Why should you always wash your hands after holding your ball python?

It's not just after a snake.. you should wash your hands before and after handling any kind of reptile (turtles, snakes, etc.) 
This is because more than likely, the animal contains salmonella. (Be aware that anything the snake touches, salmonella could spread to IF the reptile has it.)

I hope this helps you and keep asking questions! (:

The question may be incomplete (there are not the possible answers), but according to the scenario, kaley and her coworkers could be in a humanitarian organization like red cross (in the us or in other countries). it's an organization which organizes health and safety services, disaster services, and blood donations.