Yellow fever Health Article

Definition

Yellow fever is a viral infection transmitted by mosquitoes.

Causes, incidence, and risk factors

Yellow fever is caused by a small virus that is spread by the bite of mosquitoes. This disease is common in South America and in sub-Saharan Africa.

Anyone can get yellow fever, but the elderly have a higher risk of severe infection. If a person is bitten by an infected mosquito, symptoms usually develop 3 - 6 days later.

Yellow fever has three stages:

1. Early stage: Headache, muscle and joint aches, fever, flushing, loss of appetite, vomiting, and jaundice are common. After approximately 3 - 4 days, often symptoms go away briefly (remission).
2. Period of remission: After 3 - 4 days, fever and other symptoms go away. Most people will recover at this stage, but others may move onto the third, most dangerous stage (intoxication stage) within 24 hours.
3. Period of intoxication: Multi-organ dysfunction occurs. This may include heart, liver, and kidney failure, bleeding disorders, hemorrhage, and brain dysfunction including delirium, seizures, coma, shock, and death.

Symptoms

• Arrhythmias, heart dysfunction
• Bleeding (may progress to hemorrhage)
• Coma
• Decreased urination
• Delirium
• Fever
• Headache
• Jaundice
• Muscle aches (myalgia)
• Red eyes, face, tongue
• Seizures
• Vomiting
• Vomiting blood

Signs and tests

A person with advanced yellow fever may show signs of liver failure, renal failure, and shock.

If you have symptoms of yellow fever, tell your doctor 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 for symptoms can include:

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

Expectations (prognosis)

Yellow fever varies in severity. Severe infections with internal bleeding and fever (hemorrhagic fever) are deadly in up to half of cases.

Complications

• Coma
• Death
• Disseminated intravascular coagulation (DIC)
• Kidney failure
• Liver failure
• Parotitis
• Secondary bacterial infections
• Shock