Acting as a messenger between the central nervous system and the major organs, the vagus nerve slows the heart rate (through the release of the neurotransmitter acetylcholine), calms the immune response (by controlling the release of proteins called cytokines), and communicates with the muscles that control respiration and digestion.
The bacteria interacts with a molecule called IL-8 which should act as the messenger to rally other parts of the immune system to attack the "invader".
The strain affecting the patient was isolated and grown in the lab, and biochemical analysis found that the bacteria prevented the immune system responding as normal by "shooting the messenger".
Prof Solomon said that what Messenger finds not only unlocks secrets about the innermost planet in our Solar System, but could also shed light on those of other planets.