Rickettsia parkeri Rickettsiosis and Its Clinical Distinction from Rocky Mountain Spotted Fever

• Published in: Clinical infectious diseases Vol. 47; no. 9; pp. 1188 - 1196
• Main Authors: Paddock, Christopher D., Finley, Richard W., Wright, Cynthia S., Robinson, Howard N., Schrodt, Barbara J., Lane, Carole C., Ekenna, Okechukwu, Blass, Mitchell A., Tamminga, Cynthia L., Ohl, Christopher A., McLellan, Susan L. F., Goddard, Jerome, Holman, Robert C., Openshaw, John J., Sumner, John W., Zaki, Sherif R., Eremeeva, Marina E.
• Format: Journal Article
• Language: English
• Published: Chicago, IL The University of Chicago Press 01.11.2008; University of Chicago Press; Oxford University Press
• Subjects: Adult; Aged; Amblyomma maculatum; Animals; Antibodies; Antibodies, Bacterial - blood; Antigens; Arachnid Vectors - microbiology; Articles and Commentaries; Bacterial diseases; Biological and medical sciences; Diagnosis, Differential; DNA, Bacterial - genetics; Epidemiology; Exanthema; Female; Fever; Human bacterial diseases; Humans; Infections; Infectious diseases; Ixodidae; Ixodidae - microbiology; Male; Medical sciences; Middle Aged; Rickettsia; Rickettsia - genetics; Rickettsia - immunology; Rickettsia - isolation & purification; Rickettsia - pathogenicity; Rickettsia Infections - diagnosis; Rickettsia Infections - microbiology; Rickettsia Infections - transmission; Rickettsia parkeri; Rickettsial diseases; Rocky Mountain spotted fever; Rocky Mountain Spotted Fever - diagnosis; Specimens; Ticks; Tropical bacterial diseases; United States; United States; United States > US; Infection; Rickettsiales; Rickettsialosis; Rickettsial infection; Bacteriosis; Bacteria; Rocky mountain spotted fever; Rickettsieae; Rickettsia; Rickettsiaceae
• ISSN: 1058-4838; 1537-6591
• DOI: 10.1086/592254

Background. Rickettsia parkeri rickettsiosis, a recently identified spotted fever transmitted by the Gulf Coast tick (Amblyomma maculatum), was first described in 2004. We summarize the clinical and epidemiological features of 12 patients in the United States with confirmed or probable disease attributable to R. parkeri and comment on distinctions between R. parkeri rickettsiosis and other United States rickettsioses. Methods. Clinical specimens from patients in the United States who reside within the range of A. maculatum for whom an eschar or vesicular rash was described were evaluated by ⩾1 laboratory assays at the Centers for Disease Control and Prevention (Atlanta, GA) to identify probable or confirmed infection with R. parkeri. Results. During 1998–2007, clinical samples from 12 patients with illnesses epidemiologically and clinically compatible with R. parkeri rickettsiosis were submitted for diagnostic evaluation. Using indirect immunofluores-cence antibody assays, immunohistochemistry, polymerase chain reaction assays, and cell culture isolation, we identified 6 confirmed and 6 probable cases of infection with R. parkeri. The aggregate clinical characteristics of these patients revealed a disease similar to but less severe than classically described Rocky Mountain spotted fever. Conclusions. Closer attention to the distinct clinical features of the various spotted fever syndromes that exist in the United States and other countries of the Western hemisphere, coupled with more frequent use of specific confirmatory assays, may unveil several unique diseases that have been identified collectively as Rocky Mountain spotted fever during the past century. Accurate assessments of these distinct infections will ultimately provide a more valid description of the currently recognized distribution, incidence, and case-fatality rate of Rocky Mountain spotted fever. An unnamed, apparently new rickettsia has been repeatedly isolated at the Rocky Mountain Laboratory during the past nine years from specimens of Amblyomma maculatum, a tick of wide distribution in the Southern States…the presumptive evidence from animal experimentation suggests that human infection might be confusingly similar to spotted fever. Parker Ralph R. 1948 [1, p. 146]