Absolutely no health issues as long as basic sanitation practices are kept, as with any domesticated animal. With attentive parental guidance as mentioned above, snakes are safer than most other animals with young children.
I would definitely buy an enclosure that has some kind of locking mechanism on it. Not so much for the child's safety, but to prevent an inquisitive toddler from releasing the snake from the cage. Definitely a non-keyed lock. Kids eventually find keys. Coded locks are always safer.