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passive transfer of antibody to ehrlichia risticii protects mice from ehrlichiosis.mice that recovered from ehrlichia risticii infection were immune to a challenge dose of 100 50% lethal doses. immune or normal mouse serum was passively transferred to mice challenged with e. risticii. clinical signs of ehrlichiosis were completely prevented in 22 of 24 recipients of immune serum, and the onset of signs of illness was delayed in the remaining two mice compared with the onset of illness in 24 of 24 recipients of nonimmune serum. purified immunoglobulin g (igg) was used to passiv ...19912037365
infectious diseases. 19912041125
[human infection by ehrlichia canis in spain?]. 19912041392
ehrlichiosis.ehrlichiae are tick-borne rickettsial organisms that are well known as veterinary pathogens. however, since 1986, over 100 cases of human infection by ehrlichia canis or a closely related species have been identified primarily in the southeastern and south central united states. human ehrlichiosis is characterized by high fever, rigors, headache, myalgia, anorexia, and, sometimes, gastrointestinal complaints. rash occurs in a minority of cases. commonly observed laboratory abnormalities include ...19912051014
human ehrlichiosis. 19912054119
[canine ehrlichiosis in senegal: human and canine seroepidemiological survey in dakar].since 1986, several cases of human ehrlichiosis due to ehrlichia canis have been reported in the u.s.a. suspecting a pathology transmissible from dog to man the authors conducted an epidemiologic survey in an ehrlichiosis zone in senegal on a population of 42 men and 66 dogs. in 1987, this rickettsiosis accounted for the deaths of a good half of the military dogs stationed in dakar. yet two years after implementing a prophylactic policy the seroprevalence rate in the kennel dropped from 53% to 1 ...19912072850
cowdria ruminantium is recognized by a monoclonal antibody directed against the major outer membrane protein of chlamydia trachomatis.the relationship between cowdria ruminantium and chlamydia trachomatis was studied by immunofluorescence. a monoclonal antibody directed against the major outer membrane protein of c. trachomatis recognized rickettsial colonies of c. ruminantium in infected goat brain. no specific fluorescence was observed in non-infected brain. two commercial chlamydia-specific monoclonal antibodies as well as polyvalent anti-chlamydia rabbit serum recognized c. trachomatis, but did not recognize cowdria. moreo ...19911712142
serologically atypical canine ehrlichiosis associated with ehrlichia risticii "infection". 19911752762
isolation and characterization of an ehrlichia sp. from a patient diagnosed with human ehrlichiosis.a new disease was recognized in the united states in 1986. the etiologic agent, although not previously isolated from a human, appeared to be serologically related to ehrlichia canis, a canine leukotropic rickettsia. we obtained blood specimens from 27 febrile patients with a history of tick exposure. leukocytes from 24 patients not treated with tetracycline were placed onto a monolayer of dh82 cells. we performed indirect immunofluorescence on sera from all 27 febrile patients as well as sera f ...19911757543
rickettsiae and borrelia burgdorferi in ixodid ticks.nymphs and adults of hard-bodied ticks were collected in connecticut and tested by direct and indirect immunofluorescence staining methods for rickettsiae and borrelia burgdorferi. of the 609 ixodes dammini ticks examined, 59 (9.7%) harbored rickettsialike microorganisms in hemocytes (blood cells). these bacteria reacted with fluorescein-conjugated antiserum to ehrlichia canis, the etiologic agent of with fluorescein-conjugated antiserum to ehrlichia canis, the etiologic agent of canine ehrlichi ...19911757551
ehrlichia chaffeensis, a new species associated with human ehrlichiosis.the bacterial 16s rrna genes from blood samples of two patients with human ehrlichiosis and from an isolate recovered from one of the patients were amplified by using the polymerase chain reaction. the amplimers were then cloned and sequenced. the 16s rrna gene sequence was also determined for ehrlichia canis (two strains), e. equi, e. phagocytophila (two strains), and e. sennetsu (two strains). these sequences, along with a previously published 16s rrna gene sequence of e. risticii, were compar ...19911757557
a cloned dna probe identifies cowdria ruminantium in amblyomma variegatum ticks.heartwater, caused by cowdria ruminantium and transmitted by ticks of the genus amblyomma, is a constraint to ruminant animal production in sub-saharan africa. this rickettsial disease could spread from endemically infected areas of sub-saharan africa and certain caribbean islands to other countries, including the united states, in which amblyomma ticks exist. to detect c. ruminantium in tick vectors and animals, we made dna probes from c. ruminantium dna isolated from endothelial cell cultures. ...19911774264
isolation and continuous culture of neorickettsia helminthoeca in a macrophage cell line.experimental evidence is presented supporting the development of a system for the isolation and propagation of a neorickettsia sp. in a continuous canine macrophage cell line (dh82). to isolate a neorickettsia sp. pathogenic to the canine species, three naive dogs were fed metacercaria-encysted kidneys of salmon caught in a river where infection of metacercariae with neorickettsia helminthoeca has been circumstantially known for decades. clinically, the classic course of salmon poisoning disease ...19911774317
cross-reacting antigens between neorickettsia helminthoeca and ehrlichia species, shown by immunofluorescence and western immunoblotting.dogs orally infected with neorickettsia helminthoeca developed immunoglobulin g titers against erlichia risticii, erlichia sennetsu, and erlichia canis similar to those against n. helminthoeca antigen, as determined by immunofluorescence. western immunoblotting showed that the major common antigens shared among the microorganisms were 80- or 78-kda and 64-kda polypeptides. in contrast, horse anti-e. risticii and anti-e. sennetsu and dog anti-e. canis sera reacted more weakly to n. helminthoeca a ...19911774330
