"When we began and living more closely alongside them, we shared diseases with our new companions. And keeping animals with less than in the wild in crowded, stressful conditions also made them more susceptible to disease. Today, intensive has created highly pathogenic forms of that have infected herds of cattle and their farmers in the US. Then there’s . By and disturbing other habitats, we’ve caused animals stress and forced them to live more closely together. That may have contributed to the spread of from s to apes, monkeys and small forest antelopes known as s. contributes too, by forcing animals and plants to move to cooler regions, and mixing them up with other species. An encounter with a disease that your body hasn’t evolved immunity to is always dangerous."