The Experts below are selected from a list of 5646 Experts worldwide ranked by ideXlab platform
Jacqueline E. Dawson - One of the best experts on this subject based on the ideXlab platform.
-
Research ch Serologic Evidence of Human Monocytic
2013Co-Authors: Granulocytic Ehrlichiosis In Israel, Jacqueline E. Dawson, Trevor WanerAbstract:We conducted a retrospective serosurvey of 1,000 persons in Israel who had fever of undetermined cause to look for Ehrlichia chaffeensis antibodies. Four of five cases with antibodies reactive to E. chaffeensis were diagnosed in the summer, when ticks are more active. All patients had influenzalike symptoms with high fever. None of the cases was fatal. Three serum samples were also seroreactive for antibodies to E. canis, and one was also reactive to the human granulocytic Ehrlichiosis (HGE) agent. The titer to the HGE agent in this patient was higher than the serum titer to E. chaffeensis, and the Western blot analysis also indicated that the HGE agent was the primary cause of infection. We present the first serologic evidence that the agents of human monocytic Ehrlichiosis (HME) and HGE are present in Israel. Therefore, human Ehrlichiosis should be included in the differential diagnoses for persons in Israel who have been exposed to ticks and have influenzalike symptoms. Human Ehrlichiosis (HME) and human granulocytic Ehrlichiosis (HGE), two emerging infectious diseases transmitted by ticks, ar
-
TISSUE DIAGNOSIS OF EHRLICHIA CHAFFEENSIS IN PATIENTS WITH FATAL Ehrlichiosis BY USE OF IMMUNOHISTOCHEMISTRY, IN SITU HYBRIDIZATION, AND POLYMERASE CHAIN REACTION
2013Co-Authors: Jacqueline E. Dawson, Christopher D. Paddock, Ulrike G Munderloh, Cynthia K. Warner, Patricia W. Greer, S. A. Ewing, Jeanine H. Bartlett, R. Zaki, Infectious Disease Pathology ActivityAbstract:Abstract. In the United States, human Ehrlichiosis is a complex of emerging tick-borne diseases caused by 3 distinct Ehrlichia species: Ehrlichia chaffeensis, Ehrlichia ewingii, and the human granulocytotropic Ehrlichiosis agent. Ehrlichioses are characterized by a mild to severe illness, and � 4 % of cases are fatal. Because these obligate intracellular bacteria are difficult to resolve with routine histologic techniques, their distribution in tissues has not been well described. To facilitate the visualization and detection of ehrlichiae, immunohistochemistry (IHC), in situ hybridization (ISH), and polymerase chain reaction (PCR) assays were developed by use of tissues from 4 fatal cases of E. chaffeensis infection. Evidence of E. chaffeensis via IHC, ISH, and PCR was documented in all 4 cases. Abundant immunostaining and in situ nucleic acid hybridization were observed in spleen and lymph node from all 4 patients. Significantly, in 2 of these patients, serologic evidence of infection was absent. Use of IHC, ISH, and PCR to visualize and detect Ehrlichia in tissues can facilitate diagnosis of ehrlichial infections
-
serologic evidence of human monocytic and granulocytic Ehrlichiosis in israel
Emerging Infectious Diseases, 2000Co-Authors: Avi Keysary, Jacqueline E. Dawson, Lili Amram, Gershon Keren, Zev Sthoeger, Israel Potasman, Amir Jacob, Carmella Strenger, Trevor WanerAbstract:We conducted a retrospective serosurvey of 1,000 persons in Israel who had fever of undetermined cause to look for Ehrlichia chaffeensis antibodies. Four of five cases with antibodies reactive to E. chaffeensis were diagnosed in the summer, when ticks are more active. All patients had influenzalike symptoms with high fever. None of the cases was fatal. Three serum samples were also seroreactive for antibodies to E. canis, and one was also reactive to the human granulocytic Ehrlichiosis (HGE) agent. The titer to the HGE agent in this patient was higher than the serum titer to E. chaffeensis, and the Western blot analysis also indicated that the HGE agent was the primary cause of infection. We present the first serologic evidence that the agents of human monocytic Ehrlichiosis (HME) and HGE are present in Israel. Therefore, human Ehrlichiosis should be included in the differential diagnoses for persons in Israel who have been exposed to ticks and have influenzalike symptoms.
