Description

Lassa fever is a severe, often fatal, hemorrhagic fever that is caused by a virus transmitted from asymptomatically infected rodent reservoirs to humans.

Occurrence

This illness is limited to rural areas of West Africa with hyperendemic areas in eastern Sierra Leone, Liberia, and Nigeria. Periodomestic exposure to infected rodents is the most likely source of infection. Transmission to humans can occur via inhalation of primary aerosols from rodent urine or by ingestion of contaminated food. Rodent infestation and inappropriate food storage enhance human infection. Person-to-person transmission of Lassa fever has also been described, most notably in the hospital setting.

Risk for Travelers

The risk of infection in international travelers is considered small. Only a few cases (one recent) were confirmed in international travelers staying or living in traditional habitations in the countryside or in small villages. There is no risk for travelers staying in hotels and having no contact with rodents or patients at home or in a health center. Medical personnel and relief workers involved in the close management of patients and relief workers in endemic areas should be aware of the risk of nosocomial transmission.

Preventive Measures

No vaccine is currently available. Strict barrier nursing precautions (use of gloves, gowns, masks, and goggles to prevent direct contact between medical personnel and patients or patient secretions, excretions, or biological samples) are recommended to avoid nosocomial infections. Travelers should be advised to avoid contact with rodents in endemic areas.

Treatment

Treatment with the antiviral drug ribavirin can be life saving if started early.

© National Center for Infectious Diseases - Center for Disease Control