A Comprehensive Review on Lassa Fever in Africa: Epidemiology, Diagnosis, Prevention and Control

Abstract

Lassa fever is a highly prevalent viral zoonosis that affects two to three million people in West Africa. This is a rodent-borne disease, which has serious consequences on the population and hospital staff in endemic areas. Lassa fever is a public health concern inflicting severe morbidity and important mortality (Case rate (CFR) ≥ 50%), particularly in epidemic cases. The disease has emerged as one of the most prevalent and debilitating viral hemorrhagic fevers and is endemic in the West Africa region. The control and prevention of the regular outbreak of the disease have become a herculean task in the affected; there is inadequate healthcare facility (including laboratory/diagnostic and care centers), poor socioeconomic environment, lack of awareness among the populace, and presence of favorable ecologic niche for the survival and propagation of the natural host and reservoir mouse (Mastomys natalensis) of Lassa virus. It is mainly transmitted by contact with excretions and secretions of infected rats via foods and water as well as exposure to other contaminated items. It is an enveloped, single-stranded (SS) segmented RNA virus with the ability to replicate very rapidly. The virus infects almost every tissue in the human body resulting in multisystem dysfunction. The incubation period is generally between 6 to 21 days resulting in 3 stages of clinical manifestation viz: Acute phase characterized by flu-like, non-specific illness; hemorrhagic phase accompanied with gastrointestinal symptoms and cardiovascular/neurologic complications. Laboratory help is required in order to make an unequivocal diagnosis of the disease. Early diagnosis and prompt therapy are crucial to saving the life of the patient. Currently, there is no clinically certified Lassa fever vaccine thus complicating preventive, and control measures.