| [lytic antibodies in antibacterial sera. ii. lytic activity of antibodies of different immunochemical type]. | | 1971 | 4938664 |
| comparison of the ultrastructure of several rickettsiae, ornithosis virus, and mycoplasma in tissue culture. | anderson, douglas r. (national cancer institute, bethesda, md.), hope e. hopps, michael f. barile, and barbara c. bernheim. comparison of the ultrastructure of several rickettsiae, ornithosis virus, and mycoplasma in tissue culture. j. bacteriol. 90:1387-1404. 1965.-in an effort to make a valid comparison of the ultrastructure of several intracellular parasites, selected agents were propagated under identical conditions in a single type of tissue culture cell; such infected preparations were pro ... | 1965 | 4954556 |
| rocky mountain spotted fever: clinical and laboratory observations of monkeys after respiratory exposure. | | 1966 | 4956209 |
| infectious diseases in wild animals in utah. vi. experimental infection of birds with rickettsia rickettsii. | lundgren, d. l. (university of utah, salt lake city), b. d. thorpe, and c. d. haskell. infectious diseases in wild animals in utah. vi. experimental infection of birds with rickettsia rickettsii. j. bacteriol. 91:963-966. 1966.-chickens, pigeons, pheasants, sparrow hawks, red-tailed hawks, ravens, magpies, and a marsh hawk were inoculated with rickettsia rickettsii, the etiological agent of rocky mountain spotted fever. the development and persistence of complement-fixing (cf) antibodies and ric ... | 1966 | 4956338 |
| aerosol infection of monkeys with rickettsia rickettsii. | | 1966 | 4958344 |
| relationship of cryptococcus neoformans to pigeons in milwaukee, wisconsin. | | 1966 | 4959230 |
| the pathogenesis of rocky mountain spotted fever in monkeys, infected by inhalation. | | 1967 | 4964161 |
| experimental infection of the cotton rat sigmodon hispidus with rickettsia rickettsii. | studies of experimental infection of the cotton rat, sigmodon hispidus, with the virulent sheila smith (r type) and the avirulent si 7 (u type) strains of rickettsia rickettsii were undertaken to evaluate the role of this native wild mammal in the ecology of rocky mountain spotted fever. the sheila smith strain, which was highly lethal for guinea pigs, was nonpathogenic for cotton rats. serial passage of the r-type strain in the cotton rat did not alter the virulence of the agent for cotton rats ... | 1967 | 4964475 |
| experimental infection of lagomorphs with rickettsia rickettsii. | | 1968 | 4967159 |
| fundus changes in rocky mountain spotted fever. | | 1969 | 4974502 |
| [exanthematous typhus in ecuador]. | | 1968 | 4976285 |
| plaque assay for rickettsia rickettsii. | a plaque technique for the assay of rickettsia rickettsii is described. the method employs primary chick or green monkey kidney monolayer cell cultures with either an agarose or special noble agar overlay. plaques were counted in 6 days and resultant titers correlated well with ld(50) end points obtained by a standard assay in embryonated eggs. identification of the plaque-forming organisms was accomplished by direct observation of rickettsiae-like bodies in the monolayer lesions, inhibition of ... | 1969 | 4977475 |
| [development of the antitoxin level in rabbit blood after injection of antidiphtheria serum. effect of a simultaneous injection of anatoxin]. | | 1969 | 4981112 |
| tests on ticks from wild birds collected in the eastern united states for rickettsiae and viruses. | | 1969 | 4982220 |
| evaluation of chloramphenicol acid succinate therapy of induced typhoid fever and rocky mountain spotted fever. | | 1970 | 4982445 |
| plaque assay system for several species of rickettsia. | the plaque assay developed in this laboratory for the bitter root strain of rickettsia rickettsii has recently been shown to be appropriate for other rickettsiae. | 1969 | 4984178 |
| rocky mountain spotted fever. laboratory infection in a vaccinated individual. | | 1970 | 4984704 |
| serologic evidence of rickettsia canada infection of man. | | 1970 | 4985949 |
| [detection of rickettsial and ornithosis antigens in the indirect hemagglutination test using erythrocytes chemically joined to polycondensed immune globulins. 1. use of sensitized erythrocytes prepared with the use of borofluoride bis-diphenyldiazonium for rapid demonstration of the agent of tick-borne rickettsioses]. | | 1970 | 4990580 |
| hemolymph test. a technique for detection of rickettsiae in ticks. | | 1970 | 4992724 |
| amount, class and specificity of antibody to the lipopolysaccharide of salmonella enteritidis after immunization by various schedules. | | 1971 | 4993854 |
| tick-borne typhus (rocky mountain spotted fever). epidemiologic trends, with particular reference to virginia. | | 1971 | 4995481 |
| rickettsioses of central america. | | 1971 | 5002247 |
| effect of dietary lysine level on plasma free amino acids in adult cockerels. | | 1972 | 5022194 |
| [pathogenesis of inflammation and mechanism of the anti-inflammatory action of experimental peloid therapy]. | | 1972 | 5029442 |
| the influence of chlorprothixene, methiothepine and reserpine on the resistance of the central nervous system of the rats against ischemia during ontogeny. | | 1972 | 5052812 |
| natural history of tick-borne spotted fever in the usa. susceptibility of small mammals to virulent rickettsia rickettsii. | in the ecology of spotted fever rickettsiae, one of the as yet unsolved problems concerns the significance of small animals in the distribution of rickettsia rickettsii in nature. in the bitter root valley of western montana, a great variety of rodents, rabbits and hares are known to serve as the preferred hosts for the immature stages of the vector tick, dermacentor andersoni.the authors analyse the susceptibility of various species of small mammals to virulent r. rickettsii and evaluate their ... | 1966 | 5296999 |
