Yellow Fever

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.


What is yellow fever?

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.


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Who does yellow fever affect?

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.

How common is this condition?

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.


Symptoms and Causes

What are the signs and symptoms of yellow fever?

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.

What causes yellow fever?

Yellow fever is caused by a virus that’s spread by certain kinds of mosquitoes.


How does yellow fever spread?

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.

Is yellow fever contagious?

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.

Diagnosis and Tests

How is yellow fever diagnosed?

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.

Management and Treatment

Is there a cure for yellow fever?

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.


How can I prevent yellow fever?

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:

  • Use a mosquito repellent with DEET.
  • Wear long pants, long-sleeved shirts and socks. It’s best if you wear clothing that’s treated to repel mosquitoes.
  • Consider using a bed net if the lodging doesn’t have air conditioning or screens on the windows.
  • Avoid being outside during times when mosquitoes are active. In most cases, this means dusk to dawn, but one of the mosquitoes that spread yellow fever feeds during the daytime.
  • If you’ve been diagnosed with yellow fever, continue to cover up. You don’t want a mosquito to bite you and then bite someone else.

Outlook / Prognosis

What is the outlook for someone with yellow fever?

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.

Living With

When should I see my healthcare provider about 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.

Additional Common Questions

Is yellow fever the same as malaria?

Yellow fever is not the same disease as malaria, but they do have some things in common:

  • They are both spread by mosquitoes.
  • They both cause fever and other flu-like symptoms.
  • They both can cause jaundice, severe sickness and even death.

There are also significant differences between malaria and yellow fever, such as:

  • Malaria is caused by a parasite, while yellow fever is caused by a virus.
  • The types of mosquitoes that spread malaria are different than the mosquitoes that spread yellow fever.
  • There is a vaccine to prevent yellow fever, but no vaccine to prevent malaria. If you’re traveling to an area with malaria, talk to your provider about preventative medications for malaria.

How long did the yellow fever pandemic in the United States last?

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.

Why is yellow fever called yellow fever?

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.

Does yellow fever still exist today?

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.

Medically Reviewed

Last reviewed on 06/24/2022.

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