in vitro and in vivo antibiotic susceptibilities of elb rickettsiae.the activities of doxycycline, rifampin, chloramphenicol, and erythromycin against elb rickettsiae (rickettsia azadi) were determined by dye uptake and plaque assays. plaque formation in vero cells was inhibited by 0.12 microgram of doxycycline per ml. the data presented demonstrate the susceptibility of elb rickettsiae to commonly used antibiotics for the treatment of rickettsial diseases.19958585746
rickettsia felis: a new species of pathogenic rickettsia isolated from cat fleas.a flea-borne rickettsia, previously referred to as elb, has been implicated as a cause of human illness. using sequence data obtained from a fragment of the citrate synthase gene, we compared elb, rickettsia australis, r. rickettsii, and r. akari with the louse-borne r. prowazekii. we tallied 24 base pair differences between elb and r. prowazekii and 25 between r. rickettsii and r. prowazekii; there were 30 base pair differences between r. australis and r. prowazekii and 29 between r. akari and ...19968904435
molecular phylogeny and rearrangement of rrna genes in rickettsia 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 ...199910406115
genome degradation is an ongoing process in study reductive evolutionary processes in bacterial genomes, we examine sequences in the rickettsia genomes which are unconstrained by selection and evolve as pseudogenes, one of which is the metk gene, which codes for adomet synthetase. here, we sequenced the metk gene and three surrounding genes in eight different species of the genus rickettsia. the metk gene was found to contain a high incidence of deletions in six lineages, while the three genes in its surroundings were functionally cons ...199910486973
infection and seroconversion of cats exposed to cat fleas (ctenocephalides felis bouché) infected with rickettsia felis.cats with no prior exposure to cat fleas were exposed to fleas infected with rickettsia felis and monitored monthly for seroconversion via an indirect fluorescent assay (ifa). each of 12 cats continually infested with fleas, seroconverted by four months post-exposure. three of six cats fed on by 50 fleas for 15 minutes once per week also seroconverted by month four. rickettsia felis dna was detected by pcr in the blood of five of the 16 cats.200010925806
rickettsia felis rickettsiosis in yucatán.three patients with fever, exanthem, headache, and central-nervous-system involvement were diagnosed with rickettsia fells infection by specific pcr of blood or skin and seroconversion to surrogate rickettsia antigens. although r. felis's relationship to other rickettsia species is known and the pathogenic potential of this clade is well documented, r. felis's role as a pathogen has not been fully understood.200011009147
a flea-associated rickettsia pathogenic for humans.a rickettsia named the elb agent, or "rickettsia felis," was identified by molecular biology techniques in american fleas in 1990 and later in four patients from texas and mexico. we attempted to isolate this rickettsia from infected fleas at various temperatures and conditions. a representative isolate of the elb agent, the marseille strain, was characterized and used to develop a microimmunofluorescence test that detected reactive antibodies in human sera. the elb agent was isolated from 19 of ...200111266297
phylogenetic analysis of the rompb genes of rickettsia felis and rickettsia prowazekii european-human and north american flying-squirrel strains.the rickettsial outer membrane protein b (rompb) gene encodes the major surface antigens of rickettsia species. we undertook sequencing and molecular analysis of the rompb gene of rickettsia felis and a comparison with its homologs in spotted fever group (sfg) and typhus group (tg) rickettsiae, including the complete sequences of two north american flying squirrel strains and two european human strains of rickettsia prowazekii. we sequenced 5,226 base pairs (bp) of the r. felis rompb, encoding a ...200011289671
rickettsia felis: molecular characterization of a new member of the spotted fever this report, placement of rickettsia felis in the spotted fever group (sfg) rather than the typhus group (tg) of rickettsia is proposed. the organism, which was first observed in cat fleas (ctenocephalides felis) by electron microscopy, has not yet been reported to have been cultivated reproducibly, thereby limiting the standard rickettsial typing by serological means. to overcome this challenge, several genes were selected as targets to be utilized for the classification of r. felis. dna fro ...200111321078
presence of rickettsia felis in the cat flea from southwestern europe.rickettsia felis, formerly called elb agent, was identified by using molecular biology techniques in the cat flea (ctenocephalides felis felis) from southwestern spain. for the first time this flea-transmitted rickettsia has been detected within its vector in eurasia.200211749758
rickettsia felis infection acquired in europe and documented by polymerase chain reaction.we report the first case of rickettsia felis infection in europe to be documented by polymerase chain reaction (pcr) and serologic testing.200211897076
rickettsia felis in ctenocephalides spp. fleas, june 2000, suspected cases of brazilian spotted fever (bsf) occurred in coronel fabriciano municipality, minas gerais state, brazil. pooled fleas collected near two fatal cases contained rickettsial dna. the nucleotide sequence alignment of the 391-bp segment of the 17-kda protein gene showed that the products were identical to each other and to the r. felis 17-kda gene, confirming circulation of r. felis in brazil.200211927031
geographic association of rickettsia felis-infected opossums with human murine typhus, texas.application of molecular diagnostic technology in the past 10 years has resulted in the discovery of several new species of pathogenic rickettsiae, including rickettsia felis. as more sequence information for rickettsial genes has become available, the data have been used to reclassify rickettsial species and to develop new diagnostic tools for analysis of mixed rickettsial pathogens. r. felis has been associated with opossums and their fleas in texas and california. because r. felis can cause h ...200212023908
