Lassa fever is part of the viral hemorrhagic fevers (FEV), diseases of viral origin in systemic nature, characterized by sudden onset, acute and often accompanied by hemorrhagic manifestations. In general, the staff responsible for Fev are RNA viruses (arena-viruses, bunyavirus, filo-virus, flavivirus), whose survival is ensured by natural reservoirs such as animals or insects. The viruses are geographically confined areas where the host species live.
Lassa fever is named after the Nigerian city where, in 1969, two missionary nurses died from the disease, hitherto unknown. The causative agent is a RNA virus belonging to the family of Arenaviridae, widespread mainly in Africa, which are the main reservoir rodent Mastomys.
As for all the hemorrhagic fevers, men are not natural reservoirs for the virus, but can be infected through contact with infected animals or arthropod vectors. Lassa fever was transmitted by direct contact with rodent excreta or through aerosol excreta and saliva of rodents.
In some cases, after the accidental transmission, can be transmitted between humans, direct contact with blood, tissue, secretions, or excretions of infected people, especially within the family and nosocomial. (more…)