-footed mice at fort detrick, maryland. | twelve species of parasitic arthropods (one sucking louse, two fleas, one tick, and eight mites) were recovered from 51 meadow voles, microtus pennsylvanicus (ord); whereas nine species (one sucking louse, one bot, three fleas, one tick, and three mites) were collected from 48 white-footed mice, peromyscus leucopus (rafinesque), live-trapped on the grounds of fort detrick, frederick county, md., during 1990 and 1991. the most commonly collected arthropods from m. pennsylvanicus were the fur mite ... | 1992 | 1404254 |
| cotton rats and other small mammals as hosts for immature dermacentor variabilis (acari: ixodidae) in central oklahoma. | eight species of small mammals were evaluated as potential hosts for american dog ticks, dermacentor variabilis (say), in an upland, tallgrass prairie study site in central oklahoma. only hispid cotton rats, sigmodon hispidus, and deer mice, peromyscus maniculatus, were found to be important hosts for immature d. variabilis. although d. varibilis larvae and nymphs frequently infested both cotton rats and deer mice, cotton rats were the most important host species for both immature stages in the ... | 1992 | 1404263 |
| tick (acari: ixodidae) attachment cement and salivary gland cells contain similar immunoreactive polypeptides. | a specific antiserum (12c) raised to a 90-kda immunogenic component of salivary glands of the tick rhipicephalus appendiculatus recognized similar 90-kda polypeptides from salivary glands of the american dog tick, dermacentor variabilis, and the lone star tick, amblyomma americanum, as well as 70-kda polypeptides in the cement of d. variabilis, a. americanum, and r. sanguineus (brown dog tick). the reduction in size of the polypeptide for these ticks suggests that it is modified in some way duri ... | 1992 | 1495047 |
| tick sweep: modification of the tick drag-flag method for sampling nymphs of the deer tick (acari: ixodidae). | we describe a version of the standard tick drag-flag modified for use in close-growing and tangled vegetation, as well as under ornamental shrubbery and fallen branches. two major features of the sweep are: (1) it allows the user to remain upright with the flag parallel to the ground, thus sampling effectively beneath low and fallen branches and around shrubs, as well as capturing host-seeking ticks in advance of the operator; and (2) the use of a flannel rubberized-laminate fabric (crib sheet) ... | 1992 | 1495058 |
| attempted transmission of borrelia burgdorferi (spirochaetales: spirochaetaceae) (jdi strain) by ixodes scapularis (acari: ixodidae), dermacentor variabilis, and amblyomma americanum. | laboratory-reared ixodes scapularis say, amblyomma americanum (l.), and dermacentor variabilis (say) were fed on new zealand white rabbits experimentally infected with borrelia burgdorferi (jdi strain). at repletion, spirochetes could be detected by dark-field microscopy only in i. scapularis. acquisition rates were 18 and 21%. when previously exposed nymphs of each species were fed on susceptible rabbits, i. scapularis was the only tick of the three species that transmitted b. burgdorferi. when ... | 1992 | 1495078 |
| diversity of tick species biting humans in an emerging area for lyme disease. | although most tick bites in humans in areas of the northeastern united states in which lyme disease is highly endemic are due to ixodes dammini, no study documents the frequency of i. dammini bites in low-prevalence or emerging areas for lyme disease. data on the proportion of tick bites in humans that are due to i. dammini in a region may have implications for public health policy and clinical management. | 1992 | 1536337 |
| a redescription of schizogony of cytauxzoon felis in the domestic cat. | cytauxzoon felis is a protozoan parasite that is transmitted by dermacentor variabilis ticks and causes a uniformly fatal disease in domestic cats. in order to study schizogony and merozoite formation, d. variabilis nymphs were allowed to feed on domestic cats experimentally infected with c. felis, after which the molted adult ticks were fed on susceptible cats. lung and liver tissues were collected from the cats during clinical cytauxzoonosis and were fixed for light and transmission electron m ... | 1992 | 1626865 |
| the role of the fat body, midgut and ovary in vitellogenin production and vitellogenesis in the female tick, dermacentor variabilis. | polyclonal antibodies directed against d. variabilis vitellin were utilized for immunocytochemistry at the ultrastructural level. we localized vitellogenin (vg) in rough endoplasmic reticulum cisternae, secretory granules and secreted products of fat body trophocytes and midgut vitellogenic cells from feeding and ovipositing females. vg was localized in the oocyte golgi bodies and in the yolk bodies of both feeding and ovipositing females. uptake of exogenous vg was indicated by the presence of ... | 1992 | 1639570 |
