SymptomsYellow fever has three stages:
- Stage 1 (infection): headache, muscle and joint aches, fever, flushing, loss of appetite, vomiting, and jaundice are common. Symptoms often go away briefly after about 3-4 days.
- Stage 2 (remission): fever and other symptoms go away. Most people will recover at this stage, but others may get worse within 24 hours.
- Stage 3 (intoxication): problems with many organs occur. This may include heart, liver, and kidney failure, bleeding disorders, seizures, coma, and delirium.
If a person is bitten by an infected mosquito, symptoms usually develop after 3 – 6 days.
- Irregular heart beats
- Bleeding (may progress to haemorrhage)
- Delirium (state of violent mental agitation)
- Bleeding from your nose, mouth and eyes
- Yellow skin and eyes (jaundice)
- Muscle aches
- Red eyes
- Vomiting blood
CausesYellow fever is caused by a virus (Flavivirus) that is spread by the Aedes aegypti mosquito
- Humans and monkeys are most commonly infected with the yellow fever virus
- When a mosquito bites a human or monkey infected with yellow fever, the virus enters the mosquitos bloodstream and circulates before settling in the salivary glands
- When the infected mosquito bites another monkey or human, the virus then enters the hosts bloodstream, where it may cause illness
- Yellow fever cannot be spread by close contact between two people