| [the application of pcr to epidemiological study on spotted fever group rickettsiae]. | it was the first time that a primer pairs derived from the 190kda protein antigen gene of r. rickettsii were used to amplify sfgr dna in ticks, tick ova, larva, tick faeces and rodent organs which were collected in hebei, heilongjiang, hainan and beijing. a 532bp fragment was respectively amplified from above samples. the results were partially in concordance with data obtained through rickettsiae isolation. it was suggested that pcr is a rapid, specific, sensitive and practical method for detec ... | 1995 | 7767922 |
| genomic identification of rickettsia slovaca among spotted fever group rickettsia isolates from dermacentor marginatus in armenia. | restriction fragment length polymorphism (rflp) analysis of polymerase chain reaction (pcr) amplified genes was used for genomic identification of armenian isolates of the spotted fever group (sfg) rickettsiae with unclear taxonomic position. analysis was performed by using one genus-specific primer pair derived from r. prowazekii citrate synthase gene and two species-specific primer pairs derived from r. rickettsii genes for 190 k and 120 k antigens following alui, psti and rsai digestion of am ... | 1994 | 7793355 |
| detection of dna of causative agent of spotted fever group rickettsiosis in japan from the patient's blood sample by polymerase chain reaction. | the polymerase chain reaction (pcr) was applied for the etiological diagnosis of spotted fever group (sfg) rickettsiosis in japan. nucleotide primers derived from the 17-kda antigen gene of rickettsia rickettsii primed a rickettsia-specific 246-base-pair product for all of the katayama, abe, misaka and kojima strains, which we had isolated previously. moreover, we were able to detect the same product by pcr amplification from the peripheral blood of a patient in the acute stage of the illness. t ... | 1994 | 7799840 |
| differential activity of rickettsia rickettsii opma and ompb promoter regions in a heterologous reporter gene system. | the outer membrane of the gram-negative obligate intracellular parasite rickettsia rickettsii contains two large surface protein antigens with approximate molecular masses of 200 and 135 kda termed rompa and rompb, respectively. rompb is the most abundant protein in the outer membrane, while rompa is a relatively minor constituent. densitometry of intrinsically radiolabelled protein profiles from r. rickettsii-infected vero cells indicated a molar ratio of approximately 1:9 between rompa and rom ... | 1994 | 7812435 |
| nucleotide sequence of polymerase chain reaction product amplified from rickettsia japonica dna using rickettsia rickettsii 190-kilodalton surface antigen gene primers. | the pcr product amplified from rickettsia japonica with the primer pair rr 190.70p and rr 190.602n of r. rickettsii 190-kda antigen gene was cloned into m13mp19 rf dna at the eco ri site and sequenced by chemiluminescent dna sequencing. the sequence revealed a molecular size of 533 base pairs (bp). the primer-flanking region of 491 bp, an open reading frame, was compared with the corresponding region of r. rickettsii, demonstrating 35 nucleotide substitutions in r. japonica. the sequence of prim ... | 1994 | 7898385 |
| differentiation of rickettsia japonica by restriction endonuclease fragment length polymorphism using products of polymerase chain reaction amplification with rickettsia rickettsii 190-kilodalton surface antigen gene primers. | restriction fragment length polymorphism of polymerase chain reaction (pcr) amplification products differentiated rickettsia japonica, a causative agent of oriental spotted fever, from other spotted fever group (sfg) rickettsiae. primer pair rr190. 70p and rr190. 602n of r. rickettsii 190-kda antigen gene sequence primed genomic dnas obtained from r. japonica, type strain yh and strains nt, nk, yki, and tkn. the products were cleaved by psti but not by afai restriction endonuclease. the psti dig ... | 1993 | 7901739 |
| dna typing of rickettsiae in naturally infected ticks using a polymerase chain reaction/restriction fragment length polymorphism system. | we used the polymerase chain reaction/restriction fragment length polymorphism (pcr/rflp) rickettsial typing system of regnery and others to rapidly identify rickettsiae in naturally infected ticks. unlike previously described methods, our pcr assays type rickettsiae directly from tick tissues without first isolating the organisms. we collected 226 adult dermacentor andersoni ticks in the bitterroot mountains of western montana and analyzed them for possible rickettsial infection by hemolymph te ... | 1994 | 7906924 |
| identification of rickettsia conorii infection by polymerase chain reaction in a soldier returning from somalia. | a soldier developed characteristic manifestations of boutonneuse fever shortly after leaving somalia. rickettsial dna was detected in a biopsy sample of the tache noire by a polymerase chain reaction (pcr) in which primers derived from the 190-kd antigen gene of rickettsia rickettsii were used. the source of this dna was identified as rickettsia conorii by restriction fragment length polymorphism (rflp) analysis of the pcr product. r. conorii was also isolated from the skin biopsy specimen. the ... | 1994 | 7948564 |
| rickettsialpox in a new york city hospital, 1980 to 1989. | rickettsialpox is caused by rickettsia akari, which is transmitted from rodents to humans by bloodsucking mites. the initial skin lesion forms an eschar and is followed by the development of fever, malaise, myalgia, and 5 to 40 maculopapules and papulovesicles. the disease, which responds to tetracycline, can be mistaken for chickenpox. the diagnosis has been based on an increase in serum antibody titers against r. akari over a period of three to eight weeks. we discuss a more rapid technique th ... | 1994 | 7969341 |
| ancestral divergence of rickettsia bellii from the spotted fever and typhus groups of rickettsia and antiquity of the genus rickettsia. | the eubacterial genus rickettsia belongs to the alpha subgroup of the phylum proteobacteria. this genus is usually divided into three biotypes on the basis of vector host and antigenic cross-reactivity characteristics. however, the species rickettsia bellii does not fit into this classification scheme; this organism has characteristics common to both the spotted fever group and the typhus group biotypes and also exhibits some unique features. sequences of the 16s rrna and 23s rrna genes from ric ... | 1994 | 7981106 |
| sequence analysis of the sbsa gene encoding the 130-kda surface-layer protein of bacillus stearothermophilus strain pv72. | bacillus stearothermophilus (bs) contains a surface-layer (s-layer) protein (sbsa), which forms a hexagonal array on the cell wall. in order to understand the structural/functional relationship of sbsa from bs pv72, the entire nucleotide (nt) sequence of the sbsa gene was determined from three overlapping fragments. the 3'-end was cloned and expressed in escherichia coli, whereas the 5'-region was amplified from the genome of bs pv72 by the polymerase chain reaction using two overlapping fragmen ... | 1994 | 8045409 |
