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Viruses are a very common type of infectious disease. Many of the most common human diseases are viral. Viruses are the smallest life-form existing, since they are not even a single cell. It is almost like they are not alive at all. They are small strands of DNA-like cell material. A virus consists mostly of RNA and cannot survive without host cells. A virus can enter the body in many ways besides food, fluids, and bites from insects or animals. The infectious secretions from viruses are passed on to others by coming in contact with them. They can be inhaled from airborne particles from coughs and sneezes. Touching or holding hands with an infected person and then rubbing the eyes or nose is a common way to "catch" a virus. There are approximately 200 known viruses that cause disease in humans. Over 100 of these cause "colds." Viral diseases include: HIV/AIDS, the common cold, flu, measles, rubella, chicken pox, mumps, polio, mononucleosis, ebola, West Nile fever, chickenpox, smallbox, hepatitis, meningitis, encephalitis, pneumonia, and SARS. Many viruses are hard to destroy without damaging or killing the living cells they infect; this is why drugs are not used to control them. Many viral diseases can be prevented by immunization.

Who is at Risk?

Young children are highly sensitive to viruses because their immune system is still developing.

Sources: CureResearch.com, University of Iowa Health Care

Recent Virus Research and News at The Scripps Research Institute

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