kinetics of antibody response to ehrlichia canis assayed by the indirect fluorescent antibody method.the kinetics of antibody production response to experimentally induced infection of dogs with ehrlichia canis was determined by ion-exchange and molecularsieve chromatography and by indirect fluorescent antibody (ifa) test. the first ifa antibody at 7 days after inoculation resided in immunoglobulin m (igm) and immunoglobulin a (iga) classes. at approximately 21 days after inoculation, the antibody was in igm, iga, and immunoglobulin g (igg) classes. thereafter, antibody concentrations continued ...197549162
clinico-pathological study of heartwater in goats.the clinico-pathological features of heartwater were studied in goats experimentally infected with a nigerian isolate of cowdria ruminantium. significant drop in haemoglobin values and marked leukopaenia caused by lymphopaenia and neutropaenia and a fall in total serum protein were observed during the course of the disease. a significant increase in the alpha-globulins and an apparent fall in the gamma-globulins also occurred. marked depletion of lymphocytes in the follicles of spleen and lymph ...197877071
electron microscopy of cowdria ruminantium infected reticulo-endothelial cells of the mammalian electron microscopic study of structures suspected to represent a possible developmental cycle of cowdria ruminantium in reticulo-endothelial cells of mice and ruminants is reported. after infection dense bodies increase in size and undergo division to form fragmented dense bodies. these in turn apparently sub-divide and become organized to give rise to mature "organisms". in none of these structures do limiting membranes separate the parasitic inclusions from the host cell cytoplasm. present ...1975171605
laboratory diagnosis of viral and other infectious diseases. 1976186928
canine ehrlichiosis: the role of the spleen in protection against the disease. 1979261003
tick-borne diseases of domestic animals in northern nigeria. ii. research summary, 1966 to 1976.during the first 10 years of its existence, the department of parasitology and entomology of the faculty of veterinary medicine, ahmadu bello university in zaria, nigeria, confirmed or described for the first time the occurrence of 25 different tick-borne parasites of domestic animals in the northern part of the country. most of these organisms occur as inapparent infections but may serve as complicating factors in any adverse host condition. the transmission of babesia bigemina by boophilus dec ...1977339447
immune response of ponies to experimental infection with ehrlichia equi.four ponies experimentally infected with ehrlichia equi developed substantial cell-mediated immune responses, as measured by the leukocyte migration-inhibition test. serum anti-e equi antibodies up to 1:1,280 were demonstrated by the indirect fluorescent antibody test. cell-mediated immune responses returned to a base-line value by day 200 after primary inoculation, but serum antibody titers persisted for at least 300 days after inoculation. two additional susceptible ponies, which were inoculat ...1978343663
platelet migration inhibtion as an indicator of immunologically mediated target cell injury in canine ehrlichiosis.a platelet migration inhibition test was devised to determine the presence of antiplatelet activity in serum collected from experimentally produced and natural cases of canine ehrlichiosis. the maximum platelet migration inhibition effect was observed during the acute phase of the disease and before the appearance of specific humoral antibody, measured by the indirect fluorescent-antibody test. platelet migration inhibition may be one of the earliest events leading to pancytopenia. in most cases ...1978352929
ehrlichiosis in wolves, dogs, and wolf-dog crosses.canine ehrlichiosis was diagnosed in wolves, dogs, and wolf-dog crosses at a small zoo in northcentral florida. five of 9 adult canids and all 8 pups confined to a common kennel died as a result of the infection. the epizootic was associated with a massive rhipicephalus sanguineus infestation. hematologic and pathologic findings in an adult wolf-dog cross that died were characteristic of canine ehrlichiosis. that animal and four other canids were seropositive for ehrlichia canis. no deaths occur ...1979521367
the detection of rickettsia-like microorganisms within the ovaries of female ixodes ricinus ultrastructural study of tick-borne fever (tbf)-infected ixodes ricinus ticks revealed the presence of rickettsia-like microorganisms within the ooplasm and the mitochondria of developing oocytes. these microorganisms are similar in appearance to the tbf agent and it is possible that although transovarial transmission of the tbf agent apparently does not occur, the rickettsiae are at least able to establish themselves in the ovaries of infected ticks.1979539071