equine monocytic ehrlichiosis (potomac horse fever): a review.in the late 1970s, a new infectious disease in horses, involving acute enteritis, was recognised in the potomac river area of maryland, u.s.a. the causative agent was identified subsequently as a new species of rickettsial organism, later named ehrlichia risticii. since then, the disease has been reported in many other states, and in enzootic areas vaccination is common. signs associated with the clinical disease included depression, fever, anorexia, decreased or absent intestinal sounds, profus ...19911778155
the tick-borne rickettsia cowdria ruminantium has a chlamydia-like developmental cycle.the development of the tick-borne rickettsial pathogen cowdria ruminantium (s stock) was studied in bovine umbilical endothelial (bue) cell cultures and in goat choroid plexus, by light- and electron microscopy. cowdria divided by binary fission within intracytoplasmic vacuoles resulting in large colonies of reticulate bodies. after three to four days in culture, reticulate bodies developed into smaller intermediate bodies characterized by an electron-dense core. shortly before disruption of the ...19911780122
pulmonary aspergillosis associated with acute enteritis in a horse.invasive pulmonary aspergillosis was detected at postmortem examination of an 8-year-old quarter horse mare that had a history of diarrhea, laminitis, and bilateral nasal discharge. a diagnosis of ehrlichia risticii infection was made on the basis of clinical signs of diarrhea and pyrexia, high serum antibody titer to e risticii (1:2,560), and multiple salmonella-negative cultures obtained from fecal and colonic specimens. possible pathogenic mechanisms contributing to the development of pulmona ...19911787116
a modification of the indirect immunofluorescence test for detection of ehrlichia phagocytophila antibodies.a modified technique for production of antigen and performance of the test is described. a suspension of infected neutrophils was directly applied to multiwell slides. multichannel pipettes may be used for dilution and application of sera. the modification increases the capacity both by production of the antigen and by performance of the test. this paper also gives a quantitative determination of the antibodies.19911818509
lack of cross-protection between cowdria ruminantium and ehrlichia phagocytophila.antigenically distinct stocks of cowdria ruminatium from senegal and south africa were compared with a dutch isolate of ehrlichia phagocytophila in cross-immunity trials in goats. there was a complete absence of cross-immunity between e. phagocytophila and c. ruminantium, despite previous observations that both rickettsial organisms have certain antigenic determinants in common.19911843823
[equine monocytic ehrlichiosis (eme), a review].serological surveys showed that equine monocytic ehrlichiosis (eme) occurs in the usa, canada and europe. the causative agent is rickettsia ehrlichia risticii, isolated for the first time in 1984. the clinical features of the disease are sluggishness, anorexia, colic and fever, possibly followed by watery diarrhoea. complications of an infection with e. risticii are laminitis and abortion. colitis of the ascending colon may be observed at autopsy. following a positive serological diagnosis (igm ...19911862502
ehrlichia. 19911865539
competitive enzyme-linked immunosorbent assay for heartwater using monoclonal antibodies to a cowdria ruminantium-specific 32-kilodalton protein.hybridomas producing monoclonal antibodies (mab) to cowdria ruminantium were raised. four mabs of the igg isotype reacted in western blots with a 32-kilodalton cowdria protein (cr32), which had previously been shown to be conserved and immunodominant. a fifth mab of the igm isotype recognized a 40-kda cowdria protein. the latter mab was negative in an indirect fluorescent antibody test (ifa), whereas the other four were positive. mab no. 4f10b4 showed the strongest signal in western blots using ...19911871954
protection against murine potomac horse fever by an inactivated ehrlichia risticii vaccine.ehrlichia risticii propagated in a murine macrophage cell line were freed from the host cell by hypotonic lysis of the infected cells. the cell-free ehrlichiae were inactivated with beta-propiolactone and combined or not combined with polymyxin-b. the vaccines were administered to mice with quil-a (saponin) as an adjuvant twice at 2 to 3 week intervals and the mice were challenged with live e. risticii 2 to 3 weeks after the last vaccination. with or without the addition of polymyxin-b, the vacc ...19911882507
epidemiology of rickettsial diseases.rickettsial diseases have a diversity of epidemiologic characteristics reflective of the variety of ecologic situations in which the obligate intracellular bacteria are transmitted to humans. for the spotted fever group (sfg) rickettsiae, rickettsia typhi, r. tsutsugamushi, coxiella burnetii, and the human ehrlichial agent, humans are a dead-end host who plays no role in the maintenance of the organism in nature. all rickettsioses exist as zoonoses. moreover, all rickettsiae are found in infecte ...19911884775
an overview of research on ehrlichiosis.ehrlichiosis is a disease caused by a group of rickettsiae, known as ehrlichiae, which parasitize circulating leukocytes of man and a variety of domestic and wild animals. a characteristic morphologic feature of ehrlichiae is their occurrence in membrane-bound vacuoles in the cytoplasm of leukocytes, forming inclusions that contain variable numbers of organisms. the tick is the apparent vector of ehrlichiae, but such evidence is not available for all species.19911884776
biology of ehrlichiae.the isolation and cultivation of the agent of potomac horse fever, ehrlichia risticii, by holland, ristic, et al., afforded weisburg et al. an opportunity to examine its phylogeny. e. risticii is clearly related to the genus rickettsia and not to chlamydiae. a reevaluation of the significance of phenotypic characteristics is thus required, since ehrlichiae, in some respects, resemble chlamydiae. for example, unlike rickettsiae, ehrlichiae and chlamydiae multiply in the phagosome of their host ce ...19911884777
the tribe ehrlichieae and ehrlichial diseases.the tribe ehrlichieae consists of gram-negative minute cocci that are obligate intracellular parasites classified in the family rickettsiaceae. although ehrlichial organisms have been observed in leukocytes for many years, only a few species have been cultured in quantities sufficient for biochemical and molecular analyses. recents studies on 16s-rrna sequence analysis and energy metabolism showed that the genus ehrlichia is closely related to the genus rickettsia. there is, however, no antigeni ...19911889044
