Diagnosis of Q Fever Using Indirect Microimmunofluorescence

A microimmunofluorescence technique for the diagnosis of Q fever is described. Although this method is useful for serological diagnosis of Q fever, some technical difficulties are associated with it. First, the test antigens must be produced by a cell culture method in a level-3 biohazard facility and, second, the antigen Coxiella burnetii , which is the causative agent of Q, is characterized by the presence of two phases. To obtain phase I antigen, mice must be inoculated with C. burnetii . The materials obtained from the spleens of the infected mice are then used for cell inoculation. After purification, the antigens of both phases are deposited and fixed on multiple-well microscope slides. The serially diluted sera to be tested are incubated on these slides, then rinsed and overlaid with anti-IgG, -IgM and/or IgA secondary antibodies. Finally, the slides are examined under a fluorescence microscope for presence of C. burnetii .