LYMPHOCYTIC CHORIOMENINGITIS

Lymphocytic choriomeningitis LCM is an enzootic, viral disease of lower animals, which when present, is a hazard to people who work with laboratory animals for the following reasons. Being prevalent in wild rodents, it readily spreads to most species of laboratory animals unless specific precautions are taken to keep it out. Although generally occurring in a subclinical form it is so readily transmitted directly, indirectly, or via insect vectors that it may become widely spread throughout an animal colony before its presence is known. From experimental animals it has frequently contaminated other viruses being studied, invalidating results. Contact with infected animals and contaminated materials has resulted in numerous human cases varying in severity from inapparent to rarely fatal. As the name implies, in its acute form it produces an encephalomyelitis with lymphocytic infiltration of the choroid plexus, meninges and ependyma. The immunologic character of the disease in mice varies with the manner of infection. Periodic checking of an animal colony for the presence of LCM is recommended.