phylogenetic analysis of spotted fever group rickettsiae isolated from ticks in japan.eight spotted fever group (sfg) rickettsiae isolated from ticks in japan were classified by phylogenetic analysis based on the nucleotide sequences of both the citrate synthase-encoding gene (glta) and 190-kda antigen-encoding gene (rompa). in the phylogenetic tree of glta, strains dt-1 and fla-1 isolated from the dermacentor taiwanensis and haemaphysalis frava ticks, respectively, were placed as rickettsia japonica, and strains io-1, io-2, io-25, im-1 and ip-2 from genus ixodes ticks were place ...200212061626
vertical transmission of rickettsia felis in the cat flea (ctenocephalides felis bouché).rickettsia felis can be maintained in cat fleas by vertical transmission for up to 12 generations without the benefit of an infected host. horizontal transmission or the acquisition of r. felis by fleas feeding on cats or artificially infected meals were not demonstrated in this study. horizontal transmission of r. felis by the ingestion of feces or eggs by flea larvae was not detected. we also tested for and found no evidence to support horizontal transmission by contact among positive fleas an ...200212125879
evaluation of antibiotic susceptibilities of three rickettsial species including rickettsia felis by a quantitative pcr dna assay.rickettsiae grow only intracellularly, and the antibiotic susceptibilities of these bacteria have been assessed by either plaque, dye uptake, or immunofluorescence assays, which are time-consuming. we used a quantitative pcr (with the lightcycler instrument) to assess the levels of inhibition of rickettisa felis, r. conorii, and r. typhi dna synthesis in the presence of various antibiotics. we established the kinetics of rickettsial dna during growth and showed that r. conorii grows more quickly ...200212183224
emended description of rickettsia felis (bouyer et al. 2001), a temperature-dependent cultured bacterium.on the basis of phenotypic data obtained on the strain marseille-urrwfxcal2(t), isolated from the cat flea ctenocephalides felis, the description of rickettsia felis (bouyer et al., 2001) is emended and marseille-urrwfxcal2(t) is proposed as the type strain of the species. on the basis of polyphasic characterization, especially the inability to grow at temperatures higher than 32 degrees c on vero cells that allow growth of other rickettsia to at least 35 degrees c, it is confirmed that this age ...200212508865
antigenic classification of rickettsia felis by using monoclonal and polyclonal antibodies.rickettsia felis is a flea-transmitted rickettsia. there is a discrepancy between its reported phylogenic and phenotypic identifications. following the first report of r. felis, it was considered by tests with serologic reagents to be closely related to another recognized flea-transmitted rickettia, r. typhi. subsequently, it appeared to be more closely related to spotted fever group (sfg) rickettsiae by genetic analysis. in the present work, r. felis was studied by microimmunofluorescence (mif) ...200312626446
molecular detection of bartonella quintana, b. koehlerae, b. henselae, b. clarridgeiae, rickettsia felis, and wolbachia pipientis in cat fleas, france.the prevalences of bartonella, rickettsia, and wolbachia were investigated in 309 cat fleas from france by polymerase chain reaction (pcr) assay and sequencing with primers derived from the glta gene for rickettsia, the its and pap31 genes for bartonella, and the 16s rrna gene for anaplasmataceae. positive pcr results were confirmed by using the lightcycler and specific primers for the rompb of rickettsia and glta of bartonella. r. felis was detected in 25 fleas (8.1%), w. pipientis, an insect s ...200312643829
urban zoonoses caused by bartonella, coxiella, ehrlichia, and rickettsia species.the last half of the 20th century witnessed an increase in the occurrence and recognition of urban zoonoses caused by members of the genera bartonella, coxiella, ehrlichia, and rickettsia, all traditionally considered to be members of the family rickettsiaceae. in recent years, new human pathogens (bartonella elizabethae, bartonella henselae, and rickettsia felis) have been recognized in urban environments. other newly recognized pathogens (ehrlichia chaffeensis and ehrlichia phagocytophila in t ...200112653141
identification of ctenocephalides felis fleas as a host of rickettsia felis, the agent of a spotted fever rickettsiosis in yucataƄ, search for the vector of the recently recognized spotted fever rickettsiosis of the yucatán, ticks, fleas, and lice were collected from vegetation and dogs in localities where seropositive persons had been found. the arthropods were examined by polymerase chain reaction (pcr) using primers for the genus-specific 17-kda protein gene followed by restriction fragment length polymorphism (rflp) and dna sequencing. eleven (20%) of 54 pools of ctenocephalides felis fleas contained dna of rickettsia ...200212653300
emerging rickettsioses of the thai-myanmar investigate the presence of rickettsioses in rural residents of the central thai-myanmar border, we tested the blood of 46 patients with fever. four patients had murine typhus, three patients had scrub typhus, and eight patients had spotted fever group rickettsioses, including the first case of rickettsia felis infection reported in asia.200312737744
identification of rickettsia spp. and bartonella spp. in ffrom the thai-myanmar border.during a survey for possible rickettsial vectors in villages of the central part of the thai-myanmar border from september 2001 to february 2002, four species of fleas were collected from common peridomestic animals. all fleas were tested by pcr to detect dna of bacteria of the genera rickettsia (glta and ompb genes) and bartonella (its and ftsz genes). sequencing of pcr-amplified products was done using glta fragments for rickettsia and ftsz fragments for bartonella: two genotypes related to ri ...200312860622
detection of r. felis and r. typhi in fleas using monoclonal antibodies.rickettsia typhi and r. felis are flea-transmitted human pathogenic rickettsial species. to investigate the distributional dynamics of these rickettsiae we designed a micro-immunofluorescence assay (mif) using species-specific monoclonal antibodies (mabs) applied to flea cryosections. our assay was performed in less than 3 h and its applicability was demonstrated by the detection of r. typhi in 50 artificially infected human body lice but in none of 50 uninfected lice. with mif, we identified 31 ...200312860628