| salivary gland antigens of ixodes dammini are glycoproteins that have interspecies cross-reactivity. | serum from rabbits and rats exposed to ixodes dammini adults and larvae, respectively, contain antibodies to a large number of antigens in salivary gland homogenates from adult ticks that cross react with the antigens of a closely related species, ixodes scapularis, and significantly with dermacentor variabilis antigens. the salivary gland antigens of i. dammini are glycoproteins composed of both n- and o-linked carbohydrate chains. the antigenic determinants reside in both the polypeptide and c ... | 1991 | 1723426 |
| rickettsiae and borrelia burgdorferi in ixodid ticks. | nymphs and adults of hard-bodied ticks were collected in connecticut and tested by direct and indirect immunofluorescence staining methods for rickettsiae and borrelia burgdorferi. of the 609 ixodes dammini ticks examined, 59 (9.7%) harbored rickettsialike microorganisms in hemocytes (blood cells). these bacteria reacted with fluorescein-conjugated antiserum to ehrlichia canis, the etiologic agent of with fluorescein-conjugated antiserum to ehrlichia canis, the etiologic agent of canine ehrlichi ... | 1991 | 1757551 |
| rectal infusion and aspiration of material through the guts of ixodid ticks (acari: ixodidae). | a technique for inoculating and removing substances via the anus of vector ticks was devised to define features of vector competence precisely. calibrated inocula (greater than 5 nanoliter) containing aqueous dye and polystyrene beads as well as infectious agents were infused into the rectal sacs of ticks using glass microcapillary pipettes placed within the expanded anal orifice. the guts of preadult and adult ticks, ixodes dammini spielman, clifford, piesman & corwin, dermacentor variabilis (s ... | 1991 | 1770516 |
| role of genital sex pheromones in amblyomma americanum and a. maculatum (acari: ixodidae). | amblyomma americanum and a. maculatum were studied to determine if genital sex pheromones were present, as reported in dermacentor species. chemical analysis of methanol extracts of the anterior reproductive tracts (source of the genital sex pheromone) of a. americanum and a. maculatum confirmed the presence of the same fatty acids that act as components of the genital sex pheromone in dermacentor variabilis and d. andersoni. in both amblyomma species, removal of the anterior reproductive-tract ... | 1991 | 1860418 |
| tick resistance in mast cell-deficient mice: histological studies. | mast cell-deficient w/wv mice and their mast cell-sufficient +/+ genetic controls were allowed to undergo three successive infestations with dermacentor variabilis larvae. histological examination of the skin of infected mice revealed large dermal accumulations of eosinophils and smaller numbers of neutrophils. the numbers of both eosinophils and neutrophils increased significantly in w/wv and +/+ mice during secondary and tertiary infestations. mast cell numbers were also found to increase in t ... | 1991 | 1869363 |
| ectoparasites of a population of urban gray squirrels in northern florida. | ectoparasites infesting a population of urban gray squirrels (sciurus carolinensis gmelin) in northern florida were collected monthly during 1974. eleven species were identified: one flea (orchopeas howardi (baker], three suckling lice (enderleinellus longiceps kellogg & ferris, hoplopleura sciuricola ferris, and neohaematopinus sciuri jancke), one tick (dermacentor variabilis say), two mesostigmatid (gamasid) mites (androlaelaps casalis (berlese) and a. fahrenholzi (berlese], and four chiggers ... | 1991 | 1875375 |
| effect of ivermectin on the volume of blood ingested by two species of ticks (acari: ixodidae) feeding on cattle. | females of the lone star tick, amblyomma americanum (l.), and the american dog tick, dermacentor variabilis (say), were fed on ivermectin (ivomec)-treated and untreated bovines to determine the effect of the acaricide on volume of blood ingested and to compare the weight differences between the treatment and control groups at various time intervals after attachment. adult females from each genus were collected from bos tarus hosts and subjected to hematin assays on three collection dates to esti ... | 1991 | 1875376 |
| borrelia burgdorferi in ticks (acari: ixodidae) from coastal virginia. | ixodid ticks removed from hosts and from vegetation during march-november 1987 at sites in coastal virginia and north carolina were examined for borrelia burgdorferi. b. burgdorferi was evident in nine (22%) ixodes cookei packard removed from rice rats (oryzomys palustris), a white-footed mouse (peromyscus leucopus), and raccoons (procyon lotor); four (6%) amblyomma americanum (l.) removed from raccoons; and two (3%) dermacentor variabilis (say) removed from a raccoon and a rice rat. b. burgdorf ... | 1991 | 1941936 |