the use of doxycycline in the treatment of canine ehrlichiosis.the use of doxycycline in the treatment of twenty dogs with canine ehrlichiosis is described. the drug was found to be effective even in cases which did not respond to treatment with oxytetracycline.1979553959
the transmission of canine ehrlichiosis to the wild dog lycaon pictus (temminck) and black-backed jackal canis mesomelas schreber.canine ehrlichiosis was successfully transmitted from the domestic dog to three wild dogs lycaon pictus and three black-backed jackals canis mesomelas. wild dogs showed symptoms of anorexia and depression as well as anaemia, leucopaenia and mild thrombocytopaenia. black-backed jackals were asymptomatic. morulae of ehrlichicia canis were found in peripheral blood smears from all experimental animals. the disease was also successfully transmitted from black-backed jackal to the domestic dog.1979553960
field experience with heartwater (cowdria ruminantium) in cattle.observations are reported on 2743 animals immunised against heartwater since 1958. the methods of immunisation and control of reactions are discussed. this procedure is not without risk and 0,83% of the animals died in spite of treatment. bos indicus breeds appear to have a greater resistance to heartwater and are relatively easy to immunise. of the box taurus breeds the south devon, the jersey and the charolais seem to be particularly susceptible. older animals and pregnant cows are considered ...1979553971
investigations on the natural and acquired resistance of cattle to artificial infection with cowdria ruminantium.sixty cattle, artificially immunized against c. ruminantium, were challenged 3, 6, 12 and 24 months later. levels of conglutinin were determined in pre-immunization serum samples. there appeared to be a relationship between the pre-infection levels of conglutinin and the susceptibility of the animals to heartwater: at the time of immunization 31 out of 60 cattle (51,6%) with levels in the low-titre range (1:100-1:160) showed a typical febrile response, whereas 29 (48,4%) with conglutinin levels ...1979553974
the haematology of experimentally-induced b divergens and e phagocytophila infections in splenectomised examination was made of the haematology of spenectomised calves experimentally infected with babesia divergens and ehrlichia phagocytophila, inoculated separately or simultaneously. animals infected with both pathogens had less marked changes in their haematology than those inoculated with either pathogen separately. this appeared to result from the early elimination of the more pathogenic babesia as ehrlichia spread through the granulocytes. the apparent suppression of babesia by ehrlichia w ...1977576085
the brown dog tick rhipicephalus sanguineus and the dog as experimental hosts of ehrlichia rhipicephalus sanguineus ticks efficiently transmitted ehrlichia canis to susceptible dogs for 155 days after detachment as engorged nymphs from a dog in the acute phase of ehrlichiosis. adult ticks that had similarly engorged on a dog in the chronic phase of ehrlichiosis failed to transmit e canis to susceptible dogs. infected but unfed adult ticks may be of greater importance than the chronically infected carrier dog as a natural reservoir of e canis.1977596693
retrospective study of an ehrlichia canis epizootic around phoenix, arizona.antibodies to ehrlichia canis were detected by indirect immunofluorescence in sera from 40 of 339 dogs (12%) examined from around phoenix, az, during 1975. the prevalence was higher in purebred and crossbred german shepherd dogs (21%), as compared with 8% in the remaining breeds. the difference in antibody prevalence between sexes was not significant. dogs 12 weeks to 13 years old were seropositive. the causative agent was isolated by inoculation of whole blood from a seropositive dog into a sus ...1978624663
heartwater in nigeria. ii. the isolation of cowdria ruminantium from live and dead animals and the importance of routes of inoculation.a study was carried out to determine which materials from animals dying or dead of heartwater could initiate the disease in susceptible goats, using the intravenous and subcutaneous routes. c. ruminantium was consistently isolated by intravenous injection of the whole blood or of lung macrophages and by subcutaneous injection of brain homogenate. in animals dead of heartwater, it appeared that isolation of the organism was achieved only when extensive post-mortem autolysis had not supervened. ex ...1978625798
