Reovirus-like agent in acute epidemic gastroenteritis in Japanese infants: fecal shedding and serologic response

Peak rotavirus activity shifted from winter to early spring in Japan

BACKGROUND

Since 1910, there have been many studies on acute gastroenteritis in children in Japan. These diseases, namely Kasei-shoni-kolera (pseudocholera infantum) or banshu-otosho (late autumn vomiting disease), are historically known to occur in the cooler season with a peak in November or December. Earlier we confirmed their causation by rotaviruses but found peaks in January or February from 1974 to 1981. The aim of the present study was to confirm the temporal shift in peak rotavirus activity.

METHODS

Under the National Epidemiological Surveillance of Infectious Diseases program from 1983 through 2003, rotavirus positive patients 0-3 years old and clinically diagnosed with "infantile vomiting and diarrhea" at sentinel clinics were examined. Fecal samples were screened by electron microscopy and/or using commercial latex agglutination kits at prefectural/municipal Public Health Institutes, and we determined the trend for the "peak" month during 21 seasons.

RESULTS

Peak rotavirus activity shifted gradually from January to March during the 21 consecutive seasons. The mean duration from December to the peak month (mean beginning peak duration) of the rotavirus season significantly varied among 3 periods of 7 consecutive seasons (1.7 +/- 0.5 months in 1982/1983-1988/1989, 2.3+/-0.8 months in 1989/1980-1995/1996, and 3.1 +/- 0.7 months in 1996/1997-2002/2003, respectively; P = 0.0026 by 1-way analysis of variance). This time series shift in the peak rotavirus infection was statistically significant (P = 0.0003 for trend).

CONCLUSION

Our findings confirmed that the temporal trend in peak rotavirus activity in Japan has shifted gradually from winter to early spring for unknown reasons.

Population-based study of rotavirus vaccination and intussusception

BACKGROUND

During the first year that the rhesus rotavirus tetravalent vaccine (RRV-TV) was licensed, the Vaccine Adverse Event Reporting System received several reports of intussusception after vaccination. To evaluate the risk of intussusception, we conducted a retrospective cohort study in ten managed care organizations.

METHODS

Cases of intussusception were identified by searching electronic databases for diagnoses of intussusception (ICD-9 Code 560.0) in infants 1 to 11 months of age and confirmed by medical chart review. Vaccination and enrollment data were obtained from administrative databases. Incidence rate ratios (RR) of intussusception were computed by dividing incidence rates in prespecified risk intervals after vaccination by the background rate of intussusception and adjusted for age by Poisson regression. Cox proportional hazard regression was used to evaluate risk by vaccine dose.

RESULTS

Of 463,277 children 56,253 had been vaccinated with a total of 91 371 doses of RRV-TV. The incidence rate of intussusception was 25/100,000 person years among unexposed infants and 340/100,000 person years 3 to 7 days postvaccination. In the interval 3 to 7 days after vaccination, the age-adjusted RR was 16.0 (95% confidence interval, 5.5 to 46.7) for all doses combined and 30.4 (95% confidence interval, 8.8 to 104.9) after the first dose. RRs for the 8- to 14- and 15- to 21-day risk intervals were >1.0, but the confidence intervals substantially overlapped 1.0. The attributable risk was one case of intussusception per 11 073 children vaccinated.

CONCLUSIONS

RRV-TV is associated with an increased risk of intussusception. The risk is greatest 3 to 7 days after the first vaccination dose.

Rotavirus infection and intussusception: a view from retrospect

A live orally-administrable rhesus rotavirus (RRV) tetravalent (TV) vaccine, licensed in the U.S.A. and the European Union, was recalled from the market because it was suspected to increase the risk of intussusception during the week following immunization. In contrast, natural rotavirus infection is generally believed not to cause intussusception. Because my experience contributed to the first paper that linked intussusception with rotavirus infection, I have re-examined our own data published 22 years ago and other studies on this issue. I also made a case study of adenovirus and intussusception as a paradigm to establish an etiological association of viral infection and intussusception. My hypothesis postulated in this review is that natural infection of susceptible (or predisposed) infants with some rotavirus strains, probably serotype G3 rotaviruses, will result in an appreciable fraction of idiopathic intussusception. Thus, the number of rotavirus-induced intussusception cases may change reflecting the relative frequency of G3 strains, which I believe was much higher in the 70s than during the last two decades. The epidemiological data indicate that the RRV-TV vaccine triggers intussusception at a rate significantly higher than the background incidence rate following the week of vaccination, particularly after the first dose. In contrast, the data do not suggest that the cumulative incidence among the vaccine recipients increases accordingly, implicating that the risk of intussusception attributable to the RRV-TV vaccine may be minimal.

