What are the symptoms of Lassa fever?

Symptoms begin 6-21 days after exposure. Mild cases present with fever, general weakness, headache, sore throat, and mild gastrointestinal symptoms. Severe cases (about 20% of infections) include high fever, chest pain, vomiting, diarrhoea, facial swelling, and haemorrhagic manifestations (bleeding from gums, nose, or eyes). A key late complication is sensorineural hearing loss, occurring in 25-30% of patients — including those who recover from acute illness — and is often permanent.