| species-specific balb/c mouse antibodies to rickettsiae studied by western blotting. | balb/c mice were inoculated intraperitoneally either once only, or up to four times at weekly intervals, with viable rickettsia rickettsii, rickettsia conorii or the israeli spotted fever group rickettsia. sera collected one week after the last inoculation were tested for the presence of antibodies reactive with the above organisms by indirect fluorescent antibody testing and western blot. with repeated inoculations there was a general progressive rise in homologous and heterologous immunofluore ... | 1994 | 8050715 |
| in vitro susceptibilities of spotted fever group rickettsiae and coxiella burnetti to clarithromycin. | the in vitro bacteriostatic activity of clarithromycin, a new macrolide derivative, against rickettsia rickettsii, rickettsia conorii, and "rickettsia israeli" was determined by the plaque assay and the dye uptake assay. both bacteriostatic and bactericidal activities of clarithromycin against the nine mile, q212, priscilla, and me9 strains of coxiella burnetti were evaluated by using three cell culture systems. clarithromycin showed improved antibacterial activity compared with that of erythrom ... | 1993 | 8109928 |
| rickettsia rickettsii infection of cultured human endothelial cells induces tissue factor expression. | microvascular thrombi underlie many of the clinical manifestations of rocky mountain spotted fever (rmsf), a disease characterized by rickettsia rickettsii infection of vascular endothelial cells. studies were designed to determine whether r rickettsii-infection of cultured human umbilical vein endothelial cells results in tissue factor (tf) induction, a process that could directly activate coagulation in infected vessels. whereas uninfected endothelial cell cultures showed essentially undetecta ... | 1994 | 8123842 |
| characterization of a rickettsia rickettsii dna fragment analogous to the fir a-orf17-lpxa region of escherichia coli. | the fira and lpxa genes, as well as an orf coding for a putative 16-kda protein of unknown function, have been identified and characterized in the obligate intracellular bacterium. rickettsia rickettsii. this is the first description of these genes, which code for enzymes involved in the biosynthesis of lipid a, in a species outside of the enterobacteriaceae. the deduced amino acid (aa) sequences of fira, orf16 and lpxa of r. rickettsii, when compared to their escherichia coli analogs, exhibited ... | 1994 | 8125326 |
| infection of human endothelial cells by rickettsia rickettsii causes a significant reduction in the levels of key enzymes involved in protection against oxidative injury. | the activities of glucose-6-phosphate dehydrogenase, catalase, and glutathione peroxidase were significantly decreased in human endothelial cells infected with the obligate intracellular bacterium rickettsia rickettsii, the causative agent of rocky mountain spotted fever. this observation lends additional support to our hypothesis implicating oxidative damage in endothelial cell injury caused by this microorganism. | 1994 | 8188386 |
| evaluation of immunoperoxidase techniques to detect rickettsia rickettsii in fixed tissue sections. | standard immunoperoxidase techniques were evaluated in the diagnosis of rocky mountain spotted fever (rmsf). formalin-fixed, paraffin-embedded tissue was tested to detect rickettsia rickettsii using the same antibody provided by the centers for disease control and prevention that is used for direct immunofluorescence (dif). tissues from 23 patients with suspected rmsf were divided: some were snap-frozen for dif; the remainder were fixed in formalin, processed routinely, and embedded in paraffin ... | 1994 | 8209863 |
| preliminary evaluation of the indx dip-s-ticks with positive rickettsial samples in malaysia. | forty-four serum samples of various reactivities to rickettsial antigens demonstrated by the indirect immunoperoxidase technique were tested with indx dip-s-ticks (indx integrated diagnostics inc., usa) kit for the detection of tick borne diseases. the kit utilised rickettsia rickettsii the causative agent of rocky mountain spotted fever (rmsf) as antigens. the samples positive for endemic typhus were also tested against r. typhi, the agent for endemic typhus by the same method. the aim of this ... | 1993 | 8277794 |
| human endothelial cells as an alternative to dh82 cells for isolation of ehrlichia chaffeensis, e. canis, and rickettsia rickettsii. | ehrlichia chaffeensis, etiologic agent of human ehrlichiosis, and rickettsia rickettsii, etiologic agent of rocky mountain spotted fever (rmsf), are both tick-borne agents that cause nonspecific symptoms that may be indistinguishable from each other early in the course of infection. e. canis is a canine pathogen closely related to e. chaffeensis and was initially suspected of being the causative agent of human ehrlichiosis. if a febrile illness is reported, after tick exposure, neither ehrlichio ... | 1993 | 8297496 |
| the use of a polymerase chain reaction as a diagnostic test for rocky mountain spotted fever. | a polymerase chain reaction (pcr) for amplifying ribosomal dna of rickettsia rickettsii was performed on blood clots and urine samples from 10 patients with suspected rocky mountain spotted fever (rmsf) and five controls with nonrickettsial diseases. the results of this pcr-based procedure were positive in four of the five patients with probable rmsf, but reamplification was required in three patients. rickettsia rickettsii was grown from the blood of two of these four patients. the urine from o ... | 1994 | 8304573 |
| brazilian spotted fever in espirito santo, brazil: description of a focus of infection in a new endemic region. | although brazilian spotted fever is known to occur in several adjacent states, infection with spotted fever group (sfg) rickettsiae has not previously been documented in the brazilian state of espirito santo. we report a cluster of two proven and four suspected cases of brazilian spotted fever in a small valley near colatina, espirito santo. four patients died without confirmatory serologic or pathologic studies. the two surviving patients had serologic and/or pathologic evidence of infection wi ... | 1993 | 8357085 |
| comparison of latex agglutination, indirect immunofluorescent antibody, and enzyme immunoassay methods for serodiagnosis of rocky mountain spotted fever in dogs. | indirect immunofluorescent antibody (ifa), latex agglutination (la), and enzyme immunoassay (eia) methods were compared for evaluation of the serum antibody responses of dogs experimentally and naturally exposed to spotted fever-group rickettsiae. selected sera (obtained on days 1, 42, 53, 124, 145, 236, 255, 264, and 292) were examined from three 8-month-old female beagles inoculated with rickettsia rickettsii on days 34 and 250 of the study. a second group of dogs comprised three 8-month-old f ... | 1993 | 8427468 |
| directional actin polymerization associated with spotted fever group rickettsia infection of vero cells. | members of the spotted fever group (sfg) of rickettsiae spread rapidly from cell to cell by an unknown mechanism(s). staining of rickettsia rickettsii-infected vero cells with rhodamine phalloidin demonstrated unique actin filaments associated with one pole of intracellular rickettsiae. f-actin tails greater than 70 microns in length were seen extending from rickettsiae. treatment of infected cells with chloramphenicol eliminated rickettsia-associated f-actin tails, suggesting that de novo prote ... | 1993 | 8478082 |
