Viruses are responsible for many common human diseases, such as colds, flu, diarrhea, chicken pox, measles, and mumps. Some viral diseases—such as rabies, hemorrhagic fevers, encephalitis, polio, yellow fever, and acquired immunodeficiency syndrome (AIDS)—can result in death. German measles and cytomegalovirus can cause serious abnormalities or death in unborn infants.
