Interesting philosphical question? Maybe...
Why do people seem to get sick more often than animals?
Well, it could be:
1) Because most people are much better at recognizing disease in humans. Ask a vet how many sick animals they see walking down the street, and compare to how many you recognized.
(2) Because wild animals have strong selection pressure to hide symptoms of disease as long as possible, since predators preferentially target the sick.
(3) Because animals are much more likely to die early on in a disease, whether due to the disease itself or to a predator; so the duration of a disease, and the total number of diseases an individual can experie.nce, which are far higher for humans.