| rocky mountain spotted fever complicated by gangrene: report of six cases and review. | although mortality due to fulminant rocky mountain spotted fever (rmsf) is well appreciated, the ability of the disease to cause survivors to become permanently disabled is not as widely known. we report six cases of rmsf complicated by gangrene. although four patients required multiple limb and/or digital amputations, only one death resulted. our review of the english-language literature revealed 23 additional cases of rmsf complicated by gangrene. pathophysiologically, gangrene is most likely ... | 1993 | 8507753 |
| rocky mountain spotted fever in an endemic area in minas gerais, brazil. | only one species of spotted fever-group rickettsiae that is pathogenic for humans has been isolated in brazil, where few physicians are familiar with this disease. in order to obtain information on tick-borne rickettsiosis, a study was performed in the county of santa cruz do escalvado, state of minas gerais, brazil, where a fatal clinical case confirmed by specific immunofluorescence had been reported. serum samples obtained from 679 humans and 96 dogs were tested by indirect immunofluorescence ... | 1994 | 8524052 |
| tissue factor mrna expression in the endothelium of an intact umbilical vein. | tissue factor (tf) mrna expression was measured by in situ hybridization in the endothelium of the intact human umbilical vein after infection with rickettsia rickettsii. at 4 hours, r rickettsii organisms were clearly visible within approximately 70% of endothelial cells by immunocytochemical staining. quantitation of tf mrna expression revealed that the level within endothelial cells of the infected vein was significantly greater (3.7-fold, p < .0001) than that detected in uninfected endotheli ... | 1996 | 8547639 |
| hemocytic rickettsia-like organisms in ticks: serologic reactivity with antisera to ehrlichiae and detection of dna of agent of human granulocytic ehrlichiosis by pcr. | ixodid ticks were collected from connecticut, massachusetts, missouri, pennsylvania, rhode island, and british columbia (canada) during 1991 to 1994 to determine the prevalence of infection with hemocytic (blood cell), rickettsia-like organisms. hemolymph obtained from these ticks was analyzed by direct and indirect fluorescent antibody (fa) staining methods with dog, horse, or human sera containing antibodies to ehrlichia canis, ehrlichia equi, or rickettsia rickettsii. of the 693 nymphal and a ... | 1995 | 8567911 |
| rocky mountain "spotless" fever with an erythema migrans-like skin lesion. | we report a case of rocky mountain "spotless" fever with a localized rash at the site of the tick bite that resembled the erythema migrans rash of lyme borreliosis. physicians who practice in geographic areas where rocky mountain spotted fever occurs should be aware of this unusual presentation. | 1995 | 8589170 |
| interleukin-1 alpha production during rickettsia rickettsii infection of cultured endothelial cells: potential role in autocrine cell stimulation. | rickettsia rickettsii infection results in numerous responses by cultured endothelial cells, among them a rapid, transient increase in steady-state levels of tissue factor mrna (l.a. sporn, p.j. haidaris, r.-j. shi, y. nemerson, d.j. silverman, and v.j. marder, blood 83:1527-1534, 1994). in this study, production of interleukin-1 (il-1) was measured during infection and its potential role in autocrine cell stimulation was investigated. a fivefold increase in levels of il-1 alpha antigen was meas ... | 1996 | 8613368 |
| deletion in the 190 kda antigen gene repeat region of rickettsia rickettsii. | the 190 kda outer membrane protein of rickettsia rickettsii is a major immunodominant protective antigen which contains 13 tandem nearly identical repeating sequences. we have identified a deletion in the 190 kda antigen gene of r. rickettsii strain smith maintained in the laboratory. the deletion occurred within the repeat region of this gene and the mutated repeat region corresponded to one repeating unit in size. | 1996 | 8692010 |
| tick-borne illness increasing in oklahoma. | | 1996 | 8720556 |
| detection of spotted fever group rickettsiae in ticks and rodents by polymerase chain reaction technique in people's republic of china. | the polymerase chain reaction (pcr) technique for amplification of genomic fragments of spotted fever group (sfg) rickettsiae directly from field samples of ticks, tick ova, tick larvae, tick faeces and organs of wild mice was employed for the first time in p.r. of china. ticks and rodents were collected in beijing and heilongjiang, hainan and hebei provinces. the pcr primers were designed from the dna sequence encoding the 190 k protein of r. rickettsii for a 532 bp long product. seven of ten t ... | 1995 | 8722295 |
| rocky mountain spotted fever. | | 1996 | 8727127 |
| laboratory diagnosis of rickettsial diseases. | | 1996 | 8727134 |
| genetic variation in australian spotted fever group rickettsiae. | rickettsiae were isolated by cell culture of buffy coat blood from six patients with spotted fever from southeastern australia and flinders island in bass strait. the isolates were genetically compared with two previous rickettsia australis patient isolates. the genus-specific 17-kda genes from the isolates were compared after dna amplification and restriction fragment analysis of the amplified dna. this comparison revealed that mainland rickettsial isolates from southeastern australia were iden ... | 1996 | 8735110 |
| [spotted fever group rickettsiosis and vectors in kanagawa prefecture]. | primer pairs for pcr were designed from the gene encoding the 17,000-molecular-weight genus-common antigen of rickettsia japonica, rickettsia rickettsii, rickettsia conorii, rickettsia typhi and rickettsia prowazekii. primers r1, r2 were designed for amplifying the genomic dna from spotted fever group (sfg) rickettsiae and epidemic typhus rickettsiae. primers rj5, rj10 were designed for amplifying the genomic dna from only r. japonica. using the primers r1, r2, about a 540-bp fragment was observ ... | 1996 | 8741704 |
| increased expression of plasminogen activator inhibitor-1 in r. rickettsii-infected endothelial cells. | changes in pai-1 expression in human umbilical vein endothelial cells (huvec) were studied following in vitro infection with rickettsia rickettsii. a 1.8-fold increase in secreted pai-1 activity occurred in infected versus control cultures (p = 0.03) at 24 h but not at earlier timepoints. a similar increase (1.4-fold) in secreted pai-1 antigen (p < 0.005) was measured by elisa. to determine whether this increase was due to increased synthesis of pai-1, huvec were metabolically labeled with 35s-m ... | 1996 | 8743186 |
| unrecognized spotted fever group rickettsiosis masquerading as dengue fever in mexico. | although rocky mountain spotted fever was documented in northern mexico during the 1940s, spotted fever group (sfg) rickettsioses have subsequently received little attention in mexico. in this study, sera collected in 1993 from 50 patients from the mexican states of yucatan and jalisco, who were suspected clinically to have dengue fever but had no antibodies to dengue virus, were examined by indirect immunofluorescence for igm antibodies reactive with rickettsia rickettsii, r. akari, and r. typh ... | 1996 | 8780453 |
