Lassa Fever: The Who, What, Where & Why

Lassa fever is an acute viral hemorrhagic illness that is an endemic in parts of West Africa. The Lassa virus is spread by the common African rat, also known as the multimammate rat or Mastomys natalensis, and is excreted in the rat’s urine and feces. Humans contract the virus either through ingestion of mastomys natalensis or inhalation of dried rat feces or urine. Mastomys can be eaten and tend to live in and around homes, so contamination of food and homes is common, increasing the likelihood of exposure. Symptoms of Lassa fever develop typically 1-3 weeks after exposure and can range from mild to severe and include slight fever, general malaise, hemorrhage, pain in chest, back, and abdomen, tremors, and encephalitis. Exposure risks increase in people who visit and live in endemic regions such as Liberia, Guinea, Nigeria, and Sierra Leone and areas where Mastomys inhabit. Lassa fever is diagnosed using enzyme-linked immunosorbent serologic assays (ELISA) and reverse transcription polymerase chain reaction (RT-PCR) which detects IgM and IgG antibodies and the Lassa virus genomic material, respectively. The antiviral drug, Ribavirin has been used in the treatment of Lassa fever patients alongside hydration, and other symptomatic treatments. Putting food in sealed containers, keeping homes and areas around homes clean, eliminating rodents as a source of food, and trapping rodents for safe removal can prevent the transmission and spread of Lassa fever. 


 Britannica: Guinea


 Britannica: Liberia