For instance, all members of the family Herpesviridae are enveloped viruses that contain an icosahedral particle and double-stranded DNA, whereas all members of the family Adenoviridae are nonenveloped viruses that contain an icosahedral particle and double-stranded DNA, with projecting fibers at the vertices of the protein shell.

Standard diagnostic evaluations on these stools included culture for Campylobacter, Salmonella, Shigella, Vibrio cholerae, Aeromonas, and Plesiomonas; identification of Rotavirus, Adenoviridae, Astrovirus, and Caliciviridae by enzyme immunoassay; and microscopy for Entamoeba histolytica, Cryptosporidium parvum, Cyclospora cayetanensis, Isospora belli, and Giardia lamblia.