| infectious diseases in wild animals in utah. vii. experimental infection of rodents with rickettsia rickettsii. | | 1966 | 5917635 |
| injury restricted to cells infected with spotted fever group rickettsiae in parabiotic chambers. | one chamber of paired parabiotic chambers separated by 0.2 micron poresized membrane filters which prevented passage of rickettsiae were infected with either rickettsia rickettsii or r. conorii. infected vero cell monolayers underwent necrosis. uninfected monolayers in adjoining chambers which shared the same extracellular milieu including soluble rickettsial products did not undergo necrosis. | 1984 | 6152112 |
| production and characterization of monoclonal antibodies to rickettsia rickettsii. | five mouse ascitic fluids (mafs) containing monoclonal antibody to rickettsia rickettsii were produced from three original fusions by murine hybridoma technology. the five mafs were fractionated and purified; each contained monoclonal antibody of the immunoglobulin g2a subclass. each monoclonal antibody-containing maf was titrated by indirect immunofluorescence against three r. rickettsii isolates from humans and four other spotted fever group rickettsiae. each maf was also titrated in the compl ... | 1984 | 6209219 |
| biological properties of rabbit antibodies to a surface antigen of rickettsia rickettsii. | because of the potential significance of external components of the obligate intracellular parasite rickettsia rickettsii in host-parasite interactions, we have begun the first phase of a study to isolate and characterize surface antigens of this organism. an antiserum to a rickettsial surface component was obtained from rabbits inoculated with immune precipitates prepared by crossed immunoelectrophoresis of triton x-100 extracts of r. rickettsii strain r. this antiserum (i) protected guinea pig ... | 1983 | 6403467 |
| role of phospholipase-associated penetration mechanism in cell injury by rickettsia rickettsii. | the cholesterol receptor-binding drugs amphotericin b and digitonin reduced rickettsial plaque formation, presumably by blocking rickettsial attachment, even when added to the plaque model on day 4 post-inoculation when infected foci were well established. the phospholipase inhibitor phentermine reduced plaque formation, presumably by inhibiting the phospholipase-associated entry step of penetration. | 1983 | 6404837 |
| absorption of rickettsia rickettsii antibodies by rickettsia rickettsii antigens in four diagnostic tests. | immunoabsorption profiles were determined for rickettsia rickettsii antigens used in four confirmatory tests for detection of antibodies to rocky mountain spotted fever. a human serum reactive in the four tests was absorbed with each test antigen and then reexamined by all four tests. the results indicated that the whole organism and complement-fixation antigen absorbed the whole array of antibodies to r. rickettsii, whereas erythrocyte-sensitizing substance coated on latex or erythrocytes did n ... | 1983 | 6404927 |
| latex-rickettsia rickettsii test reactivity in seropositive patients. | in correlating results obtained from a new latex-rickettsia rickettsii test with results obtained from a reference microimmunofluorescence test for rocky mountain spotted fever, we found that for seropositive patients each microimmunofluorescence titer (up to 4,096) was usually double the median titer obtained from the latex-r. rickettsii test. the pattern of immunoserological response indicated that latex-r. rickettsii is reactive with sera containing either anti-r. rickettsii immunoglobulin m ... | 1983 | 6404929 |
| rickettsiae-infected ticks (acari: ixodidae) and seropositive mammals at a focus for rocky mountain spotted fever in connecticut, usa. | | 1983 | 6405035 |
| summertime and ticks. | | 1983 | 6405617 |
| correlation of rickettsial titers, circulating endotoxin, and clinical features in rocky mountain spotted fever. | blood rickettsial titers, skin biopsy results, and circulating endotoxin measurements were correlated with the clinical course of disease in patients with rocky mountain spotted fever (rmsf). nine of 11 patients with documented rmsf had rickettsia rickettsii isolated from plasma samples. of the eight patients in whom rickettsial titers were measured, seven had 10(0.7) to 10(1.2) median tissue culture infective doses (tcid50) per milliliter; all seven had mild to moderately severe disease. one pa ... | 1983 | 6407418 |
| [survey of natural infection of ticks with rickettsia of the spotted fever group in the northwestern section of xinjiang province]. | | 1983 | 6411346 |
| detection of fibrils associated with rickettsia rickettsii. | the ultrastructural appearance of the "halozone" formed at the interface between the spotted fever agent rickettsia rickettsii and the cytoplasm of persistently infected cultured vole cells (microtus pennsylvanicus) was studied by transmission electron microscopy. in sections of epoxy-embedded specimens stained with uranyl acetate and lead citrate, the halozone appeared clear and devoid of ultrastructural features. however, when unembedded preparations of whole infected cells were examined at 1, ... | 1983 | 6411620 |
