Yellow Fever

What is yellow fever?

Yellow fever is a disease caused by a virus that is transmitted by the bite of certain mosquito species. It does not occur in the United States, but is common in parts of Africa and South America, particularly in jungle areas where wild monkey populations are common.

Who gets yellow fever?

Yellow fever occurs in people who live or travel in tropical or subtropical areas. Yellow fever is very rarely a cause of illness in persons from the United States who travel to these areas.

How is yellow fever spread?

The disease is transmitted by the bite of an infected Aedes aegypti mosquito in urban areas, but may also be transmitted by other species of mosquitos in jungle areas. Mosquitoes acquire the virus by feeding on infected primates (human or non-human). The mosquitoes can then can transmit the virus to other primates. When an uninfected mosquito bites a person that is infected with the yellow fever virus within the first five days of illness, that mosquito may become infected and may transmit the disease to other people it bites. Yellow fever cannot be transmitted directly from person to person.

What are the symptoms of yellow fever?

The symptoms of yellow fever include fever, chills, severe headache, back pain, general body aches, nausea, vomiting, fatigue and weakness. Most people improve after these initial symptoms occur. Some cases progress to more serious forms of illness, with symptoms including jaundice (yellowing of the skin and whites of the eyes), high fever, bleeding (especially in the gastrointestinal tract), and eventually shock and failure of many organs which leads to patient death.

How soon after exposure do symptoms appear?

The symptoms appear from three to six days after an infectious mosquito bite.

Does past infection with yellow fever make a person immune?

Yes, people who have had yellow fever will not get the disease again.

How is yellow fever diagnosed?

The disease may be confirmed by a blood test or various other laboratory tests.

What is the treatment for yellow fever?

There is no specific treatment for yellow fever, except to relieve the patient’s symptoms as much as possible. Patients with yellow fever should be hospitalized for treatment of their symptoms and close observation and care by health care workers. Certain medications should be avoided, such as aspirin or other non-steroidal anti-inflammatory drugs, because these may increase the risk of bleeding. Yellow fever has a fatality rate that ranges from 25 to 50% in places that lack good access to healthcare.

How can yellow fever be prevented?

Vaccination of citizens, mosquito control, and the use of treated bed nets are the primary methods used to prevent yellow fever in countries where the disease occurs. People traveling to these areas should receive the vaccination prior to travel. Yellow fever vaccine is recommended for people age nine months or older who are traveling to or living in areas at risk for yellow fever virus transmission in South America and Africa. Certain individuals should not receive the vaccine. Consult with your healthcare provider to determine if you can safely receive the vaccine.

When outdoors in areas where yellow fever occurs, use an effective insect repellent on exposed skin. Wear long sleeves, long pants and socks when outdoors. Spraying clothes with an appropriate repellent such as permethrin gives extra protection. Finally, staying in lodging with screens or air-conditioned rooms or bed nets will also reduce risk of mosquito bites.

Where can I obtain yellow fever vaccine?

A list of clinics in Virginia where yellow fever vaccine can be obtained is located at the VDH Division of Immunization's page on international travel.

How can I get more information about yellow fever?

December 2018

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