Yellow fever

Background

• A Flavi virus transmitted by Aedes and Haemagogus mosquitos
• 200,000 cases per year with 30,000 deaths mostly in Africa
• Endemic in tropical areas of sub-Sahara Africa and South America

Clinical Features

3 stages

• Infection- 3 to 4 days of fever, myalgias, knee pain, nausea, vomiting
  • Faget’s sign-low pulse compare to high fever
• Remission- either recovers or progresses to next stage in 48 hours
• Intoxication- 15% of patients with return of symptoms plus:
  • Hepatic dysfunction
  • Renal failure
  • Myocardial injury
  • CNS dysfunction
  • Bleeding complications

Differential Diagnosis

• Influenza
• Acute Hepatitis

Fever in traveler

• Normal causes of acute fever!
• Malaria
• Dengue
• Leptospirosis
• Typhoid fever
• Typhus
• Viral hemorrhagic fevers
  • Ebola virus disease
  • Marburg virus disease
  • Lassa fever
  • Crimean-Congo hemorrhagic fever
• Chikungunya
• Yellow fever
• Rift valley fever
• Q fever
• Amebiasis
• Zika virus

Diagnosis

• CBC
• Chem
• LFTs
• Coags
• Viral PCR
• ELISA for IgM

Management

• Symptomatic
• Vaccination in endemic areas

Disposition

• Admit

References

• Lupi O. Mosquito-Borne Hemorrhagic Fevers. Dermatologic Clinics, 2011-01-01, Volume 29, Issue 1, Pages 33-38
• WHO Yellow fever: http://www.who.int/mediacentre/factsheets/fs100/en/