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Cabler SS, Hogan PG, Fritz SA, Bednarski JJ, Hunstad DA. Incidence and treatment of hemophagocytic lymphohistiocytosis in hospitalized children with Ehrlichia infection. Pediatr Blood Cancer 2020; 67:e28436. [PMID: 32706439 DOI: 10.1002/pbc.28436] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/06/2020] [Accepted: 05/07/2020] [Indexed: 12/23/2022]
Abstract
We report a large cohort of pediatric patients with human monocytic ehrlichiosis (HME), enabling an estimated incidence of secondary hemophagocytic lymphohistiocytosis (HLH) in hospitalized children with HME. Among 49 children with PCR-confirmed Ehrlichia infection, 8 (16%) met current criteria for HLH. Those with HLH had more significant hematologic abnormalities and longer durations from symptom onset to admission and definitive anti-infective therapy. Among these eight, three received chemotherapy plus doxycycline, one of whom died; the other five were treated with doxycycline without chemotherapy, and all survived without HLH recurrence. Our findings demonstrate that antimicrobial therapy alone can successfully resolve Ehrlichia-associated HLH.
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Affiliation(s)
- Stephanie S Cabler
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri
| | - Patrick G Hogan
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri
| | - Stephanie A Fritz
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri
| | - Jeffrey J Bednarski
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri
| | - David A Hunstad
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri
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Simpson DT, Teague MS, Weeks JK, Lewis AD, D'Addio PM, Moore JD, Thompson JA, Harris AC, Cannella RT, Kaup BZ, Kerscher O, Leu M. Broad, Multi-Year Sampling Effort Highlights Complex Dynamics of the Tick-Borne Pathogen Ehrlichia chaffeensis (Rickettsiales: Anaplasmatacae). J Med Entomol 2019; 56:162-168. [PMID: 30295826 DOI: 10.1093/jme/tjy171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Indexed: 06/08/2023]
Abstract
Ehrlichia chaffeensis (Rickettsiales: Anaplasmatacae), an understudied bacterial pathogen emerging in the eastern United States, is increasing throughout the range of its vector, the lone star tick [Amblyomma americanum, L. (Acari: Ixodidae)]. To mitigate human disease risk, we must understand what factors drive E. chaffeensis prevalence. Here, we report patterns of E. chaffeensis prevalence in southeastern Virginia across 4 yr and ask how seasonal weather patterns affect variation in rates of E. chaffeensis occurrence. We collected A. americanum nymphs at 130 plots across southeastern Virginia in 2012, 2013, 2015, and 2016, and used polymerase chain reaction and gel electrophoresis to test for the presence of E. chaffeensis DNA. Prevalence estimates varied among years, ranging from 0.9% to 3.7%, and persistence of E. chaffeensis occurrence varied across space, with some sites never testing positive, and one site testing positive every year. Using generalized linear mixed-effects models, we related E. chaffeensis occurrence to temperature, humidity, vapor-pressure deficit, and precipitation during seasons up to 21 mo prior to sampling. Surprisingly, all support was lent to a positive effect of temperature during the previous fall and winter (i.e., prior to the nymphs' hatching), which we hypothesize to influence reservoir host population dynamics through changes to mortality or natality. Although further work is necessary to truly elucidate the mechanisms at play, our study shows E. chaffeensis distribution to be very dynamic across multiple dimensions, demanding broad concerted monitoring efforts that can consider both space and time.
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Affiliation(s)
| | | | | | | | | | - Julia D Moore
- Biology Department, William & Mary, Williamsburg, VA
| | - Joseph A Thompson
- Biology Department, William & Mary, Williamsburg, VA
- VHB Vanasse Hangen Brustlin, 351 McLaws Circle, Suite, Williamsburg, VA
| | - Alan C Harris
- Biology Department, William & Mary, Williamsburg, VA
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, E. Marshall Street, Richmond, VA
| | | | - Brent Z Kaup
- Department of Sociology, William & Mary, Williamsburg, VA
| | | | - Matthias Leu
- Biology Department, William & Mary, Williamsburg, VA
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Loftis AD, Kelly PJ, Paddock CD, Blount K, Johnson JW, Gleim ER, Yabsley MJ, Levin ML, Beati L. Panola Mountain Ehrlichia in Amblyomma maculatum From the United States and Amblyomma variegatum (Acari: Ixodidae) From the Caribbean and Africa. J Med Entomol 2016; 53:696-698. [PMID: 26744465 DOI: 10.1093/jme/tjv240] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Accepted: 12/03/2015] [Indexed: 06/05/2023]
Abstract
Panola Mountain Ehrlichia (PME) has been suggested as an emerging pathogen of humans and dogs. Domestic goats and white-tailed deer (Odocoileus virginianus) are also susceptible and likely serve as reservoirs. Experimentally, both the lone star tick (Amblyomma americanum (L.)) and the Gulf Coast tick (Amblyomma maculatum Koch) can transmit PME among deer and goats. In the current study, we detected PME in adult wild-caught A. maculatum from the United States and Amblyomma variegatum (F.) from the Caribbean and Africa. This significantly expands the range, potential tick vectors, and risk for exposure to PME.
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Affiliation(s)
- Amanda D Loftis
- Ross University School of Veterinary Medicine, P.O. Box 334, Basseterre, St. Kitts, St. Kitts and Nevis (; ),
| | - Patrick J Kelly
- Ross University School of Veterinary Medicine, P.O. Box 334, Basseterre, St. Kitts, St. Kitts and Nevis (; )
| | - Christopher D Paddock
- Centers for Disease Control and Prevention, 1600 Clifton Road NE, Atlanta, GA 30333 (; )
| | - Keith Blount
- Department of Biology, U.S. Air Force Academy, CO 80840
| | - Jason W Johnson
- College of Veterinary Medicine, Lincoln Memorial University, 6965 Cumberland Gap Parkway, Harrogate, TN 37752
| | - Elizabeth R Gleim
- Warnell School of Forestry and Natural Resources, The University of Georgia, Athens, GA (; )
- Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, The University of Georgia, 589 DW Brooks Drive, Athens Georgia 30602
- Joseph W. Jones Ecological Research Center at Ichauway, Newton, GA, and
| | - Michael J Yabsley
- Warnell School of Forestry and Natural Resources, The University of Georgia, Athens, GA (; )
- Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, The University of Georgia, 589 DW Brooks Drive, Athens Georgia 30602
| | - Michael L Levin
- Centers for Disease Control and Prevention, 1600 Clifton Road NE, Atlanta, GA 30333 (; )
| | - Lorenza Beati
- The U.S. National Tick Collection, Georgia Southern University, Georgia Avenue - Building 204, P.O. Box 8056, Statesboro, Georgia 30460
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Koh FX, Panchadcharam C, Tay ST. Vector-Borne Diseases in Stray Dogs in Peninsular Malaysia and Molecular Detection of Anaplasma and Ehrlichia spp. from Rhipicephalus sanguineus (Acari: Ixodidae) Ticks. J Med Entomol 2016; 53:183-187. [PMID: 26494821 DOI: 10.1093/jme/tjv153] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 09/13/2015] [Indexed: 06/05/2023]
Abstract
Little data are available on the prevalence and transmission of vector-borne diseases in stray dogs in Peninsular Malaysia. This study was designed to determine the occurrence of vector-borne pathogens in Malaysian stray dogs using serological and molecular approaches. In total, 48 dog blood samples were subjected to serological analysis using SNAP 4Dx kit (IDEXX Laboratories, Westbrook, ME). The presence of Ehrlichia and Anaplasma DNA in the dog blood samples and Rhipicephalus sanguineus (Latreille) ticks was detected using nested polymerase chain reaction assays. Positive serological findings against Ehrlichia canis and Anaplasma phagocytophilum were obtained in 17 (39.5%) and four (9.3%) of 43 dog samples, respectively. None of the dog blood samples were positive for Borrelia burgdorferi and Dirofilaria immitis. DNA of E. canis and A. phagocytophilum was detected in 12 (25.5%) and two (4.3%) of 47 dog blood samples, and 17 (51.5%) and one (3.0%) of 33 R. sanguineus ticks, respectively. Additionally, DNA of Ehrlichia spp. closely related to Ehrlichia chaffeensis was detected in two (6.1%) R. sanguineus ticks. This study highlights the prevalence of anaplasmosis and ehrlichiosis in dogs in Malaysia. Due to the zoonotic potential of Ehrlichia and Anaplasma spp., appropriate measures should be instituted for prevention and control of vector-borne diseases in dogs.
