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Hoang MTT, Ngo VP, Stenos J, Ng-Nguyen D. The presence of Rickettsia felis in communities in the central highlands of Vietnam. Acta Trop 2023; 248:107034. [PMID: 37793492 DOI: 10.1016/j.actatropica.2023.107034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 09/26/2023] [Accepted: 10/01/2023] [Indexed: 10/06/2023]
Abstract
Rickettsia felis is an emerging flea-borne spotted fever pathogen that causes febrile illness in humans. In Vietnam, R. felis was detected in hospitalized patients, but there is no information on its presence in the Vietnamese community. This cross-sectional study aimed to determine the presence of R. felis in humans of the Central Highlands of Vietnam. A total of 158 blood and 213 serum samples were subjected to PCR and IFAT, respectively, to detect the presence of R. felis DNA and antibodies against R. felis. PCR assays detected R. felis DNA in four out of 158 blood samples, accounting for a prevalence of 2.53 % (95 % CI: 0.81 %-6.76 %). Phylogenetic analysis indicated the presence of R. felis and R. felis genotype RF2125 in the communities in the Central Highlands of Vietnam. The result of IFAT identified seven out of 213 serum samples (3.29 %, 95 % CI: 1.45 %-6.93 %) positive for antibodies against R. felis. This study was the first to demonstrate the presence of active R. felis infections in the communities in the Central Highlands of Vietnam utilizing both molecular and serological methods.
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Affiliation(s)
- Minh-Trang Thi Hoang
- Faculty of Medicine, Buon Ma Thuot Medical University, 298 Ha Huy Tap St., Buon Ma Thuot City, Dak Lak Province, Vietnam
| | - Van-Phuong Ngo
- Faculty of Medicine, Buon Ma Thuot Medical University, 298 Ha Huy Tap St., Buon Ma Thuot City, Dak Lak Province, Vietnam
| | - John Stenos
- Australian Rickettsial Reference Laboratory, Barwon Health, Geelong, VIC, Australia
| | - Dinh Ng-Nguyen
- Faculty of Animal Sciences and Veterinary Medicine, Tay Nguyen University, 567 Le Duan St., Buon Ma Thuot City, Dak Lak Province, Vietnam.
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Nguyen TV, Nguyen HQ, Stenos J, Nguyen TV, Ng-Nguyen D. Molecular detection of Rickettsia sp. genotype RF2125 from household dogs in the central highlands of Vietnam. Res Vet Sci 2023; 163:104989. [PMID: 37639804 DOI: 10.1016/j.rvsc.2023.104989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 07/12/2023] [Accepted: 08/20/2023] [Indexed: 08/31/2023]
Abstract
Rickettsia felis, a zoonotic vector-borne bacteria, is reported globally in humans, animals, and its invertebrate hosts. This study was designed to detect antibodies against R. felis and the DNA of R. felis in blood of domestic dogs in the Central Highlands of Vietnam using immunofluorescence antibody test (IFAT), and ompB- and gltA-PCRs, respectively. Using IFAT, 23 out of 338 plasma samples collected from household dogs were seropositive for R. felis, accounting for 6.80% (CI 95%: 4.45-10.1%). Of 171 buffy coat samples from household dogs, 50 were positive for spotted fever group rickettsioses using ompB-PCR assay, accounting for 29.2% (CI 95%: 22.6-36.7%). The gltA-PCR assay detected R. felis in 30% (15/50) of ompB-positive samples. DNA sequencing of ompB-PCR and gltA-PCR products confirmed the presence of R. felis and Rickettsia sp. genotype RF2125 / R. asembonensis. Our findings suggest a potential risk of R. felis infection in the communities in the Central Highlands of Vietnam, and the reservoir role of dogs to Rickettsia sp. genotype RF2125.
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Affiliation(s)
- Trong Van Nguyen
- Faculty of Animal Sciences and Veterinary Medicine, Tay Nguyen University, 567 Le Duan, Buon Ma Thuot City, Dak Lak Province, Viet Nam
| | - Hieu Quoc Nguyen
- Faculty of Animal Sciences and Veterinary Medicine, Tay Nguyen University, 567 Le Duan, Buon Ma Thuot City, Dak Lak Province, Viet Nam
| | - John Stenos
- Australian Rickettsial Reference Laboratory, Geelong, Victoria, Australia
| | - Thai Van Nguyen
- Faculty of Animal Sciences and Veterinary Medicine, Tay Nguyen University, 567 Le Duan, Buon Ma Thuot City, Dak Lak Province, Viet Nam
| | - Dinh Ng-Nguyen
- Faculty of Animal Sciences and Veterinary Medicine, Tay Nguyen University, 567 Le Duan, Buon Ma Thuot City, Dak Lak Province, Viet Nam.
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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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Domestic dogs are mammalian reservoirs for the emerging zoonosis flea-borne spotted fever, caused by Rickettsia felis. Sci Rep 2020; 10:4151. [PMID: 32139802 PMCID: PMC7058065 DOI: 10.1038/s41598-020-61122-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Accepted: 02/17/2020] [Indexed: 11/08/2022] Open
Abstract
Rickettsia felis is an obligate intracellular bacterium that is being increasingly recognized as an etiological agent of human rickettsial disease globally. The agent is transmitted through the bite of an infected vector, the cat flea, Ctenocephalides felis, however there is to date, no consensus on the pathogen's vertebrate reservoir, required for the maintenance of this agent in nature. This study for the first time, demonstrates the role of the domestic dog (Canis familiaris) as a vertebrate reservoir of R. felis. The ability of dogs to sustain prolonged periods of rickettsemia, ability to remain asymptomatically infected with normal haematological parameters and ability to act as biological vehicles for the horizontal transmission of R. felis between infected and uninfected fleas provides indication of their status as a mammalian reservoir of this emerging zoonosis.
