Lassa Fever

Lassa fever, also called Lassa hemorrhagic fever, is a viral hemorrhagic fever caused by the Lassa virus. Many infections cause no symptoms, but when illness does occur it typically brings fever, weakness, headache, vomiting and muscle pain, with bleeding from the mouth or gut in less common severe cases; about one percent of those infected die, usually within two weeks of symptoms starting, and about a quarter of survivors are left with hearing loss. It spreads to humans mainly through contact with the urine or feces of the multimammate mouse and can then pass directly between people, and there is no vaccine, though the antiviral ribavirin is sometimes used despite weak evidence for its effect. The disease was first described from a 1969 case in the town of Lassa in Nigeria and remains relatively common in West Africa, causing an estimated 300,000 to 500,000 cases and 5,000 deaths a year.