Case Definition
Clinical evidence of illness1
AND
Laboratory confirmation of infection by one of the following methods:
- Serological evidence of a fourfold change in IgG titre reactive with Ehrlichia antigen by indirect immunofluorescence assay (IFA) or enzyme immunoassay (EIA) between paired serum specimens (one taken in the first week of illness and a second 2-4 weeks later).
- Detection of Ehrlichia nucleic acid in a clinical specimen via amplification of a specific target by PCR assay.
- Demonstration of Ehrlichia antigen in a biopsy or autopsy specimen by immunohistochemistry (IHC).
- Isolation of Ehrlichia spp. from a clinical specimen in cell culture.
Clinical evidence of illness1
AND
Serological evidence of elevated IgG antibody reactive with Ehrlichia spp. antigen by IFA at a titre ≥1:128 in a sample taken within 60 days of illness onset.
OR
Microscopic identification of intracytoplasmic morulae in leukocytes in a sample taken within 60 days of illness onset.
1Clinical evidence of illness is characterized by any reported fever and one or more of the following: chills/sweats, rash, headache, myalgia, nausea/vomiting, fatigue/malaise, anemia, leukopenia, thrombocytopenia, or any hepatic transaminase elevation.