| reliving a nightmare: a hard (and tragic) lesson in humility. | | 1996 | 8816145 |
| remember rocky mountain spotted fever--a lesson in ethical principles. | | 1996 | 8816146 |
| parasites and selected diseases of collared peccaries (tayassu tajacu) in the trans-pecos region of texas. | fifty-five collared peccaries (tayassu tajacu) were collected from october 1988 through april 1991 from five counties within the trans-pecos region of texas (usa) to monitor for diseases and parasites. no endoparasites were recovered on gross examination. antibody to borrelia burgdorferi was documented in one (2%) of 55 specimens. three (6%) of 54 collared peccaries were positive for yersinia pestis antibodies. all collared peccaries were negative for antibodies against brucella spp., francisell ... | 1996 | 8827690 |
| differentiation of spotted fever group rickettsiae by sequencing and analysis of restriction fragment length polymorphism of pcr-amplified dna of the gene encoding the protein rompa. | currently, the genotypic identification of the spotted fever group (sfg) rickettsiae is based on restriction fragment length polymorphism analysis of pcr-amplified genes coding for the enzyme citrate synthase and the surface proteins rompa and rompb. a set of useful restriction endonucleases was found following comparison of rickettsia rickettsii and r. prowazekii sequences. however, by using three pcr amplifications and four enzyme digestions with this set, it was impossible to differentiate be ... | 1996 | 8862558 |
| prednisolone at anti-inflammatory or immunosuppressive dosages in conjunction with doxycycline does not potentiate the severity of rickettsia rickettsii infection in dogs. | dogs were experimentally inoculated with rickettsia rickettsii to determine if anti-inflammatory or immunosuppressive dosages of prednisolone, when administered in conjunction with an antirickettsial antibiotic (doxycycline), induced therapeutically relevant pathophysiological consequences that ultimately influence disease outcome. although the duration of rickettsemia was prolonged in dogs receiving immunosuppressive, but not anti-inflammatory, corticosteroids, concurrent administration of doxy ... | 1997 | 8980770 |
| predictors of prognosis and risk of acute renal failure in patients with rocky mountain spotted fever. | acute renal failure has long been associated with severe rocky mountain spotted fever (rmsf). despite many descriptions of the protean manifestations of this disease, relatively little is known concerning the risk factors for acute renal failure. only a few studies have examined the outcome of patients infected with rickettsia rickettsii who develop renal insufficiency, and these studies had methodological problems. | 1996 | 9003109 |
| [spotted fever in the municipality of pedreira, ps, brazil. serologic survey]. | cases of brasilian spotted fever (bsf) have been occurred since 1985, in the rural area of pedreira town, situated 160 km away from the city of são paulo (longitude 46 degrees 54'07", latitude 22 degrees 44'21"). aiming at evaluating the prevalence of brasilian spotted fever in this endemic area, single-serum samples were collected from 473 healthy persons, amongst city-dwellers and the local china industry workers. the obtained samples were tested by indirect immunofluorescence (ifa), in order ... | 1996 | 9026831 |
| primary isolation of spotted fever group rickettsiae from amblyomma cooperi collected from hydrochaeris hydrochaeris in brazil. | this paper reports the first isolation of a spotted fever group rickettsia from an amblyomma cooperi ixodid collected from a capybara (hydrochaeris hydrochaeris) in an endemic area of spotted fever in the county of pedreira, state of são paulo, brazil. isolation was performed in vero cell culture and submitted to immunofluorescence, using antibody from rickettsia rickettsii-positive human serum. | 1996 | 9040845 |
| in vitro susceptibilities of bartonella henselae, b. quintana, b. elizabethae, rickettsia rickettsii, r. conorii, r. akari, and r. prowazekii to macrolide antibiotics as determined by immunofluorescent-antibody analysis of infected vero cell monolayers. | the in vitro susceptibilities of bartonella (rochalimaea) henselae, b. quintana, b. elizabethae, rickettsia akari, r. conorii, r. prowazekii, and r. rickettsii to different concentrations of azithromycin, clarithromycin, dirithromycin, erythromycin, and roxithromycin in vero cell cultures were evaluated. bartonella and rickettsia spp. were allowed to initiate infection of the antibiotic-free vero cell monolayers, which were maintained in 16-chamber microscope slides in the absence of antibiotics ... | 1997 | 9055996 |
| clinical and clinicopathologic abnormalities in greyhounds with cutaneous and renal glomerular vasculopathy: 18 cases (1992-1994) | to determine clinical signs and clinicopathologic abnormalities in greyhounds with cutaneous and renal glomerular vasculopathy and to determine whether there were any differences between dogs with and without renal azotemia. | 1997 | 9074681 |
| clinical features and serology of 14 dogs affected by granulocytic ehrlichiosis in sweden. | the clinical features and the titres to ehrlichia equi, e canis, e risticii, rickettsia rickettsii and borrelia afzelii in 14 swedish dogs, in which ehrlichiosis was diagnosed on the basis of the presence of inclusions in granulocytes, are reported. most of the dogs were moderately ill but made a rapid recovery after treatment with doxycycline. the dogs with inclusions were thrombocytopenic. analysis of the antibody titres indicates that serology to e equi will remain the most appropriate serolo ... | 1997 | 9076917 |
| citrate synthase gene comparison, a new tool for phylogenetic analysis, and its application for the rickettsiae. | using pcr and an automated laser fluorescent dna sequencer, we amplified and sequenced a 1,234-bp fragment of the citrate synthase-encoding gene (glta) of 28 bacteria belonging to the genus rickettsia. comparative sequence analysis showed that most of the spotted fever group (sfg) rickettsiae belonged to one of two subgroups. the first subgroup included rickettsia massiliae, strain bar 29, rickettsia rhipicephali, "rickettsia aeschlimanni," and rickettsia montana, which have been isolated only f ... | 1997 | 9103608 |
| rickettsia peacockii sp. nov., a new species infecting wood ticks, dermacentor andersoni, in western montana. | rickettsia peacockii, a new species of spotted fever group rickettsiae, was identified from rocky mountain wood ticks (dermacentor andersoni) collected in the sapphire mountain range on the eastern side of bitterroot valley, montana. dna from r. peacockii skalkahot (t = type strain) in naturally infected tick tissue was amplified by a pcr assay with primer sets derived from eubacterial 16s ribosomal dna (rdna), rickettsial citrate synthase, and 190-kda surface antigen (rompa) genes. partial 16s ... | 1997 | 9103635 |