identification of ehrlichia in human tissue. 19911891018
antigenic diversity of cowdria ruminantium isolates determined by cross-immunity.antigenic diversity in five stocks of the tick-borne rickettsia cowdria ruminantium, the causal agent of heartwater disease of ruminants, was studied by cross-immunity trials in goats and sheep. complete absence of cross-protection was found only between the kümm and kwanyanga stocks, and in all other combinations there were various degrees of cross-immunity. immunological strain differences were more pronounced in goats than in sheep.19911896626
human ehrlichiosis diagnosed in wisconsin.a man developed a febrile illness shortly after he returned to wisconsin from florida, where he had received tick bites. this illness was associated with a rash, thrombocytopenia, leukopenia, and elevated hepatic enzymes, and it resolved on doxycycline. serologic studies confirmed ehrlichiosis, a tick-borne rickettsial intraleukocytic infection endemic to the southeastern united states. this case expands the spectrum of tick-borne illnesses that must be considered by wisconsin clinicians.19911897237
neurologic manifestations of trypanosomiasis in a dog.a 13-month-old doberman pinscher was evaluated because of slowly progressive paraparesis and signs of depression. the dog had temporal, supraspinatus, and infraspinatus muscle atrophy, bilateral enophthalmos, superficial inguinal lymphadenopathy, tachycardia with pulse deficits, and lesions of active and inactive chorioretinitis. neurologic abnormalities included hyperreflexic patellar reflexes, lack of conscious proprioception, signs of superficial pain in the hind limbs, and depressed hopping ...19911899857
some contributions of electron microscopy to the study of the rickettsiae.electron microscopy has provided valuable insights into the study of rickettsiae as intracellular parasites from several important perspectives. this tool has allowed researchers to delineate the fine structural features of these organisms and to show that they truly resemble free-living bacteria. furthermore, it has been shown that there are subtle, but distinct differences in the outer envelope structure of some members of the genus rickettsia that may explain reported differences in tinctoria ...19911909242
inhibition of ehrlichia risticii infection in murine peritoneal macrophages by gamma interferon, a calcium ionophore, and concanavalin a.ehrlichia risticii incubated with mouse peritoneal macrophages elicited with thioglycolate broth survived and replicated, thereby allowing examination of the effects of several immunopotentiating agents. treatment of the macrophages with recombinant murine gamma interferon (rmuifn-gamma) in vitro at 1 day before or 3 h after infection made the macrophages resistant to infection with e. risticii, and macrophages treated with rmuifn-gamma at 1 to 3 days after infection developed the capacity to er ...19911910000
immunocytochemical detection of ehrlichia platys antigens in canine blood platelets.an avidin-biotin immunoperoxidase complex (abc) immunocytochemical (icc) stain procedure was optimized for detection of ehrlichia platys antigens. positive immunoreactivity was detected with dilutions of canine immune serum on acetone-fixed smears of platelet-rich plasma from e. platys-infected dogs. no e. platys antigens were detected when this icc stain was applied to frozen or paraffin-embedded formalin- or acetone-fixed tissue sections from dogs with acute e. platys infection. acetone fixati ...19911911994
canine ehrlichiosis in six dogs with persistently increased antibody titers.chronic ehrlichiosis was diagnosed in six dogs on the basis of increased immunofluorescent antibody titers to ehrlichia canis. although clinical signs varied, all six dogs were anemic, hyperglobulinemic, and an igg monoclonal gammopathy was documented in five dogs in which serum protein electrophoreses were performed. all dogs were treated with tetracycline for at least 14 days; four dogs also received immunosuppressive drugs. clinical signs resolved within 1 week, hematologic abnormalities reso ...19911920256
t cell-mediated immunity to cowdria ruminantium in mice: the protective role of lyt-2+ t cells.the inability of athymic nude mice to make a drug-aided recovery from infection with either the kümm or the welgevonden stocks of cowdria ruminantium and their inability to mount an immune response, suggest that immunity in heartwater is cell-mediated. the adoptive transfer of immunity with the spleen cells of mice immune to the welgevonden stock is supportive evidence. immune spleen cells depleted of lyt-2+ t cells are unable to confer resistance to challenge to recipient mice, whereas the depl ...19911923379
ultrastructural morphology of cowdria ruminantium in midgut epithelial cells of adult amblyomma hebraeum female ticks.amblyomma hebraeum male and female ticks, experimentally infected as larvae with the ball 3 stock of cowdria ruminantium, were fed on a heartwater susceptible sheep. the initial attachment of the males was required as a pre-requisite for female attachment. reticulate bodies were the predominant morphologic form of cowdria observed in gut epithelial cells after 1-3 days of feeding. single intermediate bodies and no elementary bodies were observed. organisms were found within a membrane-bound vacu ...19911923381
antigenic analysis of four species of the genus ehrlichia by use of protein immunoblot.the antigenic profile of ehrlichia canis, e risticii, e sennetsu, and e equi was investigated by the use of protein (western) immunoblot technique. results of analysis of serum from acutely and chronically infected animals indicated that the 4 ehrlichia species share a unique 25-kd polypeptide in addition to other peptides. immune sera from dogs inoculated with e canis recognized a wide range of e canis polypeptide antigens, as determined by western blot analysis. a larger number of e sennetsu p ...19911928904
diagnostic application of polymerase chain reaction for detection of ehrlichia risticii in equine monocytic ehrlichiosis (potomac horse fever).genomic amplification by the polymerase chain reaction (pcr) was used to identify a unique genomic sequence of ehrlichia risticii directly in dna isolated from peripheral-blood buffy coat cells of e. risticii-infected horses (potomac horse fever) and from infected cell cultures. a specific primer pair, selected from a cloned, species-specific, 1-kb dna fragment of the e. risticii genome as a template, was used for the amplification of the target dna of 247 bp. the optimal number of 40 pcr cycles ...19911939575