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Affiliation(s)
- Fui Xian Koh
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia (; )
| | | | - Sun Tee Tay
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia (; ),
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Killmaster LF, Loftis AD, Zemtsova GE, Levin ML. Detection of bacterial agents in Amblyomma americanum (Acari: Ixodidae) from Georgia, USA, and the use of a multiplex assay to differentiate Ehrlichia chaffeensis and Ehrlichia ewingii. J Med Entomol 2014; 51:868-872. [PMID: 25118421 PMCID: PMC5659119 DOI: 10.1603/me13225] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Amblyomma americanum, the lone star tick, is the most common and most aggressive human biting tick in the Southeastern United States. It is known to transmit the agents of human ehrlichioses, Ehrlichia chaffeensis and Ehrlichia ewingii. In addition, it carries agents of unspecified pathogenicity to humans, including Rickettsia amblyommii, Borrelia lonestari, and the newly emerging Panola Mountain Ehrlichia (PME). Surveillance of these ticks for recognized or emerging pathogens is necessary for assessing the risk of human infection. From 2005 to 2009, we surveyed A. americanum ticks from four locations in the state of Georgia. Ticks (1,183 adults, 2,954 nymphs, and 99 larval batches) were tested using a multiplex real-time polymerase chain reaction (PCR) assay designed to detect and discriminate DNA from Rickettsia spp., E. chaffeensis, and E. ewingii. This assay was capable of detecting as few as 10 gene copies of the aforementioned agents. Ticks were also tested for PME and B. lonestari by nested PCR. The prevalence of infection ranged from 0 to 2.5% for E. chaffeensis, 0 to 3.9% for E. ewingii, 0 to 2.2% for PME, 17 to 83.1% for R. amblyommii, and 0 to 3.1% for B. lonestari. There were 46 (4.1%) individual adults positive for two agents, and two females that were each positive for three agents. Two larval batches were positive for both B. lonestari and R. amblyommii, indicating the potential for transovarial transmission of both agents from a single female. Although infrequent in occurrence, the dynamics of coinfections in individual ticks should be explored further, given the potential implications for differential diagnosis and severity of human illness.
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Pandey R, Kochar R, Kemp S, Rotaru D, Shah SV. Ehrlichiosis presenting with toxic shock-like syndrome and secondary hemophagocytic lymphohistiocytosis. J Ark Med Soc 2013; 109:280-282. [PMID: 23808094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Human monocytotropic ehrlichios is a tick borne illness caused by Ehrlichia chaffeensis. Ehrlichiosis presenting with septic shock and severe azotemia is rare, and may be seen in immunocompromised individuals. We present a case of ehrlichia induced toxic shock like syndrome in a patient with rheumatoid arthritis on disease modifying agents. He also had oliguric renal failure requiring dialysis on presentation and later found to have Hemophagocytic Lymphohistiocytosis secondary to severe ehrlichia sepsis.
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Affiliation(s)
- Richa Pandey
- Department of Internal Medicine, University of Arkansas for Medical Sciences Little Rock, AR, USA
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Zhang XC, Zhang LX, Li WH, Wang SW, Sun YL, Wang YY, Guan ZZ, Liu XJ, Yang YS, Zhang SG, Yu HL, Zhang LJ. [Investigation on Ehrlichia chaffeensis and Anaplasma phagocytophilum infection among farmers and domestic animals in rural areas of Beijing, China]. Zhonghua Liu Xing Bing Xue Za Zhi 2012; 33:517-520. [PMID: 22883182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
OBJECTIVE To investigate the status of Ehrlichia (E.) chaffeensis and Anaplasma (A.) phagocytophilum infection among farming populations and domestic animals in the rural area of Beijing, China. METHODS Blood samples from 562 farmers and 163 blood samples including 90 goats, 71 ox and 2 dogs, were collected. Specificity of IgG antibodies against E. chaffeensis and A. phagocytophilum were tested by micro-indirect immunofluorescent assay (mIFA). 16S rRNA genes of A. phagocytophilum were amplified from the domestic animal blood samples and products were sequenced and analyzed by nested PCR. RESULTS The positive rates of E. chaffeensis and A. phagocytophilum antibody were 16.5% and 14.0% respectively for farmers. The total positive rates of A. phagocytophilum were 2.3% and 0 for both goats and oxen respectively. No antibody was found for the 2 tested dogs. The PCR positive rates were 48.9% and 23.9% for goats and oxen respectively. Three dominant varieties of A. phagocytophilum were demonstrated in goats and oxen. CONCLUSION The prevalence rates of E. chaffeensis and A. phagocytophilum were identified in the rural areas of Beijing.
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Affiliation(s)
- Xiu-chun Zhang
- Beijing Center for Disease Control and Prevention, Beijing 100013, China
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9
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Watson ME, Storch GA, Dunne WM, Burnham CAD. A 2-year-old female with Fever and rash. J Clin Microbiol 2011; 49:2389, 2784. [PMID: 21719732 PMCID: PMC3147883 DOI: 10.1128/jcm.00081-11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Michael E Watson
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri 63110,
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Ndip LM, Ndip RN, Esemu SN, Walker DH, McBride JW. Predominance of Ehrlichia chaffeensis in Rhipicephalus sanguineus ticks from kennel-confined dogs in Limbe, Cameroon. Exp Appl Acarol 2010; 50:163-168. [PMID: 19693681 PMCID: PMC2797824 DOI: 10.1007/s10493-009-9293-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Accepted: 07/14/2009] [Indexed: 05/28/2023]
Abstract
Rhipicephalus sanguineus ticks (n = 63) collected from five dogs (two adults and three puppies) housed in a kennel were screened for Ehrlichial agents (Ehrlichia canis, E. chaffeensis, and E. ewingii) using a species-specific multicolor real-time TaqMan PCR amplification of the disulphide bond formation protein (dsb) gene. Ehrlichia chaffeensis DNA was detected in 33 (56%) ticks, E. canis DNA was detected in four (6%) ticks, and one tick was coinfected. The E. chaffeensis and E. canis nucleotide sequences of the amplified dsb gene (374 bp) obtained from the Cameroonian R. sanguineus ticks were identical to the North American genotypes.
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Affiliation(s)
- Lucy M Ndip
- Department of Biochemistry, University of Buea, P. O. Box 63, Buea, Cameroon.
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Seddighzadeh A, Pinger RR, Zercher A, Steiner FE, Klyachko O, Vann CN, Clay K, Fuqua C. Strains of Ehrlichia chaffeensis in southern Indiana, Kentucky, Mississippi, and North Carolina. J Med Entomol 2009; 46:1468-1473. [PMID: 19960699 DOI: 10.1603/033.046.0633] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Rates of infection of Amblyomma americanum (L.) by Ehrlichia chaffeensis were compared in 100 ticks collected from sites in each of four states: Indiana, North Carolina, Kentucky, and Mississippi. The overall infection rates were similar among sites, ranging from 1 to 4%. Because pathogenic differences may exist between E. chaffeensis strains, nested polymerase chain reaction (PCR) amplification of the variable-length PCR target (VLPT), and sequencing of the amplicons were performed to differentiate between strains. The most common infecting strains at all sites exhibited a repeat profile of 1,2,3,4 (corresponding to the Arkansas/Jax/Osceola and Liberty strains). To determine whether the minimum infection rates (MIRs) or the most common infecting strain were changing over time in southern Indiana sites, 2765 ticks from six counties in 2000 and 837 ticks from seven counties in 2004 also were examined in pools of five ticks per pool. The MIRs for 2000 and 2004 were 3.5 and 4.2% respectively, suggesting that the overall MIRs remained low. At two sites, in Pike and Harrison counties, however, infection rates more than doubled from 2000 to 2004 (7 to 16% and 0.3 to 2.7% respectively). Across all sites, the most common infecting strains (Arkansas/Jax/Osceola and Liberty) did not significantly change (68% in 2000; 79% in 2004).
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Thomas RJ, Stephen Dumler J, Carlyon JA. Current management of human granulocytic anaplasmosis, human monocytic ehrlichiosis and Ehrlichia ewingii ehrlichiosis. Expert Rev Anti Infect Ther 2009; 7:709-22. [PMID: 19681699 PMCID: PMC2739015 DOI: 10.1586/eri.09.44] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
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.