| coating of polymeric surfaces for immunoassay by a forced adsorption technique. | a forced adsorption technique for coating polymeric surfaces is described. this technique is simple and allows us to use (i) relatively impure ligands to be coated on latex surface and (ii) the minimum amount of ligands for preparation of large-volume lots of latex reagent. the serologic results are highly reproducible from lot to lot of the reagent, in contrast to the variability found with passively adsorbed reagents. use of this technique could be extended to coat flat surfaces for solid-phas ... | 1983 | 6411771 |
| rocky mountain spotted fever vaccine in an animal model. | formalin-killed, purified rickettsia rickettsii vaccine was evaluated in a guinea pig model of r. rickettsii infection. vaccinated guinea pigs were partially protected by the vaccine when challenged with virulent, viable rickettsiae. greater protection was observed when higher doses of vaccine were given and when frequent booster injections were administered. stimulation of cell-mediated immunity to the vaccine antigens was variable and also appeared to be achieved more reproducibly with booster ... | 1983 | 6413529 |
| detection of rickettsia rickettsii antibodies in human sera by crossed immunoelectrophoresis. | to identify rickettsia rickettsii antigens of immunological importance, we examined sera from patients with serologically confirmed cases of rocky mountain spotted fever by crossed immunoelectrophoresis for antibodies to antigens extracted from the r strain of r. rickettsii with the detergent triton x-100. sixteen antigens were identified in the detergent extract by crossed immunoelectrophoresis with a hyperimmune rabbit serum raised against whole rickettsiae. when the rabbit antiserum was place ... | 1983 | 6415093 |
| evaluation of latex-rickettsia rickettsii test for rocky mountain spotted fever in 11 laboratories. | a latex-rickettsia rickettsii test for detection of antibodies to rocky mountain spotted fever (rmsf) was evaluated during the 1980 rmsf season in 11 laboratories in nine states where the disease is endemic. in a double-blind study, all sera submitted to each laboratory for rmsf testing were also examined by the latex-r. rickettsii test. a portion of each specimen was then sent to the new york state laboratory for testing by latex-r. rickettsii and by the reference microimmunofluorescence test. ... | 1983 | 6415103 |
| serodiagnosis of rocky mountain spotted fever: comparison of igm and igg enzyme-linked immunosorbent assays and indirect fluorescent antibody test. | to characterize igm and igg antibody responses in rocky mountain spotted fever (rmsf), a microtiter enzyme-linked immunosorbent assay (elisa) using density gradient-purified rickettsia rickettsii as antigen was developed. sera of vaccinated individuals and patients with rmsf were tested by elisa and by indirect fluorescent antibody (ifa) tests. diagnostic agreement between elisa and the ifa test was 76% and 52% for igg and igm antibody, respectively. diagnostic agreement between the elisa for ig ... | 1983 | 6415180 |
| reactogenicity, immunogenicity, and efficacy of a chick embryo cell-derived vaccine for rocky mountain spotted fever. | a new formalin-inactivated vaccine prepared by sucrose density gradient centrifugation of tissue culture-grown rickettsia rickettsii was evaluated for safety and immunogenicity in a placebo-controlled, double-blind study. most of the 52 seronegative adult vaccinees, 88% after the first and 66% after the second dose, experienced brief, mild (mostly local) reactions, but only 50% exhibited a systemic immune response to vaccination. six unvaccinated volunteers (controls) and 16 of these vaccinees w ... | 1983 | 6415182 |
| susceptibility of inbred mice to rickettsiae of the spotted fever group. | a mouse strain susceptible to lethal infection with rickettsia conorii was required for testing vaccine efficacy and for studying the immunology and pathogenesis of infection. among 20 strains of inbred mice inoculated intraperitoneally with the malish strain of r. conorii, the c3h/hej mouse strain was the most susceptible, with a 50% lethal dose of approximately 10 pfu. infection of all mouse strains resulted in a measurable antibody response; the highest titers correlated with the greatest deg ... | 1984 | 6418657 |
| rocky mountain spotted fever in an urban canine population. | a survey for the prevalence of rocky mountain spotted fever antibodies in dogs from a well-defined endemic area in columbus, ohio (franklin county), was conducted during the summer of 1981. seventy-three blood samples from dogs in this area were tested by microimmunofluorescence for antibodies to rickettsia rickettsii and other rickettsial antigens. thirty-three (45.2%) of these samples were positive for r rickettsii, with titers ranging from 1:8 to 1:2,048. for comparison, 137 blood samples fro ... | 1983 | 6418697 |
| rocky mountain spotted fever in dogs associated with human patients in ohio. | | 1983 | 6418831 |
| infection of human vascular endothelial cells by rickettsia rickettsii. | rocky mountain spotted fever is caused by rickettsia rickettsii, an obligate intracellular bacterial parasite. the organism primarily attacks endothelial cells and occasionally attacks smooth-muscle cells of small blood vessels. an effective means of examining host-parasite interaction in rocky mountain spotted fever would be to use an in vitro model system with a host-cell type that is similar in structure and function to the putative target cell in human infections. because human umbilical-vei ... | 1984 | 6421942 |
