Electron microscope image of the yellow fever virus. Symptoms of yellow fever commonly include chills, nausea and muscle pain. It may also damage the liver and lead to the skin turning yellow. An effective vaccine for yellow fever exists, but despite this it still kills around 30,000 people a year. Ninety per cent of these deaths occur in Africa. Yellow fever is common in tropical and subtropical areas of Africa and South America.
Alain Grillet, Sanofi Pasteur/Flickr