rickettsia felis in the united kingdom. 200312971375
scrub typhus and tropical rickettsioses.recent developments in molecular taxonomic methods have led to a reclassification of rickettsial diseases. the agent responsible for scrub typhus (orientia tsutsugamushi ) has been removed from the genus rickettsia and a bewildering array of new rickettsial pathogens have been described. an update of recent research findings is therefore particularly timely for the nonspecialist physician.200314501995
rickettsia felis, bartonella henselae, and b. clarridgeiae, new zealand. 200415216855
pathogen carriage by the cat flea ctenocephalides felis (bouché) in the united kingdom.the carriage of bartonella, rickettsia felis and haemoplasma species was investigated in cat fleas (ctenocephalides felis) collected from 121 cats and dogs in the united kingdom. dna extracted from fleas was analysed using genus and species-specific pcr and amplicons were characterised using dna sequencing. fifty percent of flea samples were pcr positive for at least one pathogen. twenty one percent were positive for r. felis, 17% for bartonella henselae, 40% for haemoplasma species and 20% were ...200415327793
clinical and laboratorial evidence of rickettsia felis infections in latin america.after the discovery and initial characterization of rickettsia felis in 1992 by azad and cols, and the subsequent first description of a human case of infection in 1994, there have been two communications of human rickettsiosis cases caused by rickettsia felis in latin america. the first one was published in 2000 by zavala-velazquez and cols in mexico. in 2001 raoult and cols described the occurrence of two human cases of rickettsia felis rickettsiosis in brazil. in the present discussion these ...200415330064
characterization of spotted fever group rickettsiae in flea and tick specimens from northern peru.evidence of spotted fever group (sfg) rickettsiae was obtained from flea pools and individual ticks collected at three sites in northwestern peru within the focus of an outbreak of febrile disease in humans attributed, in part, to sfg rickettsia infections. molecular identification of the etiologic agents from these samples was determined after partial sequencing of the 17-kda common antigen gene (htra) as well as pairwise nucleotide sequence homology with one or more of the following genes: glt ...200415528680
a review of bacterial pathogens in ctenocephalides felis in new zealand.the cat flea, ctenocephalides felis, is the recognised vector of bartonella henselae, b. clarridgeiae and rickettsia felis. although these gram-negative bacteria were only described in the last decade, they are already known to cause a variety of diseases in people, particularly children and the immunosuppressed. such diseases include cat-scratch disease, bacillary angiomatosis, endocarditis, bacteraemia, encephalopathy, neuroretinitis, osteomyelitis and peliosis hepatis. although most infection ...200415768135
detection of rickettsia felis in a new world flea species, anomiopsyllus nudata (siphonaptera: ctenophthalmidae).the flea and rodent samples studied in this project were collected from field study sites in new mexico from winter 1998 to spring 2001. during this period, 155 small rodents (14 different species) were live-trapped and combed for the presence of fleas. a total of 253 fleas were collected, comprising 21 species. two of the 253 fleas collected were polymerase chain reaction (pcr) positive for the rickettsia 17-kda protein gene. these two fleas were both anomiopsyllus nudata baker, each collected ...200515799525
the genome sequence of rickettsia felis identifies the first putative conjugative plasmid in an obligate intracellular parasite.we sequenced the genome of rickettsia felis, a flea-associated obligate intracellular alpha-proteobacterium causing spotted fever in humans. besides a circular chromosome of 1,485,148 bp, r. felis exhibits the first putative conjugative plasmid identified among obligate intracellular bacteria. this plasmid is found in a short (39,263 bp) and a long (62,829 bp) form. r. felis contrasts with previously sequenced rickettsia in terms of many other features, including a number of transposases, severa ...200515984913
rickettsia felis infection rates in an east texas population.murine typhus (rickettsia typhi), endemic in southern california and south texas, is maintained within a host-vector system consisting of the opossum and cat flea. in the early 1990s, a second rickettsial species, rickettsia felis, was also found to be maintained within the opossum-cat flea system and is, in fact, found more commonly than r. typhi in the opossum and cat flea. recognized as a human pathogen in 1994, r. felis causes an infection that produces symptoms indistinguishable from classi ...200516130886
transcription of the rickettsia felis ompa gene in naturally infected fleas.rickettsia felis is maintained transovarially in ctenocephalides felis fleas in a widespread geographic distribution and is transmitted to humans and animals, including opossums. this rickettsia is phylogenetically a member of the spotted fever group, most closely related to rickettsia akari and r. australis. an unusual feature of this rickettsia is that the gene for the outer membrane protein a (ompa) is interrupted by stop codons. to determine if this putatively dying gene is expressed, mrna w ...200516222005
for better or worse: genomic consequences of intracellular mutualism and parasitism.bacteria that replicate within eukaryotic host cells include a variety of pathogenic and mutualistic species. early genome data for these intracellular associates suggested they experience continual gene loss, little if any gene acquisition, and minimal recombination in small, isolated populations. this view of reductive evolution is itself evolving as new genome sequences clarify mechanisms and outcomes of diverse intracellular associations. recently sequenced genomes have confirmed a trajector ...200516230003
