Lymphocytic choriomeningitis is caused by an arenavirus. It usually causes a flu-like illness or aseptic meningitis, sometimes with rash, arthritis, orchitis, parotitis, or encephalitis. Diagnosis is by viral isolation, polymerase chain reaction (PCR), or indirect immunofluorescence. Treatment is supportive.
Lymphocytic choriomeningitis virus is endemic in rodents in many places around the world, most commonly in the Americas, Australia, Europe, and Japan. Human infections are probably significantly underdiagnosed. Infection results most commonly from exposure to dust or food contaminated by the gray house mouse (Mus musculus) or hamsters, which harbor the virus and excrete it in urine, feces, semen, and nasal secretions. The percentage of infected house mice in a population may vary by geographic location; in some urban areas is the United States, 9% of captured wild mice carried the virus (1, 2). When transmitted by mice, the disease occurs primarily during autumn and winter.
General references
1. Bonthius DJ. Lymphocytic choriomeningitis virus: an underrecognized cause of neurologic disease in the fetus, child, and adult. Semin Pediatr Neurol. 2012;19(3):89-95. doi:10.1016/j.spen.2012.02.002
2. Centers for Disease Control and Prevention: Lymphocytic Choriomeningitis: About Lymphocytic Choriomeningitis. January 30, 2025. Accessed June 17, 2025.
Symptoms and Signs of Lymphocytic Choriomeningitis
The incubation period for lymphocytic choriomeningitis is 1 to 2 weeks.
Most patients have no or minimal symptoms. Some develop a flu-like illness. Fever, usually 38.5 to 40° C, with rigors is accompanied by malaise, weakness, myalgia (especially lumbar), retro-orbital headache, photophobia, anorexia, nausea, vomiting, and light-headedness. Patients may sometimes have sore throat, cough, chest pain, testicular pain, and parotid gland pain.
After 5 days to 3 weeks, patients may improve for 1 or 2 days. Many relapse with recurrent fever, headache, rashes, swelling of metacarpophalangeal and proximal interphalangeal joints, meningeal signs, orchitis, parotitis, or alopecia of the scalp.
Aseptic meningitis occurs in a minority of patients. Rarely, frank encephalitis, ascending paralysis, bulbar paralysis, transverse myelitis, or other neurologic symptoms can occur. Neurologic sequelae are rare in patients with meningitis but occur more often in patients with encephalitis.
Infection during pregnancy may cause fetal abnormalities, including hydrocephalus, chorioretinitis, and intellectual disability. Infections that occur during the first trimester may result in fetal death.
Diagnosis of Lymphocytic Choriomeningitis
Polymerase chain reaction (PCR), cerebrospinal fluid analysis, antibody detection, and viral culture
Lymphocytic choriomeningitis is suspected in patients with exposure to rodents and an acute illness, particularly aseptic meningitis or encephalitis.
In patients with meningitis, cerebrospinal fluid (CSF) analysis may reveal mild decrease in CSF glucose (occasionally as low as 15 mg/dL [0.83 mmol/L]) and CSF white blood cell (WBC) counts ranging from 100 to a few thousand cells, predominantly lymphocytes (> 80%). Complete blood count during the first week of illness may show mild leukopenia and thrombocytopenia (WBC count 2000 to 3000/mcL [2 to 3 × 109/L] and platelet counts 50,000 to 100,000/mcL [50 to 100 × 109/L]) (1, 2).
Diagnosis can be made by:
PCR or by isolation of the virus from the blood or CSF during the acute stage of illness
Indirect immunofluorescence assays of inoculated cell cultures, although these tests are most likely to be used in research laboratories
Tests that detect seroconversion of antibody to the virus
Diagnosis references
1. Centers for Disease Control and Prevention: Lymphocytic Choriomeningitis: About Lymphocytic Choriomeningitis. January 30, 2025. Accessed June 17, 2025.
2. Lendino A, Castellanos AA, Pigott DM, Han BA. A review of emerging health threats from zoonotic New World mammarenaviruses. BMC Microbiol 2024;24(1):115. Published 2024 Apr 4. doi:10.1186/s12866-024-03257-w
Treatment of Lymphocytic Choriomeningitis
Supportive care
Treatment of lymphocytic choriomeningitis is supportive. If aseptic meningitis, encephalitis, or meningoencephalitis develops, patients should be hospitalized, and treatment with ribavirin can be considered, although its effectiveness is uncertain (, or meningoencephalitis develops, patients should be hospitalized, and treatment with ribavirin can be considered, although its effectiveness is uncertain (1).
Anti-inflammatory medications (eg, glucocorticoids) may be considered, but evidence of effectiveness is lacking.
Treatment reference
1. Hickerson BT, Westover JB, Jung KH, Komeno T, Furuta Y, Gowen BB. Effective Treatment of Experimental Lymphocytic Choriomeningitis Virus Infection: Consideration of Favipiravir for Use With Infected Organ Transplant Recipients. J Infect Dis 218(4):522-527, 2018. doi:10.1093/infdis/jiy159
Key Points
In humans, lymphocytic choriomeningitis is usually acquired via exposure to dust or consumption of food contaminated by mouse or hamster excreta.
Most patients have no or minimal symptoms, but some develop a flu-like illness, and a few develop aseptic meningitis.
Infection during pregnancy may cause fetal abnormalities; if infection occurs during the first trimester, the fetus may die.
