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Medical Author:

Steven Doerr, MD

Steven Doerr, MD

Steven Doerr, MD, is a U.S. board-certified Emergency Medicine Physician. Dr. Doerr received his undergraduate degree in Spanish from the University of Colorado at Boulder. He graduated with his Medical Degree from the University Of Colorado Health Sciences Center in Denver, Colorado in 1998 and completed his residency training in Emergency Medicine from Denver Health Medical Center in Denver, Colorado in 2002, where he also served as Chief Resident.

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Medical Editor:

Mary D. Nettleman, MD, MS, MACP

Mary D. Nettleman, MD, MS, MACP

Mary D. Nettleman, MD, MS, MACP is the Chair of the Department of Medicine at Michigan State University. She is a graduate of Vanderbilt Medical School, and completed her residency in Internal Medicine and a fellowship in Infectious Diseases at Indiana University.

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In this Article

• What is yellow fever? What is the history of yellow fever?
• What causes yellow fever?
• How is yellow fever transmitted?
• What areas are high-risk for contracting yellow fever?
• What is the incubation period for yellow fever?
• What are yellow fever symptoms and signs?
• How is yellow fever diagnosed?
• What is the treatment for yellow fever?
• What is the prognosis for people with yellow fever?
• Can yellow fever be prevented?
• Where can people get more information on yellow fever?
• Yellow Fever At A Glance
• Find a local Doctor in your town
• Yellow Fever Index

Because the symptoms during the initial phase of yellow fever are nonspecific and similar to a flu-like illness, diagnosis during this stage can be difficult. Therefore, the preliminary diagnosis is often made clinically based on the patient's signs and symptoms, the travel history (when and where), and the related travel activities.

Various blood test abnormalities may be present in individuals with yellow fever, particularly those who go on to develop the second toxic phase of the disease. Blood test abnormalities may include a low white blood cell count (leukopenia), a low platelet count (thrombocytopenia), elevations in liver function tests, abnormally prolonged blood clotting times, and abnormal electrolyte and kidney function tests. Urine tests may demonstrate elevated levels of urinary protein and urobilinogen. An electrocardiogram (ECG) may reveal heart conduction or rhythm disturbances if cardiac involvement has occurred.

The laboratory diagnosis of yellow fever requires specialized testing. Blood tests may demonstrate the presence of virus-specific antibodies produced in response to the infection, though cross-reactivity with antibodies from other flaviviruses may occur, sometimes necessitating additional testing. A variety of other specialized laboratory techniques and tests may be used to identify and confirm the presence of the virus using blood, body fluids, or body-tissue samples.