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Mathews KO, Phalen D, Norris JM, Stenos J, Toribio JA, Wood N, Graves S, Sheehy PA, Nguyen C, Bosward KL. Serological Evidence of Exposure to Spotted Fever Group and Typhus Group Rickettsiae in Australian Wildlife Rehabilitators. Pathogens 2021; 10:pathogens10060745. [PMID: 34204809 PMCID: PMC8231516 DOI: 10.3390/pathogens10060745] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/15/2021] [Accepted: 05/28/2021] [Indexed: 12/14/2022] Open
Abstract
Rickettsioses are arthropod-borne zoonotic diseases, several of which occur in Australia. This study aimed to assess the exposure levels and risk factors for Rickettsia spp. among Australian wildlife rehabilitators (AWRs) using serology, PCR and a questionnaire. Antibody titres against Spotted Fever Group (SFG), Typhus Group (TG) and Scrub Typhus Group (STG) antigens were determined using an immunofluorescence assay. PCR targeting the gltA gene was performed on DNA extracts from whole blood and serum. Logistic regression was used to identify risk factors associated with seropositivity. Of the 27 (22.1%; 27/122) seropositive participants all were seropositive for SFG, with 5/27 (4.1%) also positive for TG. Of the 27 positive sera, 14.8% (4/27) were further classified as exposure to R. australis, 3.7% (1/27) to R. honei, 3.7% (1/27) to R. felis and 77.8% (21/27) were classified as ‘indeterminate’—most of which (85.7%; 18/21) were indeterminate R. australis/R. honei exposures. Rickettsia DNA was not detected in whole blood or serum. Rehabilitators were more likely to be seropositive if more than one household member rehabilitated wildlife, were older than 50 years or had occupational animal contact. These findings suggest that AWRs are at increased risk of contracting Rickettsia-related illnesses, however the source of the increased seropositivity remains unclear.
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Affiliation(s)
- Karen O. Mathews
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, NSW 2570, Australia; (D.P.); (J.M.N.); (J.-A.T.); (P.A.S.)
- Correspondence: (K.O.M.); (K.L.B.)
| | - David Phalen
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, NSW 2570, Australia; (D.P.); (J.M.N.); (J.-A.T.); (P.A.S.)
| | - Jacqueline M. Norris
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, NSW 2570, Australia; (D.P.); (J.M.N.); (J.-A.T.); (P.A.S.)
| | - John Stenos
- Australian Rickettsial Reference Laboratory, University Hospital Geelong, Geelong, VIC 3220, Australia; (J.S.); (S.G.); (C.N.)
| | - Jenny-Ann Toribio
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, NSW 2570, Australia; (D.P.); (J.M.N.); (J.-A.T.); (P.A.S.)
| | - Nicholas Wood
- Discipline of Paediatrics and Child Health, Sydney Medical School, The University of Sydney, Camperdown, NSW 2006, Australia;
- National Centre for Immunisation Research and Surveillance, Westmead, NSW 2145, Australia
| | - Stephen Graves
- Australian Rickettsial Reference Laboratory, University Hospital Geelong, Geelong, VIC 3220, Australia; (J.S.); (S.G.); (C.N.)
| | - Paul A. Sheehy
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, NSW 2570, Australia; (D.P.); (J.M.N.); (J.-A.T.); (P.A.S.)
| | - Chelsea Nguyen
- Australian Rickettsial Reference Laboratory, University Hospital Geelong, Geelong, VIC 3220, Australia; (J.S.); (S.G.); (C.N.)
| | - Katrina L. Bosward
- Sydney School of Veterinary Science, Faculty of Science, The University of Sydney, Camden, NSW 2570, Australia; (D.P.); (J.M.N.); (J.-A.T.); (P.A.S.)
- Correspondence: (K.O.M.); (K.L.B.)
