Enteral adenoviruses (EAds) comprise two related groups of viruses which appear to cause gastroenteritis in infants. Studies of these viruses and the diseases they produce were hampered until recently by an inability to grow them in tissue culture. During the past year we have developed and reported an already widely used method for growing these viruses. Numerous isolates from around the world have now been grown in our laboratory and are characterized by restriction endonuclease analyses. These analyses have permitted us to distinguish epidemiologically unrelated strains from around the world. Virus-specific antisera have been prepared and used in an ELISA system for rapid detection of antigen in stool specimens. EAd DNA fragments have been cloned in plasmid vectors, and the first DNA restriction maps have been completed. We have also completed collaborative studies documenting an outbreak of EAd-associated gastroenteritis in which we showed that respiratory illness is also a common feature of EAd infection. Our current efforts are directed at better defining the structures of the viral genomes and the homology between the EAd groups and conventional adenoviruses.