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Affiliation(s)
- Rachael J Thomas
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, VA, USA
| | - J Stephen Dumler
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, MA, USA
| | - Jason A Carlyon
- Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Molecular Medicine Research Building, 1220 East Broad Street, Room 4052, PO Box 980678, Richmond, VA 23298-0678, USA Tel.: +1 804 628 3382 Fax: +1 804 828 9946
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Tomassone L, Nuñez P, Gürtler RE, Ceballos LA, Orozco MM, Kitron UD, Farber M. Molecular detection of Ehrlichia chaffeensis in Amblyomma parvum ticks, Argentina. Emerg Infect Dis 2009; 14:1953-5. [PMID: 19046533 PMCID: PMC2634635 DOI: 10.3201/eid1412.080781] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Affiliation(s)
- María C. Martínez
- University of Carabobo, Aragua, Venezuela
- Biomedical Research Institute, Maracay, Venezuela
| | - Clara N. Gutiérrez
- University of Carabobo, Aragua, Venezuela
- Biomedical Research Institute, Maracay, Venezuela
| | | | - Johanny Ruiz
- Biomedical Research Institute, Maracay, Venezuela
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Abstract
BACKGROUND Disease maps are used increasingly in the health sciences, with applications ranging from the diagnosis of individual cases to regional and global assessments of public health. However, data on the distributions of emerging infectious diseases are often available from only a limited number of samples. We compared several spatial modelling approaches for predicting the geographic distributions of two tick-borne pathogens: Ehrlichia chaffeensis, the causative agent of human monocytotropic ehrlichiosis, and Anaplasma phagocytophilum, the causative agent of human granulocytotropic anaplasmosis. These approaches extended environmental modelling based on logistic regression by incorporating both spatial autocorrelation (the tendency for pathogen distributions to be clustered in space) and spatial heterogeneity (the potential for environmental relationships to vary spatially). RESULTS Incorporating either spatial autocorrelation or spatial heterogeneity resulted in substantial improvements over the standard logistic regression model. For E. chaffeensis, which was common within the boundaries of its geographic range and had a highly clustered distribution, the model based only on spatial autocorrelation was most accurate. For A. phagocytophilum, which has a more complex zoonotic cycle and a comparatively weak spatial pattern, the model that incorporated both spatial autocorrelation and spatially heterogeneous relationships with environmental variables was most accurate. CONCLUSION Spatial autocorrelation can improve the accuracy of predictive disease risk models by incorporating spatial patterns as a proxy for unmeasured environmental variables and spatial processes. Spatial heterogeneity can also improve prediction accuracy by accounting for unique ecological conditions in different regions that affect the relative importance of environmental drivers on disease risk.
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Affiliation(s)
- Michael C Wimberly
- Geographic Information Science Center of Excellence, South Dakota State University, Brookings, SD, USA.
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Abstract
Human monocytic ehrlichiosis (HME) is a tick-borne disease transmitted during the summer months in the mid-Atlantic, southeastern and south-central United States. A large proportion of patients presenting with ehrlichiosis must be hospitalized because of the severity of their presenting signs, symptoms and lab abnormalities. We report a case of HME presenting with negative serologies and positive DNA PCR for Ehrlichia chaffeensis during the acute illness. The patient was empirically treated with doxycycline before the availability of diagnostic test results and had a rapid recovery. This report summarizes the common findings of ehrlichiosis on presentation, diagnostic strategies, and treatment options. This case emphasizes the importance of considering tick-borne diseases in the differential diagnosis for patients presenting with nonspecific febrile syndromes in endemic areas and using the clinical scenario to determine whether empiric treatment for a tick-borne disease is necessary. Delaying treatment while awaiting confirmatory tests is unnecessary, and may result in a less favorable patient outcome.
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Affiliation(s)
- Lisa K Prince
- Infectious Disease Department at Walter Reed Army Medical Center, 6900 Georgia Ave, NW, Washington, DC 20307, USA
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Abstract
Amblyomma americanum is an aggressive ixodid tick that has been implicated as a vector for several bacterial agents. Among these is Ehrlichia chaffeensis, which causes human monocytic (or monocytotropic) ehrlichiosis. In this study, experimental tick transmission of E. chaffeensis from infected lone star ticks to deer was revisited, and the question of whether it would be possible to re-isolate the organism from deer was asked, because this had not been done previously. Here, we were able to transmit a wild strain of E. chaffeensis from acquisition-fed lone star ticks to white-tailed deer. Ehrlichia chaffeensis was re-isolated from one white-tailed deer on multiple days during the infection and from another deer on one day during the infection. Peak rickettsemias for E. chaffeensis-infected deer were 17 DPI with acquisition-fed ticks and 14 DPI with needle-inoculated deer. This study supports the role of the lone star tick and white-tailed deer as vector and reservoir host for E. chaffeensis, demonstrating culture re-isolation of E. chaffeensis in deer infected by experimental tick transmission for the first time.
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Affiliation(s)
- A S Varela-Stokes
- Department of Infectious Diseases, College of Veterinary Medicine, The University of Georgia, Athens, Georgia 30602, USA.
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Yabsley MJ, Davidson WR, Stallknecht DE, Varela AS, Swift PK, Devos JC, Dubay SA. Evidence of tick-borne organisms in mule deer (Odocoileus hemionus) from the western United States. Vector Borne Zoonotic Dis 2007; 5:351-62. [PMID: 16417431 DOI: 10.1089/vbz.2005.5.351] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Free-ranging mule deer (MD; Odocoileus hemionus) from Arizona and California were tested for evidence of infection with several tick-borne pathogens, including species of Ehrlichia, Anaplasma, Babesia, and Borrelia. Of 125 mule deer tested from Arizona, 29 (23%) and 11 (9%) had antibodies reactive to E. chaffeensis and A. phagocytophilum by indirect immunofluorescent antibody testing, respectively; none of the six MD tested from California were seropositive. Using a commercial competitive ELISA kit, antibodies reactive to Anaplasma spp. were detected in 19 (15%) MD from Arizona and four of six (67%) MD from California. Polymerase chain reaction (PCR) testing for tick-borne pathogens was conducted on blood samples from 29 MD from Arizona and 11 MD from California. Twenty-two of 29 (75.9%) MD from Arizona had PCR evidence of infection with at least one tick-borne pathogen. We detected an Anaplasma sp. in 19 of 29 (65.5%) MD and a Babesia sp. in 10 of 29 (34%) MD. Sequencing of these amplicons indicated that the Anaplasma sp. was the same that had previously been detected in MD from California and the Babesia sp. was similar to one previously detected in a reindeer (Rangifer tarandus tarandus) from California. All of the California MD had evidence of infection with a tick-borne pathogen. Two different species of Anaplasma spp. were detected in MD from California, eight of of 11 MD were infected with an Anaplasma sp., and three of 11 MD were infected with A. ovis. This is the first report of a mule deer naturally infected with A. ovis. Ten of 11 MD from California were infected with a Babesia-like organism previously associated with human disease, and a single MD was PCR positive for Borrelia coriaceae, which has been associated with epizootic bovine abortion. Together, these data suggest that MD in northern Arizona and eastern California are exposed to several pathogens of human and veterinary importance.
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Affiliation(s)
- Michael J Yabsley
- Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, The University of Georgia, Athens, Georgia 30602, USA.
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Machado RZ, Duarte JMB, Dagnone AS, Szabó MPJ. Detection of Ehrlichia chaffeensis in Brazilian marsh deer (Blastocerus dichotomus). Vet Parasitol 2006; 139:262-6. [PMID: 16621285 DOI: 10.1016/j.vetpar.2006.02.038] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Revised: 01/26/2006] [Accepted: 02/24/2006] [Indexed: 11/22/2022]
Abstract
Ehrlichia chaffeensis was detected for the first time in blood samples from Brazilian marsh deers (Blastocerus dichotomus) captured in the marshes of Parana River in Southeast Brazil in 1998. Seven EDTA-blood samples from deers were analyzed by PCR and nested PCR for presence of Ehrlichia chaffeensis, Ehrlichia ewingii, Ehrlichia canis, Neoriickettsia risticii, Anaplasma phagocytophilum and Anaplasma marginale. Three samples showed positive reactions for E. chaffeensis and Anaplasma marginale. None contained detectable A. phagocytophilum, E. ewingii, E. canis or Neorickettsia risticii DNA. In Brazil, the wild marsh deer may be a natural reservoir of the agents that cause human monocytotropic ehrlichiosis and ruminant erythrocytic anaplasmosis.
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Affiliation(s)
- Rosangela Zacarias Machado
- Universidade Estadual Paulista, UNESP-Campus de Jaboticabal, Departamento de Patologia Veterinária, FCAV/UNESP-Rodovia de Acesso Paulo Donato Castellane, s/n - Jaboticabal, SP, Brazil.