-
natural coinfection of a white tailed deer odocoileus virginianus population with three ehrlichia spp
Journal of Parasitology, 1998Co-Authors: Susan E Little, Jacqueline E. Dawson, David E Stallknecht, J M Lockhart, William R DavidsonAbstract:The ticks Amblyomma americanum and Ixodes scapularis, strongly implicated vectors of Ehrlichia chaffeensis and the human granulocytic Ehrlichiosis (HGE) agent, respectively, commonly are found on white-tailed deer (Odocoileus virginianus). As deer can be infected with E. chaffeensis, the HGE agent, and another Ehrlichia-like organism, a deer population parasitized by both tick species in coastal Georgia was tested for evidence of Ehrlichia spp. infection using serologic, molecular, and culture techniques. Antibodies to both E. chaffeensis (geometric mean titer = 111) and Ehrlichia equi, surrogate antigen for the HGE agent, (geometric mean titer = 1,024) were detected by indirect fluorescent antibody testing. Nested polymerase chain reaction employing species-specific primers demonstrated sequence-confirmed 16S rDNA fragments of 3 distinct Ehrlichia spp. in this population: E. chaffeensis (1/5), the HGE agent (3/5), and an Ehrlichia-like organism previously described from white-tailed deer (5/5). Ehrlichia chaffeensis was isolated in culture from the inguinal lymph node of a single deer. An Ehrlichia-type morula was identified in a neutrophil of 1 deer on examination of blood smears. This work provides the first evidence of the HGE agent in a nonhuman host in the southeastern United States and documents infection with both E. chaffeensis and the HGE agent in a single deer population, thereby supporting the importance of white-tailed deer in the natural history of the human ehrlichioses agents.
-
notes ehrlichia ewingii sp nov the etiologic agent of canine granulocytic Ehrlichiosis
International Journal of Systematic and Evolutionary Microbiology, 1992Co-Authors: Burt E. Anderson, D C Jones, Craig E Greene, Jacqueline E. DawsonAbstract: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 phylogenetically much more distant. Our results, coupled with previous serologic data, provide conclusive evidence that the canine granulocytic Ehrlichiosis agent is a new species of the genus Ehrlichia that is related to, but is distinct from, E. canis and all other members of the genus. We propose the name Ehrlichia ewingii sp. nov.; the Stillwater strain is the type strain.
Philippe Parola - One of the best experts on this subject based on the ideXlab platform.
-
factors contributing to emergence of ehrlichia and anaplasma spp as human pathogens
Veterinary Parasitology, 2010Co-Authors: B Doudier, Juan P Olano, Philippe Parola, Philippe BrouquiAbstract:Ehrlichioses and anaplasmoses are caused by α-proteobacteria within the family of Anaplasmataceae. These diseases have been known for a long time in veterinary medicine and recently in human medicine. These tick-borne zoonoses are considered as emerging diseases. The first case of human monocytotropic Ehrlichiosis occurred in 1986. Human granulocytic anaplasmosis was described as a separate entity in 1994 and Ehrlichiosis caused by Ehrlichia ewingii was reported in humans in 1999. The number of cases has been rising steadily due to better diagnostic techniques and better surveillance worldwide. In this review, we will present human and animal ehrlichioses and anaplasmoses as emerging diseases and present candidate(s) for the future.
-
tick and flea borne rickettsial emerging zoonoses
Veterinary Research, 2005Co-Authors: Philippe Parola, Bernard Davoust, Didier RaoultAbstract:Between 1984 and 2004, nine more species or subspecies of spotted fever rickettsiae were identified as emerging agents of tick-borne rickettsioses throughout the world. Six of these species had first been isolated from ticks and later found to be pathogenic to humans. The most recent example is Rickettsia parkeri, recognized as a human pathogen more than 60 years after its initial isolation from ticks. A new spotted fever rickettsia, R. felis was also found to be associated with fleas and to be a human pathogen. Similarly, bacteria within the family Anaplasmataceae have been considered to be of veterinary importance only, yet three species have been implicated in human diseases in recent years, including Ehrlichia chaffeensis, the agent of human monocytic Ehrlichiosis, Anaplasma phagocytophilum, the agent of human anaplasmosis (formerly known as human granulocytic Ehrlichiosis agent, E. equi and E. phagocytophila), and finally Ehrlichia ewingii, which causes granulocytic Ehrlichiosis in humans. We present here an overview of the various tick- and flea-borne rickettsial zoonoses described in the last 20 years, focusing on the ecological, epidemiological and clinical aspects.