| rocky mountain spotted fever vaccine: a regional need. | because the killed rickettsia vaccines have failed to provide protection against rocky mountain spotted fever, we approached the problem of protective immunity to rickettsia rickettsii with a closely related, live, less pathogenic spotted fever rickettsia. guinea pigs vaccinated with r conorii produced antibodies to spotted fever group rickettsiae and did not have fever or other signs of illness after challenge with r rickettsii. a vaccine against rocky mountain spotted fever would be useful in ... | 1984 | 6424239 |
| 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 |
| effect of synthetic protease inhibitors of the amidine type on cell injury by rickettsia rickettsii. | to evaluate the importance of proteolytic activity in the pathogenesis of cell injury by rickettsia rickettsii, a series of four aromatic amidine inhibitors of trypsin-like proteases were introduced into the plaque model. the compounds were shown to be active toward plaque reduction with their order of effectiveness parallel to their antitrypsin activity. one of the compounds, bis(5-amidino-2-benzimidazolyl)-methane, at a concentration of 10(-5) m demonstrated complete inhibition of plaque forma ... | 1984 | 6428311 |
| epidemiology of rocky mountain spotted fever in ohio, 1981: serologic evaluation of canines and rickettsial isolation from ticks associated with human case exposure sites. | a survey for the prevalence of rocky mountain spotted fever (rmsf) antibodies in dogs associated with confirmed human cases in ohio was conducted during 1981. twelve of 14 confirmed cases (85%) had a history of dog association prior to onset of rmsf. a total of 29 dogs were included in the study, with 16 dogs providing serum samples for antibody testing and the remainder providing tick samples. serum samples tested by indirect microimmunofluorescence techniques revealed 12/16 dogs (75%) to be se ... | 1984 | 6435461 |
| rocky mountain spotted fever. gastrointestinal and pancreatic lesions and rickettsial infection. | recent clinical studies have shown a high incidence of nausea, vomiting, diarrhea, and abdominal pain in rocky mountain spotted fever (rmsf), and case reports have documented rickettsial infection and vascular injury in the small intestine, appendix, and gallbladder. to determine the incidence and distribution of rickettsia rickettsii and rickettsial lesions that might be the basis for these clinical manifestations of rmsf, tissues that were available from the stomach, small intestine, colon, an ... | 1984 | 6439172 |
| susceptibility and reservoir potential of the dog to spotted fever-group rickettsiae. | this study was initiated to determine the degree of susceptibility of dogs to virulent and nonvirulent spotted fever-group rickettsiae and to evaluate dogs as sources of infection for ticks. dogs were exposed either by inoculation (syringe) or by infective tick bite to the following rickettsial serotypes: (1) rickettsia rickettsii (wachsmuth and sawtooth female 2 strains), (2) r montana (m/5-6 b strain), and (3) r rhipicephali (3-7-female 6 strain). results indicated that dogs inoculated with 1, ... | 1984 | 6548617 |
| [the occurrence of rickettsiosis of the rickettsia rickettsii group]. | | 1983 | 6675165 |
| rickettsia rickettsii-induced cellular injury of human vascular endothelium in vitro. | the endothelial cell is the putative primary target cell in humans infected with rickettsia rickettsii, the etiological agent of rocky mountain spotted fever. although the clinical manifestations of infection by this organism are well documented, the mechanism of injury to the endothelial cell is not understood. the ability to culture human endothelial cells in vitro provides a unique system with which to study this host-parasite interaction directly. human vascular endothelial cells derived fro ... | 1984 | 6724689 |
| antibodies to rickettsia rickettsii in peromyscus leucopus from a focus of rocky mountain spotted fever in connecticut. | during 1980-1982, white-footed mice (peromyscus leucopus) were captured in newtown, connecticut, an area where rickettsia rickettsii, the etiologic agent of rocky mountain spotted fever, is thought to be enzootic. an indirect microimmunofluorescence test identified specific antibodies to this organism in 16 of 237 (7%) sera: titration end points for 14 samples were relatively high (1:128-1:2048). antibodies were detected in mice during 1980 and 1981 with monthly prevalences varying from 8 to 22% ... | 1984 | 6744122 |
| pathogenesis of myocarditis in rocky mountain spotted fever. | because myocarditis has been noted frequently as present at necropsy in fatal rocky mountain spotted fever (rmsf) and ecg alterations may also accompany the disease, we studied the pathogenesis of myocarditis in rmsf. increased heart weight in eight of nine cases and increased interstitial volume in six of nine cases suggest that myocardial edema is present. specific immunofluorescent demonstration of rickettsia rickettsii in myocardial capillaries, venules, and arterioles in eight of nine cases ... | 1980 | 6767463 |
| properties of selected rickettsiae of the spotted fever group. | eight strains of spotted fever group rickettsiae were studied to gain insight into the extent of variation of their properties. two standard strains of rickettsia rickettsii and one strain of rickettsia conorii were included among the eight for comparison. the molar percentage of guanine plus cytosine for each strain did not differ significantly from that for r. rickettsii, 32.6 +/- 0.7%. two strains caused extended fever in guinea pigs, one strain caused fever of short duration, and the other s ... | 1980 | 6769801 |