prevalence of human pathogens in cat and dog fleas in new provide further information on the prevalence of rickettsia felis, bartonella hensela, and b. clarridgeiae in cat and dog fleas in new zealand and their distribution in the country.200516311612
bartonella quintana and rickettsia felis in gabon.we detected rickettsia felis dna in ctenocephalides felis and bartonella quintana dna in 3 pulex irritans fleas taken from a pet cercopithecus cephus monkey in gabon, sub-saharan africa. this is the first report of b. quintana in the human flea.200516318727
food for thought. 200516350281
first detection of rickettsia felis in ctenocephalides felis fleas parasitizing rats in cyprus.rickettsia felis was identified by polymerase chain reaction amplification and dna sequencing analysis in ctenocephalides felis fleas parasitizing rats in cyprus. murine typhus caused by r. typhi was believed to be the only flea-transmitted rickettsiosis on the island. this is the first report of this pathogen in southeastern europe.200616407355
serological evidence of infection with rickettsia typhi and rickettsia felis among the human population of catalonia, in the northeast of spain.murine typhus (mt) is a cause of fever of intermediate duration in the south of spain. rickettsia typhi has been described as the mt etiological agent. rickettsia felis produces an infection similar to mt. the aim of the study is to determine their seroprevalence in humans in catalonia. antibodies to rickettsia typhi and rickettsia felis from 217 serum samples were examined by indirect immunofluorescence assay (ifa). age, gender, residence area, contact with animals, and occupation were surveyed ...200616407356
isolation of rickettsia felis in the mosquito cell line c6/36.we report the isolation and establishment of rickettsia felis in the c6/36 cell line. rickettsial growth was intense, always with 90 to 100% of cells being infected after few weeks. the rickettsial isolate was confirmed by testing infected cells by pcr and sequencing fragments of three major rickettsia genes (glta, ompb, and the 17-kda protein gene).200616461734
rickettsia felis, from culture to genome sequencing.rickettsia felis has been recently cultured in xtc2 cells. this allows production of enough bacteria to create a genomic bank and to sequence it. the chromosome of r. felis is longer than that of previously sequenced rickettsiae and it possess 2 plasmids. microscopically, this bacterium exhibits two forms of pili: one resembles a conjugative pilus and another forms hair-like projections that may play a role in pathogenicity. r. felis also exhibits several copies of ankyrin-repeat genes and tetra ...200516481487
new perspectives on rickettsial evolution from new genome sequences of rickettsia, particularly r. canadensis, and orientia tsutsugamushi.the complete genome sequences available for eight species of rickettsia and information for other near relatives in the rickettsiales including orientia and species of anaplasmataceae are a rich resource for comparative analyses of the evolution of these obligate intracellular bacteria. differences in these organisms have permitted them to colonize varied intracellular compartments, arthropod vectors, and vertebrate reservoirs in both pathogenic and symbiotic relationships. we summarize some com ...200516481489
preliminary transcriptional analysis of spot gene family and of membrane proteins in rickettsia conorii and rickettsia felis.rickettsiae survival implicates adaptation to different environmental conditions. we hypothesized that multiple copies of genes in bacteria with reduced genomes might account for such a process. transcription of spot and sca paralogs was thus analyzed in r. conorii and r. felis.200516481494
phylogenic analysis of rickettsial patatin-like protein with conserved phospholipase a2 active sites.genome analysis of rickettsia felis highlighted the presence of three patatin-like protein (plp) genes (pat1, pat2a, and pat2b), whereas only one plp gene (pat1) is found in the other sequenced rickettsial genomes. here, we aligned the rickettsial plps with characterized patatins from plants and found that they possess all the conserved amino acid residues identified as important for phospholipase a(2) activity. we also carried out a phylogenic analysis of the rickettsial plps together with bact ...200516481495
old and new human rickettsiosis in minas gerais state, brazil.the authors describe cases of brazilian spotted fever (bsf) diagnosed in minas gerais state, brazil, by the minas gerais public health laboratory, ezequiel dias foundation from 1995 to 2004. in addition they present three cases of human rickettsia felis rickettsiosis from minas gerais diagnosed in france in 1999, and the first two suspected cases of human monocytic ehrlichiosis (hme) diagnosed in ezequiel dias foundation in 2001. in both cases a differential diagnose was made with bsf.200516481542
human rickettsia felis infection, canary islands, spain.we report the first cases of human infection by rickettsia felis in the canary islands. antibodies against r. felis were found in 5 adsorbed serum samples from 44 patients with clinically suspected rickettsiosis by western blot serology. fleas from 1 patient's dog were positive for r. felis by polymerase chain reaction.200516485491
rickettsia felis infection, tunisia.we report, for the first time, serologic evidence of rickettsia felis and r. aeschlimannii infections acquired in tunisia from 1998 to 2003. we found that most patients with antibodies against both r. conorii and r. typhi had serologic evidence of r. felis infection.200616494731
rickettsia felis, the agent of an emerging infectious disease: report of a new case in mexico.the fourth case of human infection with rickettsia felis in yucatán, mexico was documented by serologic testing and polymerase chain reaction (pcr). the role of r. felis in human disease has been demonstrated by molecular methods in a few patients from the u.s., yucatán, brazil and germany. apparently, there is a wide spectrum in the clinical presentation of the worldwide reported cases.200616513497