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2
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Dehhaghi M, Kazemi Shariat Panahi H, Holmes EC, Hudson BJ, Schloeffel R, Guillemin GJ. Human Tick-Borne Diseases in Australia. Front Cell Infect Microbiol 2019; 9:3. [PMID: 30746341 PMCID: PMC6360175 DOI: 10.3389/fcimb.2019.00003] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 01/07/2019] [Indexed: 12/26/2022] Open
Abstract
There are 17 human-biting ticks known in Australia. The bites of Ixodes holocyclus, Ornithodoros capensis, and Ornithodoros gurneyi can cause paralysis, inflammation, and severe local and systemic reactions in humans, respectively. Six ticks, including Amblyomma triguttatum, Bothriocroton hydrosauri, Haemaphysalis novaeguineae, Ixodes cornuatus, Ixodes holocyclus, and Ixodes tasmani may transmit Coxiella burnetii, Rickettsia australis, Rickettsia honei, or Rickettsia honei subsp. marmionii. These bacterial pathogens cause Q fever, Queensland tick typhus (QTT), Flinders Island spotted fever (FISF), and Australian spotted fever (ASF). It is also believed that babesiosis can be transmitted by ticks to humans in Australia. In addition, Argas robertsi, Haemaphysalis bancrofti, Haemaphysalis longicornis, Ixodes hirsti, Rhipicephalus australis, and Rhipicephalus sanguineus ticks may play active roles in transmission of other pathogens that already exist or could potentially be introduced into Australia. These pathogens include Anaplasma spp., Bartonella spp., Burkholderia spp., Francisella spp., Dera Ghazi Khan virus (DGKV), tick-borne encephalitis virus (TBEV), Lake Clarendon virus (LCV), Saumarez Reef virus (SREV), Upolu virus (UPOV), or Vinegar Hill virus (VINHV). It is important to regularly update clinicians' knowledge about tick-borne infections because these bacteria and arboviruses are pathogens of humans that may cause fatal illness. An increase in the incidence of tick-borne infections of human may be observed in the future due to changes in demography, climate change, and increase in travel and shipments and even migratory patterns of birds or other animals. Moreover, the geographical conditions of Australia are favorable for many exotic ticks, which may become endemic to Australia given an opportunity. There are some human pathogens, such as Rickettsia conorii and Rickettsia rickettsii that are not currently present in Australia, but can be transmitted by some human-biting ticks found in Australia, such as Rhipicephalus sanguineus, if they enter and establish in this country. Despite these threats, our knowledge of Australian ticks and tick-borne diseases is in its infancy.
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Affiliation(s)
- Mona Dehhaghi
- Neuroinflammation Group, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia.,Department of Microbial Biotechnology, School of Biology and Centre of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Tehran, Iran
| | - Hamed Kazemi Shariat Panahi
- Neuroinflammation Group, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia.,Department of Microbial Biotechnology, School of Biology and Centre of Excellence in Phylogeny of Living Organisms, College of Science, University of Tehran, Tehran, Iran
| | - Edward C Holmes
- Charles Perkins Centre, School of Life and Environmental Sciences and Sydney Medical School, Marie Bashir Institute for Infectious Diseases and Biosecurity, The University of Sydney, Sydney, NSW, Australia
| | - Bernard J Hudson
- Department of Microbiology and Infectious Disease, Royal North Shore Hospital, Sydney, NSW, Australia
| | | | - Gilles J Guillemin
- Neuroinflammation Group, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
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3
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Izzard L, Chung M, Dunning Hotopp J, Vincent G, Paris D, Graves S, Stenos J. Isolation of a divergent strain of Rickettsia japonica from Dew's Australian bat Argasid ticks (Argas (Carios) dewae) in Victoria, Australia. Ticks Tick Borne Dis 2018; 9:1484-1488. [PMID: 30025798 PMCID: PMC6135670 DOI: 10.1016/j.ttbdis.2018.07.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 07/08/2018] [Accepted: 07/10/2018] [Indexed: 11/20/2022]
Abstract
A divergent strain of Rickettsia japonica was isolated from a Dew's Australian bat argasid tick, Argas (Carios) dewae, collected in southern Victoria, Australia and a full-genome analysis along with sequencing of 5 core gene fragments was undertaken. This isolate was designated Rickettsia japonica str. argasii (ATCC VR-1665, CSUR R179).
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Affiliation(s)
- Leonard Izzard
- Australian Rickettsial Reference Laboratory, Geelong, Victoria, Australia
| | - Matthew Chung
- University of Maryland School of Medicine, Baltimore, Maryland, USA
| | | | - Gemma Vincent
- Australian Rickettsial Reference Laboratory, Geelong, Victoria, Australia
| | - Daniel Paris
- Department of Medicine, Swiss Tropical and Public Health Institute, Basel, Switzerland
| | - Stephen Graves
- Australian Rickettsial Reference Laboratory, Geelong, Victoria, Australia
| | - John Stenos
- Australian Rickettsial Reference Laboratory, Geelong, Victoria, Australia.
