The Arenaviruses

Abstract

The arenaviruses are a group of enveloped, single-stranded, RNA-containing viruses that are harbored in nature by rodent hosts and are important to man for clinical and scientific reasons. Humans can become infected with arenaviruses when they come into contact with the secretions or excretions of infected rodents.

Several dozen arenaviruses have been identified. However, lymphocytic choriomeningitis virus (LCMV) is the prototypical arenavirus and is the most important clinically and scientifically. LCMV is a prevalent virus that is harbored in nature by wild mice. The signs and symptoms of LCMV infection in humans depend strongly on the age of the person at the time of infection. In particular, they depend on whether the patient is prenatal or postnatal. In most postnatal infections, the clinical effects are relatively mild and are those of aseptic meningitis. In contrast, for the prenatal patient, the effects of LCMV are typically severe, as the virus has a strong tropism for the fetal brain, where it causes substantial and permanent injury.

LCMV is a strong activator of cytotoxic T-lymphocytes and has been used by scientists for decades to study important issues in immunology and immunopathology. The rat model has been highly valuable as a tool to study human congenital LCMV infection, as the rat model faithfully recapitulates virtually all of the effects observed in children with congenital LCMV. With the use of the rat model, scientists are learning the mechanisms by which LCMV induces focal destructive brain lesions, cerebellar hypoplasia, and neuronal migration disturbances.

Besides LCMV, there are several other clinically important arenaviruses, such as Lassa Fever virus, Chapare virus, and Whitewater Arroyo virus. Human infections with these other arenaviruses are more rare than with LCMV, but are still clinically important, as they often cause fatal hemorrhagic fevers.