Lymphocytic choriomeningitis virus (LCMV) is a rodent-borne arenavirus. House mice are the natural reservoir, and an estimated 5% of house mice in the United States are infected. The virus can be transmitted to humans by direct contact or by aerosolization of rodent urine or feces. Infection is most common in the winter, when mice are indoors.
Incubation period is approximately 1 to 2 weeks. Most infections are mild and self-limiting. A minority of patients develop a biphasic illness that begins as an influenza-like syndrome, which is followed by a convalescent period of several days and then the onset of meningitis.
Diagnosis can be established by the detection of LCMV nucleic acids in the CSF during the acute stage of illness or by antibody seroconversion during the acute and convalescent stages. LCMV nucleic acid testing may detect viral ribosomal nucleic acids in the blood or CSF only during the first 2 weeks after phase 1 symptoms begin. An enzyme-linked immunosorbent assay (ELISA) for LCMV is available only at the Centers for Disease Control and Prevention. Serologic testing by immunofluorescent antibody assay, that is available at most commercial laboratories, is less sensitive than ELISA.
Reference
Stone GS, et al. Case 40-2019: A 26-year old returning traveler with headache. New Engl J Med 2019; 381:2553-2560.