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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] [MESH Headings] [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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Tshokey T, Stenos J, Tenzin T, Drukpa K, Gurung RB, Graves SR. Serological Evidence of Rickettsia, Orientia, and Coxiella in Domestic Animals from Bhutan: Preliminary Findings. Vector Borne Zoonotic Dis 2018; 19:95-101. [PMID: 30148695 DOI: 10.1089/vbz.2018.2336] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
There is no information on rickettsial diseases in domestic animals in Bhutan. This study provides preliminary serological data on exposure of domestic animals to Rickettsia, Orientia, and Coxiella. Animal sera were collected opportunistically from Bhutan and tested in the Australian Rickettsial Reference Laboratory for IgG antibodies against spotted fever group (SFG) and typhus group (TG) Rickettsia, scrub typhus group (STG), and Q fever (QF). Of the 294 animals tested, 136 (46%) showed serological evidence of past exposure to one or more rickettsiae: 106 (36%), 62 (21%), 45 (15%), and 11 (4%) being positive against SFG Rickettsia, Orientia, TG Rickettsia, and Coxiella, respectively. Dogs appeared to exhibit the highest seropositivity against SFG (55%) and TG Rickettsia (45%), horses against STG (91%), while goats were mostly positive for Coxiella (9%). Dogs also appeared to have high risk of being exposed to SFG Rickettsia (odd ratios [OR] 5.71, 95% confidence interval [CI] 3.02-10.80, p < 0.001), TG Rickettsia (OR 48.74, 95% CI 11.29-210.32, p < 0.001), and STG (OR 6.80, 95% CI 3.32-13.95, p < 0.001), but not against QF (OR 1.95, 95% CI 0.42-8.95, p = 0.390). Differences in seropositivity rates between animal species may have been significant for SFG, TG, and STG, but not for QF. The differences in the seropositivity rates of the four infections between districts appeared to be significant for TG and STG, but not for SFG and QF. The seropositivity rates of domestic animals to the four rickettsial infections were consistent with similar studies on the human population in the same areas and appear to demonstrate a high prevalence of exposure to rickettsiae in Bhutan. These preliminary findings constitute baseline data for Bhutan. The findings of this study call for an increased human-livestock sector collaboration in rickettsial diseases research aimed at developing diagnostic and therapeutic guidelines and formulating preventive and control measures through a One Health approach.
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Affiliation(s)
- Tshokey Tshokey
- 1 Faculty of Health and Medicine, University of Newcastle , Newcastle, Australia .,2 Australian Rickettsial Reference Laboratory, University Hospital Geelong , Geelong, Australia .,3 Department of Laboratory Medicine, Jigme Dorji Wangchuck National Referral Hospital (JDWNRH) , Thimphu, Bhutan
| | - John Stenos
- 2 Australian Rickettsial Reference Laboratory, University Hospital Geelong , Geelong, Australia
| | - Tenzin Tenzin
- 4 Department of Livestock, National Centre for Animal Health (NCAH) , Thimphu, Bhutan
| | - Kinzang Drukpa
- 4 Department of Livestock, National Centre for Animal Health (NCAH) , Thimphu, Bhutan
| | - Ratna Bahadur Gurung
- 4 Department of Livestock, National Centre for Animal Health (NCAH) , Thimphu, Bhutan
| | - Stephen R Graves
- 1 Faculty of Health and Medicine, University of Newcastle , Newcastle, Australia .,2 Australian Rickettsial Reference Laboratory, University Hospital Geelong , Geelong, Australia
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A Concise Review of the Epidemiology and Diagnostics of Rickettsioses: Rickettsia and Orientia spp. J Clin Microbiol 2018; 56:JCM.01728-17. [PMID: 29769278 DOI: 10.1128/jcm.01728-17] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Rickettsioses are globally distributed and caused by the family Rickettsiaceae, which comprise a diverse and expanding list of organisms. These include two genera, Rickettsia and Orientia Serology has been traditionally the mainstay of diagnosis, although this has been limited by cross-reactions among closely related members and diminished sensitivity/utility in the acute phase of illness. Other techniques, such as nucleic acid amplification tests using blood specimens or tissue swabs/biopsy specimens, sequencing, and mass spectrometry, have emerged in recent years for both pathogen and vector identification. This paper provides a concise review of the rickettsioses and the traditional and newer technologies available for their diagnosis.
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Tshokey T, Graves S, Tshering D, Phuntsho K, Tshering K, Stenos J. Scrub Typhus Outbreak in a Remote Primary School, Bhutan, 2014. Emerg Infect Dis 2018; 23:1412-1414. [PMID: 28726604 PMCID: PMC5547789 DOI: 10.3201/eid2308.162021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Scrub typhus in Bhutan was first reported in 2009. We investigated an outbreak of scrub typhus in a remote primary school during August–October 2014. Delay in recognition and treatment resulted in 2 deaths from meningoencephalitis. Scrub typhus warrants urgent public health interventions in Bhutan.
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Rickettsial Infections and Q Fever Amongst Febrile Patients in Bhutan. Trop Med Infect Dis 2018; 3:tropicalmed3010012. [PMID: 30274410 PMCID: PMC6136613 DOI: 10.3390/tropicalmed3010012] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 01/10/2018] [Accepted: 01/21/2018] [Indexed: 12/04/2022] Open
Abstract
There is limited evidence of rickettsial diseases in Bhutan. We explored the contribution of rickettsioses as a cause of undifferentiated febrile illness in patients presenting to 14 Bhutanese hospitals from October 2014 to June 2015. Obvious causes of fever were excluded clinically. Clinico-demographic information and acute blood samples were collected. Samples were tested by immunofluorescence assay (IFA) and qPCR against scrub typhus group (STG), spotted fever group (SFG) and typhus group (TG) rickettsiae, and Q fever (QF). Of the 1044 patients, 539 (51.6%) were female and the mean age was 31.5 years. At least 159 (15.2%) of the patients had evidence of a concurrent rickettsial infection. Of these, 70 (6.7%), 46 (4.4%), 4 (0.4%), and 29 (2.8%) were diagnosed as acute infections with STG, SFG, TG, and QF respectively. Ten (1.0%) patients were seropositive for both SFG and TG. Seven of the 70 STG patients were positive by qPCR. Eschar (p < 0.001), myalgia (p = 0.003), and lymphadenopathy (p = 0.049) were significantly associated with STG, but no specific symptoms were associated with the other infections. Disease incidences were not different between age groups, genders, occupations, and districts, except for students with significantly lower odds of infection with STG (OR = 0.43; 95% CI = 0.20, 0.93; p = 0.031). Rickettsioses were responsible for at least 15% of undifferentiated febrile illnesses in Bhutan, scrub typhus being the commonest. Health authorities should ensure that health services are equipped to manage these infections.
