The tsetse fly can spread sleeping sickness to cattle and horses. Sleeping sickness is spread in much the same way as malaria. The fly bites an infected animal or person, picks up the germs, and infects the next person it bites. Sleeping sickness is a disease that attacks the nervous system and often results in a prolonged sleep. It affects human beings and other vertebrates (animals with backbones) and is usually fatal if untreated. This disease occurs only in Africa and is a serious health problem there for both humans and animals. Its effect on horses and cattle makes raising livestock impossible in some areas of the continent.