Other species evolved clever ways to protect themselves from catching illness long before we developed treatments. What do they do?
Humans are constantly at war with disease. We lob antibiotic missiles at bacteria and toss vaccine-shaped grenades at viruses. We drop bombs made of antibacterial soap and hand sanitiser on everything we can. The battle between humans and parasites (an umbrella term that includes viruses, bacteria and much larger creatures that thrive on a host) has ancient roots, and exert as strong a force on evolution as predators, drought or famine.