-
detection and identification of spotted fever group rickettsiae and ehrlichiae in african ticks
Emerging Infectious Diseases, 2001Co-Authors: Philippe Parola, Jean-louis Camicas, Hisashi Inokuma, Philippe BrouquiAbstract:Spotted fever group Rickettsiae and Ehrlichiae are obligate intracellular gram-negative bacteria associated with arthropods, mainly ticks. While feeding, ticks can transmit these microorganisms to humans and animals (1). Two human tick-borne rickettsioses are known to occur in Africa (2). Mediterranean spotted fever, caused by Rickettsia conorii, is transmitted by the brown dog tick, Rhipicephalus sanguineus, which is well adapted to urban environments. R. conorii is prevalent in the Mediterranean area (Tunisia, Algeria, Morocco, Libya, and Egypt) and has also been isolated or detected in Kenya, Central Africa, Zimbabwe, and South Africa (2). Although African tick bite fever has been recognized since the beginning of the century as a rural disease usually contracted from ticks of cattle and game, it was regarded as synonymous with Mediterranean spotted fever, until the first human infection with R. africae was reported from Zimbabwe in 1992. Subsequently, numerous cases have been reported in tourists returning from southern Africa, where the cattle tick Amblyomma hebraeum is the vector (2,3). R. africae has also been recovered from A. variegatum ticks in Ethiopia and central Africa (2). In 1992, a survey for antibodies against Ehrlichia chaffeensis (the agent of human monocytic Ehrlichiosis) in human sera from eight African countries indicated that human ehrlichioses might occur on the continent (4), and subsequently a case (diagnosed by serology only) was reported from Mali (5). Recently, new molecular methods have enabled the development of useful, sensitive, and rapid tools to detect and identify tick-borne pathogens in arthropods, including ticks (6). In this work, we tested ticks from Africa for rickettsial and ehrlichial DNA using polymerase chain reaction (PCR) and sequence analysis of amplified products.
Stephen J Dumler - One of the best experts on this subject based on the ideXlab platform.
-
Ehrlichiosis and anaplasmosis subcommittee report to the tick borne disease working group
Ticks and Tick-borne Diseases, 2021Co-Authors: Dennis M Dixon, Stephen J Dumler, Harold W Horowitz, Gregory A. Storch, John A Branda, Stephen H Clark, Samuel S Perdue, Bobbi S Pritt, Daniel J Sexton, David H. WalkerAbstract:Abstract Ehrlichioses and anaplasmosis have undergone dramatic increases in incidence, and the geographic ranges of their occurrence and vectors have also expanded. There is marked underreporting of these diseases owing to deficient physician awareness and knowledge of the illnesses as well as limited access to appropriate diagnostic tests. Human monocytic Ehrlichiosis and anaplasmosis are life threatening diseases with estimated case fatality rates of 2.7 and 0.3%, respectively. However, knowledge of their full range of signs and symptoms is incomplete, and the incidence of subclinical infections is unknown. Currently available laboratory diagnostic methods are poorly utilized, and with the exception of nucleic acid amplification tests are not useful for diagnosis during the acute stage of illness when timely treatment is needed. The Ehrlichiosis and Anaplasmosis Subcommittee of the Tick-Borne Disease Working Group recommended active clinical surveillance to determine the true incidence, full clinical spectrum, and risk factors for severe illness, as well as standardized surveillance of ticks for these pathogens, and enhanced education of primary medical caregivers and the public regarding these diseases. The subcommittee identified the needs to develop sensitive, specific acute stage diagnostic tests for local clinical laboratories and point-of-care testing, to develop approaches for utilizing electronic medical records, data mining, and artificial intelligence for assisting early diagnosis and treatment, and to develop adjunctive therapies for severe disease.