hemophagocytic syndrome: a cause of pancytopenia in human ehrlichiosis.a 67-year-old white man with human ehrlichiosis infection complicated by pancytopenia, hemophagocytic syndrome, disseminated intravascular coagulopathy and septic shock is presented. the patient had been on a three-week camping trip to california, colorado, utah, and new mexico. the diagnosis of human ehrlichiosis was confirmed by sixteen-fold rise in antibody titer to ehrlichia canis, and supported by the characteristic cytoplasmic inclusions. human ehrlichiosis should be considered in the diff ...19911951324
evaluation of rhipicephalus sanguineus as a potential biologic vector of ehrlichia platys.the brown dog tick, rhipicephalus sanguineus (acari: ixodidae), transmits several diseases among dogs including ehrlichia canis infection. the role of rhipicephalus sanguineus as a biologic vector for e platys, the rickettsial agent of infectious canine cyclic thrombocytopenia, was studied in dogs. laboratory-cultured, pathogen-free nymph ticks were fed to repletion on dogs acutely infected with e platys. tick engorgement coincided with the development of initial parasitemia and thrombocytopenia ...19911952347
human pathogenicity of ehrlichia canis. 19911674051
first european case of ehrlichiosis. 19911679172
lymphocyte subpopulations in peripheral blood of sheep experimentally infected with tick-borne fever.the lymphocyte subpopulations in the peripheral blood of normal sheep and sheep experimentally infected with cytoecetes phagocytophila, the causative agent of tick-borne fever, were analysed by flow cytometry, using a panel of monoclonal antibodies against specific lymphocyte epitopes. experimental infection with tick-borne fever was characterised by a significant reduction in the total number of circulating lymphocytes six days after experimental infection (p less than 0.001). this lymphocytope ...19911680243
natural and experimental canine infections with a greek strain of ehrlichia platys. 199112673539
identification of the protective 44-kilodalton recombinant antigen of ehrlichia risticii.protective studies were conducted with mice by using recombinantly produced antigens, polyacrylamide gel electrophoresis-fractionated antigens, and a monoclonal antibody specific to the 28-kda antigen of ehrlichia risticii. analysis of e. risticii-infected cell culture used as the challenge inoculum indicated an inverse relationship between the progression of cell culture infection and the infective capability of e. risticii for mice. a recombinant 44-kda antigen was found to protect mice consid ...19921730496
analyses of ehrlichia canis and a canine granulocytic ehrlichia infection.ehrlichia canis and canine granulocytic ehrlichia sp. (cge) infect canine monocytes and granulocytes, respectively. e. canis has been cultured in vitro and used to develop an immunofluorescence assay. cge has not been cultured, and a serologic assay is not available. the sera of dogs infected with cge were reported to react with e. canis by immunofluorescence. in this study, the temporal response of immunoglobulin g (igg) was determined by an enzyme-linked immunosorbent assay (elisa) with purifi ...19921734046
antigenic and genomic relatedness among ehrlichia risticii, ehrlichia sennetsu, and ehrlichia canis.antigenic and genomic relatedness among ehrlichia risticii, e. sennetsu, and e. canis was analyzed by enzyme-linked immunosorbent assay, western blotting (immunoblotting) and dna-dna hybridization. e. risticii and e. sennetsu were serologically related, and their western blot antigen profiles were nearly identical. two antigens of e. sennetsu corresponding to the 28- and 51-kda antigens of e. risticii were apparently larger than the e. risticii antigens, and the 55-kda antigen of e. risticii app ...19921736961
detection of the etiologic agent of human ehrlichiosis by polymerase chain reaction.polymerase chain reaction (pcr) primers derived from a variable region of the 16s rrna gene sequence were used to amplify dna specifically from ehrlichia chaffeensis (the recently proposed name for the etiologic agent of human ehrlichiosis). the 389-bp product defined by the specific primers was not detected when dna samples from any of the other recognized species of ehrlichia were used as amplification templates. when the pcr was applied to five suitable blood specimens obtained from patients ...19921374076
phylogenetic position of cowdria ruminantium (rickettsiales) determined by analysis of amplified 16s ribosomal dna sequences.the 16s ribosomal dna sequence of cowdria ruminantium, the causative agent of heartwater disease in ruminants, was determined. an analysis of this sequence showed that c. ruminantium forms a tight phylogenetic cluster with the canine pathogen ehrlichia canis and the human pathogen ehrlichia chaffeensis. although a close relationship between the genus cowdria and several members of the tribe ehrlichieae has been suspected previously, the tight phylogenetic cluster with e. canis and e. chaffeensis ...19921380292
experimental transmission of cowdria ruminantium (rickettsiales) by the american reptile tick amblyomma dissimile koch, 1844.a senegalese isolate of the rickettsia cowdria ruminantium was transmitted transstadially by nymphs of the american reptile tick amblyomma dissimile. only eight nymphs, fed as larvae on a saanen goat reacting to heartwater, were required to transmit fatal heartwater to another susceptible goat. since a. dissimile usually feeds on snakes, iguanas and lizards in central america, the tick is not considered to play a significant role in the transmission of heartwater between ruminants. however, the ...19921395974
attempted mechanical transfer of ehrlichia risticii by tabanids (diptera: tabanidae).the ability of tabanid mouthparts to retain and to transfer mechanically ehrlichia risticii holland, weiss, burgdorfer, cole & kakoma was evaluated by feeding flies on infected and noninfected mice and on capillary tubes containing infected cells and cell-free medium. flies representing two genera and 29 species were collected at equine boarding stables, farms, and along riding trails in wake, johnston, and duplin counties in north carolina for the feeding trials. two species, tabanus fulvulus w ...19921404259
