Most arenavirus infections cause a flu-like illness that starts within a week of exposure. The initial symptoms are often mild, but may quickly worsen.

The most common initial symptoms of arenavirus infection include:

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

After 3-5 days, signs and symptoms of hemorrhage may occur in some patients.

Additional symptoms of arenavirus infection may include:

• Blood in the urine
• Blood in the vomit or stool
• Liver enlargement
• Rash that looks like broken blood vessels in the skin, or bruises

Severe symptoms of arenavirus infection may also include:

• Coma
• Neck pain
• Confusion
• Lethargy:
• A condition of excessive sleepiness or drowsiness.
• Low blood pressure
• Severe bleeding

Lymphocytic choriomeningitis causes encephalitis symptoms similar to many arboviruses.