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4
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Stewart A, Armstrong M, Graves S, Hajkowicz K. Rickettsia australis and Queensland Tick Typhus: A Rickettsial Spotted Fever Group Infection in Australia. Am J Trop Med Hyg 2017; 97:24-29. [PMID: 28719297 DOI: 10.4269/ajtmh.16-0915] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Rickettsia australis, the etiologic agent of Queensland tick typhus (QTT), is increasingly being recognized as a cause of community-acquired acute febrile illness in eastern Australia. Changing human population demographics, climate change, and increased understanding of expanding vector distribution indicate QTT is an emerging public health threat. This review summarizes the epidemiology, pathogenesis, clinical features, treatment principles, and future directions of this disease. Increased recognition of QTT will enable consideration of and prompt treatment of R. australis infection by clinicians in Australia.
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Affiliation(s)
- Adam Stewart
- Department of Infectious Diseases, Royal Brisbane and Women's Hospital, Brisbane, Australia
| | - Mark Armstrong
- Department of Infectious Diseases, Royal Brisbane and Women's Hospital, Brisbane, Australia
| | - Stephen Graves
- Australian Rickettsial Reference Laboratory, Geelong, Australia
| | - Krispin Hajkowicz
- School of Medicine, University of Queensland, Brisbane, Australia.,Department of Infectious Diseases, Royal Brisbane and Women's Hospital, Brisbane, Australia
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5
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Stewart A, Armstrong M, Graves S, Hajkowicz K. Clinical Manifestations and Outcomes of Rickettsia australis Infection: A 15-Year Retrospective Study of Hospitalized Patients. Trop Med Infect Dis 2017; 2:tropicalmed2020019. [PMID: 30270878 PMCID: PMC6082078 DOI: 10.3390/tropicalmed2020019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 06/13/2017] [Accepted: 06/17/2017] [Indexed: 11/16/2022] Open
Abstract
Queensland tick typhus (QTT; Rickettsia australis) is an important cause of community-acquired acute febrile illness in eastern Australia. Cases of QTT were identified retrospectively from 2000 to 2015 at five sites in Northern Brisbane through a pathology database. Those included had a fourfold rise in spotted fever group (SFG)-specific serology, a single SFG-specific serology ≥ 256 or SFG-specific serology ≥ 128 with a clinically consistent illness. Cases were excluded on the basis of clinical unlikelihood of QTT infection. Thirty-six cases were included. Fever was found in 34/36 (94%) patients. Rash occurred in 83% of patients with maculopapular being the dominant morphology (70%). Thrombocytopenia, lymphopenia, and raised transaminases were common and occurred in 58%, 69%, and 89% of patients, respectively. Thirty-one of 36 (86%) patients received antibiotic therapy (usually doxycycline) and the time to correct antibiotic (from admission) ranged from 3 to 120 h (mean 45.5 h). Four of 36 (11%) required intensive care unit (ICU) admission for severe sepsis and end-organ support. There were no deaths. QTT has a wide range of clinical and laboratory features. Early and appropriate antimicrobial therapy is important and may prevent severe disease. Further prospective studies are required to identify factors associated with severe infection and sepsis.
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Affiliation(s)
- Adam Stewart
- Department of Infectious Diseases, Royal Brisbane and Women's Hospital, Brisbane, QLD 4029, Australia.
| | - Mark Armstrong
- Department of Infectious Diseases, Royal Brisbane and Women's Hospital, Brisbane, QLD 4029, Australia.
| | - Stephen Graves
- Australian Rickettsial Reference Laboratory, Geelong, VIC 3220, Australia.
| | - Krispin Hajkowicz
- Department of Infectious Diseases, Royal Brisbane and Women's Hospital, Brisbane, QLD 4029, Australia.
- School of Medicine, University of Queensland, Brisbane, QLD 4067, Australia.
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6
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Derne B, Weinstein P, Musso D, Lau C. Distribution of rickettsioses in Oceania: past patterns and implications for the future. Acta Trop 2015; 143:121-33. [PMID: 25446172 DOI: 10.1016/j.actatropica.2014.10.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Revised: 10/04/2014] [Accepted: 10/17/2014] [Indexed: 11/16/2022]
Abstract
Rickettsioses present a threat to human health worldwide, but relatively little is known on their epidemiology and ecology in Oceania. These bacteria are the cause of potentially fatal febrile illnesses in humans (categorized into scrub typhus, typhus group and spotted fever group rickettsioses). They are transmitted by arthropod vectors such as ticks, mites, fleas and lice, which are associated with vertebrate host animals including rodents and companion animals. We conducted a search in the scientific and grey literature of Rickettsia spp. and Orientia tsutsugamushi within the Oceania region. Human case reports, human serosurveys and PCR-based testing of vectors and host animals reviewed here highlight the widespread distribution of these pathogens in the region, with the majority of human serological and vector surveys reporting positive results. These findings suggest that rickettsioses may have a significantly higher burden of disease in Oceania than is currently appreciated due to diagnostic challenges. Furthermore, consideration of the ecology and risk factors for rickettsioses reported for Oceania suggests that their importance as a cause of undifferentiated acute febrile illness may grow in the future: environmental and social changes driven by predicted climate change and population growth have the potential to lead to the emergence of rickettsioses as a significant public health problem in Oceania.
