Left untreated, many things are fatal. For the developed world, I'd say those don't count. HIV is even being treated effectively in most cases today. There are vaccinations for Hep B and about 70 of cancer-causing HPV. Hep C has death rates of less than 2 in 1st world countries. That leaves HIV if you're unlucky and treatment doesn't work for you, and a few forms of HPV. Not too many after all. Thanks for your input.