Adenoviruses are double-stranded DNA viruses that mainly cause respiratory and gastrointestinal infections in children. They can be spread through contact, respiratory droplets, or ingestion. Common clinical manifestations include respiratory disease, conjunctivitis, hemorrhagic cystitis, and infections of the eye. Diagnosis involves virus isolation from body fluids or detection of viral antigens and antibodies via immunoassays. There is no specific treatment for adenovirus infections.