Infected mosquitoes transmit the viral disease called yellow fever to people. Symptoms range from mild symptoms like body aches and fever to serious symptoms like organ failure. It can be fatal, but it can also be prevented by getting vaccinated.
Yellow fever is a viral disease spread by the bite of specific kinds of mosquitoes. These mosquitoes and yellow fever are found in areas of Africa and South America located in the tropics and subtropics. The mosquitoes are infected when they bite primates who have the virus.
The yellow fever virus can have a range of symptoms. Some people may have no symptoms. It can present with mild flu-like symptoms but can also be deadly in its most severe form. You could have flu-like symptoms with aches, pains and fever or you could begin bleeding and develop liver disease. Symptoms take about three to six days to develop.
People who work or live in the jungles of subtropical and tropical Africa and South America are most affected by yellow fever. Travelers from the U.S. or other countries to these areas are exposed to this disease by contaminated mosquitoes.
There are about 200,000 people in the world who are infected each year with yellow fever. The condition causes about 30,000 deaths per year. Most of these cases and deaths (about 90%) are in Africa.
It’s possible to have yellow fever and have no symptoms at all. If you do have signs and symptoms of yellow fever, they might be less severe or more severe.
Less severe symptoms may include:
More severe symptoms include:
About 30% to 60% of the people who have the severe form of yellow fever will die.
Yellow fever is caused by a virus that’s spread by certain kinds of mosquitoes.
Yellow fever is spread by specific types of mosquitoes found in tropical and subtropical Africa (Saharan Africa) and South America. The infection spreads when the infected mosquito bites a person.
You can’t spread yellow fever to another person if you have it. For instance, you can’t spread it by coughing or kissing. However, if you are infected, a mosquito can bite you and then infect someone else.
If you’ve been to any area that has yellow fever and you develop any symptoms, you should see your healthcare provider immediately. In addition to asking you about your symptoms and the places that you’ve visited, your provider will order tests to find out if the virus is in your blood.
No, there’s no cure or treatment for yellow fever. That’s why it’s so important to get the vaccine and to avoid mosquitoes.
Your healthcare provider may advise you to get a lot of rest and drink lots of fluids to feel better. If you need to take a pain reliever, avoid those which can cause bleeding, such as aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs).
If you have a more serious form of yellow fever, you should be admitted to a hospital.
If you’ll be spending time in any area known to have yellow fever, get the vaccine about three to four weeks before going on your trip. For most people, a single dose provides lifelong protection. Other tips include:
If you have a less severe form of yellow fever, you’ll probably recover from your symptoms in about seven days. You may feel tired and weak for much longer than a week. After you recover, you’ll have immunity to yellow fever.
If you’ve traveled to Africa or South America and you have any type of symptom like fever or body aches, you should contact your healthcare provider.
If you’ve been diagnosed with yellow fever and you have any new or worsening symptoms, contact your provider.
Yellow fever is not the same disease as malaria, but they do have some things in common:
There are also significant differences between malaria and yellow fever, such as:
There were outbreaks of yellow fever in the U.S. at various times, starting in the 1600s. One of the worst outbreaks happened in Philadelphia in 1793. About 10% of the population of the city died from yellow fever. While there were other outbreaks in the U.S., the last major outbreak of yellow fever happened in New Orleans in 1905.
The “yellow” in yellow fever refers to the color of your skin if you have jaundice. The infection also usually comes with fever. Thus, the condition was called yellow fever.
Yes, the virus is still active in Africa and South America. The U.S. hasn’t had an outbreak since 1905.
A note from Cleveland Clinic
Yellow fever is a viral disease that happens in parts of Africa and South America that is spread by mosquito bites. It can be fatal, but you can prevent it entirely by getting the yellow fever vaccine. You can also use mosquito repellent and protective clothing to try to stop mosquitoes from biting. Some areas practice mosquito control programs. If you have symptoms like fever or body aches, and you’ve been to areas known to have outbreaks of yellow fever, contact your healthcare provider. Yellow fever isn’t a disease of the past.
Last reviewed by a Cleveland Clinic medical professional on 06/24/2022.
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