| apparent incompetence of dermacentor variabilis (acari: ixodidae) and fleas (insecta: siphonaptera) as vectors of borrelia burgdorferi in an ixodes dammini endemic area of ontario, canada. | from april to october 1990, white-footed mice, peromyscus leucopus (rafinesque), were examined for ectoparasites on long point, ontario, the only endemic area for ixodes dammini clifford, spielman, piesman & corwin and borrelia burgdorferi johnson, schmid, hyde, steigerwalt & brenner known in canada. larval and nymphal i. dammini and dermacentor variabilis (packard), and adult fleas orchopeas leucopus (baker), epitedia wenmanni (rothschild), and ctenophthalamus pseudagrytes baker were common on ... | 1991 | 1941949 |
| ehrlichiosis in children. | tick-borne rickettsiae of the genus ehrlichia have recently been recognized as a cause of human illness in the united states. in the years 1986-1988, 10 cases of ehrlichiosis were diagnosed in children in oklahoma. fever and headache were universal: myalgias, nausea, vomiting, and anorexia were also common. rash was observed in six patients but was a prominent finding in only one. leukopenia, lymphopenia, and thrombocytopenia were common laboratory abnormalities. six patients were treated with t ... | 1991 | 1987531 |
| parasitic and phoretic arthropods of sylvatic and commensal white-footed mice (peromyscus leucopus) in central tennessee, with notes on lyme disease. | sixteen species of parasitic or phoretic arthropods were collected from 56 white-footed mice, peromyscus leucopus, live-trapped in central tennessee from april through november 1987. arthropod infestation was compared for mice taken from sylvatic (woodland) versus commensal (household) habitats. three species were recorded from hosts in both habitats: the sucking louse hoplopleura hesperomydis, the flea epitedia wenmanni, and the laelapid mite androlaelaps casalis. twelve of the 13 remaining art ... | 1991 | 2010854 |
| 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 american dog tick. dermacentor variabilis. | | 1991 | 2014624 |
| determination of vitellogenin titer in the hemolymph of dermacentor variabilis (acarina: ixodidae) using an indirect enzyme-linked immunosorbent assay. | using polyclonal antibodies against dermacentor variabilis (say) egg vitellin, we developed an indirect, competitive enzyme-linked immunosorbent assay (elisa). vitellogenin in the hemolymph of females was quantitatively monitored through feeding (slow feeding and rapid engorgement feeding periods) and postfeeding (preoviposition and oviposition) until death. vitellogenin concentrations in hemolymph ranged from 1 microgram/ml on the first day of feeding to a maximum of 430 micrograms/ml on the th ... | 1991 | 2033618 |
| experimental infection of the white-footed mouse with borrelia burgdorferi. | laboratory raised white-footed mice (peromyscus leucopus) were inoculated experimentally with live spirochetes (borrelia burgdorferi), the etiologic agent of lyme disease (borreliosis). prior to inoculation, mouse sera were tested with an indirect fluorescent antibody test, and all mice were seronegative. all inoculated mice seroconverted. in tick transmission studies, immature stages of ixodes dammini and dermacentor variabilis attached and fed to repletion on mice, but only i dammini transferr ... | 1990 | 2085225 |
| stability of dermacentor variabilis populations (acari: ixodidae). | | 1990 | 2093615 |
| hispid cotton rats (sigmodon hispidus) as a source for infecting immature dermacentor variabilis (acari: ixodidae) with rickettsia rickettsii. | hispid cotton rats (sigmodon hispidus say and ord) were susceptible to infection with rickettsia rickettsii wolbach under laboratory conditions and were capable of serving as sources for infecting ticks with rickettsiae. cotton rats developed rickettsemias that could be detected for as long as 6 h following intraperitoneal inoculation of 10(5) plaque-forming units (pfus) of r. rickettsii (morgan strain). an estimate of the median infectious dose (id50) was made by inoculating six groups (eight a ... | 1990 | 2117665 |
| basophils in skin reactions of mast cell-deficient mice infested with dermacentor variabilis. | acquired resistance to ticks in guinea pigs has been found to be associated with basophil-rich skin reactions. mice, which are generally believed to possess few, if any basophils, also acquire resistance following repeated tick infestations and this has been found to be associated with increased numbers of dermal mast cells. mast cell-deficient w/wv mice have, however, also been shown capable of acquiring resistance after two infestations with dermacentor variabilis larvae. in the studies descri ... | 1990 | 2228426 |
| comparative field evaluation of permethrin and deet-treated military uniforms for personal protection against ticks (acari). | the effectiveness of permethrin-impregnated (pi) versus permethrin-sprayed (ps) military battle dress uniforms was evaluated in protecting soldiers from tick bite. at the same time, an extended-duration formulation of n,n-diethyl-m-toluamide (deet), when applied to clothing only, was evaluated and compared with the permethrin-treated uniforms. testing consisted of exposing subjects, clothed in either untreated or the variously treated uniforms, to field populations of ticks during a series of 30 ... | 1990 | 2231620 |
