What is LCMV and how is it spread?

Lymphocytic choriomeningitis virus (LCMV) is carried by wild mice. Laboratory rodents and pet rodents, such as hamsters and guinea pigs, can become infected with LCMV from contact with wild mice. This can happen in a breeding facility, in a laboratory facility, in a pet store, or in the home (e.g., if wild mice are present).

Humans can become infected with LCMV through contact with urine, blood, saliva, droppings, or nesting materials of infected rodents. This could occur, for example, through a break in the skin or a bite from an infected rodent. Infection can also be spread by inhaling dust or droplets containing LCMV, such as while sweeping infected rodent droppings. A pregnant woman who becomes infected with LCMV can pass the infection to her unborn baby. LCMV infection can also be spread to patients who receive an organ transplant from an infected donor. However, spread of LCMV infection from one person to another is not known to occur outside these situations (1).

About 5% of adults have a positive blood test that shows they were infected with LCMV at some time in their lives (2, 3). Some people with normal immune systems have no symptoms during LCMV infection. Others have a mild illness with symptoms such as headache, fever, chills, and muscle aches. Sometimes, meningitis (inflammation around the brain and spinal cord) will occur.

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What are the risks of LCMV infection during pregnancy?

If you have an LCMV infection during your pregnancy, your unborn baby can also become infected. LCMV infection during pregnancy can result in loss of the pregnancy. Infants who are infected with LCMV before they are born can have severe birth defects. It is not known how often this happens because pregnant women with LCMV infection might have only mild symptoms or no symptoms at all, and babies often are not tested for the infection (4, 5). Since LCMV infection was first identified, more than 50 babies have been reported with LCMV infection worldwide (6, 7).