I've had many moments of terror on Africa trips, mostly at the hands of crazy drivers or bad traffic meaning I was out late on the open road. My worst sickness was in Pakistan when I ate some re-frozen ice cream. I was up all night with violent D&V, I couldn't believe so much liquid could come out of both ends of the body. Felt better by morning and manged to drink a cup of sweet tea and then, amazingly, I went out to work for the day with my agent. Nowadays you'd be carted off to hospital and put on IV fluids. In recent years I've got my company GP to give me powerful antibiotics, which deal with tummy problems effectively, firstly Ciprofloxacin, more recently Rifaximin, which works extremely effectively. I came home once with shigella, which attracted minor interest from the Public Health authorities who phoned me to check I wasn't involved in catering.
But the bad times are more than compensated by the simple friendship and hospitality you receive from people, which I will miss when I retire in June. Got Sudan, Nigeria, Kenya, Uganda and SA to visit before then.