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