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Affiliation(s)
- Bonnie Derne
- Queensland Children's Medical Research Institute, Level 4 Foundation Building, Royal Children's Hospital, Herston Rd, Herston, Brisbane 4029, QLD, Australia; Barbara Hardy Institute, City East Campus, University of South Australia, GPO Box 2471, Adelaide 5000, SA, Australia.
| | - Philip Weinstein
- School of Pharmacy and Medicine, City East Campus, University of South Australia, GPO Box 2471, Adelaide, 5000, SA, Australia; School of Biological Sciences, North Terrace Campus, University of Adelaide, Adelaide 5000, SA, Australia
| | - Didier Musso
- Unit of Emerging Infectious Diseases, Institut Louis Malardé, BP 30, Pape'ete 98713, Tahiti, French Polynesia
| | - Colleen Lau
- Queensland Children's Medical Research Institute, Level 4 Foundation Building, Royal Children's Hospital, Herston Rd, Herston, Brisbane 4029, QLD, Australia; Research School of Population Health, Australian National University, Acton 2601, ACT, Australia
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7
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Kuo CC, Huang JL, Lin TE, Wang HC. Detection of Rickettsia spp. and host and habitat associations of fleas (Siphonaptera) in eastern Taiwan. MEDICAL AND VETERINARY ENTOMOLOGY 2012; 26:341-350. [PMID: 22390200 DOI: 10.1111/j.1365-2915.2012.01009.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Rickettsia typhi and Rickettsia felis (Rickettsiales: Rickettsiaceae) are two rickettsiae principally transmitted by fleas, but the detection of either pathogen has rarely been attempted in Taiwan. Of 2048 small mammals trapped in eastern Taiwan, Apodemus agrarius Pallas (24.5%) and Mus caroli Bonhote (24.4%) (both: Rodentia: Muridae) were the most abundant, and M. caroli hosted the highest proportion of fleas (63.9% of 330 fleas). Two flea species were identified: Stivalius aporus Jordan and Rothschild (Siphonaptera: Stivaliidae), and Acropsylla episema Rothschild (Siphonaptera: Leptopsyllidae). Nested polymerase chain reaction targeting parts of the ompB and gltA genes showed six fleas to be positive for Rickettsia spp. (3.8% of 160 samples), which showed the greatest similarity to R. felis, Rickettsia japonica, Rickettsia conorii or Rickettsia sp. TwKM01. Rickettsia typhi was not detected in the fleas and Rickettsia co-infection did not occur. Both flea species were more abundant during months with lower temperatures and less rainfall, and flea abundance on M. caroli was not related to soil hardness, vegetative height, ground cover by litter or by understory layer, or the abundance of M. caroli. Our study reveals the potential circulation of R. felis and other rickettsiae in eastern Taiwan, necessitating further surveillance of rickettsial diseases in this region. This is especially important because many novel rickettsioses are emerging worldwide.
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Affiliation(s)
- C C Kuo
- Research and Diagnostic Centre, Centres for Disease Control, Taipei, Taiwan
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8
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Abstract
As newly recognized rickettsial diseases and rickettsial pathogens increase in scope and magnitude, several elements related to the concept of emerging rickettsioses deserve consideration. Newly identified rickettsiae may be mildly pathogenic, or perhaps even nonpathogenic, and have little direct impact on human or animal health, yet nonetheless wield considerable influence on the epidemiology and ecology of historically recognized diseases. In this context "new" rickettsioses provide a lens through which "old" rickettsioses are more accurately represented. Predicting pathogen from nonpathogen is not an exact science, particularly as so few rickettsiae have been broadly accepted as nonpathogenic by contemporary rickettsiologists. However, various factors relating to specific physiologic requirements and molecular machinery of the particular rickettsia, as well as characteristics of its invertebrate host that either position or exclude the rickettsia from infecting a human host, must be considered. Close inspection of mild or atypical forms of historically recognized rickettsioses and a greater emphasis on culture- and molecular-based diagnostic techniques are the keys to identifying future rickettsial agents of disease.
