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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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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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Luce-Fedrow A, Mullins K, Kostik AP, St John HK, Jiang J, Richards AL. Strategies for detecting rickettsiae and diagnosing rickettsial diseases. Future Microbiol 2016; 10:537-64. [PMID: 25865193 DOI: 10.2217/fmb.14.141] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Rickettsial diseases and scrub typhus constitute a group of the oldest known vector-borne diseases. The cosmopolitan distribution of the vectors that transmit rickettsiae and orientiae leads to a worldwide prevalence of these diseases. Despite their significant historical status, detection and diagnosis of these diseases are still evolving today. Serological methods remain among the most prevalent techniques used for the detection/diagnosis of rickettsial diseases and scrub typhus. Molecular techniques have been instrumental in increasing the sensitivity/specificity of diagnosis, identifying new Rickettsia and Orientia species and have enhanced epidemiological capabilities when used in combination with serological methods. In this review, we discuss these techniques and their associated pros and cons.
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Affiliation(s)
- Alison Luce-Fedrow
- Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910, USA
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Chochlakis D, Ioannou I, Sandalakis V, Dimitriou T, Kassinis N, Papadopoulos B, Tselentis Y, Psaroulaki A. Spotted fever group Rickettsiae in ticks in Cyprus. MICROBIAL ECOLOGY 2012; 63:314-23. [PMID: 21833539 DOI: 10.1007/s00248-011-9926-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 07/21/2011] [Indexed: 05/24/2023]
Abstract
In two surveys conducted from March 1999 to March 2001 and from January 2004 to December 2006, a total of 3,950 ticks (belonging to ten different species) were collected from seven domestic and wild animals (goat, sheep, cattle, dog, fox, hare, and mouflon) from different localities throughout Cyprus. In order to establish their infection rate with Spotted Fever Rickettsiae (SFG), ticks were pooled and tested by polymerase chain reaction targeting gltA and ompA genes, followed by sequencing analysis. When tick pools tested positive, individual ticks were then tested one by one, and of the 3,950 ticks screened, rickettsial DNA was identified in 315 ticks (infection rate, 8%). Five SFG Rickettsiae were identified: Rickettsia aeschlimannii in Hyalomma marginatum marginatum, Rickettsia massiliae in Rhipicephalus turanicus and Rhipicephalus sanguineus, Rickettsia sibirica mongolotimonae in Hyalomma anatolicum excavatum, and a Rickettsia endosymbiont of Haemaphysalis sulcata (later described as Rickettsia hoogstraalii) in Haemaphysalis punctata. Two additional genes, 17 kDa and ompB, were targeted to characterize a new genotype of "Candidatus Rickettsia barbariae" genotype in R. turanicus, designated here as "Candidatus Rickettsia barbariae" Cretocypriensis. These results confirm the presence of a spectrum of SFG Rickettsiae on the island. Further studies are necessary to gain better knowledge on the epidemiology of SFG Rickettsiae in Cyprus.
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Affiliation(s)
- Dimosthenis Chochlakis
- Laboratory of Clinical Bacteriology, Parasitology, Zoonoses and Geographical Medicine (WHO Collaborating Center), Medical School, University of Crete, Voutes, Heraklion, Crete 71100, Greece
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Wang JM, Hudson BJ, Watts MR, Karagiannis T, Fisher NJ, Anderson C, Roffey P. Diagnosis of Queensland tick typhus and African tick bite fever by PCR of lesion swabs. Emerg Infect Dis 2009; 15:963-5. [PMID: 19523304 PMCID: PMC2727311 DOI: 10.3201/eid1506.080855] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
We report 3 cases of Queensland tick typhus (QTT) and 1 case of African tick bite fever in which the causative rickettsiae were detected by PCR of eschar and skin lesions in all cases. An oral mucosal lesion in 1 QTT case was also positive.
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Affiliation(s)
- Jin Mei Wang
- Royal North Shore Hospital, St Leonards, Sydney, Queensland, Australia
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6
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Watts MR, Benn RA, Hudson BJ, Graves S. A case of prolonged fatigue following an acute rickettsial infection. QJM 2008; 101:591-3. [PMID: 18474521 DOI: 10.1093/qjmed/hcn064] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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McBride WJH, Hanson JP, Miller R, Wenck D. Severe spotted fever group rickettsiosis, Australia. Emerg Infect Dis 2008; 13:1742-4. [PMID: 18217560 PMCID: PMC3375793 DOI: 10.3201/eid1311.070099] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
We report 3 cases of spotted fever group rickettsial infection (presumed Queensland tick typhus) in residents of northern Queensland, Australia, who had unusually severe clinical manifestations. Complications included renal failure, purpura fulminans, and severe pneumonia. Clinical illness caused by Rickettsia australis may not be as benign as previously described.
