Most people become infected when they inhale dust or eat food contaminated with the urine, feces, or another body fluid of an infected mouse or hamster.
Most people with lymphocytic choriomeningitis have no or mild symptoms, but some have a flu-like illness, and a few develop meningitis or a brain infection.
To diagnose lymphocytic choriomeningitis, doctors do a spinal tap and blood tests to check for the virus.
Treatment aims to relieve symptoms, but if people have meningitis or a brain infection, they are hospitalized and may be given an antiviral drug.
Lymphocytic choriomeningitis virus is caused by an arenavirus and is spread by rodents. Usually, people become infected when they inhale dust or eat food contaminated with the urine, feces, or another body fluid of an infected hamster or gray house mouse. When lymphocytic choriomeningitis is transmitted by mice, it occurs mainly in adults during the autumn and winter.
Most people with lymphocytic choriomeningitis have no or mild symptoms.
Symptoms, if they occur, develop about 1 to 2 weeks after people are infected.
Some people have a flu-like illness, with fever, chills, a general feeling of illness (malaise), weakness, muscle aches (especially in the lower back), and pain behind the eyes. People may be sensitive to light, lose their appetite, and feel nauseated or light-headed. Sore throat occurs less often.
After 5 days to 3 weeks, people usually improve for 1 or 2 days. Many of them then worsen. Fever and headache return, and a rash may appear. The joints of the fingers and hands may swell. Infection may spread to the salivary glands (causing mumps) and to the testes.
In a few people, the tissues that cover the brain and spinal cord (meninges) become infected (called meningitis). Meningitis typically causes a stiff neck that makes lowering the chin to the chest difficult or impossible. Very few people develop a brain infection (encephalitis), which may cause paralysis, problems with movement, or other symptoms of brain dysfunction.
If pregnant women become infected, the fetus may have problems, such as hydrocephalus (accumulation of excess fluid within the brain or meninges), chorioretinitis (an eye infection), and intellectual disability. Chorioretinitis can cause blurred vision, eye pain, sensitivity to light, and blindness. If pregnant women are infected during the 1st trimester, the fetus may die.
Lymphocytic choriomeningitis is suspected in people who have typical symptoms (especially those suggesting meningitis or a brain infection) and who have been exposed to rodents.
If people have symptoms of meningitis, a spinal tap (lumbar puncture) is done to obtain a sample of cerebrospinal fluid for analysis. (Cerebrospinal fluid is the fluid that flows through the tissues that cover the brain and spinal cord.) A sample of cerebrospinal fluid is sent to a laboratory to be tested. For example, the virus, if present, can be grown (cultured) until there are enough to be identified. Or polymerase chain reaction (PCR) techniques may be used to make many copies of the virus's genetic material. This technique enables doctors to rapidly and accurately identify the virus.
Preventing exposure to the rodent urine and feces can help prevent infection. The following can help:
Treatment of lymphocytic choriomeningitis focuses on relieving symptoms and maintaining vital functions. Measures needed depend on the severity of the illness.
People with meningitis or a brain infection are hospitalized and may be treated with the antiviral drug ribavirin.
Corticosteroids are sometimes helpful.