Yellow fever is a notifiable condition that is endemic in South America, the Caribbean, and Africa. An ongoing outbreak in Brazil has raised the concern of local transmission in other countries, spread by infected returning travelers.
Infection may be asymptomatic or cause a biphasic, highly variable illness ranging from a nonspecific mild febrile illness to a potentially fatal hemorrhagic fever.
Molecular or serologic testing confirms diagnosis in the context of clinical presentation, epidemiologic context, and vaccination history.
As no specific antiviral therapy is available, treatment is supportive. A safe and effective vaccine is available.
A viral hemorrhagic fever caused by a flavivirus transmitted by the Aedes or Haemagogus mosquito. It is endemic in South America, the Caribbean, and Africa, and has been resurging in the last 2 decades. The clinical disease is variable, ranging from a nonspecific viral illness to hemorrhagic fever and death.
History and exam
Key diagnostic factors
- history of residence in, or recent travel to, endemic area
- lack of yellow fever immunization
- history of mosquito bite
- constitutional symptoms
- conjunctival injection
- relative bradycardia (Faget sign)
- biphasic illness
- hemorrhagic diathesis
- signs of renal failure
- signs of hepatic failure
Other diagnostic factors
- abdominal pain, vomiting, and lethargy
- residence in, or recent travel to, endemic area
- lack of immunization
- mosquito bite
- travel during rainy and early dry seasons
1st investigations to order
- liver function tests
- coagulation screen
- reverse transcription polymerase chain reaction (RT-PCR)
Investigations to consider
- virus isolation
- isothermal nucleic acid amplification assays
unidentified viral hemorrhagic fever
confirmed yellow fever
- Dengue fever
- Zika virus infection
- CDC health information for international travel (Yellow Book) - yellow fever
- Laboratory diagnosis of yellow fever virus infection
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