[ehrlichiosis in dogs: literature review and case description].a case of e. canis in a 7 year old intact female bearded collie is described and possible clinical signs of ehrlichiosis are discussed. non-specific findings included elevated rectal temperature, depression and anorexia. additional findings were generalized lymphadenomegaly, myalgia and painful swollen joints. significant changes in the cbc were leucopenia and thrombocytopenia. the positive e. canis titer of 1:40 and rising titer to 1:160 were specific for ehrlichiosis. doxycycline and prednisol ...19921411420
a cluster of tick-borne infections: association with military training and asymptomatic infections due to rickettsia rickettsii.during the spring of 1989, 86 members of a military unit from the state of maryland, usa, participated in two-week-long training manoeuvres in the states of arkansas (location fc) and virginia (location faph). acute febrile illnesses due to infections with two tick-borne pathogens, rickettsia rickettsii and ehrlichia sp., were confirmed serologically in 2 initial cases who were admitted to the hospital. a seroepidemiological investigation among unit members found an additional 17 of 109 individu ...19921412666
isolation of ehrlichia risticii from the aborted fetus of an infected mare. 19921441154
development and persistence of cowdria ruminantium specific antibodies following experimental infection of cattle, as detected by the indirect fluorescent antibody test.different breeds of cattle were experimentally infected with palm river, a zimbabwean isolate, or ball-3, a south african isolate of cowdria ruminantium, derived from tissue culture or tick or blood stabilates. c. ruminantium specific antibody responses were detected by an indirect fluorescent antibody test (ifat) using c. ruminantium-infected bovine aortic endothelial (bae) cell cultures as antigen. the first detection of antibodies to c. ruminantium generally coincided with the peak of the feb ...19921441219
comparison of the attachment rates of males of the ticks amblyomma hebraeum and a. variegatum to cattle, sheep and rabbits in the absence of aggregation-attachment pheromone.losses in domestic ruminants caused by heartwater (cowdria ruminantium infection) in zimbabwe and mozambique are greater when the vector is amblyomma hebraeum than when the vector is a. variegatum. it has been suggested that the epidemiology of the disease may be influenced by the rates at which unfed adults of these two tick species attach to uninfested hosts (i.e. in the absence of the male-produced aggregation-attachment pheromone [aap]). in this study we confined unfed males of a. hebraeum a ...19921446569
retrospective evaluation of factors associated with the risk of seropositivity to ehrlichia risticii in horses in new york state.a retrospective study was designed to determine the distribution of equine monocytic ehrlichiosis among the equine population in new york state, and to identify factors associated with risk of disease. serum samples submitted to the diagnostic laboratory of the university during the period from january 1985 through december 1986 were examined for antibodies to ehrlichia risticii, using the indirect fluorescent antibody technique. factors evaluated included geographic origin and date of submissio ...19921456543
effect of treatment with erythromycin and rifampin during the acute stages of experimentally induced equine ehrlichial colitis in ponies.sixteen healthy ponies were inoculated iv with ehrlichia risticii-infected p388d1 mouse monocytes. of the 16 ponies, 15 developed clinical signs of equine ehrlichial colitis. twenty-four hours after onset of fever (rectal temperature > 38.8 c), 7 ponies were treated with 25 mg of erythromycin stearate/kg of body weight and 10 mg of rifampin/kg, given orally every 12 hours for 5 days. the remaining 8 ill ponies served as nontreated controls. all ponies were observed for progression of clinical si ...19921466503
investigation of glomerular lesions in dogs with acute experimentally induced ehrlichia canis infection.six male beagles were inoculated with ehrlichia canis. transient proteinuria was confirmed during the acute phase of infection by serial determination of urinary protein-to-creatinine ratio. peak urine protein loss, consisting principally of albumin, was observed 2.5 to 3.5 weeks after inoculation. renal biopsy specimens were obtained before inoculation, during peak proteinuria, and 10 weeks after inoculation when proteinuria had resolved. renal tissue was evaluated by use of light, immunofluore ...19921476309
effect of treatment with oxytetracycline during the acute stages of experimentally induced equine ehrlichial colitis in ponies.eighteen ponies were inoculated iv with ehrlichia risticii-infected p388d1 mouse monocyte cells. twenty-four hours after onset of fever (rectal temperature > 38.8 c), 9 ponies were treated with oxytetracycline (6.6 mg/kg of body weight, iv, q 24 h) for 5 days. the remaining 9 ponies served as infected nontreated controls. mean scores of the following variables were not significantly different between groups on the day treatment was begun: rectal temperature, diarrhea, borborygmal sounds, feed in ...19921476312
in vitro antibiotic susceptibility of the newly recognized agent of ehrlichiosis in humans, ehrlichia chaffeensis.ehrlichiosis in humans, a rickettsial disease recently discovered in the united states, is generally treated successfully with tetracyclines; however treatment with these agents is usually avoided with children and pregnant women. the in vitro susceptibility of ehrlichia chaffeensis, the agent of human ehrlichiosis in the united states, was assessed by a quantitative evaluation of infected dh82 cells cultivated in 96-well microtiter plates in the presence of different concentrations of selected ...19921482148
cluster of tick-borne infections at fort chaffee, arkansas: rickettsiae and borrelia burgdorferi in ixodid ticks.human intrusion into pristine habitats increases the likelihood of acquiring infectious agents from potentially infective ticks. as part of a larger human serological investigation into tick-borne illnesses, 3,000 ixodid ticks were collected during may, august, and november 1990 at fort chaffee, arkansas. ticks were examined to determine whether they harbor rickettsiae, ehrlichiae, and borrelia burgdorferi, and to assess relationship to human exposure to tick-borne infections at fort chaffee, ar ...19921495077
