Virion Systems, Inc. (VSI) is a Maryland biotechnology corporation focused on the prevention and treatment of infectious diseases, particularly those involving infants and children. Thee firm's core technology is the use of the cotton rat as an animal model of human infectious diseases. Species of cotton rats (genus Sigmodon) have been shown to be permissive for a wide array of human viral, bacterial, rickettsial and parasitic pathogens. Most prominent among these are respiratory syncytial virus (RSV), parainfluenza virus (types 1, 2 and 3), influenza virus (types A and B), adenovirus (various serotypes), poliovirus (types 1, 2 and 3), herpes simplex virus (types 1 and 2) and human immunodeficiency virus (HIV).