| attempted ehrlichia risticii transmission with dermacentor variabilis (acari: ixodidae). | larval dermacentor variabilis (say) (n = 327) were fed on balb/c mice inoculated with ehrlichia risticii, the etiologic agent of equine monocytic ehrlichiosis (potomac horse fever). all mice displayed clinical signs of e. risticii infection at the time of feeding. after molting, resulting nymphs (n = 74) were fed on susceptible mice. no clinical signs were observed, and the mice remained seronegative for 6 wk after feeding. | 1990 | 2231630 |
| [the taxonomic aspects of the transmission of the causative agent of lyme disease]. | according to world literature data 17 species of ixodid ticks have been studied for natural infection with the lyme disease agent. analysis of the data on the level of the infection, transovarial and transphase transmission has shown that main biological vectors of borrelia burgdorferi are the species of the subgenus ixodes s. str. - i. ricinus, i. persulcatus (eurasia), i. dammini, i. pacificus (north america). potential vectors are i. scapularis, i. dentatus, amblyomma americanum, dermacentor ... | 1990 | 2259524 |
| hemocytic encapsulation of implants in the tick dermacentor variabilis. | implants of epon, inserted in dermacentor variabilis (say) through incisions in the cuticle, were encapsulated by hemocytes. we followed this process at intervals of 1,3,6, 12 and 24 h, and every 24 h thereafter up to 120 h. degranulation of type 1 granulocytes and coagulation of hemolymph were first seen at 1 h after implantation and were the earliest evidence of encapsulation. by 3 h after implantation, the degranulation and disintegration of granulocytes had formed a matrix at the epon surfac ... | 1990 | 2261820 |
| amblyomma americanum: identification of tick salivary gland antigens from unfed and early feeding females with comparisons to ixodes dammini and dermacentor variabilis. | salivary gland antigens involved in host resistance to tick feeding by amblyomma americanum (lone star tick) have been identified. gland extracts from unfed and partially fed 12-, 48-, 72-, 96-, and 120-hr females and their corresponding midgut tissues were analyzed by immunoblotting with sera from naturally immune and hyperimmune sheep and rabbits. polypeptides at 90, 75, 58, 45, 33, and 23 kda from the salivary glands of a. americanum females were consistently observed with antibodies from bot ... | 1990 | 2298277 |
| metabolism of juvenile hormone during adult development of dermacentor variabilis (acari: ixodidae). | juvenile hormone (jh)-i and -iii were used as model substrates to study the in vitro metabolism of jh in the hemolymph and body homogenates of the american dog tick, dermacentor variabilis (say). ester hydrolysis was the principal pathway of jh metabolism in hemolymph and homogenates. jh also was converted into jh-diol primarily by body homogenates, indicating the presence of jh epoxide hydrolase activity. jh epoxide hydrolase activity, alpha-naphthyl acetate esterase activity, and protein conce ... | 1990 | 2299654 |
| fine structure of the fat body and nephrocytes in the life-stages of dermacentor variabilis. | the fine structure of the fat body and associated nephrocytes of the american dog tick, dermacentor variabilis (say), was described in unfed larvae, unfed nymphs, and in unfed and fed adults of both sexes. the fat body consisted of one type of cell, the trophocyte. morphological changes that occurred in the trophocytes of both sexes were dependent on feeding. the ultrastructure of feeding male trophocytes was distinct from trophocytes of feeding females. in the feeding female, the trophocyte dev ... | 1990 | 2307068 |
| attempted transmission of ehrlichia risticii, causative agent of potomac horse fever, by the ticks, dermacentor variabilis, rhipicephalus sanguineus, ixodes scapularis and amblyomma americanum. | dermacentor variabilis, rhipicephalus sanguineus, amblyomma americanum, and ixodes scapularis ticks were investigated for their ability to transmit potomac horse fever. larval and nymphal ticks were exposed to ehrlichia risticii by feeding on mice inoculated with the organism. molted exposed ticks were then allowed to feed on susceptible ponies or mice. no evidence of transmission, either clinically or by detection of antibodies to e. risticii in mice or ponies, was observed for any tick species ... | 1990 | 2307070 |
| an australian record of the american dog tick dermacentor variabilis, and the risk of its establishment outside north america. | a living female of dermacentor variabilis (say) was collected in canberra, australia, on a human who had recently returned from the u.s.a. climatic data indicate that this could become established in eastern australia and many other parts of the world, with serious consequences for human and animal health. | 1990 | 2307072 |
