Astrovirus-associated gastroenteritis in children.

Abstract

SUMMARY In a small astrovirus-associated outbreak of gastroenteritis in a ward of a local children's hospital two out of five children with symptoms excreted astrovirus particles. No astrovirus particles were found in faeces from the remaining asymptomatic child, and no other viral or bacterial pathogens were found in any of the children. Virus excretion persisted for only a few days. Rising antibody titres to the astrovirus particles were demonstrated in one child, and IgM was also demonstrated in this patient's serum.In recent years one of the most successful techniques in the search for viral agents, which might cause gastroenteritis in man, has been the direct examination of faecal emulsions by electron microscopy (Kapikian et al., 1972;Flewett et al., 1973;Paver et al., 1973;Bishop et al., 1974;Caul et al., 1975;Caul and Egglestone, 1977;Appleton and Higgins, 1975; Cosgrove, 1975, 1976 Material and methodsTwo faecal specimens were collected from a child (patient T) who had been admitted to hospital with nephrotic syndrome and who subsequently developed severe gastroenteritis. These specimens were taken one day and three days after the child had diarrhoea.Routine 10y% faecal emulsions were prepared in phosphate-buffered saline (PBS), clarified by centrifugation for 30 minutes in a bench centrifuge, and concentrated for examination in the electron microscope by centrifugation for two hours at 50 OOOg in a Sorvall RC2-B ultracentrifuge. Two further specimens were collected from this child eight days and 14 days after the onset of symptoms. Twenty-five per cent faecal emulsions were prepared from these two specimens, clarified, and concentrated by centrifugation for four hours at 110 000 g in a Spinco Model 'L' ultracentrifuge.Single specimens of faeces were also collected from five other children in the same ward. One of these (patient M) had been discharged from hospital three days after patient T had diarrhoea but was readmitted three days later with an attack of vomiting. This lasted for two days and the child then developed diarrhoea which persisted for two days.A faecal specimen was collected the day before the onset of diarrhoea. Three other children also had gastrointestinal symptoms at some stage during their stay in hospital; two of these had vomiting without diarrhoea and the other (patient P) had diarrhoea and vomiting. The fifth child was asymptomatic during his stay in hospital. Twenty-five per cent emulsions were prepared from these five faecal samples and processed as described above.

Human viral gastroenteritis

“…Children, from infancy to 5 to 7 years of age, are most likely to develop symptomatic disease with astroviruses (7,204,210), although exposed adults can also develop mild disease, but with less frequency (204,210,278). In one study (210), older children were also found to be less likely to develop disease than younger children.…”

“…However, in another study, some children had vomiting only, while the remainder suffered from both vomiting and diarrhea (7). In a third study, the rates of symptoms were as follows: vomiting, 74%; diarrhea, 30%; abdominal pain, 49%; and fever, 30% (204).…”

“…In one study (210), older children were also found to be less likely to develop disease than younger children. Asymptomatic infection can also occur among infants and young children (7,229).…”

“…Astroviruses have been isolated in the United Kingdom (7,210,229,230) Norway (199), Federal Republic of Germany (226), Japan (204), and North America. They are responsible for about 5% of infantile gastroenteritis, including nosocomial infections.…”

Further studies of 35-40-nm virus-like particles associated with outbreaks of acute gastroenteritis

“…Caliciviruses are 30 nm in diameter, having a feathery edge and a six-pointed star with a central hollow (Madeley and Cosgrove, 1976;McSwiggan, Cubitt and Moore, 1978). Astroviruses, having a diameter of 28 nm, are characterised by a smooth edge and a five-or six-pointed star with no central hollow (Madeley and Cosgrove, 1975;Ashley, Caul and Paver, 1978).…”