Virus-like particles with T = 19 icosahedral symmetry in a human gastroenteritis stool

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

Storage of stool specimens at -70 degrees 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 degrees C to -85 degrees 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.

Virus and virus-like particles in the faeces of cats with and without diarrhoea

Negative staining electron microscopy was used to identify viruses in 166 normal and 62 diarrhoeal faecal samples from 208 cats admitted to an animal shelter during a 16-month period (March 1984 to June 1985). On the basis of size and shape 7 distinct viral types were detected: 24 nm parvovirus-like particles, 30 nm astrovirus, 30 nm picornavirus-like particles, reovirus, rotavirus, coronavirus and a 75 nm "togavirus-like" particle. The incidence of these particles in the 208 cats was 11%, 7%, 6%, 0.4%, 5%, 1% and 1% respectively. Virus isolation studies using 40 of the faecal samples succeeded in isolating reovirus 1 in 2 cases. Immune electron microscope studies demonstrated the presence of antibody in a human serum to cat astrovirus, but failed to clarify the identity of the parvovirus-like particles and picornavirus-like particles, other than showing that some of the parvovirus-like particles were not related to feline panleukopenia virus. It was found that parvovirus-like particles, astrovirus, picornavirus-like particles, reovirus and rotavirus could be excreted by cats with normal faeces as well as cats with diarrhoeal faeces. Parvovirus-like particles, astrovirus, picornavirus-like particles and rotavirus could be excreted in high concentration in normal faeces. There was no simple relationship between age and diarrhoea in the population of cats studied. Age was not a critical factor in the excretion of parvovirus-like particles, astrovirus, picornavirus-like particles and rotavirus. The incidence of diarrhoea was not clearly associated with the seasons.