Electron microscopy of stool‐shed viruses: Retention of characteristic morphologies after long‐term storage at ultralow temperatures

Williams, Fred P.

Storage of stool specimens at —70°C has been reported to destroy the characteristic morphology of calicivirus. To determine if other stool‐shed viruses are similarly affected, stool specimens previously examined by electron microscopy and observed to contain virus particles were reexamined after 6–10 years of storage at —70°C to —85°C. The stools contained virus particles of different morphological types, including astrovirus, small round structured virus, adenovirus, and rotavirus as well as calicivirus. Also reexamined were stools containing coronavirus‐like particles and T = 19 virus‐like particles. Characteristic virus particles, including calicivirus particles, were recognized in all the stools reexamined. The results indicate that long‐term storage of stools at ultralow temperatures does not present a significant problem for the morphological identification of stool‐shed viruses.