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Affiliation(s)
- Christopher D Paddock
- Infectious Disease Pathology Branch, Division of Viral and Rickettsial Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia 30333, USA.
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9
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Parola P, Paddock CD, Raoult D. Tick-borne rickettsioses around the world: emerging diseases challenging old concepts. Clin Microbiol Rev 2005; 18:719-56. [PMID: 16223955 PMCID: PMC1265907 DOI: 10.1128/cmr.18.4.719-756.2005] [Citation(s) in RCA: 716] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
During most of the 20th century, the epidemiology of tick-borne rickettsioses could be summarized as the occurrence of a single pathogenic rickettsia on each continent. An element of this paradigm suggested that the many other characterized and noncharacterized rickettsiae isolated from ticks were not pathogenic to humans. In this context, it was considered that relatively few tick-borne rickettsiae caused human disease. This concept was modified extensively from 1984 through 2005 by the identification of at least 11 additional rickettsial species or subspecies that cause tick-borne rickettsioses around the world. Of these agents, seven were initially isolated from ticks, often years or decades before a definitive association with human disease was established. We present here the tick-borne rickettsioses described through 2005 and focus on the epidemiological circumstances that have played a role in the emergence of the newly recognized diseases.
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Affiliation(s)
- Philippe Parola
- Unité des Rickettsies, CNRS UMR 6020, IFR 48, Université de la Méditerranée, Faculté de Médecine, 13385 Marseille Cedex 5, France
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10
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Rudakov NV, Shpynov SN, Samoilenko IE, Tankibaev MA. Ecology and epidemiology of spotted fever group Rickettsiae and new data from their study in Russia and Kazakhstan. Ann N Y Acad Sci 2003; 990:12-24. [PMID: 12860595 DOI: 10.1111/j.1749-6632.2003.tb07332.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Rickettsiae represent a wide range of pathogenicity from classic and new pathogens to endosymbionts of eukaryotic cells. Recent studies of rickettsiae have widened the number of representatives of genus Rickettsia, especially in the spotted fever group (SFG). Rickettsiae of SFG are tick-borne microorganisms with effective transovarial and transstadial transmission. The main hosts are ticks (Dermacentor, Rhipicephalus, Haemophysalis, Ixodes, and Amlyomma). Strategy of maintenance of tick microorganisms is vector-type transfer and tropism to endothelial cells or blood cells of animals. The main epidemiological characteristics of SFG rickettsioses are different kinds of anthropogenic activity and connection of morbidity with seasonal tick activity. Two other important characteristics are quantitative and qualitative heterogeneity of its populations (different genotypes of Rickettsia in the same territory and species of ticks, for example) and coexistence of different tick microorganisms (rickettsiae, borreliae, ehrlichiae, tick-borne encephalitis complex viruses, etc.). The role of new rickettsial genotypes in infectious diseases is poorly understood. Simultaneous study of ticks after bites, blood and skin biopsies of patients may be used for detection of spectrum of tick-borne pathogens in mixed natural foci. Interference between rickettsiae with different virulence may affect its populations and levels of morbidity.
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Affiliation(s)
- N V Rudakov
- Omsk Research Institute of Natural Foci Infections, Omsk, Russia.
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11
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Whitworth T, Popov V, Han V, Bouyer D, Stenos J, Graves S, Ndip L, Walker D. Ultrastructural and genetic evidence of a reptilian tick, Aponomma hydrosauri, as a host of Rickettsia honei in Australia: possible transovarial transmission. Ann N Y Acad Sci 2003; 990:67-74. [PMID: 12860602 DOI: 10.1111/j.1749-6632.2003.tb07339.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In 1993, a novel rickettsia was isolated from the blood of inhabitants of Flinders Island, Australia, with acute febrile illnesses. This rickettsia was found to be a new species of spotted fever group (SFG) rickettsia, eventually named Rickettsia honei. The suspected ectoparasite vector of this rickettsia has yet to be identified. The purpose of this study was to evaluate the presence of this rickettsial species in a suspected tick vector, Aponomma hydrosauri, by DNA sequencing and electron microscopy (EM). Ticks collected from an Australian blue-tongued lizard on Flinders Island and a copperhead snake in Tasmania were demonstrated to be infected with R. honei by PCR, DNA sequencing, and EM. Rickettsiae were found in ultrathin sections of salivary glands, malpighian tubules, and midgut epithelial cells. In a previous study with a R. honei-infected tick from Flinders Island, rickettsiae were found in the nuclei of midgut epithelial cells, and EM also revealed the presence of rickettsiae in the cytosol of oocytes and immature eggs, suggesting transovarial transmission. These results implicate A. hydrosauri as a possible host of R. honei on Flinders Island and Tasmania and also provide evidence favoring transovarial maintenance of R. honei.
