The clinical features of this disease appear to be due—at least in part—to the production of a superantigen—YpM (Yersinia pseudotuberculosis-derived mitogen). This is present in almost all strains from the<unk> <unk>  but only 20% of European isolates. The antigen was discovered in 1993 and is encoded by a 456-base gene. The protein has 151 amino acids, with a signal sequence of 20 amino acids. The mitogenic antigens are scattered across the protein but two cysteine residues (residues 32 and 129) which form a disulfide bridge are critical. The G+C content of this gene is 35%—lower than the genomic average (47%) suggesting that this gene has been acquired from some other organism. The organism from which this gene originated has not yet been identified. This gene seems<unk> ly to have been introduced into the genome by a bacteriophage, given the nearby presence of a phage integration site, but the mechanism of entry into the genome is not currently known.
Far East scarlet-like fever
Tomato fever
Cat Scratch Fever
Pappataci fever
Relapsing fever
Haverhill fever
Southern tick-associated rash illness
Rat-bite fever