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Affiliation(s)
- Gordon E Schutze
- University of Arkansas for Medical Sciences, College of Medicine, and Arkansas Children's Hospital, Little Rock, AR, USA
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22
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Santos-Silva MM, Sousa R, Santos AS, Melo P, Encarnação V, Bacellar F. Ticks parasitizing wild birds in Portugal: detection of Rickettsia aeschlimannii, R. helvetica and R. massiliae. Exp Appl Acarol 2006; 39:331-8. [PMID: 16897568 DOI: 10.1007/s10493-006-9008-3] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2005] [Accepted: 05/14/2006] [Indexed: 05/11/2023]
Abstract
From January 2002 to December 2004, 152 ticks were collected from 40 wild birds recovered in Santo André Natural Reserve and Monsanto Forestal Park, Portugal mainland. Five ticks species were identified from 22 species of birds, and new host record were provided for some species. In addition, 32 (21%) ticks were screened by PCR to detect infections with agents belonging to order Rickettsiales: Anaplasma phagocytophilum, Ehrlichia chaffeensis, and Rickettsia spp. PCR amplicons were obtained in 5 (15.6%) tick samples. Rickettsia DNA exhibiting gltA sequences similar to those of Rickettsia aeschilimannii, R. helvetica and R. massiliae were identified in Hyalomma marginatum, Ixodes ventalloi and in Rhipicephalus turanicus, respectively. This is the first report of rickettsiae infections in ticks collected from wild birds in Portugal. Giving the results presented above wild birds play an important role in the maintenance and dissemination of several tick species and associated rickettsiae.
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Affiliation(s)
- Maria Margarida Santos-Silva
- Centro de Estudos de Vectores e Doenças Infecciosas, Instituto Nacional de Saúde Dr. Ricardo Jorge, Avenida da Liberdade 5, 2965-575, Aguas de Moura, Portugal.
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Bell CA, Patel R. A real-time combined polymerase chain reaction assay for the rapid detection and differentiation of Anaplasma phagocytophilum, Ehrlichia chaffeensis, and Ehrlichia ewingii. Diagn Microbiol Infect Dis 2005; 53:301-6. [PMID: 16263231 DOI: 10.1016/j.diagmicrobio.2005.06.019] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2005] [Accepted: 06/30/2005] [Indexed: 10/25/2022]
Abstract
A rapid real-time polymerase chain reaction (PCR) assay capable of the simultaneous detection and differentiation of Anaplasma phagocytophilum, Ehrlichia chaffeensis, and Ehrlichia ewingii was developed using the LightCyclertrade mark instrument (Roche Applied Sciences, Indianapolis, IN). The assay targets the operon groEL of the heat shock protein. Base pair mismatches in amplified DNA in regions of detection probe hybridization allowed organism differentiation by melting curve analysis. The analytical sensitivity was at least 10 copies per reaction. DNA extracts from 59 specimens previously confirmed positive for A. phagocytophilum (n = 37), E. chaffeensis (n = 19), or E. ewingii (n = 3) were used to evaluate the assay. All of the specimens positive for 1 of the 3 organisms by conventional PCR were likewise positive by the LightCycler method. Sensitivity and specificity were at least 100% compared with conventional PCR. This assay provides a rapid method for the detection and differentiation of the causative agents of human ehrlichiosis in the United States.
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Affiliation(s)
- Constance A Bell
- Division of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA.
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Chahan B, Jian Z, Xuan X, Sato Y, Kabeya H, Tuchiya K, Itamoto K, Okuda M, Mikami T, Maruyama S, Inokuma H. Serological evidence of infection of Anaplasma and Ehrlichia in domestic animals in Xinjiang Uygur Autonomous Region area, China. Vet Parasitol 2005; 134:273-8. [PMID: 16169663 DOI: 10.1016/j.vetpar.2005.07.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2005] [Revised: 07/24/2005] [Accepted: 07/25/2005] [Indexed: 11/28/2022]
Abstract
Serological methods were utilized to detect Anaplasma and Ehrlichia infection in domestic animals in Xinjiang Uygur Autonomous Region, China. By using an indirect immunofluorescence assay (IFA), antibodies that reacted with Anaplasmaphagocytophilum and Ehrlichiachaffeensis were detected mainly in ruminants kept on pastureland in Altai, Ili and Kashgar area. Antibody titers up to 1:320 were recorded. These results indicate that ruminants kept in these areas may be infected with some species of Anaplasma and Ehrlichia.
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Affiliation(s)
- Bayin Chahan
- Veterinary College, Xingjiang Agricultural University, Urumqui, China
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25
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Fritz CL, Bronson LR, Smith CR, Crawford-Miksza L, Yeh E, Schnurr D. Clinical, epidemiologic, and environmental surveillance for ehrlichiosis and anaplasmosis in an endemic area of northern California. J Vector Ecol 2005; 30:4-10. [PMID: 16007950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Two forms of tick-borne leukocytotropic rickettsioses have been recognized in California since the mid-1990s: human monocytic ehrlichiosis (HME) caused by Ehrlichia chaffeensis and human granulocytic anaplasmosis (HGA) caused by Anaplasma phagocytophilum. Between 1997 and 1999, two cases of HME and four cases of HGA were diagnosed in residents of southern Humboldt County, California. Environmental followup at case-patients' residences revealed dense populations of Ixodes pacificus ticks, particularly in grassy roadside areas. PCR evidence of A. phagocytophilum was detected in approximately 2.0% of I. pacificus; E. chaffeensis was not detected in any of 625 ticks tested. Serologic antibody to A. phagocytophilum was detected in two of 54 participants in a community epidemiologic study; one of these also had antibody to E. chaffeensis. Over 85% of study participants reported finding a tick on themselves in the preceding 12 mo. Residents of southern Humboldt County are at significant risk of tick bites and should take appropriate prevention measures to avoid infection with rickettsia and other tick-transmitted pathogens.
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Affiliation(s)
- Curtis L Fritz
- Division of Communicable Disease Control, California Department of Health Services, Sacramento,CA 95899-7413, USA
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26
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Yabsley MJ, Wimberly MC, Stallknecht DE, Little SE, Davidson WR. Spatial analysis of the distribution of Ehrlichia chaffeensis, causative agent of human monocytotropic ehrlichiosis, across a multi-state region. Am J Trop Med Hyg 2005; 72:840-50. [PMID: 15964974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/03/2023] Open
Abstract
Ehrlichia chaffeensis, which causes human monocytotrophic ehrlichiosis (HME), is an important emerging tick-borne pathogen in the southeastern and southcentral United States. The endemnicity probability of E. chaffeensis and, by implication, locations with risk for HME, was predicted by using two modeling methods. This is first large-scale study to use geospatial analyses to estimate the distribution of E. chaffeensis, and it was conducted using data from a prototypic surveillance system that used white-tailed deer as natural sentinels. Analyses included the E. chaffeensis serostatus for 563 counties from 18 states. Both kriging and logistic regression models provided very reliable portrayals of E. chaffeensis occurrence and predicted that E. chaffeensis distribution had good concordance with human case data. The integration of a deer surveillance system with geospatial analyses was useful in developing HME risk maps that will be useful for identifying high-risk areas for public health interventions such as prevention and control efforts.
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Affiliation(s)
- Michael J Yabsley
- Southeastern Cooperative Wildlife Disease Study, D. B. Warnell School of Forest Resources, and Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, Georgia 30602, USA.
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Abstract
A 56-year-old man with a history of Wegener granulomatosis presented with 6 days of sinus congestion, fever, malaise, myalgias, episcleritis, and a morbilliform rash. An exacerbation of Wegener granulomatosis was the principal concern because of the frequency of flares in that disease. The patient developed acute renal failure, thrombocytopenia, transaminitis, and, finally, severe myocarditis that led to congestive heart failure. Additional history-taking and the evolution of his clinical features led to empirical treatment with doxycycline for human monocytic ehrlichiosis (HME). The diagnosis of HME was confirmed by both a polymerase chain reaction assay for Ehrlichia chaffeensis and by the demonstration of morulae within peripheral blood mononuclear cells. The patient improved promptly following institution of doxycycline, and his cardiac function returned to normal over a period of 4 months.
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Affiliation(s)
- John H Stone
- Johns Hopkins Vasculitis Center, Division of Rheumatology, Johns Hopkins Bayview Medical Center, Baltimore, Md 21224, USA.
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28
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Mixson TR, Ginsberg HS, Campbell SR, Sumner JW, Paddock CD. Detection of Ehrlichia chaffeensis in adult and nymphal Amblyomma americanum (Acari: Ixodidae) ticks from Long Island, New York. J Med Entomol 2004; 41:1104-1110. [PMID: 15605650 DOI: 10.1603/0022-2585-41.6.1104] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The lone star tick, Amblyomma americanum (L.), has increased in abundance in several regions of the northeastern United States, including areas of Long Island, NY. Adult and nymphal stage A. americanum collected from several sites on Long Island were evaluated for infection with Ehrlichia chaffeensis, the causative agent of human monocytic ehrlichiosis (HME), by using a nested polymerase chain reaction assay. Fifty-nine (12.5%) of 473 adults and eight of 113 pools of five nymphs each (estimated minimum prevalence of infection 1.4%) contained DNA of E. chaffeensis. These data, coupled with the documented expansion of lone star tick populations in the northeastern United States, confirm that E. chaffeensis is endemic to many areas of Long Island and that HME should be considered among the differential diagnoses of the many distinct tick-borne diseases that occur in this region.