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Tshokey T, Stenos J, Durrheim DN, Eastwood K, Nguyen C, Graves SR. Seroprevalence of rickettsial infections and Q fever in Bhutan. PLoS Negl Trop Dis 2017; 11:e0006107. [PMID: 29176880 PMCID: PMC5720829 DOI: 10.1371/journal.pntd.0006107] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 12/07/2017] [Accepted: 11/11/2017] [Indexed: 11/18/2022] Open
Abstract
Background With few studies conducted to date, very little is known about the epidemiology of rickettsioses in Bhutan. Due to two previous outbreaks and increasing clinical cases, scrub typhus is better recognized than other rickettsial infections and Q fever. Methodology A descriptive cross-sectional serosurvey was conducted from January to March 2015 in eight districts of Bhutan. Participants were 864 healthy individuals from an urban (30%) and a rural (70%) sampling unit in each of the eight districts. Serum samples were tested by microimmunofluorescence assay for rickettsial antibodies at the Australian Rickettsial Reference Laboratory. Results Of the 864 participants, 345 (39.9%) were males and the mean age of participants was 41.1 (range 13–98) years. An overall seroprevalence of 49% against rickettsioses was detected. Seroprevalence was highest against scrub typhus group (STG) (22.6%) followed by spotted fever group (SFG) rickettsia (15.7%), Q fever (QF) (6.9%) and typhus group (TG) rickettsia (3.5%). Evidence of exposure to multiple agents was also noted; the commonest being dual exposure to STG and SFG at 5%. A person’s likelihood of exposure to STG and SFG rickettsia significantly increased with age and farmers were twice as likely to have evidence of STG exposure as other occupations. Trongsa district appeared to be a hotspot for STG exposure while Punakha district had the lowest STG exposure risk. Zhemgang had the lowest exposure risk to SFG rickettsia compared to other districts. People living at altitudes above 2000 meters were relatively protected from STG infections but this was not observed for SFG, TG or QF exposure. Conclusion This seroprevalence study highlights the endemicity of STG and SFG rickettsia in Bhutan. The high seroprevalence warrants appropriate public health interventions, such as diagnostic improvements and clinical treatment guidelines. Future studies should focus on vector profiles, geospatial, bio-social and environmental risk assessment and preventive and control strategies. Rickettsial infections including scrub typhus and Q fever are not widely recognised in Bhutan although the country is situated in an endemic Asian region. With two recorded outbreaks, scrub typhus is known to occur but other rickettsial infections and Q fever have not been recorded. In this first seroprevalence study of rickettsial infections, an overall seroprevalence of 49% was detected against rickettsioses amongst 864 participants. Seroprevalence was highest against scrub typhus group (STG) (22.6%) followed by spotted fever group (SFG) rickettsia (15.7%), Q fever (QF) (6.9%) and typhus group (TG) rickettsia (3.5%). Evidence of exposure to multiple agents were also noted; the commonest being dual exposure to STG and SFG at 5%. A person’s likelihood of exposure to STG and SFG significantly increased with age and farmers were twice as likely to have evidence of STG exposure as other occupations. Trongsa district in central Bhutan appeared to be a hotspot for STG exposure. People living at altitudes above 2000 meters were relatively protected from STG infections but this was not observed for SFG, TG and QF exposure. The findings from this study may direct future research on rickettsioses in Bhutan. These neglected tropical diseases warrant specific public health interventions in Bhutan.
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Affiliation(s)
- Tshokey Tshokey
- Faculty of Health and Medicine, University of Newcastle, Newcastle, Australia
- Australian Rickettsial Reference Laboratory, University Hospital Geelong, Geelong, Australia
- Department of Laboratory Medicine, Jigme Dorji Wangchuck National Referral Hospital, Thimphu, Bhutan
- * E-mail:
| | - John Stenos
- Australian Rickettsial Reference Laboratory, University Hospital Geelong, Geelong, Australia
| | - David N. Durrheim
- Faculty of Health and Medicine, University of Newcastle, Newcastle, Australia
- Population Health, Hunter New England Local Health District, NSW Health, Newcastle, Australia
| | - Keith Eastwood
- Faculty of Health and Medicine, University of Newcastle, Newcastle, Australia
- Population Health, Hunter New England Local Health District, NSW Health, Newcastle, Australia
| | - Chelsea Nguyen
- Australian Rickettsial Reference Laboratory, University Hospital Geelong, Geelong, Australia
| | - Stephen R. Graves
- Faculty of Health and Medicine, University of Newcastle, Newcastle, Australia
- Australian Rickettsial Reference Laboratory, University Hospital Geelong, Geelong, Australia
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Graves SR, Stenos J. Tick-borne infectious diseases in Australia. Med J Aust 2017; 206:320-324. [PMID: 28403767 DOI: 10.5694/mja17.00090] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Accepted: 02/20/2017] [Indexed: 01/14/2023]
Abstract
Tick bites in Australia can lead to a variety of illnesses in patients. These include infection, allergies, paralysis, autoimmune disease, post-infection fatigue and Australian multisystem disorder. Rickettsial (Rickettsia spp.) infections (Queensland tick typhus, Flinders Island spotted fever and Australian spotted fever) and Q fever (Coxiella burnetii) are the only systemic bacterial infections that are known to be transmitted by tick bites in Australia. Three species of local ticks transmit bacterial infection following a tick bite: the paralysis tick (Ixodes holocyclus) is endemic on the east coast of Australia and causes Queensland tick typhus due to R. australis and Q fever due to C. burnetii; the ornate kangaroo tick (Amblyomma triguttatum) occurs throughout much of northern, central and western Australia and causes Q fever; and the southern reptile tick (Bothriocroton hydrosauri) is found mainly in south-eastern Australia and causes Flinders Island spotted fever due to R. honei. Much about Australian ticks and the medical outcomes following tick bites remains unknown. Further research is required to increase understanding of these areas.
