The acute disease antigen A (adaA) gene has been hypothesized to be allied to Coxiella burnetii strains causing acute Q fever. A recent publication by Frangoulidis et al. 2013, showed that this relationship might have been oversimplified and is more complex than initially described. They also descibed a discrimination system based on the sequence of the AdaA gene. This system is implemented on this platform as AdaA typing. Citations: Microevolution of the Chromosomal Region of Acute Disease Antigen A (adaA) in the Query (Q) Fever Agent Coxiella burnetii Frangoulidis D, Splettstoesser WD, Landt O, Dehnhardt J, Henning K, et al. (2013) Microevolution of the Chromosomal Region of Acute Disease Antigen A (adaA) in the Query (Q) Fever Agent Coxiella burnetii. PLOS ONE 8(1): e53440. https://doi.org/10.1371/journal.pone.0053440