Rotavirus infection in children in Japan

Currently, a high morbidity of rotavirus diarrhea has been seen in children in developed and developing countries. Improvement of the vaccines is necessary in order to reduce the burden of diarrhea caused by rotavirus. A survey of rotavirus infection from diarrheal stool specimens in children of seven regions in Japan was conducted from 1984 to 1999. The present study discusses the survey results and reviews the national and international data of more than 23 papers and congress proceedings about rotavirus infection in Japan. We analyze the prevalence of rotavirus infection in acute diarrheal in- and outpatients, the distribution of rotavirus G-serotypes and surveillance data for seasonality and age groups in Japan. The data indicated that rotavirus is the most important cause of diarrhea in Japan among young children, with the prevalence ranging from approximately 9.7 to 88%. The most common rotavirus strains belonged to serotype G1, specifically since 1993. Serotypes G2, G3 and G4 had also been documented to be predominantly based in the area and year before 1992. However, untypeable rotavirus strains had been found each year, with a prevalence up to 56.7% which suggests that rare serotypes (except G1-4) or new serotypes might exist. Unexpectedly, in Tokyo and Sapporo from 1998 to 1999, G9 was found to be the first most prevailing serotype with a high prevalence of 52.9 and 71.4%, respectively. Despite these data from different geographic areas, the year under investigation was relatively clear in respect to seasonality, with a peak of rotavirus activity in late winter (February) through early spring (March). Age distribution had also characterized that the infection was predominant among children aged 1-2 years of age, although it was also common in children of 2-3 years. In addition, mixed infection with bacteria was documented.

Extraintestinal rotavirus infections in children with immunodeficiency

Some rotavirus strains, including vaccine candidates, have been demonstrated to cause hepatitis in immunodeficient and malnourished mice and to grow in human liver cells. To determine whether rotavirus spreads outside the intestine in naturally infected children, we examined tissues from four immunodeficient children affected with severe combined immunodeficiency disease, acquired immunodeficiency disease syndrome, or DiGeorge syndrome. Chronic rotavirus-related diarrhea, which persisted until death, had also developed in each child. Using indirect immunoperoxidase techniques, we identified rotavirus antigen in the liver and kidney with a hyperimmune guinea pig antiserum prepared to double-shelled rotavirus particles. Similar immunostaining with an antiserum to a rotavirus nonstructural protein (NS26) provided evidence of active virus replication. The observed reactivity was eliminated specifically when serial sections were immunostained with the same antiserum that had been absorbed with either double-shelled rotavirus particles or NS26. Immunostaining was not observed in the liver of children with other diseases (alpha 1-antitrypsin deficiency, inspissated bile syndrome, and acute rejection of a transplanted liver). These findings demonstrate that rotavirus infections in children can extend beyond the intestinal tract. Further studies are warranted to determine whether extraintestinal rotavirus replication occurs in children without severe immunodeficiency, such as malnourished children.

Clinical features of enteric adenovirus infection in infants

During the period December 1984 to October 1988, adenoviruses (Ads) were isolated on 119 occasions (1.6%) from stool samples of patients with gastroenteritis. By DNA restriction analysis, 85 enteric adenoviruses (EAds) were identified. Sixty-seven patients with these infections were studied, of whom 18 had Ad40, 30 had Ad41 and 19 had untyped Ad infections. The incidence of Ad infection was high in children between 6 and 11 months of age. The illness was characterized by watery diarrhea (whitish in one third of patients), continuing for a mean of 4.5 days, and vomiting, which occurred more often in patients with EAds than in other types of infection. Diarrhea, fever and vomiting were seen significantly more frequently in patients with Ad40 than in Ad41 infection. Diarrhea and vomiting were also seen significantly more frequently in patients with EAds than in Ads infection. Diarrhea, fever and vomiting were observed more frequently in patients with rotavirus than EAds infection.

