There is such a thing as zombie disease. It is found in a caterpillars and insects only. (It can only effect bugs, don't worry) the disease causes the insect to not be able to think. They climb to the top of a tree and just sit there. But the weirdest part is, once the virus has run its course, they turn into goo! I think that is worthy of a horror movie. The virus that causes it is called Caterpillar brain washing virus. it takes over the caterpillar so it will do its dirty work. The only thing it does is make more viruses. Creepy.
Luckily the gene they virus uses to zombifie caterpillars and bugs causes them to not be able to molt, so they keep eating and eating. and this causes them to get bigger and make more viruses. Since people don't molt like insects do, we should be safe. Also it effects their behavior. We have completely different behavior than insects so if we do get infected with this, it probably wont do what the virus does to bugs. we have to different biology and behavior. I highly doubt the virus will turn us into undead people who like to eat brains, if it can affect us at all. Often animal viruses don't effect people or only mildly. So again we are probably safe. Its still creepy.