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Affiliation(s)
- Tonya R Mixson
- Viral and Rickettsial Zoonoses Branch, Division of Viral and Rickettsial Disease, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA
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Wagner ER, Bremer WG, Rikihisa Y, Ewing S, Needham GR, Unver A, Wang X, Stich RW. Development of a p28-based PCR assay for Ehrlichia chaffeensis. Mol Cell Probes 2004; 18:111-6. [PMID: 15051120 PMCID: PMC3066156 DOI: 10.1016/j.mcp.2003.10.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2003] [Accepted: 10/20/2003] [Indexed: 11/29/2022]
Abstract
Detection of Ehrlichia chaffeensis is necessary to study interactions between the parasite and its vertebrate and invertebrate hosts. The purpose of this study was to develop a sensitive, specific PCR assay for E. chaffeensis based on the outer membrane protein gene, p28. Candidate primer sets were identified and ranked based on annealing scores, similarities to three major p28 sequence clusters, dissimilarity to E. canis p30, an ortholog of p28, and the proximities of flanking primer sequences for nested PCR. The relative sensitivities of five optimized single-step and two nested PCR assays were determined, and the most sensitive assay was found to be a single-step PCR that was as much as 1000-fold more sensitive than a standard 16S rDNA-based nested PCR assay. This p28-based PCR assay amplified the target amplicon from isolates representative of all three major clusters of known p28 sequences, and this assay did not amplify template prepared from either of the two species most closely related to E. chaffeensis, E. canis and E. muris. These results indicate that this sensitive, specific and isolate-universal single-step PCR assay will be a useful tool in characterizing the transmission of this important zoonotic pathogen.
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Affiliation(s)
- Elizabeth R. Wagner
- Department of Veterinary Preventive Medicine, The Ohio State University, 1900 Coffey Road, Columbus, OH 43210-1092, USA
| | - William G. Bremer
- Department of Veterinary Preventive Medicine, The Ohio State University, 1900 Coffey Road, Columbus, OH 43210-1092, USA
| | - Yasuko Rikihisa
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - S.A. Ewing
- Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Glen R. Needham
- Department of Entomology, The Ohio State University, Columbus, OH 43210, USA
| | - Ahmet Unver
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Xueqi Wang
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210, USA
| | - Roger W. Stich
- Department of Veterinary Preventive Medicine, The Ohio State University, 1900 Coffey Road, Columbus, OH 43210-1092, USA
- Corresponding author. Tel.: + 1-614-292-9702; fax: + 1-614-292-4142. E-mail address: (R.W. Stich)
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30
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Park JH, Heo EJ, Choi KS, Dumler JS, Chae JS. Detection of antibodies to Anaplasma phagocytophilum and Ehrlichia chaffeensis antigens in sera of Korean patients by western immunoblotting and indirect immunofluorescence assays. Clin Diagn Lab Immunol 2004; 10:1059-64. [PMID: 14607867 PMCID: PMC262439 DOI: 10.1128/cdli.10.6.1059-1064.2003] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Two hundred seventy one serum samples from South Korean patients were tested to detect antibodies against Anaplasma phagocytophilum (the human granulocytic ehrlichiosis agent) and Ehrlichia chaffeensis (the human monocytic ehrlichiosis agent) by indirect fluorescent-antibody assay (IFA) and the Western blot assay. These sera were collected from patients with symptoms of high fever. The rate of seropositivity for Orientia tsutsugamushi was 50.9% by IFA at the Public Health & Environmental Research Institute and National Institute of Health in South Korea. By IFA, 30 (11.1%) and 39 (14.4%) of the serum samples reacted with A. phagocytophilum and E. chaffeensis antigens, respectively. By the Western blot assays, 24 (8.9%) and 29 (10.7%) of the serum samples reacted with purified A. phagocytophilum and E. chaffeensis protein antigens, respectively. This report strengthens other evidence regarding the presence of A. phagocytophilum and E. chaffeensis infections in humans in South Korea.
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Affiliation(s)
- Jin-Ho Park
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins Medical Institution, Baltimore, Maryland 21287, USA
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31
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Varela AS, Stallknecht DE, Yabsley MJ, Moore VA, Davidson WR, Little SE. Experimental infection of white-tailed deer (Odocoileus virginianus) with Ehrlichia chaffeensis by different inoculation routes. J Wildl Dis 2004; 39:881-6. [PMID: 14733284 DOI: 10.7589/0090-3558-39.4.881] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The infection dynamics of the tick-transmitted organism Ehrlichia chaffeensis were investigated in white-tailed deer (Odocoileus virginianus) using different routes of inoculation. Six deer were each inoculated with 5.4 x 10(6) DH82 cells infected with E. chaffeensis (Arkansas strain) by three different routes: intravenous (n = 2), subcutaneous (n = 2), and intradermal (n = 2). Two control deer were inoculated with uninfected cells. Infections were monitored for 54 days and were continued in one deer from each E. chaffeensis inoculated group for an additional 31 days. All deer inoculated with E. chaffeensis seroconverted (> or = 1: 64) and became 16S rDNA polymerase chain reaction and/or cell culture positive by post-inoculation day 15. There was no apparent (difference in susceptibility to infection between deer inoculated by different routes for the first 50 days based on detection of E. chaffeensis infection by PCR assay of blood or culture isolation. These results demonstrate infection of (deer by intradermal and subcutaneous routes for the first time.
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Affiliation(s)
- Andrea S Varela
- Department of Medical Microbiology and Parasitology, College of Veterinary Medicine, The University of Georgia, Athens, Georgia 30602, USA
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Abstract
Human ehrlichiosis is a potentially fatal tick-borne illness if not treated promptly. Ehrlichia infection is difficult to diagnose as the organism does not grow in standard blood culture medium and serological confirmation of infection takes several days to weeks. The most timely way of confirming Ehrlichia infection is identification of characteristic cytoplasmic morulae in peripheral blood leukocytes. A total of 23 patients with clinical and laboratory findings suggesting a rickettsial infection were tested for Ehrlichia using polymerase chain reaction and culture: 16 cases contained Ehrlichia DNA by polymerase chain reaction (15 E. chaffeensis, one E. ewingii), including 14 cases in which the blood culture grew Ehrlichia. The cases that contained Ehrlichia DNA by polymerase chain reaction had lower mean white blood cell and platelet counts and more numerous atypical lymphocytes and pronounced toxic change than cases in which Ehrlichia DNA was not detected. Cytoplasmic morulae were identified on peripheral blood smears in six (five E. chaffeensis, one E. ewingii) of 16 (38%) of the cases that contained Ehrlichia DNA, including 4/4 (100%) immunocompromised and 2/12 (17%) immunocompetent patients. Morulae were present in monocytes in E. chaffeensis-infected cases and granulocytes in the E. ewingii-infected case. In two immunocompromised patients, the number of infected cells was 1-10%, but in four patients it was <0.2%. In conclusion, peripheral blood film examination is diagnostic in a substantial number of Ehrlichia infections, particularly in immunocompromised patients. The number of infected white blood cells may be less than 0.2%, requiring examination of more than 500 white blood cells. Associated changes prompting careful film review include prominent toxic granulation and atypical large granular lymphocytes.
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Affiliation(s)
- Katherine S Hamilton
- Department of Pathology, Division of Infectious Disease, Vanderbilt University Medical Center, Nashville, TN 37232-5310, USA.
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Abstract
To determine the incidence, clinical and laboratory characteristics, and utility of molecular diagnosis of human monocytotropic ehrlichiosis (HME) in the primary care setting, we conducted a prospective study in an outpatient primary care clinic in Cape Girardeau, Missouri. One hundred and two patients with a history of fever for 3 days (>37.7°C), tick bite or exposure, and no other infectious disease diagnosis were enrolled between March 1997 and December 1999. HME was diagnosed in 29 patients by indirect immunofluorescent antibody assay and polymerase chain reaction (PCR). Clinical and laboratory manifestations included fever (100%), headache (72%), myalgia or arthralgia (69%), chills (45%), weakness (38%), nausea (38%), leukopenia (60%), thrombocytopenia (56%), and elevated aspartate aminotransferase level (52%). Hospitalization occurred in 41% of case-patients. PCR sensitivity was 56%; specificity, 100%. HME is a prevalent, potentially severe disease in southeastern Missouri that often requires hospitalization. Because clinical presentation of HME is nonspecific, PCR is useful in the diagnosis of acute HME.