Rotavirus studies in Indian (Asian) South African infants with acute gastro-enteritis: I. Microbiological and epidemiological aspects

This study, which is the first one documenting rotavirus (RV) diarrhoea in Asian infants in South Africa, describes the virological and epidemiological aspects of this disease in this population. Fifty-five per cent of 1142 hospitalized cases investigated over a 31-month period showed a positive stool ELISA for RV. Most of these children stopped shedding RV by days 4-6 of hospital admission, though prolonged excretion was recorded in some acute cases for up to 13 days. Mixed RV-bacterial infections occurred in 7% of the total gastro-enteritis (GE) patients, while 8.6% had pure bacterial gastro-enteritis. Sixteen per cent of 188 GE patients had serum anti-RV complement-fixing (CF) antibodies on admission. Rotavirus diarrhoea occurred in half of the seropositive infants. Seroconversion occurred in only two-thirds of the initially seronegative children who had RV diarrhoea. In 5.6% of the RV diarrhoea patients the infection was acquired nosocomially whilst in the hospital for other illnesses. The age-groups mainly affected were between 3 and 14 months, with a peak at 9-11 months; 3% of the RVGE patients were neonates. Both the RVGE and the total GE admissions showed well-marked winter peaks, with an inverse relationship between RV prevalence and both temperature and humidity. It is concluded that RV is the most important cause of infantile GE in this population, whereas pure bacterial infections play a relatively minor role. Circulating anti-RV antibodies do not necessarily afford protection against RV diarrhoea, probably owing to serotypic differences.

Asymptomatic excretion of rotavirus before and after rotavirus diarrhea in children in day care centers

A 12-month prospective study of diarrhea in children in day care centers (DCCs) provided an opportunity to evaluate the duration of excretion of rotavirus from children before and after episodes of diarrhea caused by rotavirus. Ninety-nine episodes of rotavirus diarrhea occurred in 94 children. Asymptomatic rotavirus excretion occurred in 50% of children tested on the day before diarrhea occurred, 31% two days before diarrhea, and 9% in days 3 through 5 before diarrhea. Two children had positive specimens 11 and 13 days, respectively, before illness. During the week after cessation of diarrhea, 32% had positive specimens; 12% had positive stool specimens during the second week after diarrhea episodes. Electrophoretic testing of rotavirus RNA from stool specimens showed different electrophoretic migration patterns of the genomic RNA among the pairs tested, but the genomic RNA was the same within each pair of symptomatic and asymptomatic specimens. Excretion of rotavirus before and after diarrhea is common in children in DCCs; the role that asymptomatic excretion plays in the spread of this disease within DCCs is unknown.

Persistent rotavirus infection in mice with severe combined immunodeficiency

Rotaviruses are important pathogens of human infants and the infants of many animal species. The disease produced by these viruses can be described as an acute, self-limiting diarrheal disease, with virus replication localized to the differentiated epithelial enterocytes of the small intestine. Immunologically normal infants shed virus for approximately 5 to 12 days after the onset of infection. Recently, it has been shown that rotavirus can produce a chronic infection in severely immunocompromised children, with virus shedding and intermittent diarrhea lasting from 6 weeks to 2 years (G. A. Losonsky, J. P. Johnson, J. A. Winkelstein, and R. H. Yolken, J. Clin. Invest. 76:2362-2367, 1985; F. T. Saulsbury, J. A. Winkelstein, and R. H. Yolken, J. Pediatr. 97:61-65, 1980). These findings point to an important role for the immune system in recovery from the disease. The study described here examined the outcome of murine rotavirus infection in mice with severe combined B- and T-cell immunodeficiency (SCID) and in immunologically normal seronegative BALB/c mice. Persistent rotavirus infection was established in all mice with SCID which had been inoculated orally as pups. Low levels of virus replication and constant fecal virus shedding characterized the chronic infection. This is the first report of a persistent rotavirus infection in an animal model.

