Yellow Fever: Causes, Symptoms, Prevention, and Treatment | Easy to Understand Guide

Yellow fever is a serious viral infection transmitted by infected mosquitoes, primarily found in parts of South America and Africa. When a person is bitten by an infected mosquito, the yellow fever virus can cause damage to the liver and other internal organs, potentially leading to death. According to the World Health Organization, there are an estimated 200,000 cases of yellow fever worldwide each year, resulting in 30,000 deaths.

How Yellow Fever Spreads

Yellow fever is typically spread to humans through bites from infected mosquitoes. The virus cannot be spread through casual contact between people. However, there is a possibility of transmission through contaminated needles directly into the blood. The mosquitoes that carry the yellow fever virus can breed in both urban areas and jungles, and they can also transmit the virus to monkeys, which serve as another host for the disease.

Symptoms of Yellow Fever

Yellow fever gets its name from two of its most recognizable symptoms: fever and yellowing of the skin (jaundice). The disease causes liver damage and hepatitis, which leads to the yellowing of the skin. Some people may not experience any initial symptoms, while others may develop symptoms three to six days after being bitten by an infected mosquito.

The infection typically progresses through three phases:

1. The first phase (Acute Phase) lasts 3-4 days and includes symptoms such as:

   • Fever and chills

   • Flu-like symptoms (muscle aches, headache, vomiting)

   • Most patients (85 percent) recover after this phase

2. The second phase is a brief remission lasting about 48 hours, during which most patients improve and recover.

3. The third phase (Toxic phase), which affects 15% of patients, is more severe and can include:

• Jaundice (yellowing of the skin and eyes)

• Hepatitis (liver inflammation)

• Internal bleeding (hemorrhaging)

• Vomiting blood

• Shock

• Multisystem organ failure, potentially leading to death within 7-10 days

Diagnosing and Treating Yellow Fever

Yellow fever is diagnosed based on symptoms, recent travel history, and blood tests. If you have recently traveled to a high-risk country and experience symptoms similar to yellow fever, contact your doctor immediately, as the symptoms can mimic other tropical diseases like malaria and typhoid.

There is no specific cure for yellow fever. Treatment focuses on managing symptoms, such as reducing fever, relieving muscle pain, and preventing dehydration. Aspirin and other nonsteroidal anti-inflammatory drugs should be avoided due to the risk of internal bleeding. Hospitalization is often necessary for monitoring and supportive care.

Preventing Yellow Fever Through Vaccination

Prevention is crucial, as there is no cure for yellow fever. The most effective prevention method is vaccination. The yellow fever vaccine is highly effective (> 95 percent) and is recommended for adults and children over 9 months old who are traveling to or living in countries with a known risk of yellow fever transmission. Some high-risk countries in Africa and Latin America require proof of vaccination before allowing entry.

Vaccinations are typically available at travel medicine clinics and state or local health departments. The vaccine provides protection for about 10 years, after which a booster dose is needed for those continuing to travel to high-risk areas. Approved vaccination centers can provide an International Certificate of Vaccination, which may be required for entry into certain countries.

It is essential to note that the yellow fever vaccine is not recommended for everyone. In rare cases, the vaccine can cause serious adverse effects. Consult your doctor before getting the vaccine if you:

• Have a weakened immune system (e.g., due to HIV or cancer)

• Have had a severe allergic reaction to eggs, chicken, gelatin, or a previous yellow fever vaccine

• Are pregnant or breastfeeding

• Are 65 years or older

• Have a child younger than 9 months old

If you are exempt from vaccination for medical reasons, you may need to provide proof of exemption for entry into some countries.

Other Prevention Measures

While vaccination is the most effective way to prevent yellow fever, there are other measures you can take to reduce your risk of infection:

• Use insect repellent containing DEET, picaridin, oil of lemon eucalyptus, or IR3535 on exposed skin, following package directions

• Wear protective clothing that covers your arms, hands, legs, and head

• Apply permethrin to the outside of clothing, mosquito netting, and other gear for added protection

• Use window and door screens, and sleep under mosquito nets to keep mosquitoes away

• Avoid outdoor activities during peak mosquito hours (usually dusk to dawn)

• Keep accurate records of your international travel dates, locations, and outdoor activities to help identify potential infections upon your return

By understanding the causes, symptoms, prevention methods, and treatment options for yellow fever, you can take the necessary steps to protect yourself and others from this potentially life-threatening disease. Always consult with your healthcare provider or a travel medicine specialist before traveling to areas where yellow fever is a risk.

For more information on yellow fever, visit the World Health Organization and the Centers for Disease Control and Prevention websites.

The Bottom Line

Vaccination is the only reliable protection against this potentially fatal infection, especially crucial for travelers to South America and sub-Saharan Africa. If you develop high fever, severe headache, or yellowing of skin after visiting endemic areas, seek immediate medical attention as early supportive care significantly improves outcomes—Doctronic can help assess your symptoms and guide next steps.