Getting a touch of food poisoning is common in many countries. In North America we used to call it "Montezuma's Revenge". The Mexicans and Central Americans had a different name but used to get it regularly on trips to North America. A few years back I was feeling pretty cocky and eating off Cambodian food carts and smoothy shops. Sure enough, I picked up a dose of the "Khmer Kiss" (I know I shouldn't have but in my defense, I'm not very bright). It's just our guts reaction to a new and unknown bacteria. Uncomfortable but it doesn't normally last that long.
Amoebic or parasitic diseases are a whole different thing. They are dangerous and life threatening. You should soon be at a doctors office requesting a tropical specialist and recounting which countries you've been in and the timeline.
I'm glad these people finally got the assistance they needed and will recover.