Characterization of monoclonal antibodies against human rotavirus hemagglutinin

Three monoclonal antibodies capable of specifically inhibiting hemagglutination of human rotavirus were produced. Their hemagglutination inhibition (HI) activity was specific to the homologous strain (KUN) used for immunization. The monoclonal antibodies with HI activity were highly effective in neutralizing the infectivity of the KUN strain. These antibodies reacted with Vp80, and 80,000 molecular weight (MW) protein present in the viral outer shell. It was confirmed by immunoblotting assay with the monoclonal antibodies that the antigenic site of human rotavirus hemagglutinin (HA) resides on Vp80 and on its smaller trypsin cleavage products Vp30 (MW 30,000) and Vp24 (MW 24,000). Immunofluorescence studies using the antibodies revealed that the HA antigen of the KUN strain developed at the final stage of virus maturation.

[Rotavirus reinfections in children of Belém, Pará, Brazil]

Reinfecções por rotavírus foram detectadas em 7 (9,2%) de 76 crianças habitantes da periferia de Belém, Pará, Brasil, no decurso de seus primeiros 20 meses de vida. A presença de rotavírus classificados no subgrupo II ("long pattern") foi assinalada, tanta na primeira como segunda infecções, em cinco desses indivíduos. Em duas situações, a primeira infecção foi causada por rotavírus subgrupo II e, a reinfecção, por rotavírus de subgrupo não claramente caracterizado. Seis diferentes padrões foram observados, não ocorrendo casos em que, numa única criança, se tenham assinalado perfis homólogos. O maior intervalo de tempo registrado entre duas infecções no mesmo indivíduo foi de 19 meses, enquanto que o menor, de 6. Formas sintomáticas em ambos os processos infecciosos se apresentaram em cinco crianças; em duas, os primeiros episódios revelaram-se assintomáticos, sucedendo-se quadros diarréicos. Em seis dos sete indivíduos, observaram-se soroconversões para rotavírus durante a segunda infecção; durante a primeira, entretanto, a elevação significativa nos níveis de anticorpos grupo-específicos se registrou em apenas um caso (Paciente F).

Rapid diagnosis of rotavirus gastroenteritis by a commercial latex agglutination test

The Rotalex test, a commercial latex agglutination test for rotavirus, was compared with direct electron microscopy (EM) and the Rotazyme test I, a commercial enzyme immunoassay, for detection of rotavirus in stools of children and neonates. For initial stool specimens from 265 children (less than 3 years old) with diarrhea, the Rotalex test had a sensitivity of 81.7% and specificity of 99.5% compared with EM results. Positive and negative predictive values were 98 and 94.9%, respectively. The Rotalex test was slightly more sensitive and specific than the Rotazyme test. When daily stool specimens from patients with rotavirus gastroenteritis were examined, the sensitivity of the Rotalex test varied depending on the time of stool collection relative to the onset of symptoms. Sensitivity was 100 (20/20), 96 (23/24), and 54% (7/13) during 1 to 4, 5 to 7, and 8 to 18 days, respectively, after the onset of symptoms. The sensitivity of the Rotazyme test varied similarly with days from onset. We also examined 214 EM-negative stool specimens from asymptomatic newborns. False positivity by the Rotalex test was only 3.3% (7/214) compared with 4.2% (9/215) for the Rotazyme test. The Rotalex test was as sensitive and specific as EM for detection of rotavirus during the acute stage of illness and much faster and cheaper than EM or the Rotazyme test. The test appears to be suitable for routine use in small hospitals, emergency wards, or even the physician's office for rapid diagnosis of rotavirus gastroenteritis.

Prevention of rotavirus infection by oral administration of cow colostrum containing antihumanrotavirus antibody

After immunizing 8-month pregnant Holstein cows with human rotavirus, Wa strain, cow colostrum containing neutralizing antibody to human rotavirus, designated as Rota colostrum, was obtained. After randomly grouping 13 infants from a single orphanage, 6 infants received 20 ml of Rota colostrum every morning and 7 control infants received 20 ml of market milk. One month later, rotavirus associated diarrhea was observed in 6 of the 7 infants given milk and 1 out of the 6 infants given Rota colostrum. Orally administered Rota colostrum significantly protected infants from diarrhea caused by rotavirus (P less than 0.05). Two out of 5 Rota colostrum recipients who were free from diarrhea showed rises in complement fixation (CF) antibody titer after the rotavirus infection epidemic. Thus, Rota colostrum prevented the outbreak of diarrhea but did not prevent immunological responses to natural rotavirus infection. In the therapeutic trial Rota colostrum had no effect on duration of diarrhea, bowel movements or virus shedding in stool. However, there were no side-effects of Rota colostrum.