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Affiliation(s)
- Juan P Olano
- Department of Pathology, University of Texas Medical Branch, Galveston, Texas 77555-0747, USA.
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DeShields A, Borman-Shoap E, Peters JE, Gaudreault-Keener M, Arens MQ, Storch GA. Detection of pathogenic Ehrlichia in ticks collected at acquisition sites of human ehrlichiosis in Missouri. Mo Med 2004; 101:132-6. [PMID: 15119113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
We collected 385 ticks from sites in Missouri associated with human monocytic ehrlichiosis. Using PCR, we detected E. chaffeensis or E. ewingii in 2 of 19 pools of adult Amblyomma americanum, 0 of 32 pools of Dermacentor variabilis, and 6 (18%) of 39 pools of unspeciated nymphal ticks from 3 of 6 sites associated with disease and one site not associated with disease. We also detected a variant of A. phagocytophila in one nymph pool.
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Affiliation(s)
- Alex DeShields
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
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Abstract
Human monocytic ehrlichiosis is an emerging tick-borne disease caused by the rickettsia Ehrlichia chaffeensis. To examine the role of helper T cells in host resistance to this macrophage-tropic bacterium, we assessed E. chaffeensis infections in three mouse strains with differing functional levels of helper T cells. Wild-type, C57BL/6J mice resolved infections in approximately 2 weeks. Major histocompatibility complex class II (MHCII) knockout, B6.129-Abb(tm1) mice lacking helper T cells developed persistent infections that were not resolved even after several months. CD4+ T-cell-deficient, B6.129S6-Cd4(tm1Knw) mice cleared the infection, but the clearance took 2 weeks longer than it did for wild-type mice. C57BL/6J mice resolved infection more rapidly following a second experimental challenge, but B6.129S6-Cd4(tm1Knw) mice did not. The B6.129S6-Cd4(tm1Knw) mice also developed active E. chaffeensis-specific immunoglobulin G responses that were slightly lower in concentration and slower to develop than that observed in C57BL/6J mice. E. chaffeensis-specific cytotoxic T cells were not detected following a single bacterial challenge in any mouse strain, including wild-type C57BL/6J mice. However, the cytotoxic T-cell activity developed in all three mouse strains, including the MHCII and CD4+ T-cell knockouts, when challenged with a second E. chaffeensis infection. The data reported here suggest that the cell-mediated immunity, orchestrated by CD4+ T cells is critical for conferring rapid clearance of E. chaffeensis.
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Affiliation(s)
- Roman R Ganta
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas 66506, USA.
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36
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Lásiková S, Moravcová L, Pícha D, Holecková D, Zdárský E. [Detection of anti-Ehrlichia antibodies and direct demonstration of Ehrlichia nucleic acid using the polymerase chain reaction (PCR) in patients in the Czech Republic]. Klin Mikrobiol Infekc Lek 2004; 10:25-9. [PMID: 15100980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
PURPOSE OF THE STUDY In patients presenting symptoms with a suspicion of ehrlichiosis we determined antiehrlichia antibodies and investigated the presence of Ehrlichia nucleic acid in the plasma. MATERIAL AND METHODS In our group were 46 patients with tick sucks in their case history, who presented symptoms compatible with ehrlichiosis. Anti-Ehrlichia antibodies were determined by an indirect immunofluorescent test with a commercial kit from MRL Diagnostics. Ehrlichia DNA was detected using a nested PCR - the target sequence was a part of the antigen Anaplasma phagocytophilum. RESULTS Antibodies against HGE agents were demonstrated in 28 % of the patients; 10.5 % of the patients had in their serum antibodies reacting to the Ehrlichia chaffeensis antigen. The nucleic acid of A. phagocytophilum was detected in 11 % of the patients. CONCLUSIONS The Czech population is relatively often exposed to Ehrlichia infections. Although most cases are asymptomatic, we should bear in mind this diagnosis, especially in immunodeficient patients, where early treatment may prevent a complicated course of the disease.
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Affiliation(s)
- Sárka Lásiková
- Department of Infectious Diseases, 2nd Medical Faculty, Charles University, Bulovka Hospital, 18081 Prague 8, Czech Republic.
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37
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Yabsley MJ, Little SE, Sims EJ, Dugan VG, Stallknecht DE, Davidson WR. Molecular variation in the variable-length PCR target and 120-kilodalton antigen genes of Ehrlichia chaffeensis from white-tailed deer (Odocoileus virginianus). J Clin Microbiol 2004; 41:5202-6. [PMID: 14605163 PMCID: PMC262520 DOI: 10.1128/jcm.41.11.5202-5206.2003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Genes encoding two surface-expressed antigens of Ehrlichia chaffeensis, the variable-length PCR target (VLPT) and the 120-kDa antigen, which contain variable numbers of tandem repeats, were characterized for E. chaffeensis from white-tailed deer (Odocoileus virginianus). Both genes from infected deer contained numbers of repeats similar to those reported in genes from humans and ticks, although a new variant of the 120-kDa antigen gene containing five repeat units and coinfection with multiple VLPT and 120-kDa antigen gene genetic types were detected. Sequence analysis of both genes revealed more nucleotide variation than previously reported for E. chaffeensis from infected humans or ticks. This is the most extensive study of E. chaffeensis VLPT and 120-kDa antigen gene genetic variation to date and is the first to examine genetic variation in E. chaffeensis from a nonhuman vertebrate host.
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Affiliation(s)
- Michael J Yabsley
- Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, The University of Georgia, Athens, Georgia 30602, USA.
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Goddard J, Sumner JW, Nicholson WL, Paddock CD, Shen J, Piesman J. Survey of ticks collected in Mississippi for Rickettsia, Ehrlichia, and Borrelia species. J Vector Ecol 2003; 28:184-189. [PMID: 14714667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
From November 1999 through October 2000, we tested ticks collected from vegetation as well as from deer, dogs, and humans for spotted fever group (SFG) rickettsiae, Ehrlichia chaffeensis, and Borrelia spp. spirochetes. A total of 149 adult ticks representing four species was collected from 11 collection sites from southwestern to northern Mississippi. Amblyomma americanum was most commonly collected (n=68), followed by Ixodes scapularis (n=53). The bird tick, Ixodes brunneus (usually rare), was the third most commonly collected tick (n=17). Eleven Dermacentor variabilis were also collected. Ticks were cut longitudinally to make smears on three microscope slides. The remaining body parts were frozen at -65 degrees C for additional testing. Tick smears were stained by direct immunofluorescence assays (DFA) for Rickettsia spp. and Borrelia spp., while indirect immunofluorescence assays (IFA) were used for Ehrlichia spp. The corresponding tick for each positive smear was evaluated using PCR analysis. None of the 149 ticks tested was DFA positive for Borrelia spp. However, smears of 30 (20%) and 32 (22%) ticks reacted with anti-E. chaffeensis sera and anti-R. rickettsii conjugate (known to react with several members of the spotted fever group), respectively. None of the ticks staining with the IFA for Ehrlichia was positive for E. chaffeensis using PCR. However, 23 (72%) of 32 FA-positive ticks for SFG rickettsiae yielded amplicons of the appropriate size when tested using a PCR assay for SFG rickettsiae, corresponding to an overall infection rate with SFG rickettsiae among the collected ticks of 15%. Smears of 12 (71%) of 17 I. brunneus revealed abundant bacilliform bacteria. PCR amplification of DNA from a single I. brunneus containing these bacteria was performed using universal primers for the 16S rRNA gene as well as Borrelia-specific primers. The predominant sequence obtained using the universal primers did not match any sequence in GenBank, but it showed 91% identity with an endosymbiont of Acanthoamoeba. Other sequences represented in the top 50 Basic Local Alignment Search (BLAST) scores were primarily from soil bacteria, although some similarity to several Anaplasma species and Ehrlichia risticii was indicated. The significance of this finding remains undetermined.
