YELLOW FEVER

An acute viral haemorrhagic fever transmitted through the bite of infected female Aedes aegypti mosquito. Incubation period is 3 to 6 days. It is a notifiable disease.

Cause

  • Yellow fever RNA virus

Risk factors

  • Residents in endemic area
  • Hunters and settlers around game parks

Clinical features

First stage:

  • Fever, chills, headache, backache, muscle pain, prostration, nausea, vomiting, fatigue. Usually resolves within 3-4 days.

Second stage:

  • About 15% of cases enter into a second or toxic stage after 1-2 day of remission: high fever, prostration, signs and symptoms of hepatic failure, renal failure and bleeding (jaundice, nose bleeding, gingival bleeding, vomiting blood, blood in stool)
  • About half of these patients die within 7-10 days

Differential diagnosis

  • Hepatitis E, liver failure
  • Malaria, Ebola

Investigations

  • PCR in early phases
  • ELISA in the late stage

Management

  • Refer all cases to regional referral hospital
  • Notify the district health team
  • There is no specific antiviral drug treatment
  • Supportive treatment is recommended:
    • Rehydration
    • Management of liver and kidney failure
    • Antipyretics for fever
    • Blood transfusion
  • Treat associated bacterial infections with antibiotics

Note

  • Individuals who have recovered from a yellow fever infection develop life-long immunity

Prevention

  • Vaccination (see chapter 18)
  • Elimination of mosquito breeding sites
  • Epidemic preparedness i.e prompt detection and treatment