| detection of colorado tick fever virus by using reverse transcriptase pcr and application of the technique in laboratory diagnosis. | colorado tick fever (ctf) virus elicits an acute illness in humans, producing nonspecific flu-like symptoms and a biphasic fever in approximately 50% of patients. the disease is transmitted by the adult rocky mountain wood tick (dermacentor andersoni), and therefore incidence is limited by the habitat and life cycle of that vector. the early symptoms of infection are difficult to distinguish from those of several other agents, especially rickettsia rickettsii. serologic testing is usually unable ... | 1997 | 9114408 |
| rickettsia rickettsii infection of cultured human endothelial cells induces nf-kappab activation. | rickettsia rickettsii, the etiologic agent of rocky mountain spotted fever, is an obligate intracellular bacterial organism that infects primarily the vascular endothelial cells (ec). a component of the ec response to infection is transcriptional activation, which may contribute to the thrombotic and inflammatory consequences of disease. in this study, we explore r. rickettsii-induced activation of the nuclear factor-kappab/rel (nf-kappab) family of transcription factors involved in early transc ... | 1997 | 9199451 |
| sequence analysis and comparison of 190 k surface antigen gene fragment of a new species of spotted fever group rickettsiae. | a 533 bp long pcr product amplified from rickettsial strain hl-93 dna with the primer pair rr 190.70p and rr 190.602n, designed from dna sequence encoding 190 k protein antigen of r. rickettsii, was cloned into plasmid vector pgem-t and sequenced. the primer-flanking region of the product, an open reading frame, was 491 bp long. the sequence of the product was compared with those of the corresponding regions of dnas of r. rickettsii (strain r), r. japonica (strain vr 1363) and r. conorii (strain ... | 1997 | 9199714 |
| bacteriostatic and bactericidal activity of levofloxacin against rickettsia rickettsii, rickettsia conorii, 'israeli spotted fever group rickettsia' and coxiella burnetii. | levofloxacin, the l-isomer of ofloxacin, is approximately twice as active as ofloxacin against most gram-positive and gram-negative bacteria, and has improved intracellular pharmacokinetic and pharmacodynamic properties. the present work deals with the in-vitro activity of levofloxacin against the obligate intracellular bacteria rickettsia rickettsii, rickettsia conorii, 'israeli spotted fever group rickettsia' (israeli sfgr) and coxiella burnetii. fluoroquinolones, including ofloxacin, have pre ... | 1997 | 9222041 |
| pcr amplification and comparison of nucleotide sequences from the groesl heat shock operon of ehrlichia species. | degenerate pcr primers derived from conserved regions of the eubacterial groesl heat shock operon were used to amplify groesl sequences of ehrlichia equi, ehrlichia phagocytophila, the agent of human granulocytic ehrlichiosis (hge), ehrlichia canis, bartonella henselae, and rickettsia rickettsii. the groesl nucleotide sequences were less conserved than the previously determined 16s rrna gene sequences of these bacteria. a phylogenetic tree derived from deduced groel amino acid sequences was simi ... | 1997 | 9230387 |
| thoracic radiographic findings in dogs infected with rickettsia rickettsii. | sixteen beagle dogs were injected intradermally with rickettsia rickettsii. the dogs were divided into four groups (n = 4): 1) infected, non-treated control; 2) infected, treated with doxycycline; 3) infected, treated with doxycycline and an anti-inflammatory dose of corticosteroid; and 4) infected, treated with doxycycline and an immunosuppressive dose of corticosteroid. thoracic radiographs were made and ocular fluorescein angiography was performed on days 6, 10, 17 post-inoculation. a mild in ... | 1997 | 9262680 |
| immunoperoxidase and immunofluorescent staining of rickettsia rickettsii in skin biopsies. a comparative study. | to compare immunofluorescent and immunoperoxidase staining of rickettsia rickettsii in skin biopsies of patients suspected of having rocky mountain spotted fever (rmsf). | 1997 | 9278621 |
| the great imitator: rocky mountain spotted fever occurring after hospitalization for unrelated illnesses. | we describe two patients who had rocky mountain spotted fever after they were admitted to the hospital for emergency and elective surgical procedures. we initially thought one patient had a hospital-acquired infection; the correct diagnosis was deduced from epidemiologic clues elicited by consultants. these two cases were also unusual in that one patient had a recurrent rash after an abbreviated course of low-dose doxycycline therapy and the other patient had transient and self-limiting postinfe ... | 1997 | 9305309 |
| rickettsia rickettsii growth and temperature-inducible protein expression in embryonic tick cell lines. | rickettsia rickettsii has limited adverse effects on its arthropod vector, but causes severe disease in man. to model differences in host-parasite interaction, r. rickettsii growth and protein expression were examined at temperatures reflective of host environment in the tick cell lines dalbe3 and ide2, the human endothelial cell line ecv304, and the african green monkey kidney cell line vero76. at low multiplicities of infection, rickettsial titres increased 10(2)-10(3)-fold in all cell lines a ... | 1997 | 9364140 |
| cutaneous histopathology of rocky mountain spotted fever. | the dermatologic diagnosis of rocky mountain spotted fever (rmsf) is often presumptive; the clinical presentation includes skin rash and febrile illness with or without a clear history of tick bite. the characteristic cutaneous manifestations include a generalized skin eruption with purpuric, blanching or non-blanching macules and papules usually involving the extremities. although skin biopsies are often performed to confirm the diagnosis, the spectrum of cutaneous histopathology in rmsf has no ... | 1997 | 9449487 |
| transcriptional regulation of endothelial cell tissue factor expression during rickettsia rickettsii infection: involvement of the transcription factor nf-kappab. | the vascular endothelial cell (ec) is a primary target of infection with rickettsia rickettsii, the etiologic agent of rocky mountain spotted fever. changes in gene transcription elicited by intracellular infection, including ec expression of the coagulation pathway initiator known as tissue factor (tf), may contribute to the vascular pathology observed during disease. nuclear run-on analysis of uninfected and infected, cultured human endothelial cells revealed that the rate of tf mrna transcrip ... | 1998 | 9488397 |
| superoxide dismutase-dependent, catalase-sensitive peroxides in human endothelial cells infected by rickettsia rickettsii. | the generation and intracellular accumulation of reactive oxygen species have been shown to be associated with the infection of human umbilical vein endothelial cells (huvec) by rickettsia rickettsii. in response to the oxidant superoxide, the activity of the enzyme superoxide dismutase (sod) increases following infection by this obligate intracellular bacterium. other oxidants which are capable of oxidizing the fluorescent probe 2',7'-dichlorofluorescin (dcfh) also accumulate intracellularly wi ... | 1998 | 9529045 |
