Lassa fever named after a Nigerian town in 1969

Lassa fever

Lassa fever or Lassa hemorrhagic fever (LHF) is an acute viral hemorrhagic fever caused by the Lassa virus and first discovered in 1969 in the town of Lassa, in Borno State, Nigeria. Lassa fever is a member of the Arenaviridae virus family. Similar to ebola, clinical cases of the disease had been known for over a decade, but had not been connected with a viral pathogen

        Cause 

 

Lassa virus is zoonotic (transmitted from animals), in that it spreads to humans from rodents, specifically multimammate mice (Mastomys natalensis). This is probably the most common mouse in equatorial Africa, ubiquitous in human households and eaten as a delicacy in some areas. In these rodents, infection is in a persistent asymptomatic state. The virus is shed in their excreta (urine and feces), which can be aerosolized. In fatal cases, Lassa fever is characterized by impaired or delayed cellular immunity leading to fulminant viremia.

Prevention

Control of the Mastomys rodent population is impractical, so measures are limited to keeping rodents out of homes and food supplies, as well as maintaining effective personal hygiene.

Treatment

All persons suspected of Lassa fever infection should be admitted to isolation facilities and their body fluids and excreta properly disposed of.

Early and aggressive treatment using ribavirin was pioneered by Joe McCormick in 1979. After extensive testing, early administration was determined to be critical to success. Additionally, ribavirin is almost twice as effective when given intravenously as when taken by mouth.Ribavirin is a prodrug which appears to interfere with viral replication by inhibiting RNA-dependent nucleic acid synthesis, although the precise mechanism of action is disputed. The drug is relatively inexpensive, but the cost of the drug is still very high for many of those in West African states. Fluid replacement, blood transfusion, and fighting hypotension are usually required. Intravenous interferon therapy has also been used