Adenovirus is a medium-sized (90-100 nm) noneveloped icosohedral virus containing double-stranded DNA. Adenovirus is an important respiratory tract agent that can produce pneumonia and bronchiolitis in small children. However, depending on the infecting serotype, it may also cause other illnesses, such as gastroenteritis, conjunctivitis or rash illness. Adenovirus infections can be diagnosed in the laboratory by three classical methods: direct antigen detection on clinical specimens; culture techniques to isolate and identify the virus and serological tests to measure rises in antibody levels.