DIARRHEA-ASSOCIATED ADENOVIRUSES: RAPID PRESUMPTIVE DIAGNOSIS BY ELECTRON MICROSCOPY

There is a need for the rapid recognition of infection by the newly-described enteral or diarrhea-associated adenoviruses (adenoviruses that are of proposed neutralizing serotypes 40 and 41, or that have restriction endonuclease electrophoretic profiles of Wadell groups F or G). These viruses especially infect infants, and they tend to be fastidious in their growth in conventional cell cultures. During a 6 minute viewing per specimen, adenoviruses were visualized by direct electron microscopy (EM) or immune EM in the stools of 52 pediatric inpatients with acute gastroenteritis. Forty (77%) of these viruses proved to be enteral adenoviruses on the basis of neutralization test in 293 cells and/or electrophoretic profile. However, only 5 (36%) of 14 patients with less than 1 adenovirus particle per minute of direct EM viewing of the original diarrhea stools were found to have an enteral adenovirus, as compared to 35 (92%) of 38 patients with 1 or more such particles per minute of viewing (X2 = 18.34, P = < .01). Thus the quantity of adenoviruses found in a diarrhea stool would appear to provide a strong presumptive indication of the presence or absence of an enteral adenovirus. This determination can be made within 15 minutes of specimen collection.