Are there diseases that affect only humans?

If I understand your question correctly then I would argue that there are, and because of this those present the best targets for eradication. read more

There is a disease called scrapie which affects only sheep and goats. There is also mange which mostly affects dogs. it’s important to note that humans and animals have very different immune systems, and so infections have developed specifically to evade them, but our immune system kills them very quickly if we are exposed to it. read more

You only hear about diseases that affect humans because you're human. Those are the diseases that we're interested in. There may be a dozen or so people at most that are interested in diseases of, say, the Malaysian Rayed Turtle. read more