Asymptomatic rotavirus infections in day care centers

Rotaviruses and other enteropathogenic agents were detected in 288 (42.1%) of 684 children in day care centers of Instituto Politecnico Nacional in Mexico City. The same agents were also found in 114 (37.7%) of 302 adults directly involved in the care of the children. The study was carried out from July to December 1982 and from July 1983 to February 1984. Rotaviruses were the main enteropathogenic agents found and were detected in 169 (29.9%) of 564 children without diarrhea and in 34 (28.3%) of 120 children with diarrhea. These viruses were present in 62 (20.5%) of 302 adults without diarrhea. Of all rotavirus-positive individuals, 20% were also positive for other enteropathogens. All these observations indicate that asymptomatic rotavirus infections are not a rare event in children and that diarrhea caused by rotavirus infections is only one of the expressions of their presence.

Comparison of three enzyme-linked immunosorbent assays suitable for the detection of antibodies to rotaviruses in epidemiological studies

Three enzyme-linked immunosorbent assays which use commercially available reagents are presented as alternatives to the complement fixation procedure for large-scale detection of rotavirus antibodies. Comparison of results in 75 sera tested by indirect, competition and blocking ELISA and by complement fixation demonstrated that the ELISA techniques were rapid, easy to perform and 26 to 29 times more sensitive than complement fixation; furthermore the ELISA techniques permitted extrapolation of an approximate titer from a single dilution test. Although it could detect class-specific antibodies, the indirect assay was less sensitive, specific and reproducible than competition and blocking assays; furthermore the titer extrapolated from a single dilution test in the indirect assay had a lower correlation with the end-point titer than in the other two methods. Competition ELISA was easier to perform whereas blocking ELISA had better reproducibility and serotype studies were possible with it using faecal rotavirus isolates. The respective ELISA technique can be recommended for use in seroepidemiologic surveys according to the study needs.

Hemagglutination by human rotavirus strains

Human rotavirus isolates, KUN , MO, and Wa strains were found to agglutinate erythrocytes of the day-old chicken and adult goose, optimally at pH 6.6. Only those fractions containing double-shelled rotavirus particles isolated by isopycnic centrifugation in cesium chloride had hemagglutinating activity. Trypsin treatment decreased the hemagglutination titer of human rotavirus strains and conversely increased their infectivity. Hemagglutination inhibition tests with antisera against type-specific antigens demonstrable by neutralization showed no type specificity.

Human rotavirus detection by agglutination of antibody-coated erythrocytes

We sensitized sheep erythrocytes (SRBC) with antibodies against human rotavirus strain Wa (SRBC-antiWa) and antibodies against calf rotavirus strain NCDV (SRBC-antiNCDV). These were readily agglutinated in the presence of homologous antigens, i.e., human rotavirus and calf rotavirus. By the hemagglutination of SRBC-antiWa and SRBC-antiNCDV (reverse passive hemagglutination [RPHA]), titration of rotavirus in extracts from feces of children suffering from diarrhea (61 specimens) was carried out. We found that the ratio of titers determined with SRBC-antiWa and SRBC-antiNCDV varied remarkably from specimen to specimen. This indicated that the antigenic determinants on human rotavirus in patients feces cross-react with antibodies against NCDV to varying extents. To express the cross-reactivity of human rotavirus with antibodies to NCDV, we propose a Wa/NCDV rotavirus index which can be calculated from the RPHA titer with SRBC-antiWa and SRBC-antiNCDV as follows: Wa/NCDV rotavirus index = (antiWa-RPHA titer of specimen/antiWa-RPHA titer of NCDV)/(antiNCDV-RPHA titer of specimen/antiNCDV-RPHA titer of NCDV).

