Lassa fever (LF) is an acute viral illness endemic to several countries in West Africa. Lassa virus (LASV) is a zoonotic, rodent-borne, single-stranded ribonucleic acid (RNA) virus from the Arenaviridae virus family. The natural reservoir of the Lassa virus, a ‘multimammate rat’, Mastomys natalensis. Mastomys spp. produce large numbers of offspring, and are abundant in the savannah and forests of West, Central and East Africa. They readily colonize human homes, thus increasing the risk of LASV spread from infected rats to humans. Although LASV was first isolated in 1969 from a missionary nurse working in Lassa town of Borno State in North-Eastern Nigeria, LF seems to have been described as early as the 1950’s in Guinea, West Africa. LF is also highly endemic in other West African countries including Sierra Leone, Liberia, and Guinea. As such, the prevalence of LASV antibodies in the general population is 8-52% in Sierra Leone, 4-55% in Guinea, and 21% in Nigeria. In the early phases of the disease, LF symptoms are similar to those of many other common febrile illnesses such as flu, malaria or typhoid; as such, misdiagnosis is a common problem in the early stages of an outbreak. While LF is mild or has no observable symptoms in about 80% of people infected with the virus, the remaining 20% develop a severe multisystem disease. During LF outbreaks, the case-fatality rate can reach as high as 50%.
Citation: Adebayo D, Nwobi EA, Vincent T, Gonzalez JP (2015) Response Preparedness to Viral Hemorrhagic Fever in Nigeria: Risk Perception, Attitude towards Lassa Fever. Epidemiology (sunnyvale) 5:199.