The prototype arenavirus.
Rodent borne.
House mice are the natural reservoir, with an estimated 5% of house mice in the United States being infected.
The virus can be transmitted by direct contact with by erosion of rodent urine or feces.
Infections are most common in the winter when mice are indoors.
Infection has a one-two week incubation period.
Most infections are mild and self-limiting.
Among patients with meningitis typical manifestations of present, with a biphasic illness characterized by an influenza like syndrome followed by a convalescent period of several days before the onset of meningismus.
Typically an asymptomatic process or associated with a mild and transient illness.
May be associated with aseptic meningitis.
Human to human transmission during pregnancy has been reported.
Infection during pregnancy may lead to fetal loss, neurologic impairment and chorioretinopathy.
Associated with marked CSF lymphocytic pleocytosis.
Diagnosis established by finding LCMV nucleic acids in the CSF with my detection of seroconversion of antibody testing during the acute and convalescent stages.