Isolation of human rotavirus subgroups 1 and 2 in cell culture

One strain of human rotavirus subgroup 1 (KUN) and one strain of subgroup 2 (MO) were isolated with the MA104 cell line, a fetal rhesus monkey kidney cell line. Their subgroup specificities and RNA patterns were identical to those of rotaviruses present in stools before cultivation. Distinct cytopathic effects consisting of obscure cell boundaries, cell fusion, cell rounding, cell detachment, and lytic foci were recognized at passage 3 of MO and passage 6 of KUN. No differences in cytopathic changes were found between the two isolates.

Detection of rotavirus antibody by inhibition of reverse passive hemagglutination

A reverse passive hemagglutination inhibition (RPHI) test was developed for detecting rotavirus antibody in patients' sera. Sheep erythrocytes coated with guinea pig antibody against Nebraska calf diarrhea virus (NCDV) were readily hemagglutinated by NCDV in a reaction called reverse passive hemagglutination (RPHA). Inhibition of this RPHA reaction was used to detect the presence of rotavirus antibody in patients' sera which cross-reacted with NCDV. The sensitivity of RPHI was consistently at least 10 times greater than that of the complement fixation test for detection of rotavirus antibody in patients' sera. Since immunoglobulin M (IgM) antibody activity detected by RPHI was destroyed by pretreatment of serum with dithiothreitol (DDT), whereas DTT-resistant antibodies such as IgG remained unchanged, the titer of IgM antibody could be distinguished from that of DTT-resistant antibody by comparing the results of two RPHI tests performed with and without DTT pretreatment. From the IgM antibody response pattern, primary and secondary rotavirus infections could be distinguished.

Etude épidémiologique de gastroentérites infantiles d'origine virale dans la région amienoise

A systematic survey was carried on stools from 130 children suffering of acute gastroenteritis. Electron microscopy, enzymo-linked immunosorbent assay (ELISA) and counter electrophoresis were employed. This survey allowed to the detection by electron microscopy of Rotavirus (40 cases), Coronaviruses (3 cases), Astroviruses (2 cases), Adenoviruses (2 cases) and Small Round Viruses (1 case). Serological tests (complement fixation, ELISA and counter electrophoresis) done with 86 sera showed a good correlation with results obtained with electron microscopy.

Virus diarrhoea associated with pale fatty faeces

Steatorrhoea was a significant feature in an outbreak of rotavirus gastroenteritis which affected adults and infants in hospital. Fat globules or fatty acid crystals were obvious by light microscopy (LM) in faeces from 14 of 25 patients examined. Ten of the fatty stools and two of the remainder were very pale. By electron microscopy (EM) a rotavirus was seen in 11 of the 14 fatty faeces and in only two of 11 specimens without visible fat. In a further study of pale or fatty faeces 20 such specimens sent for laboratory examination from patients not involved in the hospital outbreak were compared microbiologically with a similar number which were neither pale nor fatty. Viruses were found by EM in 11 (55%) of the pale or fatty stools; eight rotaviruses, two astroviruses and an uncultivable adenovirus were seen; one further patient had acute jaundice. In contrast, no viruses were seen by EM in the twenty specimens which were normally pigmented and without evident fat. Steatorrhoea was significantly associated with rotavirus infection of the alimentary tract which usually presented as a fatty enteritis. We conclude that rotaviruses certainly, and other viruses possibly, can impede both the digestion of fat and the pigmentation of the faeces. Inspection and LM of faeces are easy. In acute enteritis a fatty or pale stool is an indication for virological examination.

Rotavirus infection in children hospitalized for diarrhoea in Argentina

An epidemiological survey was undertaken to establish the importance of rotavirus as a cause of admission of children to hospital in Buenos Aires, Argentina. Between August 1978 and January 1980 rotavirus infection was detected in 62 (34%) of 180 infants and children admitted to hospital with acute gastro-enteritis. In identification of the virus, electron microscopy (EM) was found to be as sensitive as counterimmunoelectrophoresis (CIE). There was agreement between EM and CIE diagnosis in 90.5% cases. Adenovirus and coronavirus were detected by electron microscopy less often. A serological response to rotavirus was revealed by complement fixation test in 38 (72%) of 53 infected patients. Rotaviruses were detected throughout the year, but peak incidence occurred during the cooler months, May to August. Infection was commoner among children under six months of age. Diarrhoea was generally mild in these children and respiratory illness showed no significant association with rotavirus gastroenteritis. These results indicate that rotaviruses may be a major cause of infantile acute gastroenteritis in Buenos Aires, Argentina especially during the winter.