-
current management of human granulocytic anaplasmosis human monocytic Ehrlichiosis and ehrlichia ewingii Ehrlichiosis
Expert Review of Anti-infective Therapy, 2009Co-Authors: Rachael J Thomas, Stephen J Dumler, Jason A CarlyonAbstract:Anaplasma phagocytophilum, Ehrlichia chaffeensis and Ehrlichia ewingii are emerging tick-borne pathogens and are the causative agents of human granulocytic anaplasmosis, human monocytic Ehrlichiosis and E. ewingii Ehrlichiosis, respectively. Collectively, these are referred to as human ehrlichioses. These obligate intracellular bacterial pathogens of the family Anaplasmataceae are transmitted by Ixodes spp. or Amblyomma americanum ticks and infect peripherally circulating leukocytes to cause infections that range in clinical spectra from asymptomatic seroconversion to mild, severe or, in rare instances, fatal disease. This review describes: the ecology of each pathogen; the epidemiology, clinical signs and symptoms of the human diseases that each causes; the choice methods for diagnosing and treating human ehrlichioses; recommendations for patient management; and is concluded with suggestions for potential future research.
-
current management of human granulocytic anaplasmosis human monocytic Ehrlichiosis and ehrlichia ewingii Ehrlichiosis
Expert Review of Anti-infective Therapy, 2009Co-Authors: Rachael J Thomas, Stephen J Dumler, Jason A CarlyonAbstract:Anaplasma phagocytophilum, Ehrlichia chaffeensis and Ehrlichia ewingii are emerging tick-borne pathogens and are the causative agents of human granulocytic anaplasmosis, human monocytic Ehrlichiosis and E. ewingii Ehrlichiosis, respectively. Collectively, these are referred to as human ehrlichioses. These obligate intracellular bacterial pathogens of the family Anaplasmataceae are transmitted by Ixodes spp. or Amblyomma americanum ticks and infect peripherally circulating leukocytes to cause infections that range in clinical spectra from asymptomatic seroconversion to mild, severe or, in rare instances, fatal disease. This review describes: the ecology of each pathogen; the epidemiology, clinical signs and symptoms of the human diseases that each causes; the choice methods for diagnosing and treating human ehrlichioses; recommendations for patient management; and is concluded with suggestions for potential future research.
-
human monocytic Ehrlichiosis an emerging pathogen in transplantation
Transplantation, 2001Co-Authors: Henkie P Tan, Stephen J Dumler, Warren R Maley, Andrew S Klein, James F Burdick, Fred F Poordad, Paul J Thuluvath, Jay S MarkowitzAbstract:Background. The spectrum of disease caused by Ehrlichia spp. ranges from asymptomatic to fatal. Awareness and early diagnosis of the infection is paramount because appropriate therapy leads to rapid defervescence and cure. If left untreated, particularly in immunosuppressed patients, ehrlichioses may result in multi-system organ failure and death. Methods. We report the second case of human monocytic Ehrlichiosis (HME) in a liver transplant recipient, and review the literature. Results. The patient presented with fever and headache, had negative cultures, and despite broad-spectrum antimicrobial coverage appeared progressively septic. After eliciting a history of tick exposure we treated the patient empirically with doxycycline. The diagnosis of HME was confirmed by 1) polymerase chain reaction (PCR) for Ehrlichia chaffeensis, 2) acute and convalescent serum titers, and 3) in vitro cultivation of E chaffeensis from peripheral blood. Conclusion. Although human ehrlichioses are relatively uncommon, they are emerging as clinically significant arthropod-borne infections. Although epidemiological exposure is responsible for infection, immunosuppression makes patients more likely to succumb to disease. A high index of suspicion and early treatment results in a favorable outcome.
-
serial measurements of hematologic counts during the active phase of human granulocytic Ehrlichiosis
Clinical Infectious Diseases, 2001Co-Authors: Johan S. Bakken, Maria E Aguerorosenfeld, Harold W Horowitz, Gary P Wormser, Robert L Tilden, John Raffalli, Mehdi Baluch, Debbie Riddell, Jennifer J Walls, Stephen J DumlerAbstract:To describe the changes that occur in blood count parameters during the natural course of human granulocytic Ehrlichiosis, we designed a retrospective cross-sectional case study of 144 patients with human granulocytic Ehrlichiosis and matched controls who had a different acute febrile illness. Patients from New York State and the upper Midwest were evaluated from June 1990 through December 1998. Routine complete blood counts and manual differential leukocyte counts of peripheral blood were performed on blood samples that were collected during the active illness, and values were recorded until the day of treatment with an active antibiotic drug. Thrombocytopenia was observed more frequently than was leukopenia, and the risk of having Ehrlichiosis varied inversely with the granulocyte count and the platelet count. Patients with Ehrlichiosis displayed relative and absolute lymphopenia and had a significant increase in band neutrophil counts during the first week of illness. Knowledge of characteristic complete blood count patterns that occur during active Ehrlichiosis may help clinicians to identify patients who should be evaluated specifically for Ehrlichiosis and who should receive empiric antibiotic treatment with doxycycline.
