english: 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.
non_english: Toen Europese ontdekkingsreizigers zich verspreidden, brachten ze ziektekiemen mee waarvoor ze zelf immuun waren geworden. Ze hadden geleerd om honderden en duizenden jaren samen te leven met gedomesticeerde dieren die de bron waren van die ziektekiemen.