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Affiliation(s)
- Jerome Goddard
- Mississippi Department of Health, Jackson, MS 39215-1700, USA
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Yabsley MJ, Dugan VG, Stallknecht DE, Little SE, Lockhart JM, Dawson JE, Davidson WR. Evaluation of a PrototypeEhrlichia chaffeensisSurveillance System using White-Tailed Deer (Odocoileus virginianus) as Natural Sentinels. Vector Borne Zoonotic Dis 2003; 3:195-207. [PMID: 14733672 DOI: 10.1089/153036603322662183] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The natural history of Ehrlichia chaffeensis, the causative agent of human monocytotropic ehrlichiosis, includes the lone star tick (LST, Amblyomma americanum) as a vector and white-tailed deer (WTD; Odocoileus virginianus) as both a natural reservoir of E. chaffeensis and a major host of LST. The goal of the current study was to implement and evaluate a prototype surveillance system to delineate the geographic distribution of E. chaffeensis using WTD as natural sentinels. To accomplish this goal, serologic testing using the indirect immunofluorescent antibody (IFA) test was performed on WTD serum samples, and to confirm serologic results, polymerase chain reaction (PCR) assays and culture isolation were conducted. Considerations relevant to the applicability of a surveillance system utilizing WTD were analyzed (e.g., age and gender relationships to serologic status, adequacy of sample sizes needed to distinguish between uninfected and infected populations, presence of LST, and ability to detect stability and spread of E. chaffeensis in WTD populations). Of 3275 WTD serologically tested, 549 (47%) from 17 of 18 states had antibodies reactive to E. chaffeensis (IFA titer > or = 1:128). No difference between age groups or gender was noted with serologic testing, thus these variables would not be a concern for a surveillance system using WTD. Significantly more deer in younger age groups (< or = 1.5 yr) were PCR and culture positive, and 46% of 122 seropositive WTD populations were confirmed positive by PCR or culture isolation. A significant association between LST infestation and E. chaffeensis seroreactivity was noted. Furthermore, the surveillance system was able to detect stability of E. chaffeensis within WTD populations and also spread to new populations, both of which were associated with LST status. These data clearly demonstrate that WTD are useful as natural sentinels for this emerging human pathogen, and establish a prototypical framework for a WTD surveillance system.
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Affiliation(s)
- Michael J Yabsley
- Southeastern Cooperative Wildlife Disease Study, College of Veterinary Medicine, The University of Georgia, Athens, Georgia 30602.
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Abstract
This article reviews molecular techniques that have been developed and are effective in the clinical laboratory for the emerging tick-borne infections, ehrlichiosis and Lyme disease.
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Affiliation(s)
- J Stephen Dumler
- Division of Medical Microbiology, Department of Pathology, The Johns Hopkins University School of Medicine, Ross Research Building, Room 624, 720 Rutland Avenue, Baltimore, MD 21205, USA.
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Kim CM, Kim MS, Park MS, Park JH, Chae JS. Identification of Ehrlichia chaffeensis, Anaplasma phagocytophilum, and A. bovis in Haemaphysalis longicornis and Ixodes persulcatus ticks from Korea. Vector Borne Zoonotic Dis 2003; 3:17-26. [PMID: 12804377 DOI: 10.1089/153036603765627424] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A total of 1,467 tick (1,463 of Haemaphysalis longicornis, three of Ixodes persulcatus and one of I. turdus) collected from nine provinces of Korea were examined by TaqMan real-time PCR for the presence of Ehrlichia and Anaplasma species. One set of primers and a probe were designed for detection of all of the Ehrlichia and Anaplasma species. Template DNAs (total 803) were prepared either from pools of larvae, nymphs, adult males and females, or from the salivary gland and midgut of adult ticks. Only DNAs positive in TaqMan PCR were examined for A. phagocytophilum with nested PCR and for E. chaffeensis with PCR. Four A. phagocytophilum 16S rRNA gene PCR products were sequenced for comparison with sequences previously reported. Amplification of a 16S rRNA gene fragment of Ehrlichia and Anaplasma species was observed in 364 tick DNAs (45.3% of the total). Of these 364 positive ticks, species-specific PCRs confirmed that 35 H. longicornis and one I. persulcatus were positive for A. phagocytophilum and one I. persulcatus was positive in E. chaffeensis. Except for one (AB-GGHL, GenBank accession number [GAN] AF470698), three of the four 16S rRNA gene fragment sequences of the A. phagocytophilum-positive samples were similar or identical to the sequences of variants of A. phagocytophilum deposited in GenBank. The 16S rRNA gene fragment sequence of AB-GGHL was similar to that of Anaplasma (Ehrlichia) bovis 16S rRNA (GAN U03775). The identities of the Anaplasmataceae genus and species DNA in the 327 ticks that could not be confirmed infected with either E. chaffeensis, A. phagocytophilum, or A. bovis are not known. This study is the first to demonstrate the presence of E. chaffeensis, A. phagocytophilum and A. bovis in Korean ticks.
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Affiliation(s)
- Chul-Min Kim
- Bio-safety Research Institute, College of Veterinary Medicine, Chonbuk National University, Jeonju, Jeonbuk, Korea
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Abstract
Ehrlichia chaffeensis, an obligate intracellular, tick-transmitted bacterium, is susceptible to antibody-mediated host defense, but the mechanism by which this occurs is not understood. One possible explanation is that antibodies directly access the bacteria in the extracellular environment of the host, perhaps during bacterial intercellular transfer. Accordingly, we investigated whether bacteria could be found outside of host cells during infection. Host cell-free plasma obtained from infected mice was found to contain ehrlichiae, and the host cell-free ehrlichiae readily transferred disease to susceptible SCID recipients. The host cell-free ehrlichiae were found during infection of both immunocompetent BALB/c and immunocompromised BALB/c-scid mice and reached levels as high as 10(8)/ml in plasma during persistent infection in SCID mice. Approximately 10% of the blood-borne bacteria were found outside of host cells. Although it is generally accepted that replication of ehrlichiae occurs only within host cells, the cell-free bacteria were shown to undergo DNA replication and cell division in vitro for 3 to 5 days when incubated at 37 degrees C in plasma. Paradoxically, both infectivity and virulence were lost after 24 h of ex vivo culture. The data indicate that E. chaffeensis is exposed to the extracellular milieu during infection, presumably during intercellular transfer, and reveal that these intracellular bacteria do not require the environment of the host cell for replication. Our findings reveal a possible mechanism by which antibodies can access the intracellular bacteria upon their release into the extracellular milieu and mediate host defense and also have implications for understanding the replication and transmission of this vector-borne pathogen.
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Affiliation(s)
- Julia Shu-Yi Li
- Wadsworth Center, New York State Department of Health, and Department of Biomedical Sciences, School of Public Health, University at Albany, Albany, New York 12201, USA
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Abstract
A real-time PCR assay was developed for the detection of Ehrlichia chaffeensis. The assay is species specific and provides quantitative results in the range 10 to 10(10) gene copies. The assay is not inhibited by the presence of tick, human, or mouse DNA and is compatible with high sample throughput. The assay was compared with previously described assays for E. chaffeensis.
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Affiliation(s)
- Amanda D Loftis
- Viral and Rickettsial Zoonoses Branch, Division of Viral and Rickettsial Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
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Holden K, Boothby JT, Anand S, Massung RF. Detection of Borrelia burgdorferi, Ehrlichia chaffeensis, and Anaplasma phagocytophilum in ticks (Acari: Ixodidae) from a coastal region of California. J Med Entomol 2003; 40:534-539. [PMID: 14680123 DOI: 10.1603/0022-2585-40.4.534] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A study was conducted in Santa Cruz County to estimate the prevalence and distribution of the agents of Lyme disease, human granulocytic (HGE), and human monocytic (HME) ehrlichiosis in 1,187 adult ixodid ticks collected from eight public-use recreation areas over a 2-yr period. Borrelia burgdorferi, the causative agent of Lyme disease, was detected by a polymerase chain reaction (PCR) in 44 of 776 (5.67%) Ixodes pacificus ticks and in 3 of 58 (5.17%) Dermacentor variabilis ticks. Anaplasma phagocytophilum, the causative agent of HGE, was detected by PCR in 48 (6.19%) I. pacificus ticks and 5 (8.62%) D. variabilis ticks. Ehrlichia chaffeensis, the causative agent of HME, was detected by nested PCR in just five (0.64%) I. pacificus ticks and four (6.9%) D. variabilis ticks. Interestingly, eight (1.03%) I. pacificus ticks were co-infected with B. burgdorferi and A. phagocytophilum, and just one (0.12%) tick was co-infected with B. burgdorferi and E. chaffeensis. Less than 1% of 353 Dermacentor occidentalis ticks showed evidence of infection with any of the agents tested. To our knowledge, this is the first reported identification of A. phagocytophilum and E. chaffeensis in D. occidentalis ticks from California This study represents the first extensive survey of Lyme and the ehrlichial diseases across multiple areas of Santa Cruz County, and suggests that prevalence of B. burgdorferi in Santa Cruz County may be higher than other areas of the state.
