The most common (in the U.S.) type of salmonella causes gastro-intestinal problems. Usually diarhhea and possibly even vomiting. This type of gastro-intestinal problem is very closely related to E. coli. The easiest way to avoid it is to wash with warm soap and water and be sure to scrub your hands in between the fingers and fingernails very well (like singing the alphabet song in your head TWICE) while washing, before rinsing.
C-diff..........which is another gastro-intestinal infection is another that CAN be dangerous if precautions are not taken to avoid further spread. I work in the health care field and this is most common in either pediatric or geriatric patients (ie/ children and older adults). Typically, these are the age groups that have either under-developed (pediatric) or supressed (geriatric) immune systems. Most of US, unless we have a immune system disease that causes our bodies natural ability to fight disease of any type will have very minor problems with minimum exposure. That being said, WHY take the chance, especially if we or our reptiles are handled or live with children or the elderly. Again, it can be controlled and NOT allowed to be spread by simple and thorough HAND WASHING.
Now.........I'm gonna let you in on a little secret that for some reason hasn't gotten out to the "general public". MOST EVERY soap, of ANY kind has anti-bacterial tendencies. This means that when WE fork out the bigger bucks for the marketed "anti-bacterial" soaps, that the manufacturers laugh all the way to the bank. We learned this in Micro-Biology and actually had a project that showed the effeciency (or lack of) in soaps in general.
While some various strains of salmonella, C-diff and E. coli have MUCH more serious consequences than the "most common" strains and ANY and ALL of each should be taken seriously. The general public usually is unaware that one of the simplest things (thorough hand washing with soap and water) IS effective in stopping this in it's tracks.............the alcohol based "sanitizers" that are also commonly found in everyones home is INEFFECTIVE with gastro-intestinal issues.
Again...........DO NOT take the chance.........just wash your hands regularly and thoroughly and it won't be a problem.
I'm going on memory here, and it has been some time since my Micro-Biology class.............but these are the main points that I want to put out there. We have four grandchildren and they regularly handle our chameleon. The other thing that they ALWAYS do after handling him and BEFORE allowing them to touch their faces is...............thorough hand washing.
I hope this will clear up this issue for the concerns that people that own reptiles have.