If anyone is a Rush (the rock group) fan, you may recall that Neil Peart contracted some kind of parasitic disease from swimming in contaminated water while on a bike trip in Africa. It didn't manifest itself until he had been home for a few weeks. It's documented in his book "The Masked Rider: Cycling In West Africa".

I don't remember the name of the illness/disease, but he wasn't correctly diagnosed until he found it on his own by chance. I'll see if I still have the book.

Bottom line, don't waste your time on the family doctor. Get in touch with a specialist in African diseases. Good luck.