Human adenovirus strain J.J. subtype D/10 (HAdV-10). Scanning electron micrograph (SEM) of a human alveolar basal epithelial cell (A549 cell line) infected with HAdV-10. The image shows an infected cell yellow) that has not undergone lysis. The cells plasma membrane is decorated with 100nm diameter non-enveloped HAdV-10 virus particles (red) released from other lysed infected cells from the culture. Adenoviruses are a group of viruses that can cause mild to severe infection throughout the body. Adenovirus infections most commonly affect the respiratory system, eyes, and the gastrointestinal tract. These infections can cause symptoms similar to the common cold and flu or pneumonia, conjunctivitis, or acute gastroenteritis. Most adenovirus infections are mild. Magnification: x 3000 when printed 10 centimetres wide. Specimen courtesy of Virology Research Services Ltd (Scott Lawrence).