| erythema migrans-like rash illness at a camp in north carolina: a new tick-borne disease? | borrelia burgdorferi, the causative agent of lyme disease, has never been isolated from a patient thought to have acquired lyme disease in any southeastern state. | 1997 | 9531233 |
| nf-kappa b-dependent inhibition of apoptosis is essential for host cellsurvival during rickettsia rickettsii infection. | the possibility that bacteria may have evolved strategies to overcome host cell apoptosis was explored by using rickettsia rickettsii, an obligate intracellular gram-negative bacteria that is the etiologic agent of rocky mountain spotted fever. the vascular endothelial cell, the primary target cell during in vivo infection, exhibits no evidence of apoptosis during natural infection and is maintained for a sufficient time to allow replication and cell-to-cell spread prior to eventual death due to ... | 1998 | 9539792 |
| proteasome-independent activation of nuclear factor kappab in cytoplasmic extracts from human endothelial cells by rickettsia rickettsii. | interaction of many infectious agents with eukaryotic host cells is known to cause activation of the ubiquitous transcription factor nuclear factor kappab (nf-kappab) (u. siebenlist, g. franzoso, and k. brown, annu. rev. cell biol. 10:405-455, 1994). recently, we reported a biphasic pattern of nf-kappab activation in cultured human umbilical vein endothelial cells consequent to infection with rickettsia rickettsii, an obligate intracellular gram-negative bacterium and the etiologic agent of rock ... | 1998 | 9573057 |
| effects of the antioxidant alpha-lipoic acid on human umbilical vein endothelial cells infected with rickettsia rickettsii. | rickettsia rickettsii infection of endothelial cells is manifested in very distinctive changes in cell morphology, consisting of extensive dilatation of the membranes of the endoplasmic reticulum and outer nuclear envelope and blebbing of the plasma membrane, as seen by transmission electron microscopy (d. j. silverman, infect. immun. 44:545-553, 1984). these changes in cellular architecture are thought to be due to oxidant-mediated cell injury, since their occurrence correlates with dramatic al ... | 1998 | 9573120 |
| phylogenetic placement of rickettsiae from the ticks amblyomma americanum and ixodes scapularis. | a rickettsial isolate (isolate moaa) belonging to the spotted fever group (sfg) was obtained from the lone star tick amblyomma americanum. we used pcr to characterize the genes for the rickettsial outer membrane proteins rompa and rompb. we sequenced the pcr products (domains i of both the rompa gene and the rompb gene) of moaa and wb-8-2, another rickettsial isolate from a. americanum. to place moaa and wb-8-2 and two other nonpathogenic isolates (rickettsia rickettsii hip2 and rickettsia monta ... | 1998 | 9574696 |
| rompa is a critical protein for the adhesion of rickettsia rickettsii to host cells. | rompa and rompb are immunodominant, surface-exposed proteins of rickettsia rickettsii. prior evidence suggests that adhesion of r. rickettsii to the host cell is mediated by a rickettsial protein. five monoclonal antibodies to rompa, five to rompb, and one to the rickettsial lipopolysaccharide (lps) were tested for inhibition of rickettsial attachment. all the monoclonal antibodies to rompa inhibited adhesion of rickettsiae to the l-929 cells with some inhibition rates as high as 90%. in contras ... | 1998 | 9600861 |
| immunodiagnosis of human granulocytic ehrlichiosis by using culture-derived human isolates. | human granulocytic ehrlichiosis (hge) is an emerging infection caused by an ehrlichia species closely related to ehrlichia equi and ehrlichia phagocytophila. recent advances in the isolation and cultivation of this organism have allowed us to develop an immunofluorescence assay (ifa), enzyme immunoassay (eia), and western immunoblotting (wb) using hl-60 cell culture-derived human isolates. antibody was detected in sera from culture-confirmed hge patients by ifa and eia, and these samples were re ... | 1998 | 9620365 |
| dual infection with ehrlichia chaffeensis and a spotted fever group rickettsia: a case report. | well-documented cases of simultaneous human infection with more than one tick-borne pathogen are rare. to our knowledge only two dual infections have been reported: simultaneous human infection with the agent of human granulocytic ehrlichiosis and borrelia burgdorferi and simultaneous human infection with b. burgdorferi and babesia microti (1-2). rocky mountain spotted fever has long been known to be endemic in north carolina; cases of human ehrlichial infection were recognized there soon after ... | 1998 | 9621205 |
| rickettsia rickettsii infection of the ea.hy 926 endothelial cell line: morphological response to infection and evidence for oxidative injury. | ea.hy 926 is a permanent human cell line that expresses highly differentiated functions characteristic of human vascular endothelium. rickettsia rickettsii can efficiently infect and cause a cytopathic effect in ea.hy 926 cells. r. rickettsii produced visible lytic plaques in ea.hy 926 cells at 10 d post-infection (p.i.) following application of a secondary agarose overlay containing 2 micrograms emetine ml-1 and 40 micrograms naf ml-1 on day 2. rickettsial growth in ea.hy 926 cells had a simila ... | 1998 | 9720025 |
| phylogenetic analysis of spotted fever group rickettsiae by study of the outer surface protein rompa. | rickettsiae are classified in the order rickettsiales and have been included in the alpha subclass of the class proteobacteria on the basis of 16s rrna gene sequence comparison. to estimate the evolutionary forces that have shaped the members of the spotted fever group (sfg) rickettsiae, the ompa gene (apart from the tandem repeat units), encoding an antigenic high-molecular-mass membrane protein specific for the group, was amplified and sequenced from 21 isolates. the phylogenetic relationship ... | 1998 | 9734038 |
| [a molecular epidemiologic investigation of north asia fever in scenic spots of beijing suburb]. | pcr/rflp technique was used to detect spotted fever group rickettsiae (sfgr) in ticks and small mammals collected in eleven scenic spots of beijing suburb. we not only detected rickettsia sibirica in d. sinicus and hedgehog collected nearby the museum of aviation, but also isolated two strains of sfgr from them, named as bj-95 strain and bjh-95 strain respectively. the two strains were identified as r. sibirica by sds-page, western blot and pcr/rflp. the results demonstrated the existence of hor ... | 1997 | 9812516 |
| characterization of human immunoglobulin (ig) isotype and igg subclass response to bartonella henselae infection. | serologic parameters of cat scratch disease (csd) were evaluated by western blot analysis. sera from patients with serologically confirmed csd antigen were screened for immunoglobulin (ig) isotype-specific as well as igg subclass-specific reactivity against bartonella henselae whole-cell antigen. bartonella-negative control sera were used to determine baseline antibody activity. heterogeneous b. henselae-specific igg reactivity with numerous protein bands, ranging from >150 to <17 kda, was obser ... | 1998 | 9826373 |
