Northern Africa (Algeria, Egypt, Libyan Arab Jamahiriya, Morocco, and Tunisia) is characterized by a generally fertile coastal area and a desert hinterland with oases that are often foci of infections.

Arthropod-borne diseases are unlikely to be a major problem to the traveler, although dengue fever, filariasis (focally in the Nile Delta), leishmaniasis, malaria, relapsing fever, Rift Valley fever, sandfly fever, typhus, and West Nile fever do occur.

Foodborne and waterborne diseases are endemic; the dysenteries and other diarrheal diseases are particularly common. Hepatitis A and E occur throughout the area. Typhoid fever is common in some areas. Schistosomiasis (bilharziasis) is very prevalent in the Nile Delta area in Egypt and in the Nile valley; it occurs focally in other countries in the area. Alimentary helminthic infections, brucellosis, and giardiasis are common. Echinococcosis (hydatid disease) may occur. Sporadic cases of cholera occur.

Other hazards include poliomyelitis (also a food-borne or water-borne disease). However, no cases of poliomyelitis have been reported from Algeria since 1990, from Libyan Arab Jamahiriya since 1991, from Morocco since 1989, or from Tunisia since 1992. Trachoma, rabies, snakes, and scorpions are hazards in certain areas.

Sub-Saharan Africa (Angola, Benin, Burkina Faso, Burundi, Cameroon, Cape Verde, Central African Republic, Chad, Comoros, Congo, Côte d'Ivoire, Djibouti, Equatorial Guinea, Eritrea, Ethiopia, Gabon, Gambia, Ghana, Guinea, Guinea-Bissau, Kenya, Liberia, Madagascar, Malawi, Mali, Mauritania, Mauritius, Mozambique, Niger, Nigeria, Réunion, Rwanda, Sao Tome and Principe, Senegal, Seychelles, Sierra Leone, Somalia, Sudan, Togo, Uganda, United Republic of Tanzania, Zaire, Zambia, and Zimbabwe). In this area, entirely within the tropics, the vegetation varies from the tropical rain forests of the west and center to the wooded steppes of the east, and from the desert of the north through the Sahel and Sudan savannas to the moist orchard savanna and woodlands north and south of the equator.

Many of the diseases listed below occur in localized rural foci and are confined to rural areas. They are mentioned so that the international traveler and the medical practitioner concerned may be aware of the diseases that may occur.

Arthropod-borne diseases are a major cause of morbidity. Malaria in the severe falci-parum (malignant) form occurs throughout the area, except at over 2,600 meters altitude and in the islands of Réunion, and Seychelles. Various forms of filariasis are widespread; endemic foci of onchocerciasis (river blindness) exist in all the countries listed except in the greater part of Kenya and in Djibouti, Gambia, Mauritania, Mozambique, Somalia, Zambia, Zimbabwe, and the island countries of the Atlantic and Indian Oceans. However, onchocerciasis exists in the island of Bioko, Equatorial Guinea. Both cutaneous and visceral leishmaniasis may be found, particularly in the drier areas. Visceral leishma-niasis is epidemic in eastern and southern Sudan. Human trypanosomiasis (sleeping-sickness), mainly in small isolated foci, is reported from all countries except Djibouti, Gambia, Mauritania, Somalia, and the island countries of the Atlantic and Indian Oceans. In Angola and Zaire the transmission of human trypanosomiasis is very high, and there is significant risk of infection for travelers visiting or working in rural areas. Relapsing fever and louse-, flea-, and tick-borne typhus occur. Natural foci of plague* have been reported from Angola, Kenya, Madagascar, Mozambique, Uganda, the United Republic of Tanzania, Zaire, and Zimbabwe. Tungiasis is widespread. Many viral diseas-es, some presenting as severe hemorrhagic fevers, are transmitted by mosquitos, ticks, sandflies, etc., which are found throughout this region. Large outbreaks of yellow fever occur periodically in the unvaccinated population.

* A natural focus of plague is a strictly delimited area where ecological conditions ensure the persis-tence of plague in wild rodents (and occasionally other animals) for long periods of time, and where epizootics and periods of quiescence may alternate.

Foodborne and waterborne diseases are highly endemic. Schistosomiasis (bilharziasis) is present throughout the area except in Cape Verde, Comoros, Djibouti, Réunion, and the Seychelles. Alimentary helminthic infections, the dysenteries and diarrheal diseases, including giardiasis, typhoid fever, and hepatitis A and E are widespread. Cholera is actively transmitted in many countries in this area. Dracunculiasis (Guinea-worm) infection occurs in isolated foci. Paragonimiasis (oriental lung fluke) has been reported from Cameroon, Gabon, Liberia and most recently from Equatorial Guinea. Echinococ-cosis (hydatid disease) is widespread in animal-breeding areas.

Other diseases. Hepatitis B is hyperendemic. Poliomyelitis (also a food-borne and water-borne disease) is endemic in most countries except in Cape Verde, Comoros, Mauritius, Réunion, and the Seychelles. Trachoma is widespread. Among other diseases, certain, frequently fatal, arenavirus haemorrhagic fevers have attained notoriety. Lassa fever has a virus reservoir in a commonly found multimammate rat. Studies have shown that an appreciable reservoir exists in some rural areas of West Africa; people visiting these areas should take particular care to avoid rat-contaminated food or food containers, but the extent of the disease should not be exaggerated. The Ebola and Marburg hemorrhagic fevers are present but reported only infrequently.

Epidemics of meningococcal meningitis may occur throughout tropical Africa, particu-larly in the savanna areas during the dry season.

Other hazards include rabies and snake bites.

Southern Africa (Botswana, Lesotho, Namibia, St. Helena, South Africa, and Swazi-land) varies physically from the Namib and Kalahari deserts to fertile plateaux and plains and to the more temperate climate of the southern coast.

Arthropod-borne diseases such as Crimean-Congo hemorrhagic fever, malaria, plague, relapsing fever, Rift Valley fever, tick-bite fever, and typhus—mainly tick-borne—have been reported from most of this area except St. Helena, but except for malaria in certain areas, they are not likely to be a major health problem for the traveler. Trypanosomiasis (sleeping sickness) may occur in Botswana and Namibia.

Foodborne and waterborne diseases are common in some areas, particularly amebiasis and typhoid fever. Hepatitis A occurs in this area. Schistosomiasis (bilharziasis) is endemic in Botswana, Namibia, Swaziland and South Africa.

Other hazards. With the exception of an epidemic in Namibia in 1993, few cases of poliomyelitis have been reported from these countries. Hepatitis B is hyperendemic. Snakes [and rabies*] may be a hazard in some areas.

* Editor's note: CDC addition.