Dengue fever has killed at least 20 people in the West African state of Burkina Faso, where about 2,000 cases of the disease have been recorded. Dengue is a major cause of illness worldwide, causing about 100 million episodes of feverish illness a year. Its outbreak in West Africa is causing alarm and officials are trying to avoid any widespread panic. Dengue fever particularly affects young children and adults, but is not normally fatal. Most people who get it will suffer from headaches and fever. Some get rashes, aches and pains and their symptoms usually last for two or three days. An infected person can feel tired for up to three months, but will not usually need treatment.