Lassa virus is a zoonotic viral pathogen that causes a severe, life-threatening disease known as Lassa fever. It belongs to the Arenaviridae family and is primarily endemic in West Africa, specifically in countries such as Nigeria, Sierra Leone, Liberia, and Guinea. The virus is named after the town of Lassa in Borno State, Nigeria, where the first recorded cases of the disease occurred in 1969.
Lassa virus is primarily transmitted to humans through contact with the urine or droppings of infected multimammate rats (Mastomys species), which serve as the natural reservoir for the virus. Additionally, human-to-human transmission can occur through direct contact with the blood, tissues, or bodily fluids of infected individuals.
The onset of Lassa fever in humans is characterized by a range of non-specific symptoms, including fever, headache, muscle aches, weakness, and gastrointestinal symptoms such as nausea, vomiting, and diarrhea. In severe cases, it can progress to hemorrhagic manifestations, including bleeding from body orifices and multiple organ failure.
Due to its high fatality rate and potential for outbreaks, Lassa virus is classified as a Biosafety Level 4 (BSL-4) pathogen, necessitating strict containment measures when handling the virus in laboratories. There is currently no specific antiviral treatment for Lassa fever, although supportive care can significantly improve the prognosis.
Prevention efforts against Lassa virus primarily involve reducing exposure to rodents and their excreta, practicing good personal hygiene, and maintaining proper sanitation measures. Additionally, maintaining clean environments and implementing rodent-proof storage facilities are essential in preventing transmission.