| development and characterization of high-titered, group-specific fluorescent-antibody reagents for direct identification of rickettsiae in clinical specimens. | rabbits were inoculated with purified antigen preparations of coxiella burnetii and representative species of the spotted fever and typhus groups of rickettsiae. their antibody responses were monitored by complement fixation tests; high-titered antisera were fractionated with ammonium sulfate and then labeled with fluorescein isothiocyanate by the dialysis method. the conjugates had homologous 3+ staining titers of 1:256 to 1:2,048 and did not exhibit nonspecific staining. the rickettsia rickett ... | 1980 | 6769955 |
| measles in patients suspected of having rocky mountain spotted fever. | diagnostic titer rises of measles antibody were observed in six of 46 paired sera from persons originally suspected of having rocky mountain spotted fever and found to be serologically negative for this disease. atypical or typical measles is now occurring relatively more frequently in adolescents and young adults and should be considered in the differential diagnosis for patients in these age groups who have undiagnosed febrile rash illnesses. | 1980 | 6771427 |
| rickettsial infection of the pulmonary microcirculation: the basis for interstitial pneumonitis in rocky mountain spotted fever. | pulmonary tissue from 10 patients with fatal rocky mountain spotted fever was examined by brightfield microscopy for histopathologic lesions and by immunofluorescence for rickettsia rickettsii. the distribution of rickettsiae and the vasculitis of the pulmonary microcirculation coincided. the lungs demonstrated the consequent interstitial pneumonia--alveolar septal congestion and interstitial edema; alveolar edema, fibrin, macrophages, and hemorrhage; and interlobular septal edema. the effects o ... | 1980 | 6772542 |
| spotted fever group rickettsiae in dermacentor variabilis from cape cod, massachusetts. | spotted fever group (sfg) rickettsiae were identified by indirect immunofluorescent antibody tests in 1.1% of 6,956 specimens of dermacentor variabilis collected on cape cod, massachusetts. forty-one of 45 rickettsial isolates were serotyped as rickettsia montana, one as rickettsia rickettsii, and three were unidentified. studies of canines and humans with clinical evidence of spotted fever, and of healthy dogs with antibody to sfg rickettsiae, indicated that exposure of the canine population to ... | 1980 | 6773430 |
| the rickettsial plaque. evidence for direct cytopathic effect of rickettsia rickettsii. | monolayers of primary chick embryo cells were infected with rickettsia rickettsii in a plaque assay system with 0.5 per cent agarose overlay. plaques appeared 5 days after inoculation and were examined on day 6 by supravital staining, immunofluorescence for r. rickettsii, and electron microscopy. in all studies maintenance of the topographic integrity of the monolayer and the plaque allowed assessment of temporospatial relationships of rickettsial infection and cytopathologic changes. plaques co ... | 1980 | 6777602 |
| laboratory diagnosis of rocky mountain spotted fever. | to examine the use of the laboratory in the diagnosis of rocky mountain spotted fever and to determine the specificity and sensitivity of the weil-felix test, hemagglutination, complement fixation, and skin biopsy immunofluorescence in the hospital, we reviewed our experience during th year 1978. sera were submitted from 142 patients and skin biopsies from 16 patients suspected of having rmsf. sensitivity rates of methods in the acute phase were skin biopsy, 70%; proteus ox-19 agglutination, 65% ... | 1980 | 6777873 |
| serological evidence of infection by spotted fever group rickettsiae in karnataka state. | | 1980 | 6780455 |
| the liver in rocky mountain spotted fever. | hepatic tissues from nine patients who had fatal rocky mountain spotted fever were examined in sequential sections by brightfield and immunofluorescence microscopy for histologic lesions and for coincidence of these lesions with the distribution of rickettsia rickettsii. the basic hepatic lesion in rocky mountain spotted fever is an inflammation of the portal triad in which large mononuclear cells and neutrophils predominate. rickettsia were demonstrated in lesions of the portal triads in eight ... | 1981 | 6781327 |
| serotypes of spotted fever group rickettsiae isolated from dermacentor andersoni (stiles) ticks in western montana. | adult dermacentor andersoni ticks were collected by flagging vegetation in 18 canyons bordering the bitterroot valley, montana, an area where nearly 400 cases of rocky mountain spotted fever (rmsf) have occurred since 1900. three hundred and nine (8.3%) of the 3,705 ticks collected contained hemocyte-associated rickettsia-like organisms of three morphologic types, coccobacillary, fine bacillary, and coarse bacillary (long forms). only the coccobacillary and fine bacillary organisms stained with ... | 1981 | 6782899 |
| in vitro studies of rickettsia-host cell interactions: ultrastructural study of rickettsia prowazekii-infected chicken embryo fibroblasts. | secondary chicken embryo fibroblasts infected in suspension with the breinl strain of rickettsia prowazekii and grown in monolayer culture were examined by both transmission and scanning electron microscopy at specific intervals after infection to study the effects of prolonged intracellular growth on the fine structure of the host cell and the rickettsiae. cytopathological changes in the infected host cells were not apparent until late in the intracellular growth cycle when the cells began to r ... | 1980 | 6783534 |
