Lymphocytic choriomeningitis virus (LCM). Coloured Transmission Electron Micrograph (TEM) of many LCM viruses at the surface of an infected human cell. These rounded viruses (upper frame) are of the Arenavirus group, so-called because the interior of each virus has a sand-sprinkled appearance. The cell is red at lower frame. LCM is closely related to the Lassa virus and like Lassa infection occurs through rodents, particularly house or domestic mice and hamsters. Laboratory workers are at risk. Transmission is by exposure to contaminated animals or their food. Symptoms include flu, head- ache, less commonly meningitis. Treatment by anti- viral drugs. Magnification: x15,000 at 6x7cm size.