The word virus can vary in meaning. In medicine, a virus is an infectious disease agent smaller than a cell usually presenting in a rod or capsule shape. The virus contains genetic material that works by interfering with the way cells work. The virus is resistant to antibiotic and is responsible for diseases including: AIDS, genital herpes, small pox, influenza and measles.
In recent years the word virus has been attached to computer malware that work like a virus within the computer, interfering with the way the computer, often the registry works. The term viral has been attached to marketing that has moved quickly or in an epidemic-like fashion on the Internet.
For medical information on viruses, check the MRI Technician Training blog, it lists the top blogs on medical viruses. The listed blogs provide information on virology and diseases caused by viruses like bird or swine flu and also lists appropriate pharmacies which can help to locate particular medications.