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Affiliation(s)
| | - John Stenos
- Australian Rickettsial Reference Laboratory, Geelong, VIC
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12
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Teoh YT, Hii SF, Graves S, Rees R, Stenos J, Traub RJ. Evidence of exposure to Rickettsia felis in Australian patients. One Health 2016; 2:95-98. [PMID: 28616481 PMCID: PMC5441329 DOI: 10.1016/j.onehlt.2016.06.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Revised: 05/31/2016] [Accepted: 06/03/2016] [Indexed: 11/22/2022] Open
Abstract
Rickettsia felis is an emerging zoonosis, causing flea-borne spotted fever (FBSF). Serological diagnosis is typically confounded by cross-reactivity with typhus group rickettsiae and prior to the development of specific serological methods, cases of FBSF in Australia were misdiagnosed. Patient sera tested between August 2010 and December 2013 and known to be seropositive to R. typhi by immunofluorescence antibody testing (IFAT) were subsequently retested against R. felis using an R. felis-specific IFAT. Sera of 49 patients were of a sufficient quality to be included in re-analysis. A classification of FBSF and murine typhus (MT) was attributed to fourteen and seven patients respectively, based on a minimum four-fold higher antibody titre to R. felis than to R. typhi and vice versa. Twenty-eight patients were classified as indeterminate for either R. felis or R. typhi (antibody titres within two-fold of one another). Historically, it is likely that Australian patients clinically ill with FBSF were misdiagnosed. It is important that medical practitioners consider FBSF as part of their differential diagnoses, and obtain relevant history with regard to patient's exposure to domestic pets and their fleas. Australian microbiology diagnostic laboratories should include serological testing for R. felis as part of the diagnostic panel for febrile diseases. Veterinarians are encouraged to increase their awareness of this emerging zoonosis and advocate flea control in pets.
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Affiliation(s)
- Yen Thon Teoh
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Sze Fui Hii
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC 3052, Australia
| | - Stephen Graves
- The Australian Rickettsial Reference Laboratory, University Hospital, Geelong, VIC 3220, Australia
| | - Robert Rees
- Bayer Animal Health, Tingalpa, QLD 4173, Australia
| | - John Stenos
- The Australian Rickettsial Reference Laboratory, University Hospital, Geelong, VIC 3220, Australia
| | - Rebecca J. Traub
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC 3052, Australia
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An outbreak of scrub typhus in military personnel despite protocols for antibiotic prophylaxis: doxycycline resistance excluded by a quantitative PCR-based susceptibility assay. Microbes Infect 2016; 18:406-411. [PMID: 27005452 DOI: 10.1016/j.micinf.2016.03.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 12/18/2015] [Accepted: 03/11/2016] [Indexed: 11/23/2022]
Abstract
Scrub typhus is caused by the obligate intracellular bacterium Orientia tsutsugamushi and is endemic to many countries in the Asia-Pacific region, including tropical Australia. We describe a recent large outbreak amongst military personnel in north Queensland. A total of 45 clinical cases were identified (36% of all potentially exposed individuals). This occurred despite existing military protocols stipulating the provision of doxycycline prophylaxis. Doxycycline resistance in O. tsutsugamushi has been described in South-East Asia, but not Australia. In one case, O. tsutsugamushi was cultured from eschar tissue and blood. Using quantitative real-time PCR to determine susceptibility to doxycycline for the outbreak strain, a minimum inhibitory concentration (MIC) of ≤0.04 μg/mL was found, indicating susceptibility to this agent. It seems most probable that failure to adhere to adequate prophylaxis over the duration of the military exercise accounted for the large number of cases encountered rather than doxycycline resistance.
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An outbreak investigation of scrub typhus in Western Province, Solomon Islands, 2014. Western Pac Surveill Response J 2016; 7:6-9. [PMID: 27757247 PMCID: PMC5052891 DOI: 10.5365/wpsar.2015.6.3.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVE To identify the etiology and risk factors of undifferentiated fever in a cluster of patients in Western Province, Solomon Islands, May 2014. METHODS An outbreak investigation with a case control study was conducted. A case was defined as an inpatient in one hospital in Western Province, Solomon Islands with high fever (> 38.5 °C) and a negative malaria microscopy test admitted between 1 and 31 May 2014. Asymptomatic controls matched with the cases residentially were recruited in a ratio of 1:2. Serum samples from the subjects were tested for rickettsial infections using indirect micro-immunofluorescence assay. RESULTS Nine cases met the outbreak case definition. All cases were male. An eschar was noted in five cases (55%), and one developed pneumonitis. We did not identify any environmental factors associated with illness. Serum samples of all five follow-up cases (100%) had strong-positive IgG responses to scrub typhus. All but one control (10%) had a moderate response against scrub typhus. Four controls had low levels of antibodies against spotted fever group rickettsia, and only one had a low-level response to typhus group rickettsia. DISCUSSION This outbreak represents the first laboratory-confirmed outbreak of scrub typhus in the Western Province of Solomon Islands. The results suggest that rickettsial infections are more common than currently recognized as a cause of an acute febrile illness. A revised clinical case definition for rickettsial infections and treatment guidelines were developed and shared with provincial health staff for better surveillance and response to future outbreaks of a similar kind.
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Macesic N, Hall V, Mahony A, Hueston L, Ng G, Macdonell R, Hughes A, Fitt G, Grayson ML. Acute Flaccid Paralysis: The New, The Old, and The Preventable. Open Forum Infect Dis 2015; 3:ofv190. [PMID: 26788545 PMCID: PMC4716344 DOI: 10.1093/ofid/ofv190] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Accepted: 11/30/2015] [Indexed: 12/28/2022] Open
Abstract
Acute flaccid paralysis (AFP) has a changing epidemiology with ongoing polio outbreaks and emerging causes such as nonpolio enteroviruses and West Nile virus (WNV). We report a case of AFP from the Horn of Africa that was initially classified as probable polio but subsequently found to be due to WNV.