cyclic thrombocytopenia induced by a rickettsia-like agent in dogs.hematologic manifestations and the ultrastructure of a platelet-specific microorganism isolated from a dog in florida were studied. the agent was readily transmitted experimentally to adult dogs by intravenous inoculation with infected blood. parasitemias and concomitant thrombocytopenias were cyclic in that both recurred within relatively constant periods of one to two weeks following experimental infections. hemorrhage was not a manifestation of the disease even though thrombocytopenias were s ...1978627738
effect of canine immune serum on the growth of ehrlichia canis within nonimmune canine macrophages.the effect of canine immune serum (cis) on the growth of ehrlichia canis was studied in macrophage cultures derived from peripheral blood monocytes of normal dogs. ehrlichiae treated with canine normal serum and then introduced into normal macrophage cultures maintained in canine normal serum multiplied within the macrophages and destroyed them. immune serum, collected from e canis carrier dogs, suppressed ehrlichial growth in normal macrophages. an inverse relationship existed between the amoun ...1978629451
effect of canine immune macrophages and canine immune serum on the growth of ehrlichia canis.the effect of canine immune macrophages and canine immune serum (cis) on the growth of ehrlichia canis was studied in vitro. treatment of e canis organisms with cis before they were inoculated into immune macrophage cultures, coupled with pre- and postinoculation maintenance of cultures in cis, suppressed macrophage infection rates to 1% or less. immune macrophages collected from e canis-carrier dogs and maintained in canine normal serum were more resistant to the intracellular growth of e canis ...1978629452
prophylactic and therapeutic use of tetracycline during an epizootic of ehrlichiosis among military epizootic of canine ehrlichiosis at the military working dog center, pakchong, thailand, was arrested by prophylactic and therapeutic use of tetracycline and by control of ticks. oral treatment with tetracycline (66 mg/kg of body weight daily for 14 days) effected remission of signs of disease in 60 of 62 clinically affected dogs and resulted in disappearance of serum antibody in 119 (60%) of 198 seropositive dogs treated during the 2-year study period. transmission of ehrlichia canis was int ...1978640933
isolation of a virulent strain of ehrlichia phagocytophila from the blood of cattle in the isle of man.a blood sample from a cow in the isle of man caused a severe ehrlichia phagocytophila infection when inoculated into a splenectomised calf. the parasite was passaged successively into a further splenectomised calf and then into two intact animals. one of the splenectomised calves and one of the intact animals died of the infection which was characterised by causing a sustained febrile response apparently correlated with a marked invasion of monocytes by the rickettsiae.1978676008
the persistence of cowdria ruminantium in the blood of recovered animals. 1978705896
some clinical and clinico-pathological findings in canine ehrlichiosis. 1978728638
tick borne fever in association with mucosal disease and cobalt deficiency in calves.tick borne fever is considered to have played a major role in a complex disease syndrome involving mucosal disease and cobalt deficiency in a group of young calves reared on an upland farm in south west scotland. anaemia, illthrift, coat colour changes and scour were the main clinical signs.1977888311
prophylactic use of tetracycline for tropical canine pancytopenia. 1977888316
autologous lymphocyte-mediated cytotoxicity against monocytes in canine ehrlichiosis.the 51cr-release technique for detecting cytotoxicity had been adapted to immunologic studies of canine ehrlichiosis. lymphocytes from dogs infected with ehrlichia canis, cause of canine ehrlichiosis, were shown to be cytotoxic for autologous monocytes. the effect was dependent on the concentraton of lymphocytes, being optimal at 100:1 lymphocyte:monocyte ratio. neither immune serum and complement, nor anti-canine globulin had any observable effect on cytotoxicity. the monocytotoxicity bore a te ...1977931138
canine peritoneal macrophages: cultivation and infection with ehrlichia canis.canine peritoneal macrophages were obtained by repeated peritoneal lavage of dogs at 14 day intervals. intraperitoneal administration of sterile mineral oil increased the leukocyte yield approximately 20-fold and the macrophage recovery approximately 35-fold. cell recovery was maximum 7 to 21 days after administration of oil and declined slightly by 35 days. restimulation with a 2nd injection of oil promptly revitalized cell recovery. peritoneal macrophage cultures were well established by 6 day ...1977931165