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Affiliation(s)
- Ted Whitworth
- Department of Pathology and WHO Collaborating Center for Tropical Diseases, University of Texas Medical Branch, Galveston 77555-0609, USA
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12
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Affiliation(s)
- G Cowan
- University of London--North Thames, 33 Millman Street, London WC1N 3EJ, UK.
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13
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Xu W, Raoult D. Distribution of immunogenic epitopes on the two major immunodominant proteins (rOmpA and rOmpB) of Rickettsia conorii among the other rickettsiae of the spotted fever group. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 1997; 4:753-63. [PMID: 9384303 PMCID: PMC170654 DOI: 10.1128/cdli.4.6.753-763.1997] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Forty-four monoclonal antibodies were raised against strain Seven, the type strain of Rickettsia conorii. Of these 44 monoclonal antibodies, 13, 27, and 4 were demonstrated to be directed against the 116-kDa protein (rOmpA), the 124-kDa protein (rOmpB), and lipopolysaccharide-like antigen, respectively. The antiprotein monoclonal antibodies were found to be directed against 29 distinct epitopes, which were located on the two major immunodominant proteins discussed above. Further analysis showed that strain-specific epitopes were located on the rOmpA protein and species- and subgroup-specific epitopes were located on the rOmpB protein. R. conorii Manuel, Indian tick typhus rickettsia, and Kenya tick typhus rickettsia also possessed all 29 epitopes, whereas the other rickettsiae of the spotted fever group (SFG) expressed between 3 and 25 epitopes, with the exception of Rickettsia helvetica, R. akari, and R. australis which did not possess any epitopes. Additional analyses by Western immunoblotting confirmed that the epitopes shared among the SFG rickettsiae were located on the same two high-molecular-mass proteins as on R. conorii. However, although epitopes on the R. conorii rOmpB protein were expressed on the rOmpB proteins of most other SFG rickettsiae, some were found on the rOmpA proteins of R. aeschlimannii, R. rickettsii, and R. rhipicephali. Both proteins possessing the common epitopes were found to have different sizes in the SFG rickettsial species. The different distributions of common epitopes in the SFG rickettsiae were also used to build a taxonomic dendrogram, which demonstrated that all the R. conorii strains formed a relatively independent cluster within the SFG rickettsiae and was generally consistent with previously proposed taxonomies.
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Affiliation(s)
- W Xu
- Unité des Rickettsies, CNRS UPRES-A 6020, Faculté de Médecine, Université de la Mediterranée, Marseille, France
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14
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Raoult D, Roux V. Rickettsioses as paradigms of new or emerging infectious diseases. Clin Microbiol Rev 1997; 10:694-719. [PMID: 9336669 PMCID: PMC172941 DOI: 10.1128/cmr.10.4.694] [Citation(s) in RCA: 587] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Rickettsioses are caused by species of Rickettsia, a genus comprising organisms characterized by their strictly intracellular location and their association with arthropods. Rickettsia species are difficult to cultivate in vitro and exhibit strong serological cross-reactions with each other. These technical difficulties long prohibited a detailed study of the rickettsiae, and it is only following the recent introduction of novel laboratory methods that progress in this field has been possible. In this review, we discuss the impact that these practical innovations have had on the study of rickettsiae. Prior to 1986, only eight rickettsioses were clinically recognized; however, in the last 10 years, an additional six have been discovered. We describe the different steps that resulted in the description of each new rickettsiosis and discuss the influence of factors as diverse as physicians' curiosity and the adoption of molecular biology-based identification in helping to recognize these new infections. We also assess the pathogenic potential of rickettsial strains that to date have been associated only with arthropods, and we discuss diseases of unknown etiology that may be rickettsioses.
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Affiliation(s)
- D Raoult
- Unité des Rickettsies, Faculté de Médecine, CNRS UPRESA 6020, Marseille, France.
