Lassa fever: epidemiology, clinical features, and social consequences

Lassa fever is endemic in west Africa, where it probably kills several thousand people each year. With access to the region improving, the opportunity, and the need, to improve our understanding of this disease are increasing Lassa fever is a viral haemorrhagic fever transmitted by rats. It has been known since the 1950s, but the virus was not identified until 1969, when two missionary nurses died from it in the town of Lassa in Nigeria. Found predominantly in west Africa, 1 it has the potential to cause tens of thousands of deaths. Even after recovery, the virus remains in body fluids, including semen. Increasing international travel and the possibility of use of the Lassa virus as a biological weapon escalate the potential for harm beyond the local level. Access to the country is improving, so renewed efforts to understand it are feasible.