J S Dumler - One of the best experts on this subject based on the ideXlab platform.
-
serological responses to ehrlichia equi ehrlichia chaffeensis and borrelia burgdorferi in patients from new york state
Journal of Clinical Microbiology, 1997Co-Authors: Susan J Wong, G S Brady, J S DumlerAbstract:Serological testing at the New York State Department of Health for human granulocytic Ehrlichiosis in the residents of Westchester County, N.Y., was performed with specimens from 176 patients by the indirect fluorescent-antibody (IFA) technique with Ehrlichia equi MRK-infected neutrophils. To understand whether human monocytotropic Ehrlichiosis also occurs in this northeastern geographic region, specimens were also tested for antibodies to Ehrlichia chaffeensis Arkansas. Screening tests and immunoblots for Lyme disease (Borrelia burgdorferi infection) were also performed. Thirty-two patients had antibodies only to E. equi and 21 patients had antibodies to both E. equi and E. chaffeensis, whereas 12 patients had only E. chaffeensis antibodies by the IFA technique. The remaining patients did not have antibodies to either ehrlichia. Eighteen serum samples from 13 of these patients were coded and sent to the Ehrlichia Research Laboratory (Baltimore, Md.) for repeat analysis by the IFA test and for E. equi and E. chaffeensis immunoblots. Immunoblot analysis for E. equi in samples with positive IFA test results confirmed the results for eight of the nine specimens. Immunoblot analyses for E. chaffeensis were negative for all 18 serum samples. Borrelia-reactive antibodies were found in sera both from patients with granulocytic Ehrlichiosis and from patients with monocytotropic Ehrlichiosis from New York State. Our results suggest that E. equi antigen is an appropriate substrate for identifying human granulocytic Ehrlichiosis. E. chaffeensis antigen lacks appropriate sensitivity to serve as a surrogate substrate for the detection of human granulocytic Ehrlichiosis and should be used solely for the diagnosis of human monocytotropic Ehrlichiosis. Heat shock proteins may, in some cases, cause cross-reactivity between B. burgdorferi and ehrlichiae.
-
serological evidence of human granulocytic Ehrlichiosis in norway
European Journal of Clinical Microbiology & Infectious Diseases, 1996Co-Authors: J S Bakken, J S Dumler, J Krueth, R L Tilden, B E KristiansenAbstract:Human granulocytic ehriichoisis was first described in 1994. This tick-transmitted illness is increasingly recognized in the USA as well as in Europe in areas where ixodes ticks and Lyme borreliosis are endemic. Blood samples from 58 Norwegian patients with physician-diagnosed Lyme borreliosis were examined for the presence of antibodies to Ehrlichia equi, a surrogate marker of the agent of human granulocytic Ehrlichiosis. The results indicated that 10.2% of the patients may have been co-infected with human granulocytic Ehrlichiosis and Lyme borreliosis. Human granulocytic Ehrlichiosis appears to be established in southern Norway.
-
equine granulocytic Ehrlichiosis in connecticut caused by an agent resembling the human granulocytotropic ehrlichia
Journal of Clinical Microbiology, 1996Co-Authors: John E. Madigan, Jeffrey E Barlough, J S Dumler, N S Schankman, Elfriede DerockAbstract:The first recognized cases of equine granulocytic Ehrlichiosis in New England are described. The DNA sequence of the 16S rRNA gene of the causative ehrlichia was found to be identical to that of the human granulocytotropic ehrlichia, the agent of human granulocytic Ehrlichiosis.
-
ixodes pacificus acari ixodidae as a vector of ehrlichia equi rickettsiales ehrlichieae
Journal of Medical Entomology, 1996Co-Authors: Phillip Richter, John E. Madigan, Robert B Kimsey, Jeffrey E Barlough, J S Dumler, D L BrooksAbstract:Ehrlichia equi , a rickettsia described from horses in California 30 yr ago, causes equine granulocytic Ehrlichiosis throughout the Americas and possibly Europe. Here, we report experimental transmission of E. equi from infected to susceptible horses through bites of western blacklegged ticks, Ixodes pacificus (Cooley & Kohls). In preliminary field studies, only I. pacificiis consistently infested horses and vegetation at 3 locations with contemporary cases of equine ehrlichosis, and in particular, I. pacificus was the only species found attached to all of the infected horses. Exposure to bites of ticks in the genus Ixodes poses previously unrecognized and serious health risks to humans and animals.
