BASICS:
Health

Before you go, contact your health authorities or doctor to receive advise on vaccinations. These are the most likely for Sudan:

• Hepatitis A
• Typhoid
• Cholera
• Yellow fever
• Tetanus
• Meningitis

In rivers in Sudan schistosomiasis (bilharziasis) and guinea worm. Both give you diseases normally not lethal, but quite disgusting. Flukes, and up to 1,5 metre long worms live inside you, eating their way through liver, stomach, and so on.
Drinking water and salads are not more recommended in the Sudan than in other southern countries. But, as the Sudan often attracts tourists who travel for weeks, you should start slowly. Add like 1/10 of tap water to bottled water (which you only get in some areas), or to soft drinks. Increase this level slowly. There will probably be reactions in your system, but nothing dramatic. And during a longer stay in the Sudan , try to get the inevitable complications while you're in Khartoum or Port Sudan.
Snakes, scorpions, and malaria are other things you should take care of. Snakes can be found all over, but most in not the most arid areas. Scorpions is a danger in the desert, while you can get malaria in the greenest and most humid areas.
Note that the Sudan has badly developed health system, and if anything serious should happen to you, while you're far away from a city, don't count on any choppers coming for you. People with need of regular medicines or with some kind of health weakness, check with your doctor before leaving.