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Affiliation(s)
- N Macesic
- Departments of Infectious Diseases; Division of Infectious Diseases, Columbia University Medical Center, New York
| | | | - A Mahony
- Departments of Infectious Diseases
| | - L Hueston
- Arbovirus Emerging Diseases Unit , Centre for Infectious Diseases and Microbiology, Institute of Clinical Pathology and Medical Research, Westmead Hospital , Sydney
| | | | - R Macdonell
- Neurology; Department of Medicine, University of Melbourne, Australia
| | | | - G Fitt
- Radiology, Austin Health, Melbourne , Australia
| | - M L Grayson
- Departments of Infectious Diseases; Department of Medicine, University of Melbourne, Australia
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16
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Abdad MY, Cook A, Dyer J, Stenos J, Fenwick SG. Seroepidemiological study of outdoor recreationists' exposure to spotted fever group Rickettsia in Western Australia. Am J Trop Med Hyg 2014; 91:584-8. [PMID: 24935947 DOI: 10.4269/ajtmh.14-0102] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Bushland activity has previously been linked to rickettsial exposure in eastern and central regions of Australia, whereas little is known about the risks in Western Australia. The isolation of Rickettsia gravesii sp. nov. from Amblyomma triguttatum ticks and anecdotal reports of low-grade illness among bush recreationists raised the possibility of rickettsial transmission in the State. This study investigated rickettsial seroprevalence and potential risk of exposure to the spotted fever group rickettsiae in rogainers. Our results showed that rogainers active in the bush had a significantly higher risk of seropositivity (immunofluorescence total antibody titer ≥ 128) for the spotted fever group Rickettsia (odds ratio [OR] = 14.02, 95% confidence interval [CI] = 1.38-142.07) compared with a reference population, the overall seroprevalence in the rogainer group being 23.1%.
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Affiliation(s)
- Mohammad Y Abdad
- Australian Rickettsial Reference Laboratory, Geelong, Victoria, Australia; School of Population Health, University of Western Australia, Perth, Western Australia, Australia; Fremantle Hospital, Fremantle, Western Australia, Australia; School of Veterinary and Biomedical Science, Murdoch University, Murdoch, Western Australia, Australia
| | - Angus Cook
- Australian Rickettsial Reference Laboratory, Geelong, Victoria, Australia; School of Population Health, University of Western Australia, Perth, Western Australia, Australia; Fremantle Hospital, Fremantle, Western Australia, Australia; School of Veterinary and Biomedical Science, Murdoch University, Murdoch, Western Australia, Australia
| | - John Dyer
- Australian Rickettsial Reference Laboratory, Geelong, Victoria, Australia; School of Population Health, University of Western Australia, Perth, Western Australia, Australia; Fremantle Hospital, Fremantle, Western Australia, Australia; School of Veterinary and Biomedical Science, Murdoch University, Murdoch, Western Australia, Australia
| | - John Stenos
- Australian Rickettsial Reference Laboratory, Geelong, Victoria, Australia; School of Population Health, University of Western Australia, Perth, Western Australia, Australia; Fremantle Hospital, Fremantle, Western Australia, Australia; School of Veterinary and Biomedical Science, Murdoch University, Murdoch, Western Australia, Australia
| | - Stanley G Fenwick
- Australian Rickettsial Reference Laboratory, Geelong, Victoria, Australia; School of Population Health, University of Western Australia, Perth, Western Australia, Australia; Fremantle Hospital, Fremantle, Western Australia, Australia; School of Veterinary and Biomedical Science, Murdoch University, Murdoch, Western Australia, Australia
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17
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Hii SF, Abdad MY, Kopp SR, Stenos J, Rees RL, Traub RJ. Seroprevalence and risk factors for Rickettsia felis exposure in dogs from Southeast Queensland and the Northern Territory, Australia. Parasit Vectors 2013; 6:159. [PMID: 23731951 PMCID: PMC3679791 DOI: 10.1186/1756-3305-6-159] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 05/29/2013] [Indexed: 11/17/2022] Open
Abstract
Background The recent detection of Rickettsia felis DNA in dogs in Australia suggests that dogs are potential mammalian reservoir hosts for this emerging rickettsia. To date, there is no published report addressing the seroprevalence of R. felis in dogs in Australia. Methods Antigens for R. felis were produced by inoculating confluent XTC-2 monolayer cell cultures with three pools of cat flea (Ctenocephalides felis) homogenates. Infection was confirmed by real-time (qPCR), conventional or nested PCRs targeting the ompB, gltA, 17 kDa and ompA genes. Two hundred and ninety-two dogs from Southeast Queensland and the Northern Territory were tested for the presence of R. felis antibodies using a microimmunofluorescence (IF) test and the seroprevalence and associated risk factors for exposure were determined using both uni- and multi-variate analyses. Results Rickettsia felis was successfully isolated in cell culture from all three cat-flea pools. One hundred and forty-eight dogs (50.7%) showed seropositivity with titres ≥64 and 54 (18.5%) with titres ≥128. At antibody titres ≥64, dogs with active ectoparasite control were less likely to be seropositive to R. felis (OR: 2.60; 95% CI: 1.20 - 5.56). Conclusions This first reported isolation of R. felis in cell culture in Australia allowed for the production of antigen for serological testing of dogs. Results of this serological testing reflects the ubiquitous exposure of dogs to R. felis and advocate for owner vigilance with regards to ectoparasite control on domestic pets.
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Affiliation(s)
- Sze-Fui Hii
- School of Veterinary Science, The University of Queensland, Gatton, Queensland, 4343, Australia.