acute canine ehrlichiosis: platelet survival and factor 3 assay.ten dogs experimentally inoculated with ehrlichia canis were thrombocytopenic 14 days after inoculation. circulating platelet concentrations had declined rapidly by postinoculation day 10, but remained at or slightly below the 14-day concentration during the remainder of the 42-day experimental period. the percentage of circulating megathrombocytes also increased to 8.7 times preinoculation concentrations indicating the existence of accelerated thrombocytopoiesis. the release of platelet factor ...1977931166
development of ehrlichia canis, causative agent of canine ehrlichiosis, in the tick rhipicephalus sanguineus and its differentiation from a symbiotic rickettsia.certain aspects of the development of ehrlichia canis, causative agent of canine ehrlichiosis (tropical canine pancytopenia) in rhipicephalus sanguineus ticks were studied. it was found that partial feeding of nymphs infected as larvae with e canis was a desirable, if not necessary, preliminary treatment for successful infection of dogs with ground-up ticks. it remains unclear whether feeding increased the number or altered the virulence of ehrlichiae within tick tissues. ehrlichia canis organis ...1976944000
attempted artificaial infection or impala, blue wildebeest, buffalo, kudu, giraffe and warthog with heartwater.intravenous injection of cowdria ruminantium infected blood produced no sings of disease in four impala, aepyceros melampus; three blue wildebeest, connochaetes taurinus; a buffalo, syncerus caffer; a kudu, tragelaphus strepsiceros; a giraffe. giraffa camelopardalis and a warthog, phacochoerus aethiopicus. a control sheep injected with the same blood reacted severely and showed typical lesions of heartwater at autopsy.1976994140
identification of ehrlichia canis in east africa.ehrlichia canis, the causative agent of canine ehrlichiosis or tropical canine pancytopaenia (tcp) has been identified in kenya. transmission studies to two dogs resulted in signs of ehrlichiosis including marked thrombocytopaenia, pyrexia, reduction in the packed cell volume and the presence of e canis in peripheral blood mononuclear cells.1976997191
separation and recombination of babesia divergens and ehrlichia phagocytophila from a field case of redwater from eire.a blood sample received from a field case of redwater in eire caused simultaneous infections of babesia divergens and ehrlichia phagocytophila when inoculated into a splenectomised calf. each disease agent was isolated in a separate splenectomised calf by suppressive drug treatment of the other agent, and blood stabilates were made. the disease agents were inoculated synchronously or asychronously into groups of calves, whose reactions were observed. infection with b divergens had no effect on t ...19761006962
preliminary observations on the use of the capillary flocculation test for the diagnosis of heartwater (cowdria ruminantium infection).a capillary flocculation test was developed to diagnose heartwater disease of ruminants. antigen was prepared from the brains of cattle and goats highly infected with cowdria ruminantium. sera were obtained from experimentally infected ruminants which either recovered naturally or with the aid of oxytetracycline treatment. antibodies were first detected one to two weeks after clinical recovery or after treatment, and persisted for periods varying between one and four weeks. control sera collecte ...19761030824
four cases of naturally-occurring canine ehrlichiosis. 19751041641
isolation in illinois of a foreign strain of ehrlichia canis, the causative agent of canine ehrlichiosis (tropical canine pancytopenia).ehrlichiosis (tropical canine pancytopenia) was diagnosed in illinois in a 4 1/2-year-old mixed breed dog that had spent the previous 2 years in india. the dog had periodic epistaxis, anemia, leukopenia, hypoalbuminemia, and hypergammaglobulinemia. a titer of 1:160 for ehrlichia canis was detected by the indirect fluorescent antibody test (ifat). subinoculation of blood into a clinically normal dgo resulted in typical signs of canine ehrlichiosis, and e canis was identified in circulating mononu ...19751112743
experimentally induced infection of dogs, cats, and nonhuman primates with ehrlichia equi, etiologic agent of equine ehrlichiosis.dogs (german shepherd dogs and beagles), cates, rhesus macaques (macaca mulatta), and baboons (papio anubis) were inoculated with whrlichia equi, the etiologic agent of equine ehrlichiosis. within 3 to 7 days after inoculation, morulae were observed in the eosinophils of cats, neurtrophils of macaques and baboons, and in both neutrophils and eosinophils of dogs. the severe disease produced in horses by this agent was not a feature of e equi infection in dogs, cats, macaques, and baboons. however ...19751115421
