Rickettsia australis and Queensland Tick Typhus: A Rickettsial Spotted Fever Group Infection in Australia

Stewart, Adam G; Armstrong, Mark; Graves, Stephen; Hajkowicz, Krispin

doi:10.4269/ajtmh.16-0915

Cited by 22 publications

(22 citation statements)

References 49 publications

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“…3,22 One OTU completely matched the human pathogen, R. akari. 23 Some OTUs were also very similar to some human pathogens, including Rickettsia aeschilimannii, 24 Rickettsia felis, 25 and Rickettsia australis, 26 although the genetic diversity among the strains was low. Previous reports have shown that bacteria very similar to R. felis, R. australis, and R. akari were detected in L. scutellare mites in China and Korea.…”

Section: Discussionmentioning

confidence: 99%

Obligate intracellular bacteria diversity in unfed Leptotrombidium scutellare larvae highlights novel bacterial endosymbionts of mites

Ogawa

Takahashi

Matsutani

et al. 2019

Microbiology and Immunology

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It is well known that the mite Leptotrombidium scutellare carries the pathogen of scrub typhus, Orientia tsutsugamushi. However, our understanding of other bacterial endosymbionts of mites is limited. This study investigated the diversity of the obligate intracellular bacteria carried by L. scutellare using 16S rRNA gene amplicon analysis with next-generation sequencing. The results showed that the detected bacteria were classified into the genera Rickettsia, Wolbachia, and Rickettsiella and an unknown genus of the order Rickettsiales. For further classification of the detected bacteria, a representative read that was most closely related to the assigned taxonomic classification was subjected to homology search and phylogenic analysis. The results showed that some bacteria of the genus Rickettsia were identical or very close to the human pathogens Rickettsia akari, Rickettsia aeschlimannii, Rickettsia felis, and Rickettsia australis. The genetic distance between the genus Wolbachia bacteria in the present study and in previous reports is highly indicative that the bacteria in the present study can be classified as a new taxon of Wolbachia. This study detected obligate intracellular bacteria from unfed mites; thus, the mites did not acquire bacteria from infected animals or any other infectious sources. Finally, the present study demonstrated that various and novel bacterial endosymbionts of mites, in addition to O. tsutsugamushi, might uniquely evolve with the host mites throughout overlapping generations of the mite life cycle. The roles of the bacteria in mites and their pathogenicity should be further examined in studies based on bacterial isolation.

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Section: Discussionmentioning

confidence: 99%

Obligate intracellular bacteria diversity in unfed Leptotrombidium scutellare larvae highlights novel bacterial endosymbionts of mites

Ogawa

Takahashi

Matsutani

et al. 2019

Microbiology and Immunology

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“…TwKM02 ( Rickettsia australis cluster) in L. deliense collected from rodents in Kinmen and Matsu. While R. rhipicephali is an unlikely human pathogen [ 81 ], R. australis (TRG) is the etiologic agent of Queensland tick typhus [ 82 ], which occurs primarily in northeastern Australia [ 49 ]. Tsai et al [ 64 ] then isolated a novel SFG rickettsiae, Rickettsia sp.…”

Section: Emerging Vector-borne Rickettsiosesmentioning

confidence: 99%

The Re-Emergence and Emergence of Vector-Borne Rickettsioses in Taiwan

2017

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Rickettsial diseases, particularly vector-borne rickettsioses (VBR), have a long history in Taiwan, with studies on scrub typhus and murine typhus dating back over a century. The climatic and geographic diversity of Taiwan’s main island and its offshore islands provide many ecological niches for the diversification and maintenance of rickettsiae alike. In recent decades, scrub typhus has re-emerged as the most prevalent type of rickettsiosis in Taiwan, particularly in eastern Taiwan and its offshore islands. While murine typhus has also re-emerged on Taiwan’s western coast, it remains neglected. Perhaps more alarming than the re-emergence of these rickettsioses is the emergence of newly described VBR. The first case of human infection with Rickettsia felis was confirmed in 2005, and undetermined spotted fever group rickettsioses have recently been detected. Taiwan is at a unique advantage in terms of detecting and characterizing VBR, as it has universal health coverage and a national communicable disease surveillance system; however, these systems have not been fully utilized for this purpose. Here, we review the existing knowledge on the eco-epidemiology of VBR in Taiwan and recommend future courses of action.

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“…Rickettsia australis is the agent responsible for the illness called Queensland tick typhus and transmitted by Ixodes holocyclus ticks along the eastern coast of Australia. 50 Disease attributed to Rickettsia felis has been termed flea-borne spotted fever. The organism was originally described within a laboratory colony of cat fleas (Ctenocephalides felis).…”

Section: Transitional Group Rickettsiosesmentioning

confidence: 99%

“…49 The clinical presentation of Queensland tick typhus is similar to aforementioned SFG rickettsioses with maculopapular rash in 90% and eschar in up to 65% with associated regional lymphadenopathy. 50 Although more often mild, severe and fatal cases have been documented. 66 Flea-borne spotted fever also appears to to have manifestations that are on the milder side of the clinical spectrum when compared to other SFG rickettsioses.…”

Section: Transitional Group Rickettsiosesmentioning

confidence: 99%

The Rickettsioses

Blanton

2019

Infectious Disease Clinics of North America

152

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Rickettsia are small, obligately intracellular Gram negative bacilli. They are distributed among a variety of hematophagous arthropod vectors and cause illness throughout the world. Rickettsioses present as an acute undifferentiated febrile illness and are often accompanied by headache, myalgias, and malaise. Cutaneous manifestations include rash and eschar, which both occur at varying incidence depending on the infecting species. Serology is the mainstay of diagnosis, and the indirect immunofluorescence assay is the test of choice. Reactive antibodies are seldom present during early illness, so testing should be performed on both acute-and convalescent-phase sera. Doxycycline is the treatment of choice.

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Rickettsia australis and Queensland Tick Typhus: A Rickettsial Spotted Fever Group Infection in Australia

Cited by 22 publications

References 49 publications

Obligate intracellular bacteria diversity in unfed Leptotrombidium scutellare larvae highlights novel bacterial endosymbionts of mites

Obligate intracellular bacteria diversity in unfed Leptotrombidium scutellare larvae highlights novel bacterial endosymbionts of mites

The Re-Emergence and Emergence of Vector-Borne Rickettsioses in Taiwan

The Rickettsioses

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