molecular detection of bartonella quintana, b. elizabethae, b. koehlerae, b. doshiae, b. taylorii, and rickettsia felis in rodent fleas collected in kabul, afghanistan.the prevalences of bartonella spp. and rickettsia spp. were investigated using molecular methods in 77 rodent fleas collected in november 2002 by the french forces detachment in kabul, afghanistan. overall, bartonella dna was detected in 15.5% of gerbil fleas and 40.5% of rat fleas, whereas rickettsia felis was found in 9% of gerbil fleas. we described for the first time in this country bartonella quintana, b. koehlerae, b. taylorii, and rickettsia felis in fleas from the gerbil species meriones ...200616525103
polygenic detection of rickettsia felis in cat fleas (ctenocephalides felis) from israel.the presence of rickettsia felis, an emerging bacterial pathogen, was investigated in 79 cat flea (cteno-cephalides felis) pools from israel (5 to 20 fleas each) by polymerase chain reaction (pcr) and sequencing of 5 different genes. amplified targets included both metabolic (glta and fusa) and surface antigen (ompa, ompb, and the 17-kda antigen) genes. r. felis dna was detected in 7.6% of the flea pools. two genotypes similar in their housekeeping gene sequences but markedly different in their ...200616525105
first molecular detection of rickettsia felis in fleas from algeria.fleas collected in algeria in the district of oran between july and september 2003 were tested by polymerase chain reaction for the presence of rickettsia spp. dna using primers amplifying glta and ompa genes. two glta sequences identical to those of an emerging pathogen, rickettsia felis, were detected including i) r. felis california 2 in ctenocephalides canis from rodents and ii) r. felis rf2125 in archeopsylla erinacei from hedgehogs.200616606979
genome sequence of rickettsia bellii illuminates the role of amoebae in gene exchanges between intracellular pathogens.the recently sequenced rickettsia felis genome revealed an unexpected plasmid carrying several genes usually associated with dna transfer, suggesting that ancestral rickettsiae might have been endowed with a conjugation apparatus. here we present the genome sequence of rickettsia bellii, the earliest diverging species of known rickettsiae. the 1,552,076 base pair-long chromosome does not exhibit the colinearity observed between other rickettsia genomes, and encodes a complete set of putative con ...200616703114
rickettsia felis in fleas, western australia.this study is the first confirmation of rickettsia felis in australia. the organism was identified from 4 species of fleas obtained from dogs and cats in western australia, by using polymerase chain reaction amplification and dna sequencing of the citrate synthase and outer membrane protein a genes.200616704850
seroepidemiological study of rickettsia felis, rickettsia typhi, and rickettsia conorii infection among the population of southern spain.rickettsia typhi and rickettsia conorii, the etiologic agents of, respectively, murine typhus and mediterranean spotted fever, are recognized as frequent causes of fever of intermediate duration in southern spain; in addition, in recent years rickettsia felis has been detected in potential vectors in this area. nevertheless, limited data exist regarding the actual prevalence of past infection due to these three pathogens. in the present study, the prevalence of past infection due to r. felis, r. ...200616767485
borrelia, coxiella, and rickettsia in carios capensis (acari: argasidae) from a brown pelican (pelecanus occidentalis) rookery in south carolina, usa.argasid ticks are vectors of viral and bacterial agents of humans and animals. carios capensis, a tick of seabirds, infests the nests of brown pelicans, pelecanus occidentalis, and other ground nesting birds along the coast of south carolina. this tick is associated with pelican nest abandonment and could pose a threat to humans visiting pelican rookeries if visitors are exposed to ticks harboring infectious agents. we collected ticks from a pelican rookery on deveaux bank, south carolina and sc ...200616821092
cluster of cases of human rickettsia felis infection from southern europe (spain) diagnosed by pcr.the first cluster of cases of human rickettsia felis infection in spain diagnosed by pcr is reported.200616825412
rickettsia felis from cat fleas: isolation and culture in a tick-derived cell line.rickettsia felis, the etiologic agent of spotted fever, is maintained in cat fleas by vertical transmission and resembles other tick-borne spotted fever group rickettsiae. in the present study, we utilized an ixodes scapularis-derived tick cell line, ise6, to achieve isolation and propagation of r. felis. a cytopathic effect of increased vacuolization was commonly observed in r. felis-infected cells, while lysis of host cells was not evident despite large numbers of rickettsiae. electron microsc ...200616885313
impact of the excision of an ancient repeat insertion on rickettsia conorii guanylate kinase activity.the genomic sequencing of rickettsia conorii revealed a new family of rickettsia-specific palindromic elements (rpes) capable of in-frame insertion in preexisting open reading frames (orfs). many of these altered orfs correspond to proteins with well-characterized or essential functions in other microorganisms. previous experiments indicated that rpe-containing genes are normally transcribed and that no excision of the repeat occurs at the mrna level. using mass spectrometry, we now confirmed th ...200616891376
development of quantitative real-time pcr assays to detect rickettsia typhi and rickettsia felis, the causative agents of murine typhus and flea-borne spotted fever.rickettsia typhi and rickettsia felis are the etiologic agents of murine typhus and flea-borne spotted fever, respectively. we have constructed two quantitative real-time polymerase chain reaction (qpcr) assays to detect these pathogenic rickettsiae. the qpcr assays were developed utilizing unique sequences of the r. typhi and r. felis outer membrane protein b genes (ompb) to design the specific primers and molecular beacon probes. the assays were found to be species-specific and did not yield f ...200716893625
rickettsia felis in xenopsylla cheopis, java, indonesia.rickettsia typhi and r. felis, etiologic agents of murine typhus and fleaborne spotted fever, respectively, were detected in oriental rat fleas (xenopsylla cheopis) collected from rodents and shrews in java, indonesia. we describe the first evidence of r. felis in indonesia and naturally occurring r. felis in oriental rat fleas.200616965716
