Dianne
I've had encephalitis/menengitis 3 times (a rare form I got from visiting Puerto Rico)and I'm pretty much an expert on the subject. It's okay for your son to visit his friend...he will not catch it! If there's any chance of that then his friend would be in "isolation" with no visitors allowed except for family. (been there, done that, too) It's not "airborn" so it's okay for the visit...just tell him NOT to touch anything or his friend because it's passed on through physical contact. Then have him wash his hands upon leaving. Don't fear, mom....