Black Death Vector Flea

Timeline

1. c. 1340–1347Central Asian steppe · steppe beltYersinia pestis circulated among marmots and steppe rodents in Central Asia, with fleas biting infected rodents; caravans and warhorses carried infected rodents to the edges of human settlements, preparing ecological conditions for intercontinental spread.
2. 1347–1351Messina, Sicily · SicilyInfected ships brought rats and fleas into Mediterranean ports, and plague spread north and east overland; dense rat populations and limited sanitation in urban ports led to flea-bitten bubonic and septicemic plague, killing one-third to one-half of Europe's population.
3. 1351–1360London · EnglandAfter the first peak, cities like London, Cairo, and Florence still suffered intermittent plague; infected rats and fleas persisted in warehouses, docks, and slums, population recovery was slow, and labor shortages drove changes in wages and land relations.