<i>Rickettsia</i>364D: A Newly Recognized Cause of Eschar‐Associated Illness in California

Shapiro, Marc R.; Fritz, Curtis L.; Tait, Karen; Paddock, Christopher D.; Nicholson, William L.; Abramowicz, Kyle F.; Karpathy, Sandor E.; Dasch, Gregory A.; Sumner, John W.; Adem, Patricia; Scott, Jamesina J.; Padgett, Kerry A.; Zaki, Sherif R.; Eremeeva, Marina E.

doi:10.1086/649926

Cited by 118 publications

(93 citation statements)

References 22 publications

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“…The prevalence and distribution of Rickettsia species 364D in D. occidentalis ticks suggests that these infections in humans might be more common in California than currently recognized (45,46). Reported cases of Rickettsia species 364D rickettsiosis have occurred during July-September (43,44).…”

Section: Rickettsia Species 364dmentioning

confidence: 99%

“…The first confirmed case of human disease associated with Rickettsia species 364D was described in 2010 from California and likely was transmitted by the Pacific Coast tick, Dermacentor occidentalis (43). Fewer than 10 cases of Rickettsia species 364D infection, all from California, have been reported in the literature (43,44).…”

Section: Rickettsia Species 364dmentioning

confidence: 99%

“…Fewer than 10 cases of Rickettsia species 364D infection, all from California, have been reported in the literature (43,44). Cases have been documented in children and adults (44).…”

Section: Rickettsia Species 364dmentioning

confidence: 99%

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Diagnosis and Management of Tickborne Rickettsial Diseases: Rocky Mountain Spotted Fever and Other Spotted Fever Group Rickettsioses, Ehrlichioses, and Anaplasmosis — United States

Biggs¹,

Behravesh²,

et al. 2016

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Section: Rickettsia Species 364dmentioning

confidence: 99%

Section: Rickettsia Species 364dmentioning

confidence: 99%

See 1 more Smart Citation

Diagnosis and Management of Tickborne Rickettsial Diseases: Rocky Mountain Spotted Fever and Other Spotted Fever Group Rickettsioses, Ehrlichioses, and Anaplasmosis — United States

Biggs¹,

Behravesh²,

et al. 2016

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“…PCR methods for detection of R. rickettsii in clinical samples include nested assays for two SFG target genes, the 17-kDa-protein-encoding gene and the ompA outer membrane protein gene (5-7). The ompA nested amplicon may then be sequenced for species identification (8)(9)(10)(11)(12)(13)(14)(15). However, this methodology is time-consuming (1 to 2 days, minimum) and has not proven highly sensitive for the detection of Rickettsia spp.…”

mentioning

confidence: 99%

“…Thirteen of these 35 were determined to be SFG by nested PCR but were not further characterized to the species level. The remaining 22 nested PCR positives were identified by DNA sequencing as R. rickettsii (14), R. parkerii (3), R. akari (2), R. africae (1), and R. typhi (2) ( Table 3).…”

mentioning

confidence: 99%

Assessment of Real-Time PCR Assay for Detection of Rickettsia spp. and Rickettsia rickettsii in Banked Clinical Samples

et al. 2013

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Two novel real-time PCR assays were developed for the detection of Rickettsia spp. One assay detects all tested Rickettsia spp.; the other is specific for Rickettsia rickettsii. Evaluation using DNA from human blood and tissue samples showed both assays to be more sensitive than nested PCR assays currently in use at the CDC. Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever (RMSF), is a tick-borne bacterial agent that is a member of the spotted fever group (SFG) rickettsiae. Symptoms of this disease may include, but are not limited to, high fever, headache, and rash, with the potential for a fatal outcome (1). National case fatality rates are Ͻ1% but can approach 7% in some regions to which it is highly endemic; a fatal outcome may be averted with timely administration of doxycycline (2, 3).In the United States, serologic tests are most often used to diagnose RMSF with seroconversion (4-fold titer increase from acute to convalescent phase) by immunofluorescence assay (IFA), the gold standard. However, serologic tests are frequently negative during the acute phase of illness, and currently available molecular tests are not reliable for use in patient management when applied to acute-phase blood samples, which may have very few organisms (3, 4). Clinical management of suspected RMSF cases based on test results is not recommended, partly because of diagnostic assay limitations, and physicians must treat suspected cases empirically (4). While empirical treatment of suspected cases will always be recommended, the development of more sensitive molecular tests that could be applied to patient specimens during the acute phase of illness will enhance the identification of nonfatal cases, improve the timeliness of public health actions following identification of a case, and aid national surveillance efforts by better defining the spectrum and burden of tick-borne rickettsial infections.At the Centers for Disease Control and Prevention (CDC), nested PCR assays have been the standard molecular diagnostic method for testing of blood and fresh tissue specimens. PCR methods for detection of R. rickettsii in clinical samples include nested assays for two SFG target genes, the 17-kDa-protein-encoding gene and the ompA outer membrane protein gene (5-7). The ompA nested amplicon may then be sequenced for species identification (8-15). However, this methodology is time-consuming (1 to 2 days, minimum) and has not proven highly sensitive for the detection of Rickettsia spp. in blood samples during acute disease, except in cases of advanced or fatal illness (4, 16). A 2000-2007 national surveillance summary noted that Ͻ0.5% of reported cases were diagnosed using nested PCR methodology (3).Several real-time PCR assays have been developed for rickettsial agent detection, including Rickettsia genus-specific (panrickettsia) and R. rickettsii-specific assays (17-20). Panrickettsia assays have utilized conserved sites in the 17-kDa, outer membrane protein (ompB), 16S rRNA, and citrate synthase (gltA) genes, while ...

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The Expanding Spectrum of Eschar-Associated Rickettsioses in the United States

et al. 2010

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Background: Until recently, Rickettsia rickettsii was the only substantiated cause of tick-borne spotted fever group (SFG) rickettsiosis in humans in the United States. Rickettsia parkeri, originally thought to be nonpathogenic in humans, was recently proved to be another cause of tickborne SFG rickettsiosis.Observations: We report 3 cases of SFG rickettsiosis and discuss the epidemiology, clinical presentation, histopathologic features, and laboratory findings that support confirmed or probable diagnoses of R parkeri infection and describe the expanding list of eschar-associated SFG rickettsioses recognized in US patients. Conclusions:The SFG rickettsioses share many clinical manifestations and extensive antigenic cross-reactivity that may hamper specific confirmation of the causative agent.

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Rickettsia364D: A Newly Recognized Cause of Eschar‐Associated Illness in California

Cited by 118 publications

References 22 publications

Diagnosis and Management of Tickborne Rickettsial Diseases: Rocky Mountain Spotted Fever and Other Spotted Fever Group Rickettsioses, Ehrlichioses, and Anaplasmosis — United States

Diagnosis and Management of Tickborne Rickettsial Diseases: Rocky Mountain Spotted Fever and Other Spotted Fever Group Rickettsioses, Ehrlichioses, and Anaplasmosis — United States

Assessment of Real-Time PCR Assay for Detection of Rickettsia spp. and Rickettsia rickettsii in Banked Clinical Samples

The Expanding Spectrum of Eschar-Associated Rickettsioses in the United States

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