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18
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Wood H, Artsob H. Spotted Fever Group Rickettsiae: A Brief Review and a Canadian Perspective. Zoonoses Public Health 2012; 59 Suppl 2:65-79. [DOI: 10.1111/j.1863-2378.2012.01472.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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19
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Banks PB, Hughes NK. A review of the evidence for potential impacts of black rats (Rattus rattus) on wildlife and humans in Australia. WILDLIFE RESEARCH 2012. [DOI: 10.1071/wr11086] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The black rat (Rattus rattus) is among the world’s worst invasive species, having spread across the globe in close association with the spread of human settlement. It is the source of some of the worst diseases affecting humans and is thought to have had a devastating impact on native wildlife, especially in island ecosystems. Black rat is likely to have arrived in Australia with the first European settlers, making it among the first of many alien species to invade the continent, and it is now widespread. Yet, its impacts on local wildlife have largely been overlooked. Here, we review the potential for black rat impacts in Australia in terms of its role as a source of disease and threats to wildlife and humans. We first summarise the global evidence for black rat impacts as background to the potential threats it poses and then focus specifically on emerging evidence available for Australian systems. We found a significant gap in our understanding of the ecology of black rats and the ecological role that it plays in Australia. This is despite its role as a source of a diverse range of diseases affecting humans and wildlife and its actions as a predator and competitor of native wildlife in Australia and elsewhere.
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20
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Isolation of a novel Orientia species (O. chuto sp. nov.) from a patient infected in Dubai. J Clin Microbiol 2010; 48:4404-9. [PMID: 20926708 DOI: 10.1128/jcm.01526-10] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In July 2006, an Australian tourist returning from Dubai, in the United Arab Emirates (UAE), developed acute scrub typhus. Her signs and symptoms included fever, myalgia, headache, rash, and eschar. Orientia tsutsugamushi serology demonstrated a 4-fold rise in antibody titers in paired serum collections (1:512 to 1:8,192), with the sera reacting strongest against the Gilliam strain antigen. An Orientia species was isolated by the in vitro culture of the patient's acute blood taken prior to antibiotic treatment. The gene sequencing of the 16S rRNA gene (rrs), partial 56-kDa gene, and the full open reading frame 47-kDa gene was performed, and comparisons of this new Orientia sp. isolate to previously characterized strains demonstrated significant sequence diversity. The closest homology to the rrs sequence of the new Orientia sp. isolate was with three strains of O. tsutsugamushi (Ikeda, Kato, and Karp), with a nucleotide sequence similarity of 98.5%. The closest homology to the 47-kDa gene sequence was with O. tsutsugamushi strain Gilliam, with a nucleotide similarity of 82.3%, while the closest homology to the 56-kDa gene sequence was with O. tsutsugamushi strain TA686, with a nucleotide similarity of 53.1%. The molecular divergence and geographically unique origin lead us to believe that this organism should be considered a novel species. Therefore, we have proposed the name "Orientia chuto," and the prototype strain of this species is strain Dubai, named after the location in which the patient was infected.
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21
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Izzard L, Cox E, Stenos J, Waterston M, Fenwick S, Graves S. Serological prevalence study of exposure of cats and dogs in Launceston, Tasmania, Australia to spotted fever group rickettsiae. Aust Vet J 2010; 88:29-31. [PMID: 20148824 DOI: 10.1111/j.1751-0813.2009.00538.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A sero-epidemiological study of cats and dogs in the Launceston area of Tasmania, Australia was undertaken to determine the prevalence of antibodies to spotted fever group (SFG) rickettsiae. Results showed that 59% of cats and 57% of dogs were positive for antibodies, but there was no correlation between the animal's health and seropositivity at the time of testing, suggesting that rickettsial exposure is unrelated to ill-health in these two species of domestic animals.
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Affiliation(s)
- L Izzard
- Australian Rickettsial Reference Laboratory Foundation, Barwon Biomedical Research, The Geelong Hospital, Ryrie Street, Geelong, Victoria 3220, Australia.
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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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23
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Abstract
We report 3 rickettsioses on Darnley Island, Australia, in the Torres Strait. In addition to previously described cases of Flinders Island spotted fever (Rickettsia honei strain “marmionii”), we describe 1 case of Queensland tick typhus (R. australis) and 2 cases of scrub typhus caused by a unique strain (Orientia tsutsugamushi).
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Affiliation(s)
- Nathan B Unsworth
- The Australian Rickettsial Reference Laboratory, Geelong, Victoria, Australia
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24
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Özdemir D, Sencan İ, Yıldırım M, Güçlü E, Yavuz T, Karabay O. ANDISCRIMINATED ASEPTIC MENINGITIS CASE BETWEEN RICKETTSIA AND LEPTOSPIRAL MENINGITIS. ELECTRONIC JOURNAL OF GENERAL MEDICINE 2008. [DOI: 10.29333/ejgm/82576] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Unsworth NB, Stenos J, Graves SR, Faa AG, Cox GE, Dyer JR, Boutlis CS, Lane AM, Shaw MD, Robson J, Nissen MD. Flinders Island spotted fever rickettsioses caused by "marmionii" strain of Rickettsia honei, Eastern Australia. Emerg Infect Dis 2007. [PMID: 17553271 PMCID: PMC2725950 DOI: 10.3201/eid1304.060087] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We report 7 cases of rickettsiosis caused by a new rickettsial strain. Australia has 4 rickettsial diseases: murine typhus, Queensland tick typhus, Flinders Island spotted fever, and scrub typhus. We describe 7 cases of a rickettsiosis, with an acute onset and symptoms of fever (100%), headache (71%), arthralgia (43%), myalgia (43%), cough (43%), maculopapular/petechial rash (43%), nausea (29%), pharyngitis (29%), lymphadenopathy (29%), and eschar (29%). Cases were most prevalent in autumn and from eastern Australia, including Queensland, Tasmania, and South Australia. One patient had a history of tick bite (Haemaphysalis novaeguineae). An isolate shared 99.2%, 99.8%, 99.8%, 99.9%, and 100% homology with the 17 kDa, ompA, gltA, 16S rRNA, and Sca4 genes, respectively, of Rickettsia honei. This Australian rickettsiosis has similar symptoms to Flinders Island spotted fever, and the strain is genetically related to R. honei. It has been designated the “marmionii” strain of R. honei, in honor of Australian physician and scientist Barrie Marmion.
