An Overview of Lassa fever, an Rising Old World Haemorrhagic Viral Disease

Lassa fever is an acute immunosuppressive illness of increasing public health concern causing severe morbidity and significant mortality especially in epidemic cases. Lassa fever is an acute viral zoonotic illness caused by Lassa virus, an arenavirus known to be responsible for a severe haemorrhagic fever characterised by fever, muscle aches, sore throat, nausea, vomiting, chest and abdominal pain. The virus exhibits persistent, asymptomatic infection with profuse urinary virus excretion in the ubiquitous rodent vector, Mastomys natalensis. Lassa fever is endemic in West Africa and has been reported from Sierra Leone, Guinea, Liberia, and Nigeria. The virus replicates through a strategy known as the Ambisense, where two RNA strands code for genes in both the sense and antisense direction that is rapid and demonstrate temporal control in replication. Different diagnostic tests for the virus are available, which range from viral culture to serological and molecular diagnostic tests. There is an urgent need to develop drugs and vaccines against the virus because the World Health Organization (WHO) has identified Lassa virus as one of the viruses that is likely to cause a future epidemic, although a research is ongoing to evaluate Lassa virus vaccine immunogenicity in the CBA/J-ML29 mouse model. This review gives an overview on the structure, replication cycle, pathogenesis and diagnosis of the virus. Keywords: Lassa fever, Lassa virus, Arenavirus, Replication, Pathogenesis, Diagnosis