25 years ago I went to a third world country for work. My company sent us to a travel medicine specialist. My project manager and I were the first to go for a design review. We met with the doc and she gave use about half an hour of "counseling" which was actually quite helpful. The concerns were mostly malaria, cholera, typhoid, and nosocomial (hospital borne) infections as well as HIV and car accidents. Then we got to be pin cushions for her nurse. She had preordered the vaccines we needed.
Unfortunately I can't tell you how much because company paid.
Her advice was simple. Only drink bottled water, don't have sex, cover up during twilight to avoid mosquito bites, and don't eat any fruit you don't peel yourself. She did say that many things like hepatitis are routine childhood illnesses in the developing world so they are not common but westerners are susceptible.
And as reported in another thread, she prescribed cipro, said to carry immodium, and if sick, get to a major city in China, Malaysia, etc. Immodium is to shut down your intestines so you don't die of dehyration while evacuating. Constipation is easier to treat than death.
But seriously, she was an expert and her advice was very reassuring. A few simple precautions and having an exit plan get you a long way.
A former boss also gave me advice he got from a WHO nurse. Put duct tape over you mouth in the shower to avoid inadvertantly drinking any water.