Viruses are tiny microorganisms that can be seen only with a powerful microscope. They can cause infections in children that range from colds and flu to AIDS. Measles, mumps, and chicken pox are also viral infections, and so are herpes, rabies, and smallpox. Viral infections are sometimes confused with those caused by bacteria but, unlike bacterial infections, they usually can't be treated with antibiotics or other drugs; you can only treat the symptoms. Viruses usually enter the body when your child comes into contact with, or inhales, airborne droplets transmitted by infected people. Your child can be vaccinated against infections such as measles, German measles, mumps, and smallpox. A chicken pox vaccine is also available. If a child contracts a viral infection, you should see a physician who can treat the symptoms. Have the child get plenty of rest and drink fluids. Children should never be given aspirin or other salicylates (suh-LIH-suh-lates), only children's aspirin substitute. Administering aspirin, especially to children with viral infections, can result in a condition known as 'Reye's (RIZE) syndrome,' a disease of the brain and liver that's often fatal.