| anti-tick antibodies: an epidemiologic tool in lyme disease research. | in 1988, antibodies to arthropod (ixodes dammini, dermacentor variabilis, and aedes aegypti) salivary gland proteins and to borrelia burgdorferi were measured by enzyme-linked immunosorbent assay in 53 high-risk outdoor workers from the new jersey department of environmental protection. lyme disease seropositives had significantly higher anti-i. dammini antibody levels than seronegative controls (p = 0.006). anti-b. burgdorferi antibody (enzyme-linked immunosorbent assay) and anti-i. dammini ant ... | 1990 | 2356814 |
| experimental transmission of a granulocytic form of the tribe ehrlichieae by dermacentor variabilis and amblyomma americanum to dogs. | transstadial transmission of granulocytic ehrlichieae in dogs was attempted using ticks, amblyomma americanum and dermacentor variabilis. ticks were exposed by feeding as nymphs on acutely infected pups; adult ticks then fed to repletion on susceptible adult dogs that were monitored daily for signs of infection. evidence of transmission was not observed in control dogs or in those exposed to d variabilis. in contrast, dogs exposed to a americanum developed serologic or clinical evidence of infec ... | 1990 | 2368951 |
| rickettsia in texas. | since the first reported case in 1941, rocky mountain spotted fever in humans has been reported from many areas of texas, with two major foci, one located in the north-central region and the other in the eastern region of the state. during the period 1979-1988, 421 cases of rmsf were reported, reaching 108 cases in 1983 and declining in subsequent years. statewide surveillance programs to detect spotted fever group rickettsiae in tick populations were initiated in 1976. in recent years, the sfg ... | 1990 | 2378448 |
| the distribution and dynamics of rickettsia in the tick population of ohio. | a five-year survey of ticks and associated rickettsia in ohio shows a partitioning of spotted fever group rickettsia (namely, rickettsia montana and r. rickettsii) into three areas of the state where the majority of human spotted fever cases occur. the percentage of ticks infected, even in areas with a high incidence of disease, is remarkably low, less than 1%. the statewide infection rate for r. bellii approaches 3%, and this organism appears to be more evenly distributed throughout the state. ... | 1990 | 2378449 |
| ectoparasitic and phoretic arthropods of virginia opossums (didelphis virginiana) in central tennessee. | thirteen species of ectoparasitic (12) or phoretic (1) arthropods were collected from 26 adult virginia opossums, didelphis virginiana, live-trapped from april through september 1987 in davidson county, tennessee. the cat flea ctenocephalides felis and the american dog tick dermacentor variabilis were the predominant species with respect to mean intensity and prevalence. the macronyssid mite ornithonyssus wernecki and the atopomelid mite didelphilichus serrifer, both specific parasites of this h ... | 1990 | 2380870 |
| micrometeorologic factors affecting field host-seeking activity of adult dermacentor variabilis (acari: ixodidae). | fifteen micrometeorologic or microenvironmental parameters, including temperature, moisture, wind, and solar radiation, were repeatedly measured at 1 m and 2.5 cm aboveground, in the litter layer, and in the soil concurrently with drag samples of questing american dog tick, dermacentor variabilis (say), in five plots (1 by 10 m) in delaware county, ohio. multivariate statistical analyses of the resultant data showed that ambient temperature was the best general predictor of adult tick host seeki ... | 1990 | 2388223 |
| intrinsic competence of three ixodid ticks (acari) as vectors of the lyme disease spirochete. | we compared the intrinsic vector competence of ixodes dammini spielman et al., dermacentor variabilis (say), and amblyomma americanum (l.) for the lyme disease spirochete (borrelia burgdorferi johnson et al.) on prudence island, rhode island, a lyme disease-endemic site where all three ticks occur together. natural and experimental spirochete infection rates were determined in those ticks and their degree of contact with white-footed mice (peromyscus leucopus), the principal reservoir host, was ... | 1990 | 2388239 |
| computer simulation of rocky mountain spotted fever transmission by the american dog tick (acari: ixodidae). | a computer model was developed for simulation of the transmission of rickettsia rickettsii, the causative agent of rocky mountain spotted fever (rmsf), by the american dog tick, dermacentor variabilis (say). the model of rmsf was combined with a model for population dynamics of the american dog tick and included simulation of infection and transmission of rickettsiae between ticks and host mammals and transmission of rmsf to humans. the model simulated the effects of biotic and environmental var ... | 1990 | 2388242 |