A year's experience of the rotavirus syndrome and its association with respiratory illness

In a hospital study rotavirus was identified in 51% of 152 children with diarrhoea. These patients showed a clinical pattern that was distinct from patients in whom the diarrhoea was associated with bacteria, other viruses, or no pathogens. A respiratory illness was described in 66% of rotavirus patients and usually preceded the gastrointestinal symptoms. Vomiting lasted between one and 3 days and was curtailed by substituting the normal diet with clear fluids. Watery diarrhoes continued for 4 or 5 days, even when rehydration was by the intravenous rather than the oral route. Prolonged diarrhoea was rare. Most children infected with rotavirus were under 2 years of age, but dehydration was most severe in infants aged between 12 and 18 months. A clinician can thus recognise the rotavirus syndrome and expect spontaneous recovery if adequate rehydration is maintained for a critical few days.

Rotavirus gastroenteritis in infants and young children

The electronmicroscopic examination of stool samples from 18 infants and young children with gastroenteritis, hospitalized at the Clinic of Infectious Diseases in Prague, was carried out. In ten children rotavirus was found in the faeces and the bacteriological findings were negative. Rotavirus particles were aggregated by convalescent child sera and by normal human gamma globulin. The clinical picture was characterized by the sudden onset of vomiting and fever, in one case with febrile convulsions. Diarrhoea was watery and yellow-green, and usually persisted for four to five days. The condition of the children improved rapidly after rehydration and a special diet. Older siblings, and in one family also adult members, were frequently affected.

The occurrence of calicivirus in infants with acute gastroenteritis

Calicivirus was detected in 8 (1.2%) of 647 hospitalized patients during a survey of acute gastroenteritis in infants and young children, conducted between December 1974 and September 1977. Morphologically calicivirus was approximately 30 nm in diameter with an easily recognizable staining "star of David" configuration. Its buoyant density in cesium chloride was 1.38-1.40 gm/ml. The serologic response to calicivirus by immune electron microscopy (IEM) was demonstrated only in paired sera from patients who shed the virus in their stools. The results suggest that calicivirus might be a cause of acute gastroenteritis in infants and young children.

An investigation into the possible role of the family unit in the transmission of rotavirus infections of children

A survey of young children hospitalized with viral gastroenteritis, and of the members of some of their families, was carried out. Results showed rotavirus to be the principal agent associated with the condition though other types were also detected. In addition, rotavirus was found in the stools of some of the members of each of the families investigated, and it is suggested that means of spread is the faecal-oral route within family groups.

Prospective study of enteropathogens in children with diarrhea in Houston and Mexico

During a 22-month period, 595 children with diarrhea and 210 age-matched controls attending clinics in Houston (367 children) and Mexico (438) were prospectively evaluated for enteric pathogens. Enteropathogens associated with disease were Shigella (18%), rotavirus (14%), Salmonella (9%), toxigenic Escherichia coli (6%), and others (12%), including 14 Proteus isolates that caused rounding of adrenal cells. Enteropathogens were isolated from a greater (P less than 0.001) number of children with diarrhea (59%) than from asymptomatic controls (6%). Paired sera tested for antibody to heat-labile toxin of E. coli rarely demonstrated a fourfold rise during episodes of diarrhea. This study demonstrates: (1) more striking illness in children from Mexico; (2) more common occurrence of Shigella in Houston, and of rotavirus and Salmonella in Mexico; (3) lack of seasonal occurrence of rotavirus isolation in either population and a summertime occurrence of Shigella in Houston; (4) lack of toxigenic E. coli isolation in endemic diarrhea of either population; and (5) a significant (P less than 0.001) age-related acquisition of E. coli LT antibodies.

Human rotavirus infection in infants and young children with intussusception

Human rotavirus was detected by electron microscopy in 11 of 30 infants and young children with intussusception (37% of subjects under study). Serologic complement fixation tests revealed evidence of infection with the rotavirus in 70% of the patients examined who eliminated the rotavirus in their stools. These results indicate that human rotavirus, in addition to adenovirus, may be an infectious agent causing intussusception in infants and young children.