immunisation of cattle against theileriosis in nakuru district of kenya by infection and treatment and the introduction of unconventional tick control.one hundred and one cross european-boran cattle (50 cows and 51 calves), on a farm in nakuru district, kenya, were immunised against theileriosis using theileria parva lawrencei and theileria parva parva stocks from another district of kenya. the stabilates used were t.p.lawrencei (mara iii) used at 10(-1.7) dilution and t.p.parva (kilae) used at 10(-1.0) dilution. the stabilates were combined and inoculated simultaneously with a short-acting formulation of oxytetracycline hydrochloride given in ...19921496782
identification of ehrlichia chaffeensis morulae in cerebrospinal fluid mononuclear cells.we report a case of ehrlichiosis in a 72-year-old man who developed extreme lethargy, acute renal failure requiring hemodialysis, and respiratory insufficiency requiring intubation. lumbar puncture performed on the second day of hospitalization revealed significant cellular pleocytosis. ehrlichia morulae were tentatively identified in mononuclear cells in routinely processed wright-stained cytospin preparations of cerebrospinal fluid (csf). identification was confirmed by a specific immunocytoch ...19921500537
susceptibility of dogs to infection with ehrlichia chaffeensis, causative agent of human ehrlichiosis.ehrlichia chaffeensis, the newly recognized agent of human ehrlichiosis, is closely related to e canis, the causative agent of canine ehrlichiosis. eight pups were inoculated iv with e chaffeensis-, or with e canis-infected dh82 cells, or organisms released from these host cells. two additional pups served as nonexposed controls. marked thrombocytopenia was observed in the e canis-infected pups, but not in those infected with e chaffeensis. homologous serologic response was observed in the e cha ...19921510307
effects of ehrlichia phagocytophila infection on serum thyroid hormone concentrations and on antipyrine clearance and metabolite formation in dwarf goats.the influence of infection with ehrlichia phagocytophila (ep) on serum thyroid hormone concentrations and on antipyrine (25 mg/kg of body weight, iv) plasma elimination and urinary metabolite excretion was studied in castrated male dwarf goats. mean thyroid hormone concentrations moderately decreased in ep-infected goats, with maximal decrease in total and free triiodothyronine and thyroxine serum concentrations of 56, 64, 23, and 19%, respectively. the estimated pharmacokinetic values of antipy ...19921510311
adult amblyomma hebraeum burdens and heartwater endemic stability in cattle.several conclusions of importance to studies on the epidemiology of heartwater were drawn from an investigation in which the numbers of adult amblyomma hebraeum ticks, to which a closed herd of hereford cattle were exposed over a period of 6 1/2 years, were manipulated. with a tick cowdria ruminantium infection rate of 3-5%, an endemically stable situation was created by dipping the herd only when an average of 10 adult male and female a. hebraeum ticks were counted on 10 animals. when the avera ...19921513597
haematology of experimental babesiosis and ehrlichiosis in steroid immunosuppressed horses.an investigation was carried out to study the haematology of steroid immunosuppressed horses experimentally infected with babesia equi and ehrlichia equi, separately or simultaneously. horses infected with both pathogens showed less marked changes in their haematology than those inoculated with either pathogen separately. this appeared to result from early elimination of the more pathogenic babesia as ehrlichia spread through the granulocytes. the apparent suppression of babesia by ehrlichia is ...19921519411
etiologic agent of human ehrlichiosis. 19921528656
a case of human ehrlichiosis acquired in mali: clinical and laboratory findings.we report on the clinical, epidemiologic, and laboratory characteristics of the first case of human ehrlichiosis acquired outside the united states caused by an ehrlichia sp. other than e. sennetsu. the patient, a 24-year-old woman, presumably acquired the infection in mali in northern africa; the diagnosis was made when she returned to north america. the patient reported a fever and diarrhea a week before she left mali; the diarrhea resolved, but the fever and chills continued. she also reporte ...19921539750
evaluation of granulocytic ehrlichiosis in dogs of missouri, including serologic status to ehrlichia canis, ehrlichia equi and borrelia burgdorferi.canine granulocytic ehrlichiosis was diagnosed in 37 dogs by finding ehrlichial morulae in 0.1 to 26.2% of their blood neutrophils and eosinophils. all 37 dogs had clinical signs of arthritis or muscular stiffness. titer to ehrlichia canis was determined in sera from 31 of the 37 dogs; 25 dogs had titer ranging from 1:20 to 1:5,120. in the other 6 dogs, titer to e canis was less than 1:10. the most common hematologic abnormality in these dogs, other than rickettsiemia, was thrombocytopenia. gran ...19921539918
a cloned dna probe for cowdria ruminantium hybridizes with eight heartwater strains and detects infected sheep.the dna probe pcs20, which was cloned from the dna of the crystal springs heartwater strain from zimbabwe, cross-reacted with dnas of heartwater strains from all endemic areas, including four heartwater strains from zimbabwe, two strains from south africa, one strain from nigeria, and the gardel strain from the caribbean island of guadeloupe. by nucleic acid hybridization, the pcs20 dna probe detected cowdria ruminantium dna in all dna preparations made from plasma samples from infected sheep be ...19921572987
calcium crystal-associated arthropathy (pseudogout) in a dog.calcium pyrophosphate dihydrate (ca2p2o7.2h2o) crystal-associated arthropathy (pseudogout) was diagnosed in a dog. clinical signs included non-weightbearing lameness, signs of pain on joint manipulation, and high rectal temperature. arthrocentesis of carpal joints revealed extra- and intracellular crystals containing calcium. the suspected cause was polyarthritis secondary to chronic ehrlichia infection. results of joint tap performed after resolution of the clinical signs were negative for calc ...19921577646
phylogenetic relationship of cowdria ruminantium, agent of heartwater, to anaplasma marginale and other members of the order rickettsiales determined on the basis of 16s rrna sequence.the phylogenetic relationship between cowdria ruminantium and representative members of the orders rickettsiales and chlamydiales has been examined on the basis of the sequence of the 16s rrna. phylogeny reconstruction by using both parsimony and distance methods supports the conclusion that c. ruminantium is closely related to the rickettsiales and in particular to the family anaplasmataceae. a signature of nine base substitutions delineated the linkage of anaplasma marginale with c. ruminantiu ...19921581187