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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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Spratt DM. Australian ecosystems, capricious food chains and parasitic consequences for people. Int J Parasitol 2005; 35:717-24. [PMID: 15925595 DOI: 10.1016/j.ijpara.2005.01.014] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2004] [Revised: 12/23/2004] [Accepted: 01/10/2005] [Indexed: 11/17/2022]
Abstract
Characteristic Australian ecosystems or environments contain numerous food chains some of which may become capriciously side-tracked or appropriated by humans, with parasitic consequences for people in Australia and overseas. Twelve of 13 arboviruses affecting humans are of wildlife origin and all are transmitted by mosquitoes. In this case, transmission is thus associated with aquatic environments, many artificial. Zoonotic trematode (brachylaimiasis) and cestode (rodentoleposis) infections have been reported from semi-arid environments. Scabies and angiostrongylosis are associated with work, recreational and home environments. Four species of Rickettsia endemic in wildlife are acquired by humans from fleas, mites and ticks in bush and semi-urban environments. The enigmatic and life-threatening muspiceoid nematode, Haycocknema perplexum, is known from people associated with the natural environment in Tasmania; whether it comes from vertebrates, invertebrates, plants, soil or water is unknown. Food chains occurring in a range of Australian ecosystems and environments, some associated with feeding arthropods, others with accidental ingestion of invertebrates, may result in human exposure and infection. A range of organisms normally occurring in wildlife, domestic animals or the environment may be involved in causing human disease.
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Affiliation(s)
- David M Spratt
- CSIRO Sustainable Ecosystems, GPO Box 284, Canberra ACT 2601, Australia.
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11
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Cardeñosa N, Segura F, Raoult D. Serosurvey among Mediterranean spotted fever patients of a new spotted fever group rickettsial strain (Bar29). Eur J Epidemiol 2003; 18:351-6. [PMID: 12803376 DOI: 10.1023/a:1023654400796] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Mediterranean spotted fever is an endemic disease in Catalonia, Spain. A new spotted fever group (SFG) rickettsial strain (Bar29) of unknown pathogenicity for humans was isolated by our group, in 1996, from the dog brown tick, Rhipicephalus sanguineus. Interestingly, Rickettsia conorii was not isolated in this study. The aim of the present study was to assess the possible pathogenic role of the Bar29 strain. To this purpose, serum samples from 15 patients with Mediterranean spotted fever were obtained and tested by immunofluorescence for antibodies against four related rickettsial strains (R. conorii, R. africae, R. massiliae, and Bar29). Eight of the studied sera reacted at high titers with only R. conorii and Bar29 antigens. For five of the eight sera, the titers against Bar29 were clearly higher than for R. conorii. Four of these sera were also studied by Western blot immunoassay to confirm a specific response. Two of these sera reacted with the high-molecular-mass specific proteins of Bar29 as well as with the low-molecular-mass region (LPS antigen) whereas their reactions with R. conorii were located only on bands of the LPS. This specific response would support the possible pathogenic role of the Bar29 strain for humans. According to this finding, spotted fever caused by R. conorii and rickettsial strain Bar29 may be present in our area. The epidemiological implications of spotted fever caused by R. conorii and by rickettsial strain Bar29 in the Catalonia deserve further studies with isolation and characterization of more rickettsial strains.
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Affiliation(s)
- Neus Cardeñosa
- Infectious Disease Program, Department of Internal Medicine, Corporació Sanitària Parc Taulí, Sabadell, Barcelona, Spain
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12
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Abstract
Ticks are blood-sucking parasites of vertebrates that may embed in human skin and are therefore of clinical relevance to dermatologists and their medical colleagues. Depending on the species involved, consequences of tick attachment vary from minor local reactions to significant systemic sequelae. It is possible to minimize morbidity by removing the tick in its entirety as soon as it is detected. Some techniques to achieve this are described. This review will aid clinicians in the recognition and practical management of tick bites in Australia.
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Affiliation(s)
- Emma Storer
- Department of Dermatology, The Women's and Children's Hospital, North Adelaide, South Australia, Australia.