molecular detection of rickettsia felis, rickettsia typhi and two genotypes closely related to bartonella elizabethae.a total of 56 fleas were collected from mice, rats, and one hedgehog in national parks of mainland portugal and the madeira island. all fleas were tested for the presence of bacteria of the genera rickettsia and bartonella using pcr assays. in fleas from mainland portugal, we detected rickettsia felis in one archaeopsylla erinacei maura flea and in one ctenophtalmus sp. in five leptopsylla segnis fleas taken from rats in the madeira island, we identified rickettsia typhi. in addition, in four fl ...200617038702
rickettsia felis in the americas.the authors describe their work in the americas in rickettsia felis cases in humans and the presence of rickettsia felis in vectors.200617114699
evidence of infection in humans with rickettsia typhi and rickettsia felis in catalonia in the northeast of spain.murine typhus is a cause of fever of intermediate duration in the south of spain, where antibodies against rickettsia typhi and rickettsia felis were observed in humans. this study presents the first report from the northeast of spain. human serum samples were tested by serological test. r. typhi and r. felis seroprevalences were 8.8% and 3.2%, respectively.200617114700
arthropod-borne diseases in homeless.homeless people are particularly exposed to ectoparasite. the living conditions and the crowded shelters provide ideal conditions for the spread of lice, fleas, ticks, and mites. body lice have long been recognized as human parasites and although typically prevalent in rural communities in upland areas of countries close to the equator, it is now increasingly encountered in developed countries especially in homeless people or inner city economically deprived population. fleas are widespread but ...200617114713
prevalence of rickettsia felis-like and bartonella spp. in ctenocephalides felis and ctenocephalides canis from la rioja (northern spain).our aim was to determine the presence of rickettsia spp. and bartonella spp. in ctenocephalides felis and ctenocephalides canis from la rioja (spain). a total of 88 specimens were tested by polymerase chain reaction (pcr) using glta and ompb genes as targets for rickettsia spp., and 16s rrna and ribc genes for bartonella spp. rickettsia felis-like (28.4%), bartonella clarridgeiae (6.8%), and bartonella henselae (3.4%) were detected in ctenocephalides spp. other bartonella sp. different from b. c ...200617114721
prevalence of rickettsia felis in ctenocephalides felis and ctenocephalides canis from uruguay.our aim was to determine the presence of rickettsia spp. in 66 fleas from uruguay. rickettsial dna was amplified using glta and ompb pcr primers. rickettsia spp. were found in 41% of the fleas (25 ctenocephalides felis and 2 ctenocephlides canis). sequences resulted in the identification of rickettsia felis and four genotypes closely related to this species (rickettsia sp. twkm03, california 2, hf187, and rf2125). the presence of r. felis in fleas from uruguay in was demonstrated. this is the se ...200617114726
incidence and distribution pattern of rickettsia felis in peridomestic fleas from andalusia, southeast spain.the presence of rickettsia felis was investigated in three species of pulicid fleas (ctenocephalides felis, ctenocephalides canis and pulex irritans) collected in 38 locales in andalusia (spain) over the period 1999-2004. amplification of a fragment of ompb gene was positive in 54.17 % of lots of ct. felis. the identity of the pcr bands was confirmed as r. felis by sequence data obtained directly from the pcr amplicon. no rickettsia was found in ct. canis nor p. irritans.200617114737
molecular identification of rickettsia felis-like bacteria in haemaphysalis sulcata ticks collected from domestic animals in southern croatia.haemaphysalis sulcata ticks collected from sheep and goats in southern croatia were found infected with rickettsiae. molecular analysis of the complete glta gene and portion of 17 kda and ompb genes revealed the presence of rickettsia felis-like bacteria in up to 26% of tested ticks.200617114738
prevalence of rickettsia felis in the fleas ctenocephalides felis felis and ctenocephalides canis from two indian villages in sao paulo municipality, brazil.we evaluated the presence of rickettsia infection among fleas collected on domestic dogs in two guarani indian communities in the suburban area of são paulo municipality, brazil. a total of 114 ctenocephalides felis felis and 47 ctenocephalides canis were collected from 40 dogs. a total of 41 c. felis felis (36.0%) and 9 c. canis (19.1%) fleas yielded expected bands by pcr, which were all shown by dna sequencing to be indentical to the corresponding sequence of a fragment of the rickettsia felis ...200617114741
spotted fever rickettsioses in southern and eastern europe.mediterranean spotted fever due to rickettsia conorii conorii was thought, for many years, to be the only tick-borne rickettsial disease prevalent in southern and eastern europe. however, in recent years, six more species or subspecies within the spotted fever group of the genus rickettsia have been described as emerging pathogens in this part of the world. tick-borne agents include rickettsia conorii israelensis, rickettsia conorii caspia, rickettsia aeschlimannii, rickettsia slovaca, rickettsi ...200717266709
prevalence of rickettsia felis dna in the blood of cats and their fleas in the united states.rickettsia felis is associated with fever, headache, myalgia, and macular rash in some infected humans and has been detected in the cat flea (ctenocephalides felis) in many countries around the world. while some naturally exposed cats have been assessed for antibodies against r felis, to our knowledge, no one has reported use of polymerase chain reaction (pcr) to attempt to amplify r felis dna from client-owned cats and the fleas collected from them. in this study, we assayed 92 pairs of cat blo ...200717276123
