Definition

Yellow fever is a viral infection spread by mosquitoes.

Alternative Names

Tropical hemorrhagic fever caused by yellow fever virus

Causes

Yellow fever is caused by a virus carried by mosquitoes. You can develop this disease if you are bitten by a mosquito infected with this virus.

This disease is common in South America and in sub-Saharan Africa.

Anyone can get yellow fever, but older people have a higher risk of severe infection.

If a person is bitten by an infected mosquito, symptoms usually develop 3 to 6 days later.

Symptoms

Yellow fever has 3 stages:

• Stage 1 (infection): Headache, muscle and joint aches, fever, flushing, loss of appetite, vomiting, and jaundice are common. Symptoms often go away within a week.
• Stage 2 (remission): Fever and other symptoms go away. Most people will recover at this stage, but others may get worse within 24 hours.
• Stage 3 (intoxication): Problems with many organs may occur, including the heart, liver, and kidney. Bleeding disorders, seizures, coma, and delirium may also occur.

Symptoms may include:

• Fever, headache, muscle aches
• Nausea and vomiting, possibly vomiting blood
• Red eyes, face, tongue
• Yellow skin and eyes (jaundice)
• Decreased urination
• Delirium
• Irregular heartbeats (arrhythmias)
• Bleeding (may progress to hemorrhage)
• Seizures
• Coma

Exams and Tests

Your health care provider will perform a physical examination and order blood tests. These blood tests may show liver and kidney damage and evidence of shock.

It is important to tell your provider if you have traveled to areas where the disease is known to thrive. Blood tests can confirm the diagnosis.

Treatment

There is no specific treatment for yellow fever. Treatment is supportive and focuses on:

• Blood products for severe bleeding
• Dialysis for kidney failure
• Fluids through a vein (intravenous fluids)

Outlook (Prognosis)

Yellow fever can cause severe problems, including internal bleeding. Death is possible.

Possible Complications

Complications that may result include:

• Coma
• Death
• Disseminated intravascular coagulation (DIC)
• Kidney failure
• Liver failure
• Salivary gland infection (parotitis)
• Secondary bacterial infections
• Shock

When to Contact a Medical Professional

Tell your provider right away if you or your child develops fever, headache, muscle aches, vomiting, or jaundice, especially if you have traveled to an area where yellow fever is common.

Prevention

There is an effective vaccine against yellow fever. Ask your provider at least 10 to 14 days before traveling if you should be vaccinated against yellow fever. Some countries require proof of vaccination to gain entry.

If you will be traveling to an area where yellow fever is common:

• Sleep in screened housing
• Use mosquito repellents
• Wear clothing that fully covers your body

References

Centers for Disease Control and Prevention website. Yellow fever. About yellow fever. www.cdc.gov/yellow-fever/. Updated May 15, 2024. Accessed June 19, 2024.

Endy TP. Viral hemorrhagic fevers. In: Ryan ET, Hill DR, Solomon T, Aronson NE, Endy TP, eds. Hunter's Tropical Medicine and Emerging Infectious Diseases. 10th ed. Philadelphia, PA: Elsevier; 2020:chap 37.

Thomas SJ, Endy TP, Rothman AL, Barrett AD. Flaviviruses (dengue, yellow fever, Japanese encephalitis, West Nile encephalitis, Usutu encephalitis, St. Louis encephalitis, tick-borne encephalitis, Kyasanur Forest disease, Alkhurma hemorrhagic fever, Zika). In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 153.