Viral diseases: Introduction. A viral infection is any type of illness or disease caused by a virus, a type of microbe. Microbes are tiny organisms that cannot be seen without a microscope and include bacteria, fungi, and some parasites, as well as viruses.iral diseases: Introduction. A viral infection is any type of illness or disease caused by a virus, a type of microbe. Microbes are tiny organisms that cannot be seen without a microscope and include bacteria, fungi, and some parasites, as well as viruses.
OPTAR stands for Operating/Operational Target. Operating Targets. Operations, Planning, Training and Resource Support Services. Oceanside Photo & Telescope Astronomical Society (San Diego County, CA) Operational Tasking. Operational Tasking Data Link. Operational Tasking Nuclear. Occasional Papers in Translation and Textlinguistics.
optometry An autonomous, healthcare profession involved in the services and care of the eye and visual system, and the enhancement of visual performance. Syn. ophthalmic optics (term used principally in the UK and the Republic of Ireland). See primary care optometry. behavioural optometry A branch of optometry concerned with the diagnosis and treatment of visual problems taking into account not only the ocular history, signs and symptoms but also the whole person and his or her environment.