plasmids and rickettsial evolution: insight from rickettsia felis.the genome sequence of rickettsia felis revealed a number of rickettsial genetic anomalies that likely contribute not only to a large genome size relative to other rickettsiae, but also to phenotypic oddities that have confounded the categorization of r. felis as either typhus group (tg) or spotted fever group (sfg) rickettsiae. most intriguing was the first report from rickettsiae of a conjugative plasmid (prf) that contains 68 putative open reading frames, several of which are predicted to enc ...200717342200
proteome analysis of rickettsia felis highlights the expression profile of intracellular bacteria.the proteome of rickettsia felis, an obligate intracellular bacterium responsible for spotted fever, was analyzed using two complementary proteomic approaches: 2-de coupled with maldi-tof, and sds-page with nanolc-ms/ms. this strategy allowed identification of 165 proteins and helped to answer some questions raised by the genome sequence of this bacterium. we successfully identified potential virulence factors including two putative adhesins, four proteins of the type iv secretion system, four s ...200717385819
transposon insertion reveals prm, a plasmid of rickettsia monacensis.until the recent discovery of prf in rickettsia felis, the obligate intracellular bacteria of the genus rickettsia (rickettsiales: rickettsiaceae) were thought not to possess plasmids. we describe prm, a plasmid from rickettsia monacensis, which was detected by pulsed-field gel electrophoresis and southern blot analyses of dna from two independent r. monacensis populations transformed by transposon-mediated insertion of coupled green fluorescent protein and chloramphenicol acetyltransferase mark ...200717575002
prevalence of rickettsia infection in dogs from the urban and rural areas of monte negro municipality, western amazon, brazil.the present study evaluated the rickettsial infection among dogs living in the rural and urban areas of monte negro, state of rondônia, western brazilian amazon. canine sera were tested by the indirect immunofluorescence assay (ifa) using six rickettsial antigens: rickettsia bellii, rickettsia amblyommii, rickettsia rhipicephali, rickettsia rickettsii, rickettsia parkeri, and rickettsia felis. while the first three rickettsia species are known to occur in the study site, the latter three species ...200717627445
propagation of arthropod-borne rickettsia spp. in two mosquito cell lines.rickettsiae are obligate intracellular alphaproteobacteria that include pathogenic species in the spotted fever, typhus, and transitional groups. the development of a standardized cell line in which diverse rickettsiae can be grown and compared would be highly advantageous to investigate the differences among and between pathogenic and nonpathogenic species of rickettsiae. although several rickettsial species have been grown in tick cells, tick cells are more difficult to maintain and they grow ...200717766452
comparative microbiota of rickettsia felis-uninfected and -infected colonized cat fleas, ctenocephalides felis.fleas serve as arthropod vectors for several emerging and re-emerging infectious disease causing agents including, rickettsia felis. although the prevalence of r. felis infection in colonies of fleas has been examined, the influence of the r. felis infection on flea microbiota has not been investigated. we identified three colonies of cat fleas, ctenocephalides felis, with varying prevalence of r. felis infection (louisiana state university (lsu), 93.8%; professional laboratory and research serv ...200718043659
plasmids of the prm/prf family occur in diverse rickettsia species.the recent discoveries of the prf and prm plasmids of rickettsia felis and r. monacensis have contravened the long-held dogma that plasmids are not present in the bacterial genus rickettsia (rickettsiales; rickettsiaceae). we report the existence of plasmids in r. helvetica, r. peacockii, r. amblyommii, and r. massiliae isolates from ixodid ticks and in an r. hoogstraalii isolate from an argasid tick. r. peacockii and four isolates of r. amblyommii from widely separated geographic locations cont ...200818065613
rickettsia infection in five areas of the state of são paulo, brazil.this study investigated rickettsial infection in animals, humans, ticks, and fleas collected in five areas of the state of são paulo. eight flea species (adoratopsylla antiquorum antiquorum, ctenocephalides felis felis, polygenis atopus, polygenis rimatus, polygenis roberti roberti, polygenis tripus, rhopalopsyllus lugubris, and rhopalopsyllus lutzi lutzi), and five tick species (amblyomma aureolatum, amblyomma cajennense, amblyomma dubitatum, ixodes loricatus, and rhipicephalus sanguineus) were ...200718094887
rickettsia fells in chile. 200718217575
rickettsia felis in ctenocephalides felis from argentina.this article reports on the detection of rickettsia felis in argentina in ctenocephalides felis fleas collected from a dog and analyzed by polymerase chain reaction (pcr) amplification and dna sequencing.200818279005
characterization and growth of polymorphic rickettsia felis in a tick cell line.morphological differentiation in some arthropod-borne bacteria is correlated with increased bacterial virulence, transmission potential, and/or as a response to environmental stress. in the current study, we utilized an in vitro model to examine rickettsia felis morphology and growth under various culture conditions and bacterial densities to identify potential factors that contribute to polymorphism in rickettsiae. we utilized microscopy (electron microscopy and immunofluorescence), genomic (pc ...200818359823
rickettsia felis in fleas, france. 200818394302
identification of rickettsia felis in the salivary glands of cat fleas.rickettsia felis, a flea-associated rickettsial pathogen, has been identified in many tissues, including the digestive and reproductive tissues, within the cat flea, ctenocephalides felis. we utilized transmission electron microscopy and polymerase chain reaction to identify r. felis in the salivary glands of fed fleas and further define the distribution of r. felis within the arthropod host. we identified rickettsia-like organisms in salivary glands using electron microscopy. sequence analysis ...200818399779
