Lymphocytic choriomeningitis virus (LCMV) is a pathogen, normally carried in rodents, which can cause aseptic meningitis and other conditions in humans. Most people experience a relatively mild illness and fatal infections are rare; however, pregnant women may give birth to congenitally infected infants with severe defects of the brain and eye. In a few instances, this virus has been transmitted in transplanted organs, usually resulting in fatal disease. LCMV infections in rodents are often subclinical, although acute clinical signs or chronic effects may be seen in some animals. Some strains of this virus can cause life-threatening illness in New World monkeys. LCMV is also a potential bioterrorist weapon.