New prion diseases are being found in other animals and might evolve to enter humans. There is a deer version being watched - not yet found in people, AFAWK? https://www.cdc.gov/prions/cwd/index.html
There have been many cases of assorted Human Papilloma viruses (HPV) transmitted by kissing as well as assorted variances of oral sex. Recent vaccines are very effective.https://www.cdc.gov/vaccines/vpd/hpv/public/index.html