| computer simulation of management strategies for american dog ticks (acari: ixodidae) and rocky mountain spotted fever. | computer models were developed to simulate the effects of management technologies on populations of the american dog tick, dermacentor variabilis (say), principal vector of rocky mountain spotted fever (rmsf) in eastern north america. the technologies modeled were area-wide acaricide application, acaricide-food-baited tubes for self-treatment by small mammals, dipping of dogs in acaricides, acaricide-impregnated plastic dog collars, reduction of small mammal host populations (host management), a ... | 1990 | 2388243 |
| detection of borrelia burgdorferi dna in museum specimens of ixodes dammini ticks. | in order to investigate the potential for borrelia burgdorferi infection before the recognition of lyme disease as a clinical entity, the polymerase chain reaction (pcr) was used to examine museum specimens of ixodes dammini (deer ticks) for the presence of spirochete-specific dna sequences. one hundred and thirty-six archival tick specimens were obtained representing various continental u.s. locations; dna sequences characteristic of modern day isolates of b. burgdorferi were detected in 13 194 ... | 1990 | 2402635 |
| onset of vitellogenin production and vitellogenesis, and their relationship to changes in the midgut epithelium and oocytes in the tick dermacentor variabilis. | in dermacentor variabilis (say), the onset of vitellogenin production and vitellogenesis (uptake of vitellogenin into oocytes) began during the rapid-engorgement feeding period. mating was required for both vitellogenin production and vitellogenesis to complete the tick's life cycle. complete immunological identity, as measured by ouchterlony's double diffusion test, existed between vitellogenin from the fat body, midgut and hemolymph, and vitellin from the ovaries and eggs. antivitellin antibod ... | 1989 | 2501073 |
| species recognition elicited by differences in composition of the genital sex pheromone in dermacentor variabilis and d. andersoni (acari: ixodidae). | the chemical basis for the ability of fed males of dermacentor variabilis (say) and d. andersoni (stiles) to differentiate conspecific and heterospecific females was investigated using a neutered female bioassay. male d. variabilis responded strongly in a dose-response manner to increasing concentrations of stearic and palmitic acids and an extract of the anterior reproductive tract (art) of fed d. variabilis females. mating responses were greatest at 1 microgram of fatty acid and 1 female equiv ... | 1989 | 2585449 |
| infectivity and antigenicity of anaplasma marginale from tick cell culture. | the infectivity and immunogenicity of anaplasma marginale grown in a tick cell culture from embryonic dermacentor variabilis ticks were assessed in splenectomized and intact calves, respectively. culture 1 consisted of the cell line inoculated with midguts of adult ticks infected with the mississippi isolate of a marginale and dissected 5 to 10 days after repletion and detachment from an experimentally infected calf. cultures 2 and 3 consisted of the cell line inoculated with midguts of ticks in ... | 1989 | 2610428 |
| white-footed mice: tick burdens and role in the epizootiology of potomac horse fever in maryland. | one hundred ten white-footed mice (peromyscus leucopus) were captured on horse farms in south-central maryland, examined for ticks, and tested for specific antibodies to ehrlichia risticii, the causative agent of potomac horse fever. peromyscus leucopus were consistently infested with immature american dog ticks (dermacentor variabilis), with monthly prevalences as high as 80%. sera from all 97 p. leucopus tested for antibodies to e. risticii were negative. this indicates that p. leucopus is not ... | 1989 | 2668569 |
| anaplasma marginale in tick cell culture. | anaplasma marginale was propagated in a tick cell line derived from dermacentor variabilis embryos. the rickettsial organism was identified and monitored in culture by transmission electron microscopy and the indirect immunofluorescence technique, using specific monoclonal antibodies. inoculation of the embryonic tick cell line with midguts of infected adult ticks (culture 1), nymphal ticks (culture 2) and adult ticks that were infected as nymphs and dissected as adults (culture 3) resulted in 3 ... | 1989 | 2692483 |
| host associations of ticks (acari: ixodidae) parasitizing medium-sized mammals in a lyme disease endemic area of southern new york. | ticks of eight medium-sized mammal species were studied in an area of endemic lyme disease in westchester county, n.y., from 1 april 1984 to 31 march 1985. most (81%) of the 266 total mammal captures were raccoon, procyon lotor (l.) (47%), opossum, didelphis virginiana (kerr) (19%), and striped skunk, mephitis mephitis schreber (15%); these host species accounted for 91% of the 1,519 ticks collected. although the total number of ticks was rather evenly distributed among these mammals, species co ... | 1989 | 2724317 |