platelet kinetics in canine ehrlichiosis: evidence for increased platelet destruction as the cause of thrombocytopenia.a significant (p < 0.025) increase in the mean platelet diameter occurred in five ehrlichia canis-infected dogs when platelet numbers decreased to 100,000/mul or less. maximal incorporation of [(75)se]selenomethionine into platelets of six uninfected dogs was 0.080 +/- 0.019% (mean +/- standard error) and occurred 5 to 6 days after dosage, whereas maximal incorporation was 0.036 +/- 0.004% within 2 to 3 days after dosage in seven chronically infected dogs that had thrombocytopenia. analysis of t ...19751140846
transmission of ehrlichia canis to dogs by ticks (rhipicephalus sanguineus).two strains of rhipicephalus sanguineus acquired ehrlichia canis by feeding as either larvae or nymphs on acutely infected dogs and, in subsequent instars, transmitted the agent to normal dogs. three strains of r sanguineus transmitted e canis as adults after their larval and nymphal stages fed on infected dogs. more than 400 adult female ticks were fed on infected dogs as larvae or nymphs or both, but none transmitted e canis transovarially.19751147359
ehrlichia canis infection in a dog in virginia. 19751150498
preservation of cowdria ruminantium at low termperatures.a nigerian isolate of cowdria ruminantium was rapidly frozen with or without 10 per cent dimethyl sulphoxide at -85 degrees c and -196 degrees c. all animals inoculated with the frozen stabilates died of heartwater fever.19751215687
canine ehrlichiosis (tropical canine pancytopenia) in epizootic of canine ehrlichiosis has occurred in military working dogs in thailand. during the epizootic, 161 cases of ehrlichiosis were identified serologically in a population of 316 dogs, and 54 dogs exhibited clinical signs of disease. the epizootic is being controlled by elimination of ticks, by serologic identification and treatment of carriers with 30 mg/lb body weight/day of tetracycline for 14 days, and by continuous daily prophylactic administration of 3 mg/lb body weight/day of tet ...19751226540
pathogenesis of bovine petechial fever. latent infections, immunity, and tissue distribution of cytocetes ondiri. 19751237502
ultrastructural observations on ehrlichia equi organisms in equine granulocytes.the ultrastructure of the etiological agent of equine ehrlichiosis, ehrlichia equi, was studied in equine peripheral leukocytes. the organisms occurred within membrane-lined cytoplasmic vacuoles of neutrophils and eosinophils. ovoid, round, and rod-shaped profiles were observed. from 1 to 33 organisms were present in a thin-section profile of a cytoplasmic vacuole. many cells contained multiple organism-containing vacuoles. the organisms had a cell wall and plasma membrane, and internally they c ...19761248873
studies on theileriidae (sporozoa) in tanzania. i. tick transmission of haematoxenus veliferus.haematoxenus veliferus was experimentally transmitted in cattle on two occasions by the tick amblyomma variegatum; transmission was transstadial, from nymph to adult. theileria mutans and cowdria ruminatium were transmitted at the same time. h. veliferus infected at least 15% of red cells in a splenectomized steer and 10% in a normal steer. one experiment on transstadial transmission from larva to nymph was unsuccessful.19761258136
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
improved culture conditions for cowdria ruminantium (rickettsiales), the agent of heartwater disease of domestic ruminants.the causal agent of heartwater disease of domestic ruminants, cowdria ruminantium, can, with difficulty, be isolated and passaged in lines of bovine endothelial cells grown in the presence of the glasgow modification of eagle's minimal essential medium. however, when leibovitz's l-15 medium supplemented with 0.45% glucose at ph 6.0-6.5 is used as maintenance medium for these cells, isolation and serial passage may routinely be achieved.19901366994
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 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 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 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
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
identification of the antigenic proteins of cowdria ruminantium.immunoblotting of cowdria ruminantium proteins with sheep or bovine antiserum identified 2 antigenically conserved proteins, one being an immunodominant 31 kda and the other a minor 27 kda protein. these proteins are present in the electrophoretic profiles of the welgevonden, ball 3 and kwanyanga stocks and are recognized by sheep antiserum to the welgevonden, ball 3, kwanyanga, mali, comoro, breed, germishuys, kümm and mara stocks and by bovine antiserum to the welgevonden stock of c. ruminanti ...19901705686
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
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
serologically atypical canine ehrlichiosis associated with ehrlichia risticii "infection". 19911752762
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