| differential requirements for enriched atmospheric carbon dioxide content for intracellular growth in cell culture among selected members of the genus rickettsia. | in an in vitro chicken embryo cell culture system, strains of rickettsia prowazekii, r. mooseri, and r. rickettsii, but not of r. tsutsugamushi, required an atmosphere enriched in co2 for intracellular growth. | 1981 | 6785241 |
| detection of rocky mountain spotted fever antibodies by a latex agglutination test. | a latex test for immunodiagnosis of rocky mountain spotted fever, using erythrocyte-sensitizing substance from rickettsia rickettsii adsorbed to latex particles, has been developed. the test was evaluated with a total of 123 single and 118 paired human sera submitted for rocky mount spotted fever testing. this test is simple, sensitive, and specific. its efficiency, relative to the reference microimmunofluorescence test, was 95.1% for single sera and approached 100% for paired sera. | 1980 | 6785303 |
| epidemic typhus in the united states associated with flying squirrels. | between july 1977 and january 1980, seven cases of sporadic, nonepidemic "epidemic" typhus (rickettsia prowazekii) were discovered in virginia, west virginia, and north carolina. the reservoir seemed to be the southern flying squirrel (glaucomys volans), an animal indigenous to the eastern united states; however, the vector or mode of acquisition was not evident. diagnosis was established principally through complement fixation, indirect immunofluorescence, and toxin neutralization tests. patien ... | 1981 | 6785459 |
| fatty acid composition of rickettsiae. | the fatty acid compositions of selected strains of rickettsiae were studied by gas-liquid chromatography. the profiles of all the rickettsiae except coxiella burnetii were qualitatively similar. the fatty acid composition of c. burnetii was similar to that of certain legionella species. | 1981 | 6787071 |
| endemicity of spotted fever group rickettsiae in connecticut. | to compare rickettsial infectivity and seropositivity rates against spotted fever group (sfg) rickettsiae, ticks and wild mammals were collected from three areas where rickettsia rickettsii was thought to be enzootic in connecticut during 1978-1979, and from four additional sites (with no reported human cases) between 1976 and 1979. of the 1,001 dermacentor variabilis examined by the hemolymph test, 59 (5.9%) contained rickettsia-like organisms; direct immunofluorescence tests verified the prese ... | 1981 | 6789690 |
| serotypes of tick-borne spotted fever group rickettsiae from western california. | a rickettsial survey of ixodid ticks known to bite man was conducted in 1979 in four coastal counties of california to obtain isolates from tick species that might be involved in the transmission of spotted fever-like illnesses, and to examine serologic characteristics of the rickettsiae relative to defined members of the spotted fever group (sfg). one hundred and seventy (19.4%) of 877 ticks comprising three species were shown by hemolymph test to harbor rickettsia-like organisms. a total of 85 ... | 1981 | 6789691 |
| rocky mountain spotted fever in childhood. | | 1981 | 6798547 |
| rocky mountain spotted fever. serological evidence of previous subclinical infection in children. | serological tests for rocky mountain spotted fever were performed on single serum specimens from sixth graders from forsyth county, north carolina, an area highly endemic for this disease. five of 508 *.098%) sera were positive (titer greater than or equal to 1:64) using the indirect fluorescent antibody method. elevated proteus agglutination antibody titers (greater than 1:160) to ox-19, but not ot ox-2, were common (19.6%) in these children. no correlation of those with positive ox-19 titers c ... | 1982 | 6798859 |
| in vitro sensitivity of rickettsia rickettsii to doxycycline. | | 1982 | 6802907 |
| antibodies to spotted fever-group rickettsiae in dogs and prevalence of infected ticks in southern connecticut. | blood samples and ticks were obtained from dogs to assess canine exposure to spotted fever-group (sfg) rickettsiae during 1978-1980 in southern connecticut. of the 1,576 dog sera screened by microimmunofluorescence. 174 (11.0%) contained specific antibodies at titers greater than or equal to 1:64 against rickettsia montana (n = 34), r rickettsii (n = 31), r rhipicephali (n = 19), or the unclassified 369-c rickettsia (n = 90). end points greater than or equal to 1:8,192 to r rickettsii and to r r ... | 1982 | 6803626 |
| rocky mountain spotless fever: a dilemma for the clinician. | failure of the characteristic rash to develop during the course of illness in rocky mountain spotted fever may lead to the delay or failure of diagnosis and may result in fetal encephalopathic illness with disseminated vascular injury. four patients are described herein in whom a rash failed to develop and the diagnosis was initially incorrect. each patient was seen at least once before hospital admission by a physician and given ineffective antibiotic therapy, resulting in fatal complications. ... | 1982 | 6807231 |
| rocky mountain spotted fever in areas of high and low prevalence: survey for canine antibodies to spotted fever rickettsiae. | antibodies to rickettsia rickettsii were detected by indirect immunofluorescence in sera from 149 of 467 dogs (32%) examined from 4 military installations located in kentucky, north carolina, pennsylvania, and virginia. the prevalence at individual installations ranged from 4.3% at fort knox, ky, to 63.4% at fort bragg, nc. most of the seropositive dogs were in the working and sporting groups of dogs. the difference in antibody prevalence between sexes was not significant. serologic responses we ... | 1982 | 6808878 |