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Xu W, Raoult D. Production of monoclonal antibodies against Rickettsia massiliae and their use in antigenic and epidemiological studies. J Clin Microbiol 1997; 35:1715-21. [PMID: 9196180 PMCID: PMC229828 DOI: 10.1128/jcm.35.7.1715-1721.1997] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Rickettsiae are gram-negative, obligate intracellular bacteria which have historically been divided into three groups: the typhus group, the scrub typhus group, and the spotted fever group (SFG). Recently, several new SFG rickettsiae have been characterized, and most of these species are associated with ticks and have, as yet, no known pathogenicity toward humans. Rickettsia massiliae, which is widely distributed in Europe and Africa, is one such rickettsia. In order to investigate the antigenic relationships between R. massiliae and other rickettsial species and to develop a more convenient methodology for identifying R. massiliae, we produced monoclonal antibodies against the type strain (Mtu1T) of R. massiliae by fusing immunized splenocytes with SP2/0-Ag14 myeloma cells. A panel of 16 representatives were selected from the 163 positive hybridomas identified on initial screening, and their secreted monoclonal antibodies were further characterized. The reactivities of these 16 monoclonal antibodies with a large panel of rickettsial species were assessed by the microimmunofluorescence assay. All species of the SFG rickettsiae reacted with the monoclonal antibodies directed against epitopes on lipopolysaccharide, which is the common antigen among the SFG rickettsiae. Some closely related species of the SFG, such as Bar29, "R. aeschlimanni," and R. rhipicephali, showed strong cross-reactivities with the monoclonal antibodies directed against epitopes on the two major high-molecular-mass heat-labile proteins (106 and 120 kDa). In addition, species-specific monoclonal antibodies demonstrated that R. massiliae is antigenically different from other rickettsial species. Moreover, these species-specific monoclonal antibodies were successfully used for identifying R. massiliae in the ticks collected from southern France, and are therefore potentially useful tools in the identification and investigation of R. massiliae in ticks in large-scale field work.
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Affiliation(s)
- W Xu
- Unité des Rickettsies, CNRS UPRES-A 6020, Faculté de Médecine, Université de la Mediterranée, Marseille, France
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17
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Roux V, Fournier PE, Raoult D. Differentiation of spotted fever group rickettsiae by sequencing and analysis of restriction fragment length polymorphism of PCR-amplified DNA of the gene encoding the protein rOmpA. J Clin Microbiol 1996; 34:2058-65. [PMID: 8862558 PMCID: PMC229190 DOI: 10.1128/jcm.34.9.2058-2065.1996] [Citation(s) in RCA: 328] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Currently, the genotypic identification of the spotted fever group (SFG) rickettsiae is based on restriction fragment length polymorphism analysis of PCR-amplified genes coding for the enzyme citrate synthase and the surface proteins rOmpA and rOmpB. A set of useful restriction endonucleases was found following comparison of Rickettsia rickettsii and R. prowazekii sequences. However, by using three PCR amplifications and four enzyme digestions with this set, it was impossible to differentiate between all of the known serotypes of the SFG rickettsiae. We amplified by PCR and sequenced using an automated laser fluorescent DNA sequencer a fragment of the gene encoding the protein rOmpA from 21 serotypes of the SFG rickettsiae. A 632-bp amplification product was obtained for most of the strains, although no product could be obtained by using R. akari, R. australis, R. helvetica, and R. bellii DNAs. We found a characteristic sequence for all strains studied except the two isolates of R. massiliae, isolates GS and Mtul. Using the software package BISANCE, we determined the restriction map of this fragment and identified five potentially useful endonucleases, RsaI, AluI, PstI, XbaI, and AvaII. We confirmed the computer analysis-derived profiles by PCR-restriction fragment length polymorphism analysis. The combination of the profiles obtained after digestion of the PCR product by RsaI and PstI allowed for the differentiation of 16 strains. The use of AluI and XbaI allowed for the characterization of R. parkeri and strain HA-91, respectively. R. africae and strain S were differentiated by AvaII digestion. Thus, using a single PCR amplification, we were able to differentiate all of the SFG rickettsiae whose ompA gene was amplified by PCR.
