Diagnosis of rickettsial disease

Diagnosis of rickettsioses in clinical settings is a challenge due to the large range of pathogens that cause similar symptoms, and further confounded by the lack of reliable tests to confirm diagnosis. Syndromic diagnosis can be problematic due to the non-specific symptoms of the diseases, which can often lead to delays in diagnosis. The most widely used methods for diagnosing rickettsial diseases comprise of culture, nucleic acid amplification (NAAT), and serological methods such as rapid diagnostic tests (RDTs), indirect immunofluorescence assays (IFA), and enzyme-linked immunosorbent assays (ELISA). Laboratory diagnosis of rickettsial diseases relies heavily on serological methods, however, antibody evidence of infection may not be present until the second week of illness onset; this often leads to negative results in the acute phase of infection. Antigen detection in skin, eschar, or tissue biopsies and other molecular methods can be advantageous for acute phase diagnosis. Although, clinical settings and resource limitations need to be taken into consideration.


An Update on the Laboratory Diagnosis of Rickettsia spp. Infection