When European explorers and travelers spread out, they brought with them the germs that they had become essentially immune to, that they had learned how to tolerate over hundreds and hundreds of years, thousands of years, of living with domesticated animals who were the sources of those pathogens.
Quando os exploradores europeus e os viajantes se espalharam, levaram com eles os germes aos quais se tinham tornado essencialmente imunes, que tinham aprendido a tolerar ao longo de centenas e centenas de anos, de milhares de anos, vivendo com animais domésticos que eram a origem destes agentes patogénicos.