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13
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Inokuma H, Takahata H, Fournier PE, Brouqui P, Raoult D, Okuda M, Onishi T, Nishioka K, Tsukahara M. Tick paralysis by Ixodes holocyclus in a Japanese traveler returning from Australia associated with Rickettsia helvetica infection. J Travel Med 2003; 10:61-3. [PMID: 12729517 DOI: 10.2310/7060.2003.30581] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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15
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Affiliation(s)
- S R Graves
- The Australian Rickettsial Reference Laboratory, The Geelong Hospital, Victoria
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Xu W, Raoult D. Taxonomic relationships among spotted fever group rickettsiae as revealed by antigenic analysis with monoclonal antibodies. J Clin Microbiol 1998; 36:887-96. [PMID: 9542904 PMCID: PMC104656 DOI: 10.1128/jcm.36.4.887-896.1998] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The spotted fever group (SFG) is made up of more than 20 different rickettsial species and strains. Study of the taxonomic relationships among the group has been attempted by phenotypic, genotypic, and phylogenetic analyses. In this study, we determined taxonomic relationships among the SFG rickettsiae by comparative analysis of immunogenic epitopes reactive against a panel of monoclonal antibodies. A total of 98 monoclonal antibodies, which were directed against epitopes on the major immunodominant proteins or on the lipopolysaccharide-like antigens of strains of Rickettsia africae, Rickettsia conorii, Rickettsia massiliae, Rickettsia akari, Rickettsia sibirica, and Rickettsia slovaca, were used in the study. The distribution and expression of the epitopes among 29 SFG rickettsiae and Rickettsia bellii were assessed by determination of reaction titers in a microimmunofluorescence assay. The results were scored as numerical taxonomic data, and cluster analysis was used to construct a dendrogram. The architecture of this dendrogram was consistent with previous taxonomic studies, and the implications of this and other findings are discussed.
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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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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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Nilsson K, Jaenson TG, Uhnoo I, Lindquist O, Pettersson B, Uhlén M, Friman G, Påhlson C. Characterization of a spotted fever group Rickettsia from Ixodes ricinus ticks in Sweden. J Clin Microbiol 1997; 35:243-7. [PMID: 8968916 PMCID: PMC229547 DOI: 10.1128/jcm.35.1.243-247.1997] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
A spotted fever group rickettsia isolated from the common tick, Ixodes ricinus, was genetically characterized by PCR and genomic sequencing. This study was performed with nymphal and adult ticks collected in southern and central Sweden. I. ricinus is the only North European tick species of medical importance which is regularly collected from humans. No species of the genus Rickettsia has previously been found in Scandinavian ticks, nor has any case of domestic rickettsial infection in humans or animals been reported. According to the nucleotide sequencing, the present Rickettsia sp. belongs to the spotted fever group of rickettsiae. Ticks are the most common arthropod reservoirs and vectors of the rickettsiae of this group. Among 748 ticks investigated, 13 (1.7%) were positive for a Rickettsia sp. Borrelia burgdorferi was detected in 52 (7%) of the ticks, a prevalence similar to or somewhat lower than that previously been recorded in other Swedish studies. There was no evidence of ehrlichial or chlamydial DNA in these ticks. The Rickettsia sp. was further characterized by 16S ribosomal DNA (rDNA) sequencing and restriction fragment length polymorphism (RFLP). The 16S rDNA sequencing resulted in a sequence identical to that described for Rickettsia helvetica, but the pattern obtained with RFLP of the citrate synthetase gene diverged from previously known patterns. The rickettsial agent of one tick which was positive by PCR was confirmed by transmission electron microscopy. The morphology of this rickettsia was similar to that of the spotted fever and typhus group rickettsiae. This represents the first documented isolate of a Rickettsia sp. from Swedish ticks.
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Affiliation(s)
- K Nilsson
- Department of Infectious diseases and Clinical Microbiology, Uppsala University Hospital, Sweden
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Stenos J, Ross B, Feng HM, Crocquet-Valdes P, Walker D. Protein characterization of Australian spotted fever group rickettsiae and monoclonal antibody typing of Rickettsia honei. J Clin Microbiol 1997; 35:261-3. [PMID: 8968920 PMCID: PMC229551 DOI: 10.1128/jcm.35.1.261-263.1997] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Rickettsial proteins rOmp A and rOmp B exist in both Rickettsia australis and Rickettsia honei but differ in molecular weight and antigenicity; in addition, they produce distinct immunogenic responses and appear to be to conformationally dependent antigens. Species-specific monoclonal antibodies for other spotted fever group rickettsial species did not react with R. honei. A PCR product of the repeat region of the rOmp A gene from R. honei was amplified and calculated to contain 11 repeat units.
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Affiliation(s)
- J Stenos
- Victorian Infectious Diseases Reference Laboratory, Fairfield Hospital, Victoria, Australia
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