-
Geographic, clinical, serologic, and molecular evidence of granulocytic Ehrlichiosis, a likely zoonotic disease, in Minnesota and Wisconsin dogs.
Journal of clinical microbiology, 1996Co-Authors: Barbara Greig, K M Asanovich, P J Armstrong, J S DumlerAbstract:Seventeen Minnesota and Wisconsin dogs with granulocytic ehrlichosis were studied. The diagnoses were made by finding ehrlichia morulae in peripheral blood neutrophils. Eight dogs were studied retrospectively, and nine dogs were studied prospectively. The medical records of all dogs were reviewed. Eighty-eight percent of the dogs were purebred and 76% were spayed females. The median age was 8 years. Sixty-five percent of the cases were diagnosed in October and November. Fever and lethargy were the most common clinical signs. The most frequent laboratory findings were lymphopenia, thrombocytopenia, elevated activities of serum alkaline phosphatase and amylase, and hypoalbuminemia. No dogs seroreacted to Ehrlichia canis or Ehrlichia chaffeensis antigens, which are cross-reactive. Seventy-five percent of the dogs tested during the acute phase of disease and 100% of the dogs tested during convalescence were seropositive for E. equi antigens. Granulocytic ehrlichial 16S rRNA gene DNAs from six dogs were amplified by PCR. Sequence analysis of a 919-bp sequence of the ehrlichial 16S rRNA gene amplified by PCR from the blood of two dogs revealed the agent to be identical to the agent of human granulocytic Ehrlichiosis in Minnesota and Wisconsin and to be very similar to E. equi and Ehrlichia phagocytophila and less similar to E. canis, Ehrlichia ewingii, and E. chaffeensis. The geographic, clinical, serologic, and molecular evidence indicates that granulocytic Ehrlichiosis in Minnesota and Wisconsin dogs is not caused by E. ewingii, but suggests that it is a zoonotic disease caused by an agent closely related to E. equi and that dogs likely contribute to the enzootic cycle and human infection.
Burt E. Anderson - One of the best experts on this subject based on the ideXlab platform.
-
ehrlichia ewingii sp nov the etiologic agent of canine granulocytic Ehrlichiosis
International Journal of Systematic and Evolutionary Microbiology, 1992Co-Authors: Burt E. Anderson, D C Jones, Craig E Greene, Jacqueline E. DawsonAbstract: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 phylogenetically much more distant. Our results, coupled with previous serologic data, provide conclusive evidence that the canine granulocytic Ehrlichiosis agent is a new species of the genus Ehrlichia that is related to, but is distinct from, E. canis and all other members of the genus. We propose the name Ehrlichia ewingii sp. nov.; the Stillwater strain is the type strain.
-
notes ehrlichia ewingii sp nov the etiologic agent of canine granulocytic Ehrlichiosis
International Journal of Systematic and Evolutionary Microbiology, 1992Co-Authors: Burt E. Anderson, D C Jones, Craig E Greene, Jacqueline E. DawsonAbstract: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 phylogenetically much more distant. Our results, coupled with previous serologic data, provide conclusive evidence that the canine granulocytic Ehrlichiosis agent is a new species of the genus Ehrlichia that is related to, but is distinct from, E. canis and all other members of the genus. We propose the name Ehrlichia ewingii sp. nov.; the Stillwater strain is the type strain.
-
Ehrlichia chaffeensis, a new species associated with human Ehrlichiosis.
Journal of clinical microbiology, 1991Co-Authors: Burt E. Anderson, Jacqueline E. Dawson, D C Jones, Kenneth H. WilsonAbstract: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 compared. The 16S rRNA gene sequences were identical for all three sources of the human Ehrlichiosis agent. The sequence comparisons indicate that the human Ehrlichiosis agent is a new species most closely related to E. canis (98.2%) and more distantly related to other Ehrlichia spp. We propose that this species be named Ehrlichia chaffeensis sp. nov., with the Arkansas strain as the type strain.
