Rickettsial Disease

Case Definition

​​​Confirmed Case​

Clinical evidence1 of infection and lab confirmation using:

  • Serological evidence of a fourfold change in IgG titer reactive with Rickettsia2 antigen by indirect immunofluorescence assay (IFA) between paired serum specimens (one taken in the first week of illness and a second 2-4 weeks later)

    OR
  • Detection of Rickettsia2 nucleic acid in a clinical specimen via amplification of a specific target by PCR assay

    OR
  • Demonstration of Rickettsia2 antigen in a biopsy or autopsy specimen by IHC

    OR
  • Isolation of Rickettsia2 from a clinical specimen in cell culture.

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

2 Rickettsial infections include Rickettsia typhi (Typhus), Rickettsia rickettsii (Rocky Mountain Spotted Fever), Ehrlichia sp.  (Ehrlichiosis) and Anaplasma phagocytophilum (Anaplasmosis)