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Affiliation(s)
- V Roux
- Unité des Rickettsies, Faculté de Médecine, Centre National de la Recherche Scientifique EPJ 0054, Marseille, France
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Baird RW, Stenos J, Stewart R, Hudson B, Lloyd M, Aiuto S, Dwyer B. Genetic variation in Australian spotted fever group rickettsiae. J Clin Microbiol 1996; 34:1526-30. [PMID: 8735110 PMCID: PMC229054 DOI: 10.1128/jcm.34.6.1526-1530.1996] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Rickettsiae were isolated by cell culture of buffy coat blood from six patients with spotted fever from southeastern Australia and Flinders Island in Bass Strait. The isolates were genetically compared with two previous Rickettsia australis patient isolates. The genus-specific 17-kDA genes from the isolates were compared after DNA amplification and restriction fragment analysis of the amplified DNA. This comparison revealed that mainland rickettsial isolates from southeastern Australia were identical to two previous isolates of R. australis from northeastern Australia. Rickettsial isolates from Flinders Island were distinct from the mainland isolates. The 16S rRNA gene sequences from the isolates were determined and compared. The Flinders Island rickettsial agent was most closely related (0.3% structural divergence) to Rickettsia rickettsii, Rickettsia conorii, and Rickettsia slovaca. The Flinders Island rickettsial agent was 1.3 and 2.1% structurally divergent from R. australis and Rickettsia akari, respectively. The 16S rRNA gene sequence from the Flinders Island agent shows that this rickettsia is more closely related to the rickettsial spotted fever group than is R. australis. We conclude that there are two populations of spotted fever group rickettsiae in Australia and propose that the genetically distinct causative organism of Flinders Island spotted fever be designated Rickettsia honei. The extent of distribution and animal host reservoirs remain to be elucidated.
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Affiliation(s)
- R W Baird
- Microbiology Department, Melbourne Pathology, Collingwood, Victoria, Australia
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Affiliation(s)
- L I Kaplan
- Division of Internal Medicine, Cooper Hospital/University Medical Center, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School at Camden 08103, USA
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Balayeva NM, Eremeeva ME, Tissot-Dupont H, Zakharov IA, Raoult D. Genotype characterization of the bacterium expressing the male-killing trait in the ladybird beetle Adalia bipunctata with specific rickettsial molecular tools. Appl Environ Microbiol 1995; 61:1431-7. [PMID: 7747963 PMCID: PMC167400 DOI: 10.1128/aem.61.4.1431-1437.1995] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The male-killing ladybird beetle (LB) bacterium (AB bacterium) was analyzed with specific rickettsial molecular biology tools in the LB Adalia bipunctata strains. Eight phenotype-positive LB strains showing mortality of male embryos were amplified with rickettsial genus-specific primers from the gene for citrate synthase (CS) and the gene for a 17-kDa protein and spotted fever group-specific primers from the gene for the 120-kDa outer membrane protein (ompB). The specificity of amplification was confirmed by Southern hybridization and the absence of the above-listed gene products in three phenotype-negative LB strains. Restriction polymorphism patterns of three examined amplicons from the CS gene, 17-kDa-protein gene, and ompB gene were identical among the eight phenotype-positive LB strains and were unique among all known rickettsiae of the spotted fever and typhus groups. Amplified fragments of the CS genes of the AB bacterium, Rickettsia prowazekii Breinl, Rickettsia typhi Wilmington, Rickettsia canada 2678, and Rickettsia conorii 7 (Malish) were sequenced. The greatest differences among the above-listed rickettsial and AB bacterium CS gene sequences were between bp 1078 and 1110. Numerical analysis based on CS gene fragment sequences shows the close relationships of the AB bacterium to the genus Rickettsia. Expanding of knowledge about rickettsial arthropod vectors and participation of rickettsiae in the cytoplasmic maternal inheritance of arthropods is discussed.
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Affiliation(s)
- N M Balayeva
- Unité des Rickettsies, Centre National de la Recherche Scientifique EP J0054, Faculté de Médecine, Marseille, France
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Abstract
The term rickettsiae initially encompassed all intracellular bacteria. Early rickettsial taxonomy was based on a comparison of a few phenotypic characteristics and recently, molecular studies brought new bases for rickettsial taxonomy. All rickettsial species studied so far belong to the alpha and gamma groups of the Proteobacteria. Ehrlichiae complex groups Cowdria ruminantium, Anaplasma marginale and Wolbachia pipientis and the related parthenogenesis and cytoplasmic incompatibility bacteria, whereas Rochalimaea species group with Bartonella bacilliformis. Rickettsia tsutsugamushi may form an independent lineage, whereas molecular data allow to regroup serologically defined typhus and spotted fever group rickettsiae. The true scale of Rickettsia and Coxiella genera remain to be determined.
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Affiliation(s)
- M Drancourt
- Unité des Rickettsies Faculté de Médecine 27, Marseille, France
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