Lassa Fever
Lassa fever is an animal-borne, or zoonotic, acute viral illness. It is endemic in parts of West Africa including Sierra Leone, Liberia, Guinea and Nigeria. Neighboring countries are also at risk, as the animal vector for Lassa virus, the “multimammate rat” (Mastomys natalensis) is distributed throughout the region.

The illness was discovered in 1969 and is named after the town in Nigeria where the first cases occurred.

An estimated 100,000 to 300,000 infections of Lassa fever occur annually, with approximately 5,000 deaths. Surveillance for Lassa fever is not standardized; therefore, these estimates are crude. In some areas of Sierra Leone and Liberia, it is known that 10-16% of people admitted to hospitals annually have Lassa fever, demonstrating the serious impact the disease has on the region.


Transmission
People are infected through contact with an infected rodent...

Signs and Symptoms
Symptoms of Lassa fever typically occur 1-3 weeks after exposure to the virus...

Risk of Exposure
People at greatest risk are those who live in West Africa, an endemic region for Lassa fever...

Diagnosis
Typically Lassa fever is diagnosed using enzyme-linked immunosorbent serologic assays (ELISA)...

Treatment
Ribavirin has been used with success in Lassa fever patients...

Prevention
Lassa fever is prevented by avoiding contact with Mastomys rodents...