Rickettsia rickettsii is a tick-borne illness (zoonosis) among the spotted fever group rickettsioses and is the etiologic agent of Rocky Mountain Spotted Fever (RMSF).
Gram-negative obligate intracellular coccobacilli of the Rickettsiaceae family
Fatality rate higher in children than adults, especially in children <10 years.
Rickettsia rickettsii (Rocky Mountain Spotted Fever) Antibodies, IgG & IgM by IFA 0050371Method: Semi-Quantitative Indirect Fluorescent Antibody
Preferred test for acute or convalescent phase of disease
Acute and convalescent titers often necessary
Low-positive results suggest past exposure or infection, whereas high-positive results may indicate recent or past infection but are inconclusive for diagnosis
Rickettsia rickettsii (Rocky Mountain Spotted Fever) Antibody, IgG 0050369Method: Semi-Quantitative Indirect Fluorescent Antibody
Detect antibodies during convalescent phase
Rickettsia rickettsii (Rocky Mountain Spotted Fever) Antibody, IgM 0050372Method: Semi-Quantitative Indirect Fluorescent Antibody
Detect antibodies during acute phase; paired concurrent specimen with IgG reduces false-positive rate
Convalescent sera may be required for diagnosis
Couturier, Marc Roger, PhD, D(ABMM), Medical Director, Microbial Immunology, Parasitology and Fecal Testing, and Infectious Disease Antigen Testing at ARUP Laboratories; Associate Professor of Clinical Pathology, University of Utah
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Delord M, Socolovschi C, Parola P. Rickettsioses and Q fever in travelers (2004-2013). Travel Med Infect Dis. 2014; 12(5): 443-58. PubMed
Minniear TD, Buckingham SC. Managing Rocky Mountain spotted fever. Expert Rev Anti Infect Ther. 2009; 7(9): 1131-7. PubMed
Walker DH, Paddock CD, Dumler S. Emerging and re-emerging tick-transmitted rickettsial and ehrlichial infections. Med Clin North Am. 2008; 92(6): 1345-61, x. PubMed
Last Update: July 2019
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