Yellow fever is a disease spread to humans by mosquitoes. The effects of yellow fever on the human body usually include fever, chills, and vomiting. Some people also experience backache and headache. Dehydration is one of the biggest dangers associated with yellow fever, but other life-threatening effects of yellow fever are sometimes experienced. In severe cases, people may have failure of major body organs, such as the liver or kidneys.
Even in milder cases of yellow fever, some liver function is jeopardized. This frequently leads to a condition called jaundice. When the liver is not functioning properly, high levels of a chemical called bilirubin are usually present in the bloodstream. When people are suffering from jaundice, the whites surrounding the iris of the eye tend to turn a yellowish color, as does the skin. Yellow fever is believed to have gotten its name from the yellow skin and eyes of people who have the disease.
People generally begin to show effects of yellow fever about a week after being infected. There is no known cure for the disease, and because it is a virus, the immune system does most of the work toward fighting it off. About half the people who contract yellow fever do not survive, but the survival rate is much better in people who are healthy at the time they contract the disease. If victims of yellow fever are going to recover, they typically do so in about 14 days. Many people who recover from yellow fever experience muscle weakness and overall fatigue for several weeks after recovering from the worst symptoms of the illness.
Yellow fever is spread by a mosquito called Aedes aegypti. The mosquito bites people who are infected with the virus, and then in turn spreads the virus to others that it bites. The disease is common in Africa and parts of South America, but extremely rare in other parts of the world. The last outbreak of yellow fever in the United States occurred in Louisiana in 1905.
People traveling to South America and Africa from other parts of the world are urged to be immunized against yellow fever. The rarity of yellow fever in other parts of the world means that the vaccine is not a typical part of most countries' immunization schedules, however, it is usually available on request. In addition, travelers are cautioned to use insect repellent and wear long sleeves if they are traveling to an area where yellow fever is endemic. Travelers who begin to experience any of the effects of yellow fever should contact a local hospital immediately.