What Is Lymphochoriomeningitis Virus?

Lymphochoriomeningitis virus (LCMV) is a rodent-borne viral infectious disease that presents as aseptic meningitis, encephalitis, or meningoencephalitis. LCMV is a member of the family Arenaviridae. It is most commonly recognized as causing neurological disease but can cause infection without symptoms or mild febrile illnesses. Pregnancy-related infections have been associated with congenital hydrocephalus, chorioretinitis, and mental retardation.

The primary host is the common mouse, Mus musculus. Infection in these mouse populations vary by geographic location but approximately five percent of mice throughout the United States harbor LCMV. The virus is found in saliva, urine, and feces of infected mice. Other types of rodents, such as hamsters, are not the natural reservoirs but can become infected with LCMV if exposed to infected mice. Infections have been documented from pet rodents (hamsters, gerbils, and guinea pigs).

Routes of Infection

Humans become infected with LCMV after exposure to fresh urine, droppings, saliva, or even nesting materials. Transmission can also occur when these materials are directly introduced into broken skin, the nose, the eyes, or the mouth or via the bit of an infected rodent. Person-to-person transmission has not been reported (with the sole exception of vertical transmission from infected mother to fetus). However, recent investigations indicate that organ transplant may also be a mode of transmission.

Risks

Individuals of all ages who come into contact with urine, feces, saliva, or blood of infected mice are potentially at risk for infection. However, this risk can be minimized by utilizing animals from sources that regularly test for the virus, wearing proper protective clothing and gear, and following appropriate precautions.

Prevention

LCMV infection can be prevented by taking the appropriate precautions when handling rodents of unknown LCMV status. Keeping wild rodents out of the animal facility is an important step to prevention of LCMV in the laboratory rodent population.