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Affiliation(s)
- Nathan B Unsworth
- Australian Rickettsial Reference Laboratory, Geelong, Victoria, Australia
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26
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Unsworth NB, Stenos J, Graves SR, Faa AG, Cox GE, Dyer JR, Boutlis CS, Lane AM, Shaw MD, Robson J, Nissen MD. Flinders Island Spotted Fever Rickettsioses Caused by “marmionii” Strain ofRickettsia honei,Eastern Australia. Emerg Infect Dis 2007; 13:566-73. [PMID: 17553271 PMCID: PMC2725950 DOI: 10.3201/eid1304.050087] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Australia has 4 rickettsial diseases: murine typhus, Queensland tick typhus, Flinders Island spotted fever, and scrub typhus. We describe 7 cases of a rickettsiosis with an acute onset and symptoms of fever (100%), headache (71%), arthralgia (43%), myalgia (43%), cough (43%), maculopapular/petechial rash (43%), nausea (29%), pharyngitis (29%), lymphadenopathy (29%), and eschar (29%). Cases were most prevalent in autumn and from eastern Australia, including Queensland, Tasmania, and South Australia. One patient had a history of tick bite (Haemaphysalis novaeguineae). An isolate shared 99.2%, 99.8%, 99.8%, 99.9%, and 100% homology with the 17 kDa, ompA, gltA, 16S rRNA, and Sca4 genes, respectively, of Rickettsia honei. This Australian rickettsiosis has similar symptoms to Flinders Island spotted fever, and the strain is genetically related to R. honei. It has been designated the "marmionii" strain of R. honei, in honor of Australian physician and scientist Barrie Marmion.
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Affiliation(s)
- Nathan B. Unsworth
- Australian Rickettsial Reference Laboratory, Geelong, Victoria, Australia
| | - John Stenos
- Australian Rickettsial Reference Laboratory, Geelong, Victoria, Australia
| | - Stephen R. Graves
- Australian Rickettsial Reference Laboratory, Geelong, Victoria, Australia
| | - Antony G. Faa
- Warwick Hospital (Southern Downs Health Services District), Warwick, Queensland, Australia
| | - G. Erika Cox
- Launceston General Hospital, Launceston, Tasmania, Australia
| | - John R. Dyer
- Fremantle Hospital, Fremantle, Western Australia, Australia
| | - Craig S. Boutlis
- Menzies School of Health Research, Darwin, Northern Territory, Australia
| | - Amanda M. Lane
- University of Queensland, Brisbane, Queensland, Australia
| | | | - Jennifer Robson
- Sullivan Nicolaides Pathology, Brisbane, Queensland, Australia
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Dyer JR, Einsiedel L, Ferguson PE, Lee AS, Unsworth NB, Graves SR, Gordon DL. A new focus of Rickettsia honei spotted fever in South Australia. Med J Aust 2006; 182:231-4. [PMID: 15748134 DOI: 10.5694/j.1326-5377.2005.tb06673.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2004] [Accepted: 11/18/2004] [Indexed: 11/17/2022]
Abstract
We recently diagnosed rickettsial spotted fever in four patients from the south-eastern coastal region of South Australia near Adelaide, an area not known to be endemic for this infection. All infections were acquired within the geographic range of Aponomma hydrosauri, the tick vector of Rickettsia honei. Infection by R. honei was confirmed in two patients. This extension of the known geographic range of R. honei infection may be explained, in part, by alterations in host-parasite ecology.
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Affiliation(s)
- John R Dyer
- Department of Infectious Diseases, Fremantle Hospital, PO Box 480, Fremantle, 6959 WA, Australia.
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Lane AM, Shaw MD, McGraw EA, O'Neill SL. Evidence of a spotted fever-like rickettsia and a potential new vector from northeastern Australia. JOURNAL OF MEDICAL ENTOMOLOGY 2005; 42:918-21. [PMID: 16363177 DOI: 10.1093/jmedent/42.5.918] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
A spotted fever-like rickettsia was identified in a Hemaphysalis tick by polymerase chain reaction (PCR) amplification and sequencing of the 16S rDNA, ompA, and ompB genes. A comparison of these nucleotide sequences with those of other spotted fever group (SFG) rickettsiae revealed that the Hemaphysalis tick rickettsia ia was distinct from other previously reported strains. Phylogenetic analysis based on both ompA and ompB also indicates that the strain's closest relatives are the agents of Thai tick typhus (Rickettsia honei strain TT-118) and Flinders Island spotted fever (R. honei). This study represents the first report of an R. honei-like agent from a Hemaphysalis tick in Australia and of a spotted fever group rickettsia from Cape York Peninsula, Queensland.
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Affiliation(s)
- Amanda M Lane
- School of Integrative Biology, University of Queensland, Brisbane, QLD 4072, Australia
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Abstract
AIM To demonstrate that Flinders Island spotted fever (FISF), a spotted fever group rickettsial infection caused by Rickettsia honei, is found not only on Flinders Island (Bass Strait), Tasmania, but elsewhere in south-east Australia. METHODS Cases of FISF were identified by rickettsial serology, culture and the detection of rickettsial DNA via PCR. Isolates and PCR products were sequenced to identify the aetiological agent as R. honei. RESULTS Three new cases of FISF were detected outside of Flinders Island. One on Schouten Island, south of the Freycinet Peninsula, Tasmania, and two in south-eastern South Australia (McLaren Vale and Goolwa). CONCLUSIONS These cases show that FISF extends beyond Flinders Island and most likely has the same distribution across south-east Australia as its vector, the reptile tick Aponomma hydrosauri. FISF should be considered as a differential diagnosis in patients from south-eastern Australia presenting with fever, headache and rash following a tick bite.
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Affiliation(s)
- Nathan B Unsworth
- The Australian Rickettsial Reference Laboratory, Department of Clinical and Biomedical Sciences, The University of Melbourne, The Geelong Hospital, Victoria, Australia.
