Yellow fever is caused by a virus
carried by mosquitoes. It's usually
found only in tropical parts of Africa and South America. Most people who are bitten
by an infected mosquito don't get sick. People who do might have a fever or headache,
throw up, and get jaundice, which
turns the skin yellow and gives the fever its name.
Most people with yellow fever get better with no problems. There is a vaccine to
prevent yellow fever if you are travelling to places where the disease is common.