Lassa Fever in the Eastern Province of Sierra Leone, 1970–1972

Abstract

In an epidemic of Lassa fever in the Eastern Province, Sierra Leone, 63 suspected cases were identified in patients admitted to two hospitals over a 2-year period. Although hospital workers were at high risk of infection, most cases were acquired outside the hospital. There appeared to be intrafamilial outbreaks around several cases. The clustering of seropositivity in families suggested person-to-person spread. Six percent of the population surveyed had complement-fixing antibody against Lassa virus, while only 0.2% had recognized disease. This suggests that the fatality from Lassa virus infection is considerably less than the 38% observed among cases.