While the salmonella that can be present in the gutload of reptiles (this does not mean that every reptile has it)can be transmitted to humans via uncleanliness this problem has been blown out of proportion. Perhaps a better topic would be to research salmonella (by far and away the most common zoonoses in reptiles), and how to prevent transmission.
A definition that will help you: zoonoses-describes the transmission of a disease from animal to human.
I suggest calling a herp veterinarian for his opinion /- the use of his literature. A university library may also be helpfull. Try typing in reptile and zoonoses into a google search.
Although there are many other parasites in reptiles and amphibians as suggested in the post above, most are species specific and I don't think there are any that will affect humans.
(For instance, Giardia lamblia is what affects people, while G. muris affects other mammals, and another species affects reptiles and amphibians.)