ehrlichia ewingii sp. nov., the etiologic agent of canine granulocytic ehrlichiosis.the 16s rrna gene was amplified, cloned, and sequenced from the blood of two dogs that were experimentally infected with the etiologic agent of canine granulocytic ehrlichiosis. the 16s rrna sequence was found to be unique when it was compared with the sequences of other members of the genus ehrlichia. the most closely related species were ehrlichia canis (98.0% related) and the human ehrlichiosis agent (ehrlichia chaffeensis) (98.1% related); all other species in the genus were found to be phyl ...19921581189
antigenic characterization of ehrlichiae: protein immunoblotting of ehrlichia canis, ehrlichia sennetsu, and ehrlichia risticii.in recent years a febrile illness apparently associated with tick bite in patients in the united states has been attributed to infection by an ehrlichia species. this implication is based on serologic responses to e. canis, morphologic demonstration of ehrlichiae in clinical materials, and a single isolate distinct from e. canis which was obtained from a human patient by the centers for disease control. little is known about the antigens of the ehrlichiae. this report expands the breadth of avai ...19921583101
resistance to tick-borne fever in young lambs.lambs were inoculated with ehrlichia phagocytophila infected blood at the age of either two or six weeks. the temperature response and degree of parasitaemia were both most pronounced in the lambs inoculated at six weeks old. the half-life of antibodies to e phagocytophila was estimated to be 17.5 days. lambs inoculated with tick-borne fever (tbf) had lower liveweights in the autumn than tbf-free controls.19921585079
infection with ehrlichia in childhood. 19921593364
investigation of renal protein loss in dogs with acute experimentally induced ehrlichia canis infection.urinary protein-to-creatinine ratios and serum albumin concentrations were measured in 8 adult male dogs experimentally inoculated with ehrlichia canis. urinary protein concentration increased significantly, but transiently, during the acute phase of infection. urinary protein-to-creatinine ratios were highest (mean, 8.6) during the third and fourth weeks after infection, and decreased to less than 0.5 by 6 weeks after infection. correspondingly, albumin concentration decreased significantly dur ...19921595954
absence of antibody to cowdria ruminatum in sera from humans exposed to vector ticks. 19921598655
human ehrlichiosis: a newly recognized tick-borne disease.human ehrlichiosis was first described in the united states in 1986. since then, more than 215 cases have been reported, including some fatalities. ehrlichia species belong to the same family as the organism that causes rocky mountain spotted fever. human ehrlichiosis occurs most frequently in the southern mid-atlantic and south-central states, during spring and summer months. the clinical presentation is similar to that seen in rocky mountain spotted fever although, with ehrlichiosis, leukopeni ...19921621632
the role of amblyomma variegatum in the transmission of heartwater with special reference to guadeloupe.heartwater has been diagnosed in guadeloupe, marie-galante, and antigua; it induces important losses among goats and european or cross-bred cattle when local zebu creole are highly resistant to infection. amblyomma variegatum is the vector of the disease in the caribbean. the tick strain of martinique, occurring in that island that has apparently been disease-free since 1948, has not lost its ability to experimentally transmit the disease. in guadeloupe 97% of nymphs and nearly 100% of adults fe ...19921626882
distribution of heartwater in the caribbean determined on the basis of detection of antibodies to the conserved 32-kilodalton protein of cowdria ruminantium.a competitive enzyme-linked immunosorbent assay (celisa) was developed to detect immunoglobulin g antibodies to the major 32-kda protein of cowdria ruminantium. a total of 1,804 serum samples collected from cattle on 19 islands in the eastern caribbean basin were tested by this celisa. a total of 133 serum samples from 10 islands (antigua, dominica, grenada, guadeloupe, martinique, montserrat, st. kitts, st. lucia, st. martin, and st. vincent) were found to be positive. the presence of antibodie ...19921629346
infection due to ehrlichia canis in children.human ehrlichiosis has a wide spectrum of presentation. this report presents two cases that demonstrate the diversity of the manifestation of ehrlichiosis, from life threatening to a mild viral-like illness. diagnosis requires an understanding of the epidemiology and clinical manifestation of this infection and a high index of suspicion.19921631682
suppression of ia antigen expression on gamma interferon treated macrophages infected with ehrlichia risticii.ehrlichia risticii is an obligate intracellular bacterium of monocytes/macrophages. in this report, using immunofluorescence staining, flow cytometry, and kolmogorov-smirnov analysis of histograms, the response of p338d1 and peritoneal macrophages stimulated with recombinant murine interferon-gamma (rifn-gamma) was examined for the expression of major histocompatibility complex class ii gene product (ia) and effect of e. risticii infection on induction of ia surface expression. maximal expressio ...19921632064
presence of parasite antigen on the surface of p388d1 cells infected with ehrlichia risticii.indirect immunofluorescence staining of macrophages infected with ehrlichia risticii by anti-e. risticii serum revealed a punctate staining pattern on the surface of the host cell. this pattern was distinguishable by fluorescence microscopy from e. risticii bound to the surface of the macrophage and from intracellular e. risticii. the surface localization of ehrlichial antigen on infected macrophages was confirmed by electron microscopy with immunoferritin labeling. as the intracellular ehrlichi ...19921639476
flow cytometric analysis of t cell response in mice infected with cowdria ruminantium.a 3-fold increase in the numbers of lyt-2+ t cells in the circulating blood of mice infected and re-infected with the welgevonden stock of cowdria ruminantium, as determined by flow cytometry, is supportive evidence that immunity in heartwater is cell-mediated. the rise in lyt-2+ cells only after re-infection of the mice is further evidence that the development of immunity in heartwater is dependent on the unhindered and adequate replication of c. ruminantium.19921297963