molecular identification of rickettsia felis in ticks and fleas from an endemic area for brazilian spotted fever.rickettsioses are arthropod-borne diseases caused by parasites from the order rickettsiales. the most prevalent rickettsial disease in brazil is brazilian spotted fever (bsf). this work intends the molecular detection of those agents in ectoparasites from an endemic area of bsf in the state of espírito santo. a total of 502 ectoparasites, among them amblyomma cajennense, amblyomma dubitatum (a. cooperi), riphicephalus sanguineus, anocentor nitens and ctenocephalides felis, was collected from dom ...200818425272
variations of plasmid content in rickettsia felis.since its first detection, characterization of r. felis has been a matter of debate, mostly due to the contamination of an initial r. felis culture by r. typhi. however, the first stable culture of r. felis allowed its precise phenotypic and genotypic characterization, and demonstrated that this species belonged to the spotted fever group rickettsiae. later, its genome sequence revealed the presence of two forms of the same plasmid, physically confirmed by biological data. in a recent article, g ...200818509454
rickettsia felis as emergent global threat for humans.rickettsia felis is an emergent pathogen belonging to transitional group rickettsiae. first described in 1990, r. felis infections have been reported to occur worldwide in fleas, mammals, and humans. because clinical signs of the illness are similar to those of murine typhus and other febrile illnesses such as dengue, the infection in humans is likely underestimated. r. felis has been found throughout the world in several types of ectoparasites; cat fleas appear to be the most common vectors. r. ...200818598619
prevalence and infection load dynamics of rickettsia felis in actively feeding cat fleas.rickettsia felis is a flea-associated rickettsial pathogen recurrently identified in both colonized and wild-caught cat fleas, ctenocephalides felis. we hypothesized that within colonized fleas, the intimate relationship between r. felis and c. felis allows for the coordination of rickettsial replication and metabolically active periods during flea bloodmeal acquisition and oogenesis.200818665265
[use of quantitative measures of gene order similarity to phylogenetic reconstructions (exemplified by bacteria of the genus rickettsia)].data reflecting evolutionary changes in chromosomal gene order can be used for phylogenetic reconstructions along with the results of nucleotide sequence comparison. by the example of bacteria of the genus rickettsia, we have shown that phylogenetic reconstructions based on quantitative estimates of the similarity and cladistic analysis of gene order data, may, in some cases, amend and fill up classical phylogenetic trees. when applied, these approaches enabled us to substantiate the hypothesis ...200818666548
rickettsia felis in fleas, germany.among 310 fleas collected from dogs and cats in germany, rickettsia felis was detected in all specimens (34) of archaeopsylla erinacei (hedgehog flea) and in 9% (24/226) of ctenocephalides felis felis (cat flea). r. helvetica was detected in 1 ceratophyllus gallinae (hen flea).200818680660
prevalence of rickettsia species antibodies and rickettsia species dna in the blood of cats with and without fever.rickettsia species antibodies have been detected in some cats but it is unknown whether infected cats develop clinical signs. the prevalence of rickettsia species deoxyribonucleic acid (dna) in blood from clinically ill cats has not been determined. the objective of this study was to determine if cats with fever (body temperature >or=102.5 degrees f [39.2 degrees c]) were more likely to have evidence of rickettsial infection than healthy, age-matched, control cats with a body temperature<102.5 d ...200918786845
rickettsia typhi and r. felis in rat fleas (xenopsylla cheopis), oahu, hawaii.rickettsia typhi (prevalence 1.9%) and r. felis (prevalence 24.8%) dna were detected in rat fleas (xenopsylla cheopis) collected from mice on oahu island, hawaii. the low prevalence of r. typhi on oahu suggests that r. felis may be a more common cause of rickettsiosis than r. typhi in hawaii.200818826827
human case of rickettsia felis infection, taiwan. 200819046543
bartonella spp. and rickettsia felis in fleas, democratic republic of congo. 200819046544
short report: rickettsia felis outer membrane protein a: a potential tool for diagnosis of patients with flea-borne spotted fever.rickettsia felis infection in humans has been detected worldwide, causing an illness that could be confused with other viral and bacterial infections such as dengue fever. despite the high incidence of infection in humans, reservoirs, and vectors, the definitive diagnosis of r. felis infection currently requires polymerase chain reaction and sequencing because its antigens are closely related to other rickettsiae, making serologic diagnosis problematic. in this work, we report the immune reactiv ...200819052301
the prevalence of bartonella, hemoplasma, and rickettsia felis infections in domestic cats and in cat fleas in ontario.the prevalence of persistent bacteremic bartonella spp. and hemoplasma infections was determined in healthy pet cats in ontario. blood samples from healthy cats sent to a diagnostic laboratory for routine health assessment over the course of 1 y were tested for bartonella spp. using both polymerase chain reaction (pcr) and blood culture, and for the presence of hemoplasma by pcr. the overall prevalence of bartonella spp. by pcr and by culture combined was 4.3% (28/646) [3.7% (24/646) bartonella ...200819086373
rickettsia felis in cat fleas in taiwan.we describe the first detection of rickettsia felis in cat fleas (ctenocephalides felis) in taiwan. natural infections of r. felis in cat fleas were isolated and confirmed using polymerase chain reaction (pcr) and an immunofluorescence assay. the infection rate in individual fleas and the minimum infection rate in pooled fleas detected by the pcr method were found to be 18.8% (13/69) and 8.2% (8/97), respectively. partial sequences of the plasmid prf, 17-kda antigen, and outer membrane protein a ...200919125661
rickettsia rickettsii, rickettsia felis and rickettsia sp. twkm03 infecting rhipicephalus sanguineus and ctenocephalides felis collected from dogs in a brazilian spotted fever focus in the state of rio de janeiro/brazil. 200919298400
Displaying items 1 - 100 of 287