Morphological and antigenic relationships between viruses (rotaviruses) from acute gastroenteritis of children, calves, piglets, mice, and foals

Lapine rotavirus: preliminary studies on epizoology and transmission

Antibody to rotavirus was found in sera of domestic rabbits, wild cottontail rabbits and Snowshoe hares. Eight out of 187 stools from a rabbitry contained rotavirus, though no clinical symptoms were apparent. The virus extracted from one such stool infected a five week old seronegative rabbit and led to distention and congestion of the colon, excretion of virus in the stool and a serological response to virus. Human and Simian rotaviruses did not replicate in the rabbits.

Serological relationships between rotaviruses from different species as studied by complement fixation and neutralization

Human, piglet, mouse, foal, lamb, calf and rabbit rotaviruses all infected, but could not readily be subcultured in LLC MK2 cells. Cells infected with mouse and calf rotaviruses reacted by indirect immunofluorescence (FA) with convalescent serum from children, piglets, mice, foals, lambs, calves or rabbits, taken after rotavirus infection. Human, calf, piglet, mouse and foal rotaviruses reacted with human, calf, mouse, foal and lamb convalescent serum by complement fixation (CF). It was not possible to distinguish between different rotaviruses by CF or FA. Neutralization tests, however, detected species-specific rotavirus antigens. Any virus was neutralized by a much higher dilution of homologous species convalescent serum than by any heterologous serum. With the exception of the mouse virus there was very little cross reaction. However, in sera with a very high neutralizing titre for the homologous virus the titre was proportionately raised against heterologous virus. It is, therefore, now possible to type to species an unknown rotavirus by a neutralization test in LLC MK2 cells using convalescent serum from each species.

Distribution and titres of rotavirus antibodies in different age groups

Three hundred and fifty-seven sera selected at random from hospital patients of all ages were examined for rotavirus antibodies using indirect immunofluorescence (FA) and complement fixation levels (CFT). Three hundred and fourteen of these were also tested for neutralizing antibodies to human rotavirus. Sera from patients admitted with a diagnosis of acute gastroenteritis were excluded from this survey. FA antibodies were found in newborn infants but fell to undetectable titres at 3 months. The highest titres were found in children between the ages of one and three years. In older age groups, the model titre fell gradually with increasing age until, in sera from those above 70 years of age, FA antibodies were almost undetectable. The same pattern was observed with neutralizing antibodies. A high model titre of CF antibodies was only found in sera from those aged one to three years.

Rotavirus isolation and cultivation in the presence of trypsin

Rotaviruses are generally difficult to isolate and culture in vitro; therefore, virus isolation has not been used as a method of diagnosing this group of agents. The present report describes a simple procedure for isolating bovine rotaviruses directly from feces after pretreatment of fecal samples with trypsin. This procedure resulted in virus isolation from five of five samples that contained virus particles, as demonstrated by electron microscopy, and four of seven samples where virus particles could not be observed but were considered positive by the presence of immunofluorescent-staining cells in feces. Virus could not be isolated from "normal" feces. If the virus was not passaged in the presence of trypsin, the infectivity was gradually lost, but infectivity could be restored again if trypsin was added, resulting in increased virus spread and concomitant increase in virus yield. The application of this technique as a diagnostic tool for bovine and other rotaviruses is briefly discussed.

Further biochemical characterization, including the detection of surface glycoproteins, of human, calf, and simian rotaviruses

Polyacrylamide gel electrophoretic analysis of purified preparation of the simian rotavirus SA-11 indicated eight polypeptide components that migrated in a manner remarkably similar to those of the previously characterized human and calf rotaviruses. Analyses of preparations of single-shelled and double-shelled particles of human, calf, and simian an rotaviruses have also permitted assignment of the polypeptides to the inner or outer shells. The major components of the outer shells of each virus have been identified as glycoproteins, and the importance of this in terms of host cell specificity is discussed. Sensitivities of the various rotaviruses to acid, proteases, and glycosidases were also investigated.

Antigenic relationship between human and bovine rotaviruses as determined by neutralization, immune adherence hemagglutination, and complement fixation tests

Guinea pig antiserum to bovine rotavirus does not neutralize human rotavirus. Bovine and human rotaviruses were, however, extensively cross-reactive when examined by complement fixation and immune adherence hemagglutination tests with antiserum to either virus. The immune adherence hemagglutination test was 16- to 32-fold more sensitive than the complement fixation test in detecting rotavirus.

Tubular structures associated with acute nonbacterial gastroenteritis in young children

We clearly demonstrated a fine morphology of the tumbular structures antigenically related to the reovirus-like particles associated with acute nonbacterial gastroenteritis in young children. The tubular structures with a caplike structure on each end seemed to be complete forms, 75 to 80 nm in width and approximately 1,000 nm in length.

Solid-phase radioimmunoassay for detecting bovine (neonatal calf diarrhea) rotavirus antibody

An indirect solid-phase microradioimmunoassay is described for detecting antibodies against rotaviruses. The test involved ethanol fixation of microcultures of bovine rotavirus-infected BSC-1 cells and reacetion with bovine antirotavirus serum, followed by 125I-labeled rabbit anti-bovine immunoglobulin G. The technique was shown to be virus specific and highly sensitive. The fixed microcultures could be stored at 4 degrees C for at least 2 months without affecting the sensitivity of the test. The application of this system for the detection of rotavirus antibodies in humans is briefly discussed.

Isolation of reovirus-like agents from patients with Crohn's disease

220 nm filtrates of intestinal resections from 6 of 10 patients with Crohn's disease produced a cytopathic effect in WI-38 tissue-culture monolayers, whereas controls had no effect. Characterisation of the virus responsible has been completed in 3 of the 6 positive isolates and indicates that it is an R.N.A. virus, 55-60 nm in diameter, heat, ether, and acid stable, and antigenically related to Nebraska calf-diarrhoea virus. It therefore belongs to the Reoviridae family.