[asymptomatic carrier state in creole goats and cattle after recovery from cowdria infection in guadeloupe].creole goats and cattle in guadeloupe can be carriers of cowdriosis (heartwater: cowdria ruminantium) after recovery for a period as long as 11 months in goats and 2 months in cattle. the carrier status was demonstrated by feeding amblyomma variegatum nymphs on recovered animals and the resulting adult ticks on susceptible goats. cowdria ruminantium was not detected permanently during the carrier status.19921301623
ehrlichia canis infection in a child in south carolina. 19921319878
l-arginine-dependent killing of intracellular ehrlichia risticii by macrophages treated with gamma interferon.thioglycolate-induced murine peritoneal macrophages infected with ehrlichia risticii and treated in vitro with gamma interferon (ifn-gamma) developed antiehrlichial activity that eliminated the intracellular bacteria. this antiehrlichial activity was suppressed by ng-monomethyl-l-arginine, a competitive inhibitor of nitric oxide synthesis from l-arginine, but not by l-tryptophan. increased levels of nitrite, an oxidative product of nitric oxide, were measured in cultures of infected macrophages ...19921323533
loss of absorptive capacity for sodium and chloride in the colon causes diarrhoea in potomac horse fever.ehrlichia risticii, an obligate intracellular bacterium in the family rickettsiaceae, causes potomac horse fever which is often associated with severe watery diarrhoea. the mechanism of the diarrhoea is unknown. the aim of this study was to determine whether sodium and chloride transport, morphology and cyclic adenosine 3', 5'-monophosphate (cyclic amp) content of colonic mucosa was altered in e risticii-infected horses. mucosa-submucosa sheets from the large and small colon of nine infected and ...19921352409
detection of ehrlichia chaffeensis in human tissue by using a species-specific monoclonal antibody.a mouse monoclonal antibody (mab 1a9) was produced and used in detection of ehrlichia chaffeensis in human tissues including kidney, liver, and lung by using an indirect immunohistologic stain. mab 1a9 was specific to e. chaffeensis and did not react with other bacteria, including ehrlichia canis, which is the organism most closely related to e. chaffeensis. it reacted with an epitope present in two surface proteins of e. chaffeensis with molecular masses of 29 and 27 kda. e. chaffeensis was eas ...19937508458
role of interferons in infectious diseases in the bovine species: effect on viruses and rickettsias.successful protection was obtained with interferon treatment in experimental viral infections in the bovine species in a number of cases. the efficacy of the treatment against vaccinia virus infection and against rotavirus infection have been demonstrated. on the contrary, bovine herpes virus 1 (bhv 1-causing rhinotracheitis and part of the shipping fever complex) infections were not inhibited by interferon (ifn). the authors have undertaken a study in cattle in zimbabwe to assess the role of in ...19937510899
[epidemiology of cowdria infection in senegal. i. study of the transmission and infection level in amblyomma variegatum (fabricius, 1794) in the niayes region].the authors report the results of research on infection rates of amblyomma variegatum nympha and imago populations by cowdria ruminantium in the niayes region as well as on the transmission rates of a. variegatum by the various stases. the experiments were carried out on sheep from the sahelian zone where the vector tick is not endemic. the infection rate, estimated by inoculating sheep with ground ticks, gave the following prevalences: t = 13.3% for nymphae and t = 1.2% for adults. the transmis ...19938190980
[epidemiology of cowdria infection in senegal. ii. results of sero-epidemiological follow-up studies].the authors report the results of sero-epidemiological monitoring of zebu, diakoré and ndama cattle in the sahel, niayes and north guinea zones, respectively. calves aged 0-3 or 3-6 months were subjected to blood sampling every three months for a period of 20 months. in the niayes and north guinea zones, the immunofluorescence test showed that about 70% of 0-1 month old calves reacted positively to the cowdria ruminantium antigen, whereas the prevalence was 92% between 3 and 6 months. after the ...19938190981
western blot and indirect fluorescent antibody testing for antibodies reactive with ehrlichia canis in sera from apparently healthy dogs in zimbabwe.sera were collected from apparently healthy dogs in 3 major centres in zimbabwe to establish the prevalence of antibodies reactive with ehrlichia canis by indirect fluorescent antibody (ifa) testing at titres of 1/20 or greater. the overall seroprevalence was 42% (39/93) with dogs from mutare (40%) and harare (33%) having similar rates which were lower than those for bulawayo (68%). the majority of the ifa positive dogs from harare (67%) had no haematological or biochemical evidence of canine eh ...19938176682
use of serological response to evaluate heartwater immunization of cattle.frozen blood vaccine containing the ball 3 strain of cowdria ruminantium is prepared by an fao/danida project in malawi for the immunization of improved dairy cattle against heartwater. the immunogenicity of vaccine batches for cattle has been quantified and different regimens for immunization have been evaluated using indirect immunofluorescence to assess antibody responses. infected endothelial cells grown in culture are used as antigen. the proportion of animals responding serologically has v ...19938134634
the development of antibody to cowdria ruminantium in mice and its role in heartwater disease.dba/2 and balb/c mice were used as a model to study the immune responses to cowdria ruminantium. both strains of mice were inoculated with 1, 10 or 100 ld50 of the crystal springs strain of c. ruminantium. antibody to c. ruminantium started to develop in the second week post-inoculation and the titre of the antibody was dependent on the inoculation dose of c. ruminantium. the possible role of antibody in heartwater disease was studied by in vitro neutralization assays using both mouse sera and b ...19938134632
[ehrlichia and ehrlichiosis (leukocyte rickettsia and rickettsiosis)]. 19938067101
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