Virion Systems, Inc. (VSI) is a Maryland biotechnology corporation focused on the prevention and treatment of infectious diseases, particularly those involving infants and children. Our 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).

VSI performs contract research for academic and commercial groups, centered around the use of the cotton rat. In addition to research on prevention and treatment of infectious diseases, we also undertake contract research involving the use of adenoviruses as vectors for genetic therapy, as the cotton rat is the only small animal permissive for human denoviruses.

VSI is developing an array of cotton rat-specific reagents that will eventually include both RNA and antibody-based reagents for the detection and quantitation of cytokines, chemokines, immunoglobulins and cell-surface markers.