| ultrastructure of the midgut and blood meal digestion in the adult tick dermacentor variabilis. | digestive cells in the midgut of male and female dermacentor variabilis (say) took up the blood meal in coated vesicles and smooth flask-shaped vesicles, and deposited it in endosomes which were digested via heterophagy. iron was concentrated in residual bodies. digestion occurred in three distinct phases in mated females: (1) continuous digestion (initiated by feeding) occurred during slow engorgement; (2) reduced digestion (initiated by mating) occurred in mated females during the period of ra ... | 1989 | 2743838 |
| relationship between feeding, mating, vitellogenin production and vitellogenesis in the tick dermacentor variabilis. | anti-vitellin igg directed against dermacentor variabilis egg vitellin was used in sodium dodecyl sulfate polyacrylamide (sds-page) gradient gel immunoblots to detect the presence of vitellin and its precursor, vitellogenin, in the organs of feeding adults and in the immature stages of this tick. vitellin polypeptides were found in the egg, larvae, nymph, and in the unfed adult stages of both sexes. vitellin polypeptides were first detected in the ovary of mated females during the rapid-engorgem ... | 1989 | 2758940 |
| transstadial and attempted transovarial transmission of anaplasma marginale by dermacentor variabilis. | transstadial and transovarial transmission of anaplasma marginale by dermacentor variabilis were attempted with with ticks exposed to the organism once by feeding as larvae or nymphs, and twice by feeding as larvae and nymphs. typical colonies of a marginale were in gut tissues of adults that were infected as larvae, larvae and nymphs, and as nymphs; repeated exposure of ticks did not appear to result in an increase in the number of colonies in the gut of subsequently molted adults nor did it af ... | 1989 | 2782719 |
| growth of bluetongue and epizootic hemorrhagic disease of deer viruses in poikilothermic cell systems. | continuous cell lines from the ticks dermacentor variabilis, d. parumapertus, d. nitens, rhipicephalus sanguineus and r. appendiculatus, the mosquitoes aedes albopictus and culex quinquefasciatus and the african toad xenopus laevis were tested for their ability to replicate bluetongue (bt) and epizootic hemorrhagic disease of deer (ehd) viruses, and for their sensitivity as potential isolation systems. bt serotype 17 grew to peak titers of 10(4.5)-10(7.5) tcid50 ml-1 in all except one of the tic ... | 1988 | 2833002 |
| computer simulation of population dynamics of the american dog tick (acari: ixodidae). | a comprehensive computer model was developed for simulation of the population dynamics of the american dog tick (adt), dermacentor variabilis say, in north america. the model simulates the effects of major environmental variables, such as ambient temperature, saturation deficit, kind of habitat, and host density, on adt population dynamics in ecosystems with small mammals as hosts for immature ticks and medium-sized mammals or domestic dogs as hosts for adult ticks. general validity of the model ... | 1989 | 2926777 |
| isolation of st. louis encephalitis virus from adult dermacentor variabilis (acari: ixodidae). | | 1985 | 2984423 |
| parasites, diseases and health status of sympatric populations of sambar deer and white-tailed deer in florida. | from december 1983 to december 1984 a study on parasites, diseases and health status was conducted on sympatric populations of sambar deer (cervus unicolor) and white-tailed deer (odocoileus virginianus) from st. vincent island, franklin county, florida. ten sambar and six white-tailed deer were examined. white-tailed deer had antibodies to epizootic hemorrhagic disease virus and bluetongue virus. serologic tests for antibodies to the etiologic agents of bovine virus diarrhea, infectious bovine ... | 1987 | 3035242 |
| evidence of a limited schizogonous cycle for cytauxzoon felis in bobcats following exposure to infected ticks. | schizogonous tissue stages of cytauxzoon felis (apicomplexa: theileridae) were not observed by microscopic evaluation of impression smears of liver, spleen, lung and lymph nodes in 10 bobcats (lynx rufus) from oklahoma with naturally occurring piroplasm infections. schizogonous stages were observed in similar tissues from experimentally-infected bobcats at 11 days postexposure to infected dermacentor variabilis, but not at 30 days following tick feeding. the schizogonous cycle of this parasite a ... | 1987 | 3114505 |
| a focus of rocky mountain spotted fever within new york city. | in the spring and summer of 1987, four persons acquired rocky mountain spotted fever within new york city, an area in which the disease had not previously been known to be endemic. three of the four patients were residents of the soundview area of the bronx. all diagnoses were confirmed by indirect fluorescent-antibody tests. environmental investigation revealed that the tick vector for rickettsia rickettsii, dermacentor variabilis, was present in a local park. of the 66 specimens of d. variabil ... | 1988 | 3130574 |
