Vaccinations are not mandatory at present, but you should definitely seek an advice from an institute or an expert specializing in tropical disease before traveling.
Hepatitis A and B,
Proof of yellow fever vaccination is required for all travelers coming from yellow fever infected areas (endemic),e.g. Kenya).
Refer to an institute of tropical medicine for Malaria prophylaxis and they will provide you with better information, for the areas where malaria prophylaxis is required.
Do not forget to bring plenty of sunscreen, especially if you go to the mountains.
Be careful of unpeeled fruit, salads, ice and water. Drink water only from freshly opened bottles to protect yourself from stomach and intestinal complaints. Do not drink tap water in any case.
You should always carry a “first-aid kit” you. A good bug spray is recommended for traveling to Terai region (National Parks).
Talk to your doctor or your pharmacist about the medicines that are to be taken along on your trip.
Remember to put your daily medications in your hand luggage and not in your main luggage.