A rapid immunofluorescent procedure for serodiagnosis of Q fever in mice, guinea pigs, sheep, and humans.

The ability to diagnose Q fever has been hampered by the fact that diagnosis depends upon difficult serologic tests such as complement fixation (CF) or slide immunofluorescence performed only at reference laboratories. A new quantitative solid phase fluorescent antibody test (FIAX) has recently been developed and applied to measure antibodies in several microbial systems. The test takes less than 2 hr to perform and employs stable reagents. We have utilized this technique and developed a rapid immunofluorescent assay for detection of antibodies to Coxiella burnetii in man and animals. Sera from guinea pigs and mice immunized with phase I vaccine and from naturally infected sheep show high levels of fluorescence against both phase I and phase II antigens by this technique. We have tested over 100 CF positive humans from a recent laboratory outbreak of Q fever and find an excellent correlation between FIAX and CF results.