See also US Department of State tips for Travellers to Sub-Saharan Africa and A safe trip abroad . Food and waterborne diseases are the number one cause of illness in travellers. Travellers' diarrhoea can be caused by viruses, bacteria, or parasites, which are found throughout Southern Africa and can contaminate food or water. Make sure your food and drinking water are safe.
Malaria is a preventable infection that can be fatal if left untreated.
Most travellers to Southern Africa should take mefloquine to prevent malaria. Risk for malaria exists all year in the northern part of Botswana, rural areas of South Africa, all nonmountainous areas of Swaziland, and all areas of Zimbabwe except the cities of Harare and Bulawayo. There is no reported risk for travellers visiting Lesotho and St. Helena. A certificate of yellow fever vaccination may be required for entry into certain of these countries if you are coming from a country in tropical South America or sub-Saharan Africa. Protecting yourself against insect bites will help to prevent these diseases.