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Affiliation(s)
- Kevin Holden
- Department of Biological Sciences, San Jose State University, San Jose, CA 95192, USA
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Abstract
Ehrlichia chaffeensis causes human monocytic ehrlichiosis (HME) that usually includes fever, myalgias, and pancytopenia and, in 80% to 90% of patients, elevations in serum transaminase levels. Thus, the pathology of liver injury was studied in liver tissues from 7 patients with laboratory-confirmed HME. H&E and immunohistochemical stains for E chaffeensis and leukocyte markers were examined. Scattered lobular lymphohistiocytic foci and diffuse lymphohistiocytic infiltration and Kupffer cell hyperplasia with increased phagocytosis frequently were present. Various degrees of liver cell injury and death were observed. Cholestasis was evident in 6 cases, sometimes with bile duct epithelial injury. Rare to abundant E chaffeensis-infected mononuclear cells infiltrating lobules or portal regions or in Kupffer cells were observed in 5 patients. The inflammation was out of proportion to the infection in 6 cases. In the absence of infected hepatocytes or biliary epithelial cells, these findings suggest that host inflammatory or immune responses contribute to the liver injury seen in HME.
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Affiliation(s)
- Ann E Sehdev
- Dept of Pathology, Johns Hopkins Medical Institutions, Meyer B1-193, 600 N Wolfe St, Baltimore, MD 21287, USA
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Abstract
The various ticks collected from different areas of China were examined for the existence of ehrlichial agents by polymerase chain reaction (PCR) with genus- or species-specific primers designed on the basis of ehrlichial 16S rRNA genes and sequence analyses. In southern China, E. chaffeensis was detected in Amblyomma testudinarium ticks from infested cattle, Haemaphysalis yeni ticks from hare, and Ixodes ovatus ticks from Muntiacus reevesi. E. canis was identified in Rhipicephalus sanguineus ticks from dogs and Boophilus microplus ticks from goats. A new species of the genus Ehrlichia, closely related to E. chaffeensis, and Anaplasma marginale were found in B. microplus ticks from cattle in Tibet. In northern China, E. chaffeensis was detected in Dermacentor silvarum and I. persulcatus ticks; the granulocytic ehrlichial agents were detected in I. persulcatus ticks from an area where Lyme disease is endemic. Canine ehrlichiosis was found in southern China and E. canis and E. platys were identified in dogs; human ehrlichioses were demonstrated by amplifying the 16S rRNA genes of E. chaffeensis and granulocytic ehrlichial agents from patients' blood specimens. In comparison of 16S rRNA gene sequences, the sequences of E. chaffeensis, E. canis, and E. platys in China were found to be different from that in other countries at certain nucleotide positions. These results reveal that a variety of tick-borne ehrlichial agents and diseases exist in China, and the ehrlichial agents and their tick-vectors are same as or different from that in other countries at species or strain levels.
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Affiliation(s)
- Bohai Wen
- Department of Microbiology, Beijing Institute of Microbiology and Epidemiology, PR China.
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Lane RS, Foley JE, Eisen L, Lennette ET, Peot MA. Acarologic risk of exposure to emerging tick-borne bacterial pathogens in a semirural community in northern California. Vector Borne Zoonotic Dis 2003; 1:197-210. [PMID: 12653148 DOI: 10.1089/153036601753552567] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
An acarologic study was conducted in a semirural community in northern California to determine the relative abundance of, and the prevalence of infection with, three emerging bacterial pathogens in the western black-legged tick (Ixodes pacificus). These included the agents causing Lyme disease (Borrelia burgdorferi), human granulocytic ehrlichiosis [Ehrlichia phagocytophila (formerly Ehrlichia equi)], and human monocytic ehrlichiosis (Ehrlichia chaffeensis). The study area in Sonoma County consisted of two properties each with four residents and an uninhabited adjacent comparison area. Six of the eight residents had been either physician-diagnosed or serodiagnosed previously with Lyme disease, and, of these, one also had been serodiagnosed with human monocytic ehrlichiosis. Direct immunofluorescent/culture assays and bacterial species-specific polymerase chain reaction assays were used to test whole ticks individually for presence of B. burgdorferi and Ehrlichia spp., respectively. Overall, 6.5% of the nymphal (n = 589) and 1.6% of the adult ticks (n = 318) from the same generational cohort were found to contain B. burgdorferi. In contrast, none of 465 nymphs and 9.9% of 202 adults were infected with E. phagocytophila. Excised tissues from another 95 adult ticks yielded a comparable E. phagocytophila infection prevalence of 13.7%. E. chaffeensis was not detected in either nymphal or adult ticks. Using a combination of culture and polymerase chain reaction assays, coinfection of I. pacificus adults with B. burgdorferi and E. phagocytophila was demonstrated for the first time. The marked disparity in the infection prevalence of these pathogens in nymphal and adult ticks suggests that their maintenance cycles are inherently different.
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Affiliation(s)
- R S Lane
- Division of Insect Biology, University of California, Berkeley, CA 94720, USA.
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Steiert JG, Gilfoy F. Infection rates of Amblyomma americanum and Dermacentor variabilis by Ehrlichia chaffeensis and Ehrlichia ewingii in southwest Missouri. Vector Borne Zoonotic Dis 2003; 2:53-60. [PMID: 12653298 DOI: 10.1089/153036602321131841] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Both Ehrlichia chaffeensis and Ehrlichia ewingii are causative agents of human ehrlichiosis. Both pathogens are transmitted to humans through the bite of an infected lone star tick (Amblyomma americanum). Since Missouri has a high incidence of human monocytic ehrlichiosis, we investigated the prevalence of E. chaffeensis- and E. ewingii-infected A. americanum and Dermacentor variabilis (American dog tick) ticks to help assess the relative risk for humans exposed to these vectors. We used a nested polymerase chain reaction assay for the detection of ehrlichial DNA in the collected ticks. Infection rates for both ehrlichial species were calculated from the assay results for each of the tick species. E. chaffeensis was found to be present in 9.8% of adult A. americanum ticks (57 of 579) and 6.7% of D. variabilis ticks (eight of 120). E. ewingii DNA was present at an infection rate of 5.4% in adult A. americanum (31 of 579) and 3.3% of D. variabilis ticks (four of 120). A minimum infection rate for nymph pools of A. americanum was 1.7% for E. chaffeensis and 0.6% for E. ewingii.
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Affiliation(s)
- John G Steiert
- Department of Biology, Southwest Missouri State University, Springfield, MO 65804, USA.
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Abstract
Specific identification of ehrlichiae in the tissues and determination of their distribution is difficult. In this study, an in-situ hybridization method was developed to detect ehrlichial 16S rRNA in tissue specimens from mice experimentally infected with the HF strain. This strain is closely related to Ehrlichia chaffeensis, the agent of human monocytic ehrlichiosis. HF strain-specific 16S rRNA was detected in endothelial cells and monocyte-macrophages in the liver, lungs, bone marrow, spleen, lymph nodes, and large and small intestinal tissues. The results suggest that the in-situ hybridization method with a digoxigenin-labelled RNA probe specific to ehrlichial 16S rRNA will be useful for post-mortem diagnosis and for the histopathological investigation of ehrlichial infection.
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Affiliation(s)
- H Okada
- Department of Veterinary Pathology, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido, 069-8501, Japan
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Abstract
Ehrlichia chaffeensis is an obligately intracellular, tick-transmitted bacterium that is maintained in nature in a cycle involving at least one and perhaps several vertebrate reservoir hosts. The moderate to severe disease caused by E. chaffeensis in humans, first identified in 1986 and reported for more than 1,000 patients through 2000, represents a prototypical "emerging infection." Knowledge of the biology and natural history of E. chaffeensis, and of the epidemiology, clinical features, and laboratory diagnosis of the zoonotic disease it causes (commonly referred to as human monocytic ehrlichiosis [HME]) has expanded considerably in the period since its discovery. In this review, we summarize briefly the current understanding of the microbiology, pathogenesis, and clinical manifestations associated with this pathogen but focus primarily on discussing various ecological factors responsible for the recent recognition of this important and potentially life-threatening tick-borne disease. Perhaps the most pivotal element in the emergence of HME has been the staggering increases in white-tailed deer populations in the eastern United States during the 20th century. This animal serves as a keystone host for all life stages of the principal tick vector (Amblyomma americanum) and is perhaps the most important vertebrate reservoir host for E. chaffeensis. The contributions of other components, including expansion of susceptible human populations, growth and broadening geographical distributions of other potential reservoir species and A. americanum, and improvements in confirmatory diagnostic methods, are also explored.
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Affiliation(s)
- Christopher D Paddock
- Viral and Rickettsial Zoonoses Branch, Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
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