The Lassa Fever


Lassa fever is a viral hemorrhagic fever caused by a rodent borne arena virus that is endemic in West Africa. It was first described in 1969 in a town called Lassa in Borno State, Nigeria.

It actually frequently infects people in West Africa (Liberia, Sierra Leone, Guinea, and the Central African Republic) resulting in 300,000- 500,000 cases annually and about 5,000 deaths each year. The Primary animal host is the multimammate mouse (Mastomys natalensis) and it’s found in most of SubSaharan Africa.

Virus is transmitted by contact with the feaces or urine of animals that have access to food stores in residences. Transmission may also occur from person to person when an individual makes contact with any tissue, blood excretions or secretions of an infected person, but casual contact will not spread the virus. Nosocomial transmission (transmission originating in a hospital) can also occur with contaminated needles or other medical equipment.

Signs and Symptoms

Symptoms begin one to three weeks after the initial infection and may include fever, back pain, abdominal pain, and sore throat, conjunctivitis swelling in the face, diarrhea, mucosal bleeding and proteinuria.

On occasion there have been reports of neurological issues such as tremors, encephalitis, and hearing loss. Symptoms can be very diverse making diagnosis challenging.