| human endothelial cell culture plaques induced by rickettsia rickettsii. | primary cultures of human umbilical vein endothelial cells were inoculated with plaque-purified rickettsia rickettsii. after adsorption of rickettsiae, monolayers were overlaid with medium containing 0.5% agarose. small plaques appeared on day 4 postinoculation, and distinct 1- to 2-mm plaques were observed on day 5. plaquing efficiency was less than that of primary chicken embryo cells in the same medium. human endothelial cell monolayers were susceptible to infection by r. rickettsii and under ... | 1982 | 6809631 |
| penicillin-induced unstable intracellular formation of spheroplasts by rickettsiae. | penicillin g (greater than or equal to 20 micrograms/ml) is rapidly rickettsiacidal for intracellular rickettsia prowazekii. light and electron microscopic examinations revealed that penicillin g in culture medium induced a predictable transformation into typical enlarging spheroplasts deficient in the internal, putative peptidoglycan layer of the outer membrane. under certain conditions, spheroplasts ruptured to discharge contents into host cell cytoplasm and to leave empty shells of defective ... | 1982 | 6809842 |
| reactivation of rickettsia rickettsii in dermacentor andersoni ticks: an ultrastructural analysis. | virulent rickettsia in dermacentor andersoni lose their pathogenicity and virulence for guinea pigs when subjected to physiological stresses, such as starvation (overwintering), of its tick vector. however, incubation of infected ticks at an elevated temperature (37 degrees c) for 24 to 48 h or feeding for a time (usually greater than 10 h) induces r. rickettsii to revert to a virulent state, a phenomenon defined as "reactivation." electron microscopy reveals that the microcapsular and slime lay ... | 1982 | 6811439 |
| establishment of cell cultures persistently infected with spotted fever group rickettsiae. | a cell line was established from the tunica vaginalis of meadow voles, microtus pennsylvanicus, which could be persistently infected with the spotted fever group rickettsiae, rickettsia rickettsii, r. rhipicephali, and r. slovaca. as determined by light and electron microscopy, all cells in the cultures became infected and remained so even after 20 serial passages over a period of months. the rickettsiae-infected vole cell line is an excellent experimental model to study the noncytolytic host-ce ... | 1982 | 6820331 |
| serological cross-reaction and cross-protection in guinea pigs infected with rickettsia rickettsii and rickettsia montana. | antisera produced in guinea pigs inoculated with rickettsia rickettsii or rickettsia montana were cross-reactive but sufficiently specific to identify the primary infecting agent. guinea pigs immunized with r. montana were protected from fatal infection with r. rickettsii, although a few (25%) developed mild fever of short duration. | 1980 | 6893191 |
| the occurrence of eschars in rocky mountain spotted fever. | two patients with fatal, laboratory-confirmed rocky mountain spotted fever (rmsf) were noted early in their course to have a skin lesion characteristic of a rickettsial eschar. postmortem immunofluorescent and histopathologic studies demonstrated that the lesions were sites of extensive contiguous infection by rickettsia rickettsii with associated injury to numerous local blood vessels. rickettsial vasculitis and occlusive luminal thrombosis were associated with dermal and epidermal coagulative ... | 1981 | 7240465 |
| rocky mountain spotted fever in clermont county, ohio. ii. distribution of population and infected ticks in an endemic area. | the epidemiology of rocky mountain spotted fever (rmsf) in relation to the distribution of the human population and infected ticks has not been defined. a study was undertaken in clermont county, ohio, to describe the distribution of population in a highly endemic focus of rmsf and to determine the prevalence of ticks infected with rickettsiae of the spotted fever group. this area was compared to another area of similar size in the same county where the incidence of rmsf was much lower. the popu ... | 1980 | 7352458 |
| the role of cottontail rabbits (sylvilagus spp.) in the ecology of rickettsia rickettsii in the united states. | rocky mountain (sylvilagus nuttallii) and eastern (s. floridanus) cottontails were examined for their susceptibility to virulent and avirulent strains of the spotted fever agent, rickettsia rickettsii. both species of rabbits responded to inoculation of yolk sac suspensions containing 500 egg ld50 of either virulent or avirulent rickettsiae, with rickettsemias detectable as early as 3 days after inoculation and lasting up to 7 days. when fed upon by infected ticks, only one of three rocky mounta ... | 1980 | 7406116 |
| rickettsia rickettsii has proteins with cross-reacting epitopes to eukaryotic phospholipase a2 and phospholipase c. | the entry, and possibly the exit, of rickettsiae from eukaryotic cells, as well as erythrocyte lysis by some members of this group of organisms, is thought to be mediated by a phospholipase a activity even though the enzyme has not been isolated from these organisms. evidence for phospholipase c, on the other hand, has not been reported for the genus rickettsia. in this study, in a preliminary attempt to demonstrate the presence of phospholipase a2 and phospholipase c in the virulent sheila smit ... | 1994 | 7532256 |
