Yellow Fever

Yellow fever is an illness you can get from a virus when a mosquito bites you. It’s a type of viral hemorrhagic fever. The virus is most common in parts of Africa and South America.

Many people have flu-like symptoms or even no symptoms. But the virus can damage your organs and cause severe bleeding. Severe symptoms start a few days after you start feeling better from the initial symptoms.

Yellow fever can cause liver damage, which leads to yellowing of your skin or whites of your eyes (jaundice). That’s where it gets the name “yellow” fever.

Symptoms can become life-threatening quickly. Go to the emergency room if you have jaundice, belly pain, severe vomiting, bleeding or extreme tiredness.

Yellow fever symptoms

Symptoms of yellow fever can be mild to very severe. Initial symptoms start appearing three to six days after a mosquito bite. They include:

• Fever
• Tiredness
• Headache
• Backache
• Muscle pain
• Loss of appetite
• Nausea and vomiting
• Redness of the whites of your eyes

After a day or two of feeling better, your fever may return and you may develop severe symptoms. Severe symptoms include:

• Yellowing of your skin or the whites of your eyes
• Dark pee
• Belly pain
• Throwing up blood or blood in your poop
• Nose bleeds or bleeding gums

These are signs of serious complications. Get medical help immediately.

Yellow fever causes

Yellow fever virus (YFV), a type of flavivirus, causes yellow fever. It’s spread by mosquitoes — most commonly, Aedes aegypti mosquitoes. Mosquitoes become infected when they bite a human or a non-human primate (like a monkey) with yellow fever. The mosquitoes can spread it to you when they bite you and inject you with infected saliva (spit).

Risk factors

You’re at higher risk for yellow fever if you live in or travel to countries where yellow fever spreads. This includes many countries in Africa, South America and Central America.

Complications

Yellow fever can be fatal. Complications include:

• Liver damage and failure
• Kidney failure
• Shock (severe low blood pressure that can lead to organ damage)
• Heart muscle infection

How doctors diagnose yellow fever

Healthcare providers diagnose yellow fever with a blood test. Various types of blood tests can:

• Count white blood cells to determine if you have an infection
• Look for signs of yellow fever virus
• Determine how well your liver and kidneys are working
• Look for other viruses that cause similar symptoms

Your provider may also diagnose you based on symptoms before the test results come back.

Is yellow fever curable?

There’s no specific cure or treatment for yellow fever. Your healthcare provider will give you recommendations on how to manage your symptoms and when you should go to the ER. If you’re severely ill, you’ll be monitored in the hospital.

For severe symptoms, you might need:

• IV fluids
• Blood transfusion
• Vasopressor medications to treat shock
• Dialysis for kidney failure

When should I see my healthcare provider?

If you live in or have recently visited an area where yellow fever spreads, contact a healthcare provider if you have any symptoms. They’ll give you recommendations on how to take care of yourself and when to seek additional treatment.

When should I go to the ER?

If you have any symptoms of severe illness — even if your initial symptoms have gotten better — go to the nearest emergency room immediately. Severe symptoms can become life-threatening within hours.

What can I expect if I have yellow fever?

Most people recover from yellow fever within a few days of their symptoms starting. But about 10% to 15% of people develop severe illness. Out of the people who have severe yellow fever symptoms, up to half die from the disease.

Is there anything I can do to feel better?

Your provider can recommend ways to take care of yourself at home if your symptoms are mild. They may suggest:

• Keeping yourself hydrated by drinking plenty of water and fluids
• Getting as much rest as possible
• Treating pain with acetaminophen (like Tylenol®) only

Don’t take ibuprofen (like Advil® or Motrin®) or aspirin to treat pain when you have yellow fever. This can increase your risk of life-threatening internal bleeding.

Can yellow fever be prevented?

A vaccine is available to prevent yellow fever. It’s required to enter some countries where yellow fever is common. Getting vaccinated at least 10 days before traveling gives your body time to develop immunity. Protection lasts at least 10 years.

You can also reduce your risk of mosquito bites by taking some precautions:

• Use a mosquito repellent with DEET.
• Wear long pants, long-sleeved shirts and socks. You can get clothing pre-treated with mosquito repellent for extra protection.
• Keep mosquitoes out of your home by repairing holes in screens and keeping windows and doors closed, if possible.
• Use mosquito netting at night in areas where yellow fever is common.
• Avoid being outside during times when mosquitoes are active. In most cases, this means dusk to dawn. But one type of mosquitoes that spread yellow fever feeds during the daytime.

If you currently have yellow fever, avoid getting bitten by mosquitoes to help stop the spread.