The Role of Rats in Spreading the Plague
WouterThe exact origin of the plague is still a mystery. While the Black Death originated in Europe, some historians speculate that it originated in Central Asia, spread southward into China, and then migrated westward into India and Persia. William McNeill speculated that the plague originated in the Himalayas, but other historians, such as Rosemary Horrox, believe the disease originated in the steppes of eastern Asia. Either way, the disease is known to have spread from rodent reservoirs.
The plague is a bacterial disease caused by Yersinia pestis. Infection occurs when rodents become infected with the plague bacteria. However, these rodents rarely become sick and remain a reservoir of the plague bacteria. These animals are known to pass the plague bacteria to other animals and humans.
In addition to rats, fleas and lice were also thought to play a role in spreading the plague. In 1347-1353, the plague killed up to 50 per cent of the population in Europe. Because rats can tolerate high levels of bacillus in their blood, researchers believe that they greatly amplify the plague’s virulence.
Researchers still don’t understand the exact cause of the plague but do know the main factors that contributed to its spread. According to Monica Green, a medieval health historian, the main culprits were rodents and fleas.
