Rocky Mountain spotted fever

Clinical criteria

Any reported fever, and one or more of the following: rash, eschar, headache, myalgia, anemia, thrombocytopenia, or any hepatic transaminase elevation.

Laboratory criteria

Laboratory confirmed:
- Serologic evidence of a four-fold change in immunoglobulin G (IgG)-specific antibody titer reactive with Rickettsia rickettsii or other spotted fever group antigen by indirect immunofluorescence assay (IFA) between paired serum specimens (one taken in the first week of illness and a second 2-10 weeks later); or
- Detection of R rickettsiior other spotted fever group DNA in a clinical specimen via amplification of a specific target by polymerase chain reaction (PCR) assay; or
- Demonstration of spotted fever group antigen in a biopsy or autopsy specimen by immunohistochemical methods; or
- Isolation of R rickettsii or other spotted fever group Rickettsia from a clinical specimen in cell culture and molecular confirmation (e.g., PCR or sequence).

Presumptive laboratory evidence:
- Serologic evidence of elevated IgG antibody at a titer ≥1:128 reactive with R rickettsii or other spotted fever group antigen by IFA in a sample taken within 60 days of the onset of illness.
Supportive laboratory evidence:
- Serologic evidence of elevated IgG antibody at a titer <1:128 reactive with R rickettsii or other spotted fever group antigen by IFA in a sample taken within 60 days of the onset of illness.

Case classification

Suspected: case with confirmatory or presumptive laboratory evidence of past or present infection but no clinical information available (e.g., laboratory report), or a clinically compatible case that has supportive laboratory evidence.

Probable: clinically compatible case (meets clinical criteria) that has presumptive laboratory results.

Confirmed: clinically compatible case (meets clinical criteria) that is laboratory confirmed.

Use of this content is subject to our disclaimer

Criteria