| lethal effect of rickettsia rickettsii on its tick vector (dermacentor andersoni). | rickettsia rickettsii, the causative agent of rocky mountain spotted fever, was lethal for the majority of experimentally and transovarially infected rocky mountain wood ticks (dermacentor andersoni). overall, 94.1% of nymphs infected as larvae by feeding on rickettsemic guinea pigs died during the molt into adults and 88. 3% of adult female ticks infected as nymphs died prior to feeding. in contrast, only 2.8% of uninfected larvae failed to develop into adults over two generations. infected fem ... | 1999 | 9925615 |
| platelet-associated immunoglobulin (antiplatelet antibody) in canine rocky mountain spotted fever and ehrlichiosis. | antiplatelet antibodies were detected in the sera of dogs with naturally occurring and experimentally induced rickettsia rickettsii and ehrlichia canis infections. this is the first known report documenting elevated platelet-associated immunoglobulin (paig) titers in rocky mountain spotted fever (rmsf) infections. in the naturally occurring rmsf infections and ehrlichiosis, the antibodies persisted for weeks or months, even when the platelet counts had normalized. results of this study indicate ... | 1999 | 9934930 |
| serologic testing for human granulocytic ehrlichiosis at a national referral center. | an indirect immunofluorescence assay (ifa) was used to identify patients with antibodies reactive to the human granulocytic ehrlichiosis (hge) agent. serum samples collected from clinically ill individuals were submitted to the centers for disease control and prevention by physicians via state health departments from throughout the united states and tested against a panel of ehrlichial and rickettsial pathogens. antibodies reactive to the hge agent were detected in 142 (8.9%) of 1,602 individual ... | 1999 | 9986812 |
| efficacy of doxycycline, azithromycin, or trovafloxacin for treatment of experimental rocky mountain spotted fever in dogs. | dogs were experimentally inoculated with rickettsia rickettsii (canine origin) in order to compare the efficacies of azithromycin and trovafloxacin to that of the current antibiotic standard, doxycycline, for the treatment of rocky mountain spotted fever. clinicopathologic parameters, isolation of rickettsiae in tissue culture, and pcr amplification of rickettsial dna were used to evaluate the response to therapy or duration of illness (untreated infection control group) in the four groups. conc ... | 1999 | 10103185 |
| [rocky mountain spotted fever]. | | 1999 | 10201191 |
| hidden mortality attributable to rocky mountain spotted fever: immunohistochemical detection of fatal, serologically unconfirmed disease. | rocky mountain spotted fever (rmsf) is the most severe tickborne infection in the united states and is a nationally notifiable disease. since 1981, the annual case-fatality ratio for rmsf has been determined from laboratory-confirmed cases reported to the centers for disease control and prevention (cdc). herein, a description is given of patients with fatal, serologically unconfirmed rmsf for whom a diagnosis of rmsf was established by immunohistochemical (ihc) staining of tissues obtained at au ... | 1999 | 10228069 |
| serologic evidence of rickettsialpox (rickettsia akari) infection among intravenous drug users in inner-city baltimore, maryland. | we tested single serum samples from 631 intravenous (i.v.) drug users from inner-city baltimore, maryland for serologic evidence of exposure to spotted fever group rickettsiae. a total of 102 (16%) individuals had titers > or = 64 to rickettsia rickettsii by an indirect immunofluorescence assay. confirmation that infection was caused by r. akari was obtained by cross-adsorption studies on a subset of serum samples that consistently resulted in higher titers to r. akari than to r. rickettsii. cur ... | 1999 | 10403316 |
| coinfection with multiple tick-borne pathogens in a walker hound kennel in north carolina. | both dogs and humans can be coinfected with various ehrlichia, bartonella, rickettsia, and babesia species. we investigated a kennel of sick walker hounds and their owners in southeastern north carolina for evidence of tick-borne infections and associated risk factors. a high degree of coinfection was documented in the dog population. of the 27 dogs, 26 were seroreactive to an ehrlichia sp., 16 to babesia canis, and 25 to bartonella vinsonii, and 22 seroconverted to rickettsia rickettsii antigen ... | 1999 | 10405413 |
| molecular phylogeny and rearrangement of rrna genes in rickettsia species. | it has previously been observed that rickettsia prowazekii has an unusual arrangement of the rrna genes. in this species, the three rrna genes, 16s (rrs), 23s (rrl), and 5s (rrf), are not linked in the typical arrangements for bacteria. rather, the 16s rrna gene has been separated from the 23s and 5s rrna gene cluster, and the 23s rrna gene is preceded by a gene which codes for methionyl-trnaf(met) formyltransferase (fmt). in this study, we screened the genus rickettsia for the fmt-rrl motif in ... | 1999 | 10406115 |
| dynamics of actin-based movement by rickettsia rickettsii in vero cells. | actin-based motility (abm) is a virulence mechanism exploited by invasive bacterial pathogens in the genera listeria, shigella, and rickettsia. due to experimental constraints imposed by the lack of genetic tools and their obligate intracellular nature, little is known about rickettsial abm relative to listeria and shigella abm systems. in this study, we directly compared the dynamics and behavior of abm of rickettsia rickettsii and listeria monocytogenes. a time-lapse video of moving intracellu ... | 1999 | 10417192 |
| acute disseminated encephalomyelitis after rocky mountain spotted fever. | although acute disseminated encephalomyelitis has been observed after a variety of viral infections and an occasional bacterial infection, it has not been reported in association with rickettsial infections. reported is a 7-year-old male with magnetic resonance images and clinical manifestations suggestive of acute disseminated encephalomyelitis after a tick bite and serologically proven rocky mountain spotted fever. | 1999 | 10428440 |
| characterization of monoclonal antibodies to an immunodominant protein of the etiologic agent of human granulocytic ehrlichiosis. | immunodominant proteins in the range of 42-45 kd are important for the serodiagnosis of human granulocytic ehrlichiosis (hge). antigens from human isolates of the etiologic agent of hge cultivated in hl-60 cells were used to immunize balb/c mice and generate a panel of hybridomas secreting monoclonal antibodies. using an enzyme immunoassay, an immunofluorescent assay (ifa), and western blotting, we showed that culture supernatants and ascites of these hybridomas were reactive with human isolates ... | 1999 | 10432075 |
| evidence of rickettsial spotted fever and ehrlichial infections in a subtropical territory of jujuy, argentina. | between november 1993 and march 1994, a cluster 6 pediatric patients with acute febrile illnesses associated with rashes was identified in jujuy province, argentina. immunohistochemical staining of tissues confirmed spotted fever group rickettsial infection in a patient with fatal disease, and testing of serum of a patient convalescing from the illness by using an indirect immunofluorescence assay (ifa) demonstrated antibodies reactive with spotted fever group rickettsiae. a serosurvey was condu ... | 1999 | 10463693 |