| ticks and biting insects infected with the etiologic agent of lyme disease, borrelia burgdorferi. | members of 18 species of ticks, mosquitoes, horse flies, and deer flies were collected in southeastern connecticut and tested by indirect fluorescent-antibody staining methods for borrelia burgdorferi, the etiologic agent of lyme disease. an infection rate of 36.2% (116 tested), recorded for immature ixodes dammini, exceeded positivity values for all other arthropod species. prevalence of infection for hematophagous insects ranged from 2.9% of 105 hybomitra lasiophthalma to 14.3% of seven hybomi ... | 1988 | 3170711 |
| ticks parasitizing humans in a lyme disease endemic area of southern new york state. | a total of 126 tick specimens were submitted by tick bite victims to the westchester county department of health, white plains, new york, and to the new york medical college, medical entomology laboratory, armonk, new york, during 1985. these included 96 (76.2%) ixodes dammini, 26 (20.6%) dermacentor variabilis, and two (1.6%) amblyomma americanum. i. dammini parasitism was reported during all months of the year except december and february and involved all life stages. only d. variabilis adults ... | 1988 | 3189288 |
| ability to ixodes scapularis, dermacentor variabilis, and amblyomma americanum (acari: ixodidae) to acquire, maintain, and transmit lyme disease spirochetes (borrelia burgdorferi). | | 1988 | 3193425 |
| medium-sized mammal hosts of amblyomma americanum and dermacentor variabilis (acari: ixodidae) at land between the lakes, tennessee, and effects of integrated tick management on host infestations. | | 1988 | 3204625 |
| population dynamics of the american dog tick (acari: ixodidae) in relation to small mammal hosts. | | 1988 | 3204629 |
| lyme borreliosis in california. acarological, clinical, and epidemiological studies. | the relative abundance of, and spirochetal-infection rates in, adult ixodid ticks from eight lyme borreliosis clinical-case areas and two comparison areas were investigated in northern california from late fall to early spring, 1984-87. the western black-legged tick (ixodes pacificus) was the most abundant species at seven of nine sites yielding specimens as determined with a tick drag method. the pacific coast tick (dermacentor occidentalis) was the most abundant species at two sites, and lesse ... | 1988 | 3263826 |
| characterization of tick antigens inducing host immune resistance. ii. description of rabbit-acquired immunity to amblyomma americanum ticks and identification of potential tick antigens by western blot analysis. | feeding by adult amblyomma americanum ticks induced a level of immunity in rabbits to subsequent tick feeding that resulted in a significant decrease in tick feeding success and fecundity. histological analysis of tick feeding sites in hosts expressing resistance revealed a predominant eosinophil response, with weak basophil and neutrophil infiltrates. while the basophil was never the dominant granulocyte at the tick feeding sites in resistant hosts, this cell exhibited the greatest increase in ... | 1988 | 3291384 |
| role of small mammals in population dynamics and dissemination of amblyomma americanum and dermacentor variabilis (acari: ixodidae) at land between the lakes, tennessee. | | 1987 | 3295243 |
| regulation of dermacentor variabilis by limited dispersion of larvae from the egg mass (acari: ixodidae). | | 1987 | 3322991 |
| cultivation of anaplasma marginale from cattle in a dermacentor cell line. | a tick cell line derived from dermacentor variabilis (rml-15) was inoculated with bovine rbc infected with anaplasma marginale. two hours after inoculation, numerous rbc were phagocytized by the tick cells. after one passage of the cell culture, numerous groups of anaplasma-like particles were seen in the tick cell cytoplasm. increased numbers of anaplasma-like particles also were present. seemingly, anaplasma can multiply in tick cells. | 1988 | 3348535 |
| borreliosis in free-ranging black bears from wisconsin. | blood, kidney and tick samples were obtained from 18 hunter-killed black bears (ursus americanus) from three sites in northern wisconsin. a borrelia sp., morphologically and antigenically similar to borrelia burgdorferi, was isolated from the blood of two of the animals, and from the kidney of a third. ixodes dammini and dermacentor variabilis were found on the bears. this is the first report of borreliosis in the ursidae, and of the primary vector of lyme disease, i. dammini, from this host. | 1988 | 3373646 |
| cross-reactive antigens between a tick, dermacentor variabilis (acari: ixodidae), and a mite, psoroptes cuniculi (acari: psoroptidae). | | 1986 | 3512828 |