Mild subclinical infection occurs and may be more common in children. The acute form of the disease causes headache , muscle aches , fever , loss of appetite , and vomiting . The infected person may also develop a red tongue, flushed face , and reddening of the eyes. Delirium and seizures followed by coma are common. Death occurs at the end of the first week of symptoms and as many as half of the infected people may die.
Vaccination is the only sure prevention for yellow fever.
Use of mosquito repellents, full covering clothing and screened housing will decrease exposure risk. Mosquito control has decreased the risk in countries where the disease was once prevalent. The risks remain however, because the mosquito has increasing resistance to insecticides . DDT is very effective, but production has been discontinued in many areas. There is no specific treatment for yellow fever.