| serologic study of the prevalence of rickettsiosis in yucatán: evidence for a prevalent spotted fever group rickettsiosis. | because of the discovery of a spotted fever group rickettsiosis with signs and symptoms similar to dengue fever in yucatan, mexico, immunofluorescence assay (ifa) serology was performed on sera from 390 persons selected from a representative geographic distribution of rural yucatan to detect antibodies reactive with rickettsia rickettsii, r. akari, a thai strain (tt-118) that is most closely related to a rickettsia identified in amblyomma cajennense ticks in southern texas, and r. typhi. the ifa ... | 1999 | 10497980 |
| involvement of protein kinase c in rickettsia rickettsii-induced transcriptional activation of the host endothelial cell. | our laboratory has reported on a biphasic pattern of nuclear factor kappab (nf-kappab) activation in cultured human umbilical vein endothelial cells during infection with rickettsia rickettsii, an obligate, intracellular bacterium, and the etiologic agent of rocky mountain spotted fever. transcriptional activation of the tissue factor (tf) gene during this infection has been shown to involve nf-kappab. to further understand the signal transduction events underlying these phenomena, we studied th ... | 1999 | 10569758 |
| post-transcriptional regulation of endothelial cell plasminogen activator inhibitor-1 expression during r. rickettsii infection. | intracellular infection of endothelial cells with rickettsia rickettsii results in increased steady-state levels of plasminogen activator inhibitor-1 (pai-1) mrna. control mechanisms governing such increased expression in response to this novel stimulus have not been defined. in this study, we compared the stability of pai-1 mrna in infected and uninfected endothelial cells (ec) and explored the requirement for de novo host cell protein synthesis in the infection-induced increase of steady-state ... | 2000 | 10702354 |
| in vitro susceptibilities of rickettsia and bartonella spp. to 14-hydroxy-clarithromycin as determined by immunofluorescent antibody analysis of infected vero cell monolayers. | the in vitro susceptibilities of rickettsia akari, rickettsia conorii, rickettsia prowazekii, rickettsia rickettsii, bartonella elizabethae, bartonella henselae and bartonella quintana to different concentrations of clarithromycin, 14-hydroxy-clarithromycin (the primary metabolite of clarithromycin) and tetracycline in vero cell cultures, were determined by enumeration of immunofluorescently-stained bacilli. the extent of antibiotic-induced inhibition of foci was recorded for each dilution of an ... | 2000 | 10702548 |
| q fever endocarditis associated with extensive serological cross-reactivity. | | 2000 | 10722459 |
| in vitro activities of telithromycin (hmr 3647) against rickettsia rickettsii, rickettsia conorii, rickettsia africae, rickettsia typhi, rickettsia prowazekii, coxiella burnetii, bartonella henselae, bartonella quintana, bartonella bacilliformis, and ehrlichia chaffeensis. | in vitro activities of telithromycin compared to those of erythromycin against rickettsia spp., bartonella spp., coxiella burnetii, and ehrlichia chaffeensis were determined. telithromycin was more active than erythromycin against rickettsia, bartonella, and coxiella burnetii, with mics of 0.5 microg/ml, 0.003 to 0.015 microg/ml, and 1 microg/ml, respectively, but was inactive against ehrlichia chaffeensis. | 2000 | 10770788 |
| family cluster of rocky mountain spotted fever. | soon after a patient from tennessee died of rocky mountain spotted fever (rmsf), several family members developed symptoms suggestive of the disease and were treated presumptively for rmsf. fifty-four persons visiting the index patient's home were interviewed; serum samples were collected from 35. three additional cases of rmsf were confirmed, all of which occurred in first-degree relatives. time spent at the family home and going into the surrounding woods were significantly associated with dev ... | 1999 | 10825050 |
| meningoencephalitis secondary to bacterial otitis media/interna in a dog. | central nervous system (cns) complications of bacterial otitis media/interna are an infrequent occurrence in human patients and have rarely been reported in the veterinary literature. early recognition of cns involvement and the use of appropriate diagnostic tests to characterize the nature of the lesion(s) are crucial in determining the best course of treatment. in this paper, the authors describe a dog with bacterial meningoencephalitis secondary to otitis media/interna. | 2000 | 10825096 |
| [isolation of rickettsia in vero cell culture]. | the diagnosis of spotted fever is based on characteristic signs and symptoms but requires laboratorial confirmation because of the possible differential diagnosis from other diseases like leptospirosis, enterovirus, meningococcemia and typhoid fever. laboratorial confirmation may be done by detection of specific antibodies which is possible only 5-10 days after the onset of the symptoms or by the isolation of rickettsiae from blood and/or skin biopsy and from ticks collected in the patient or in ... | 1999 | 10881078 |
| report on ticks collected in the southeast and mid-west regions of brazil: analyzing the potential transmission of tick-borne pathogens to man. | specimens of ticks were collected in 1993, 1996, 1997, and 1998, mostly from wild and domestic animals in the southeast and mid-west regions of brazil. nine species of amblyommidae were identified: anocentor nitens, amblyomma cajennense, amblyomma ovale, amblyomma fulvum, amblyomma striatum, amblyomma rotundatum, boophilus microplus, boophilus annulatus, and rhipicephalus sanguineus. the potential of these tick species as transmitters of pathogens to man was analyzed. a flaviviridade flavivirus ... | 1999 | 10881097 |
| ultrastructure of rickettsia rickettsii actin tails and localization of cytoskeletal proteins. | actin-based motility (abm) is a mechanism for intercellular spread that is utilized by vaccinia virus and the invasive bacteria within the genera rickettsia, listeria, and shigella. within the rickettsia, abm is confined to members of the spotted fever group (sfg), such as rickettsia rickettsii, the agent of rocky mountain spotted fever. infection by each agent induces the polymerization of host cell actin to form the typical f (filamentous)-actin comet tail. assembly of the actin tail propels t ... | 2000 | 10899876 |
| consequences of delayed diagnosis of rocky mountain spotted fever in children--west virginia, michigan, tennessee, and oklahoma, may-july 2000. | patients with rocky mountain spotted fever (rmsf), a tickborne infection caused by rickettsia rickettsii, respond quickly to tetracycline-class antibiotics (e.g., doxycycline) when therapy is started within the first few days of illness; however, untreated rmsf may result in severe illness and death. persons aged <10 years have the highest age-specific incidence of rmsf. this report summarizes the clinical course and outcome of rmsf in four children from four regions of the united states and und ... | 2000 | 11055741 |