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30
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Affiliation(s)
- S R Graves
- The Australian Rickettsial Reference Laboratory, The Geelong Hospital, Victoria
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31
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Odorico DM, Graves SR, Currie B, Catmull J, Nack Z, Ellis S, Wang L, Miller DJ. New Orientia tsutsugamushi strain from scrub typhus in Australia. Emerg Infect Dis 1998; 4:641-4. [PMID: 9866742 PMCID: PMC2640248 DOI: 10.3201/eid0404.980416] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In a recent case of scrub typhus in Australia, Orientia tsutsugamushi isolated from the patient's blood was tested by sequence analysis of the 16S rDNA gene. The sequence showed a strain of O. tsutsugamushi that was quite different from the classic Karp, Kato, and Gilliam strains. The new strain has been designated Litchfield.
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Affiliation(s)
- D M Odorico
- James Cook University, Townsville, Queensland, Australia
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32
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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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Kovácová E, Sixl W, Stünzner D, Urvölgyi J, Kazár J. Serological examination of human and animal sera from six countries of three continents for the presence of rickettsial antibodies. Eur J Epidemiol 1996; 12:85-9. [PMID: 8817184 DOI: 10.1007/bf00144434] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Forty samples each of human sera collected in Guinea Bissau, Cape Verde, El Salvador and Iran, and animal sera (goat and cattle from Sri Lanka and sheep from Tanzania) were examined for the presence of antibodies to typhus group (TG) rickettsiae, spotted fever group (SFG) rickettsiae and Coxiella burnetii by enzyme-linked immunosorbent assay (ELISA) and indirect fluorescent antibody (IFA) test. Of human sera tested, a higher proportion of positive sera were found with ELISA and IFA test for TG, SFG rickettsiae and C. burnetii in El Salvador (42.5 vs 20.0%, 40.0 vs 32.5%, and 27.5 vs 27.5%, respectively) and in Iran (25.0 vs 15.0%, 45.0 vs 27.5%, and 27.5 vs 25.0%, respectively), than in Guinea Bissau and Cape Verde, where they were less than 20.0% except for antibodies to SFG rickettsiae in Guinea Bissau (25.0% with ELISA and 20.0% with IFA test). While all animal sera were negative for the presence of antibodies to TG rickettsiae, a high proportion of sera from Sri Lanka reacted in ELISA and IFA test with SFG rickettsiae and C. burnetii (37.5 vs 20.0% and 27.5 vs 25.0% for goat sera, and 40.0 vs 30.0%, and 17.5 vs 15.0% for cattle sera, respectively). The results obtained indicate that the studied rickettsial diseases can be spread in given territories and may pose a public health problem requiring greater attention than has been paid so far. The suitability of ELISA and IFA test for serological survey of rickettsial antibodies is discussed.
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Affiliation(s)
- E Kovácová
- WHO Collaborating Centre for Rickettsial Reference, Slovak Academy of Sciences, Slovak Republic, Austria
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Baird RW, Lloyd M, Stenos J, Ross BC, Stewart RS, Dwyer B. Characterization and comparison of Australian human spotted fever group rickettsiae. J Clin Microbiol 1992; 30:2896-902. [PMID: 1452660 PMCID: PMC270549 DOI: 10.1128/jcm.30.11.2896-2902.1992] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The microbiological and molecular characteristics of the rickettsiae isolated from humans with Queensland tick typhus (QTT) caused by Rickettsia australis and the recently described Flinders Island spotted fever (FISF) were compared. Clinically and serologically, the diseases are similar. Cell culture reveals differences in the plaque-forming abilities of the isolates. Characterization of the gene encoding the genus-specific 17-kDa antigen of R. australis revealed a unique nucleotide sequence unlike those of the FISF isolate and Rickettsia rickettsii. Southern blot analysis of rickettsial DNA from the isolates with a 17-kDa-antigen gene probe revealed the presence of this gene in all isolates but no difference in banding patterns. When a probe for the rRNA genes was used, clear differences in banding patterns of isolates from patients with QTT and FISF were revealed. Thus, the rickettsiae isolated from patients with FISF differ from those from patients with QTT and may represent a new rickettsial species.
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Affiliation(s)
- R W Baird
- Clinical Pathology Laboratory, Fairfield Hospital, Victoria, Australia
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Abstract
OBJECTIVE To present a case of murine (endemic) typhus, the first to be reported within the last 30 years in Australia. CLINICAL FEATURES A 17-year-old pregnant woman presented with a viral-like illness and later developed a spotted rash, fever and headache. INVESTIGATION AND OUTCOME: Sera taken on Day 7 and Day 30 of the illness showed seroconversion to Proteus OX19 (Weil-Felix) and to Rickettsia typhi (by immunofluorescence), indicating recent infection with Rickettsia of the typhus group. Her illness was clinically compatible with murine typhus. She responded well to erythromycin and delivered a normal infant at term. CONCLUSION Infection with Rickettsia typhi (murine typhus) still occurs in Australia. It can be diagnosed by means of specific serological tests for rickettsial disease, which are superior to the non-specific Weil-Felix test.
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Affiliation(s)
- S R Graves
- Fairfield Infectious Diseases Hospital, Vic
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Affiliation(s)
| | | | - Robert H Edis
- Department of NeurologyRoyal Perth HospitalBox X2213 GPOPerthWA6001
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Dwyer BW, Graves SR, McDonald MI, Yung AP, Doherty RR, McDonald JK. Spotted fever in East Gippsland, Victoria: a previously unrecognised focus of rickettsial infection. Med J Aust 1991; 154:121-5. [PMID: 1986189 DOI: 10.5694/j.1326-5377.1991.tb120998.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A new focus of spotted fever group rickettsial infection has been recognised in East Gippsland, Victoria. Seven cases have been identified among Melbourne residents after they holidayed in the area. The infections were confirmed serologically. The precise identity of the Rickettsia has not been determined.
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Affiliation(s)
- B W Dwyer
- Department of Clinical Pathology, Fairfield Infectious Diseases Hospital, VIC
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