| evaluation of the pathogenic potential of rickettsia canada and rickettsia prowazekii organisms in dogs. | an unusual pattern of seroreactivity to antigens of rickettsial organisms (rickettsia rickettsii, r rhipicephali, r montana, and r bellii), particularly to r bellii antigen, was detected in 3 dogs during a 2-month period. thus, studies were initiated to clarify the pathogenic potential of the more distantly related rickettsial organisms (r canada and r prowazekii) in dogs. because r bellii are nonpathogenic rickettsiae that share numerous common properties with spotted fever-group and typhus-gro ... | 1995 | 7601694 |
| rocky mountain spotted fever: a seasonal alert. | rocky mountain spotted fever occurs during seasonal tick activity. a history of exposure to tick-containing habitats within the 3- to 12-day incubation period is a key epidemiological factor. the signs of fever, headache, myalgia, nausea, vomiting, and anorexia at onset of infection are difficult to distinguish from those of self-limited viral infections. rash usually appears later and, if present, progresses through a sequence of stages and distribution that are never pathognomonic. the effects ... | 1995 | 7619984 |
| long-term sequelae of rocky mountain spotted fever. | twenty-five patients with definite or probable rocky mountain spotted fever (rmsf) who were hospitalized for > or = 2 weeks were identified from our database of 105 patients. follow-up information was collected for 20 patients, per telephone and/or medical records. the remaining five patients were lost to follow-up or died. nine patients had > or = 1 long-term sequelae (defined as complications related to an original acute infection with rickettsia rickettsii that persisted for > or = 1 year fol ... | 1995 | 7619986 |
| comparison of the rompa gene repeat regions of rickettsiae reveals species-specific arrangements of individual repeating units. | genes containing repeating units have been described for several eukaryotic and prokaryotic proteins, although none exhibit the extraordinary length and conservation seen with the rickettsia rickettsii 190-kda protein (ompa) repeat region. the genetic organization of the repeat regions of the ompa gene for r. conorii and r. akari was examined and compared to that of r. rickettsii. individual repeating units, which constitute the makeup of the repeat regions, share extensive dna homology among th ... | 1993 | 7680636 |
| e-selectin-dependent neutrophil adhesion to rickettsia rickettsii-infected endothelial cells. | increased neutrophil or hl60 cell adhesion to rickettsia rickettsii-infected endothelial cells (ecs) was observed at 6 to 8 hours after the initiation of infection, diminishing by 24 hours. similar increases were observed using formaldehyde-fixed neutrophils. cellular association and likely the intracellular presence of rickettsiae was required for enhanced neutrophil adhesion, because culture medium conditioned by infected cells or rickettsiae rendered noninfective by pretreatment with tetracyc ... | 1993 | 7683219 |
| eia with species-specific monoclonal antibodies: a novel seroepidemiologic tool for determination of the etiologic agent of spotted fever rickettsiosis. | all currently available assays for antibodies to the etiologic agents of spotted fever group rickettsioses detect reactivity with antigens of lipopolysaccharides and the major cell wall proteins, which contain epitopes that are shared among many spotted fever group rickettsiae. the hypothesis of this study was that a monoclonal antibody to a species-specific epitope of rickettsia rickettsii would be blocked from binding to the rickettsial surface if the rickettsiae were incubated previously with ... | 1993 | 7693827 |
| granulocytic ehrlichiosis and meningitis in a dog. | a 4-year-old male mixed-breed dog from the sierra nevada mountains in california was referred because of epistaxis and signs of cervical pain. dermacentor variabilis ticks were found on the dog at the time of physical examination. clinicopathologic abnormalities included nonregenerative anemia, thrombocytopenia, and rare intracytoplasmic morulae within circulating neutrophils. abnormalities of the csf included pleocytosis and intracytoplasmic morulae in approximately 9% of neutrophils. serum ant ... | 1994 | 7730122 |
| persistence of rickettsiae in the partially viable gangrenous margins of amputated extremities 5 to 7 weeks after onset of rocky mountain spotted fever. | a case of rocky mountain spotted fever complicated by gangrene of the extremities required amputation and showed persistent rickettsial infection in the margins of the gangrene at 5 and 7 weeks after onset of illness. rickettsial organisms were demonstrated by immunoperoxidase staining in the viable endothelial cells in the ischemic margins of the gangrenous tissue. we conclude that the cellular, humoral, and pharmacologic components that lead to eradication of the rickettsiae were not delivered ... | 1995 | 7748070 |
| protection of guinea-pigs from experimental rocky mountain spotted fever by immunization with baculovirus-expressed rickettsia rickettsii rompa protein. | baculovirus recombinants that express the rickettsia rickettsii rompa protein were constructed. monoclonal antibodies (mabs) against the rompa protein reacted with recombinant-infected spodoptera frugiperda (sf9) cells in indirect immunofluorescence assays. sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting of infected sf9 cell lysates with a mab against rompa showed that the recombinant-expressed rompa protein migrated slightly below rompa extracted from r. rickettsii. ... | 1995 | 7762273 |