Most yellow fever infections cause a flu-like illness that starts within a few days of the mosquito bite.

Initial symptoms of yellow fever include:

• Back pain
• Body aches
• Fever
• Chills
• Joint pains
• Nausea
• Vomiting
• Rash:
• Located on the chest

Symptoms of worsening yellow fever include:

• Hematuria:
• Blood in the urine
• Red or pink urine
• Blood clots in the urine
• Blood in the stool:
• Black stool
• Rectal bleeding
• Red stools
• Excessive bruising
• Liver enlargement
• Rash that looks like broken blood vessels under the skin

Worsening symptoms include:

• Coma
• Confusion
• Lethargy:
• Excessive sleepiness
• Low blood pressure
• Vomiting blood