The previous plague epidemic in Mallorca had been in 1652. Almost 200 years later, in May 1820, the plague returned to the island. The disease arrived on board a ship from Tangier which clandestinely disembarked on the coasts of Son Servera. Until now, historiography had described it as a late case of classical bubonic plague: the disease transmitted by infected rats and passed on to humans through the bite of rodent fleas. A study led by the Autonomous University of Barcelona (UAB) and the Open University of Catalonia (UOC), published in the scientific journal the scientific journal PNAS, has overturned the version. The data show that rats had nothing to do with it and that the plague spread directly between humans at a devastating speed.