Outbreak Notice
Yellow Fever in Sudan

This information is current as of today, February 17, 2013 at 02:00 EST

Updated: January 16, 2013

What Is the Current Situation?

The Federal Ministry of Health (FMOH) of Sudan and the World Health Organization (WHO) recently announced that there is an outbreak of yellow fever in Sudan. This ongoing outbreak started in early September and has affected 35 localities in Greater Darfur. A total of 849 suspected cases, including 171 deaths, have been reported as of January 9, 2013. Most suspected cases have been reported from Central, South, and West Darfur. WHO is assisting the FMOH of Sudan in the response activities. An emergency mass vaccination campaign to protect people at risk and to stop the spread of yellow fever in the affected areas is currently ongoing with support from international partners.

Yellow fever is always a potential health risk in areas south of the Sahara Desert in Sudan. However, this outbreak of human cases suggests a higher than usual risk of infection for travelers to the Greater Darfur region. Travelers to this area of Sudan are advised to get vaccinated against yellow fever and to take steps to prevent mosquito bites.

What Is Yellow Fever?

Yellow fever is a disease spread through mosquito bites. Symptoms take 3-6 days to develop and include fever, chills, headache, backache, and muscle aches. Most people get well on their own, but about 15% of people develop a more serious form of yellow fever that includes jaundice (yellowing of the skin and eyes), internal bleeding, shock, organ failure, and sometimes death.

How Can Travelers Protect Themselves?

Travelers can protect themselves from yellow fever by getting vaccinated against yellow fever and by preventing mosquito bites.

Get yellow fever vaccine.
- CDC recommends that all travelers 9 months of age or older receive a yellow fever vaccine if they are traveling to areas south of the Sahara Desert. The vaccine is not recommended for people traveling only to the Sahara Desert or the city of Khartoum. (See map.)
- Visit a yellow fever vaccination (travel) clinic to get your vaccine.
  - You should receive this vaccine at least 10 days before your trip
  - After you receive the vaccine, your doctor or nurse should give you a signed and stamped “International Certificate of Vaccination or Prophylaxis” (ICVP).
  - One vaccine will last 10 years.
Prevent mosquito bites
- Cover exposed skin by wearing long-sleeved shirts, long pants, and hats.
- Use an insect repellent with one of the following active ingredients. Higher percentages of active ingredient provide longer protection.
  - DEET
  - Picaridin (also known as KBR 3023, Bayrepel, and icaridin)
  - Oil of lemon eucalyptus (OLE) or PMD
  - IR3535 (Avon Skin So Soft Bug Guard Plus)
- Always use insect repellent as directed.
  - If you are also using sunscreen, apply sunscreen first and insect repellent second.
  - Reapply as directed.
- Follow package directions for using repellent on children
If you feel sick and think you might have yellow fever
- Talk to your doctor or nurse immediately if you develop a fever during or soon after travel
- Get lots of rest, and drink plenty of liquids.
- Use acetaminophen to reduce pain and fever. Do not take pain relievers that contain aspirin or nonsteroidal anti-inflammatory medications such as ibuprofen
- By avoiding mosquito bites, you are less likely to spread the disease to others.
- Seek health care immediately if you have cold, clammy skin; confusion; shortness of breath; swelling in the face; and weakness

Clinician Information:

Asymptomatic or clinically inapparent infection is believed to occur in most people infected with yellow fever virus (YFV). For people who develop symptomatic illness, the incubation period is typically 3–6 days. The initial illness presents as a nonspecific influenza-like syndrome with sudden onset of fever, chills, headache, backache, myalgias, prostration, nausea, and vomiting. Most patients will improve after the initial presentation. After a brief remission of hours to a day, approximately 15% of patients progress to a more serious or toxic form of the disease characterized by jaundice, hemorrhagic symptoms, and eventually shock and multisystem organ failure. The case-fatality ratio for severe cases with hepatorenal dysfunction is 20%–50%.

The preliminary diagnosis is based on the patient’s clinical features, places and dates of travel, and activities. Laboratory diagnosis is best performed by:

Serologic assays to detect virus-specific IgM and IgG antibodies. Because of cross-reactivity between antibodies raised against other flaviviruses, more specific antibody testing, such as a plaque reduction neutralization test should be done to confirm the infection.
Virus isolation or nucleic acid amplification tests performed early in the illness for YFV or yellow fever viral RNA. However, by the time more overt symptoms are recognized, the virus or viral RNA is usually undetectable. Therefore, virus isolation and nucleic acid amplification should not be used for ruling out a diagnosis of yellow fever.

Clinicians should contact their state or local health department or call 970-221-6400 for assistance with diagnostic testing for yellow fever infections and for questions about antibody response to vaccination.

There is no specific treatment for yellow fever, thus treatment is for the symptoms when they occur and most often requires hospitalization. Rest, fluids, and analgesics and antipyretics may relieve symptoms of fever and aching. Care should be taken to avoid certain medications, such as aspirin or nonsteroidal anti-inflammatory drugs, which may increase the risk for bleeding. Infected people should be protected from further mosquito exposure (staying indoors or under a mosquito net) during the first few days of illness, so they do not contribute to the transmission cycle.