Yellow fever is a disease that is transmitted by infected mosquitoes. The most common symptoms are fever, muscle pain with prominent backache, headache, loss of appetite, and nausea or vomiting.
A small proportion of those infected with yellow fever will develop severe disease. Symptoms of severe disease include: jaundice (yellowing of the skin and eyes), dark urine, stomach pain with vomiting and problems with liver and kidney function. Half of those that develop severe disease will die within 7 – 10 days.