Depending on what country you are entering from, proof of some inoculations may be required. Obtain an international health certificate as proof you are not carrying any diseases. Yellow fever and cholera vaccinations are a requirement. Anti-malaria medication is strongly recommended. These generally require taking pills before, during, and after your visit and should be closely followed.
Tetanus inoculations are a good idea.
Other recommended immunizations are for typhoid, tuberculosis, and polio. Gamma globulin shot provide protection against infectious hepatitis. Water is considered potable in most large cities but it never hurts to treat the water first, particularly if you are susceptible to stomach ailments. Bring along your favorite medicine for these symptoms just in case. Bottled water is available at most hotels and lodges.