Distinct reovirus-like agents associated with acute infantile gastroenteritis

Prevalence of rotavirus genotypes in South Korea in 1989-2009: implications for a nationwide rotavirus vaccine program

The epidemiology of human group A rotavirus was analyzed by examining genotypic data acquired from 1989 to 2009 in South Korea. This information was derived from all the available published articles on rotavirus studies in South Korea, retrieved from both the PubMed and KoreaMed databases. Four common G types (G1, G2, G3, and G4) and three common P types (P[8], P[4], and P[6]) accounted for approximately 93% and 99% of the rotavirus reports, respectively. The G9 type was frequently detected after 2000, and because of this prevalence, it is considered to be the fifth most important G type rotavirus after the G1.G4 genotypes. Less common G types of the virus such as G12, G11, and G10 were detected in some geographic settings, and it is important to consider the context of these subtypes and their epidemiological significance. The P[9] virus genotype was observed in the study and has been discussed in many other studies; however, the P[3], P[10] and P[25] genotypes were rarely detected in the epidemiological research. In general, the distributions of the G and P genotypes showed temporal and geographical fluctuations, and a nationwide rotavirus vaccine program that targeted these genotypes demonstrated effectiveness in protecting against the circulating rotavirus strains. However, further analysis is needed to determine the true long-term effectiveness of these vaccines; the analysis should also consider the unexpected effects of vaccinations, such as vaccine-induced diseases, herd immunity, and changes in host susceptibilities.

Risk factors for isolated biliary atresia, National Birth Defects Prevention Study, 1997–2002

Biliary atresia is a rare birth defect that affects 1 in 12,000 to 1 in 19,500 live births. We used data from the National Birth Defects Prevention Study, a multistate case-control study, to identify potential risk factors for isolated biliary atresia (no additional unrelated major birth defects diagnosed). Infants were identified from eight states from 1997 to 2002, with clinical information abstracted from medical records. Potential risk factors assessed include: demographic factors, seasonality, preterm birth, maternal smoking, maternal alcohol use, maternal illicit drug use, maternal health, maternal medication use, maternal vitamin use, and maternal nutrition. Infants of non-Hispanic black mothers were more likely to have biliary atresia than infants of non-Hispanic white mothers (adjusted odds ratio (aOR) = 2.29, 95% confidence interval (CI) 1.07-4.93) and infants conceived during the spring season were more likely to have biliary atresia than infants conceived in winter (aOR = 2.33, 95%CI 1.05-5.16). Low intakes of vitamin E, copper, phosphorus, and beta tocopherol were associated with the occurrence of isolated biliary atresia (borderline significance). Low iron intake had a borderline inverse association with biliary atresia. While this analysis provides support for previous reports of a possible association between seasonal variation and the occurrence of biliary atresia, more data are needed to evaluate whether the seasonal variation is related to infectious agents. The role of nutrients in the development of biliary atresia remains unclear. Further studies of genetic, infectious, and nutrient exposures and the association of biliary atresia are warranted.

Development of rotavirus molecular epidemiology: electropherotyping

Early in the era of rotavirology it was realized that the characteristic patterns of bands produced in polyacrylamide gels following electrophoresis of genomic dsRNA were useful for checking the identity of rotavirus isolates. However it was Romilio Espejo who first proposed the use of this technique for epidemiology, although most others did not take the suggestion seriously because the technique was then rather specialized and RNA staining methods were not very sensitive. Using samples collected by Ruth Bishop in Melbourne following the original identification of human rotaviruses, Sue Rodger recorded the "electropherotypes" of all samples available to 1979 and painstakingly compared them, side by side (since minor variations in conditions, especially temperature, alter the relative migration distances of dsRNA bands). These efforts produced the first longitudinal, extensive study of human rotavirus strain variation. Since then, technical improvements have greatly increased the sensitivity of the procedures, and electropherotyping has been recognized as a powerful and economical method for epidemiological studies of rotaviruses.

Temporal variation of Malaysian rotavirus electropherotypes

An analysis of rotavirus electropherotypes circulating in Kuala Lumpur, Malaysia, over 7 years showed that all except 1 of the 360 electropherotypes encountered were characteristic of group A rotaviruses. The long electropherotype predominated annually, and there was a rarity of short electropherotypes. Extensive genome variability and cocirculation of different electropherotypes were observed annually. A sequential appearance of the predominant electropherotype was observed in all years of the study, except for 1985 and 1988, when one electropherotype predominated throughout the study periods. There was no shift in the predominant electropherotype over a 6-year period.

[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).

Molecular epidemiology of human rotavirus infections

Recognition of rotaviruses as a major aetiological agent of acute gastroenteritis in infants and young children has prompted the investigation of their epidemiology by molecular techniques. Genome analysis by electrophoretic separation of the RNA segments has been widely used to distinguish virus isolates and to monitor patterns of virus transmission. Examination of virus isolates from different epidemics has clearly demonstrated the existance of extensive genomic variation in viruses circulating in large communities; with the co-circulation of a number of viruses of differing electrophoretype. Preliminary studies using the more advanced techniques of oligonucleotide mapping and hybridization analysis have suggested that variation among the viruses may occur by processes involving both "drift" and "shift". Because of their ease and specificity the new hybridization analysis techniques should greatly facilitate both the rapid diagnosis of rotavirus infections, and the solution of many epidemiological and evolutionary questions. Continued and expanded use of molecular techniques for the study of the epidemiology of rotavirus infections will be required to manage future outbreaks and to effect long term control measures.

Epidemiology of human rotaviruses as determined by electrophoresis of genome RNA

An epidemiological survey was made of rotavirus infection in a children's hospital by determining changes in rotaviral genome patterns by means of polyacrylamide gel electrophoresis. In 180 fecal samples collected between December 1978 and June 1981, 53 distinct patterns were obtained belonging to 13 different types. Two of these patterns dominated in endemic nosocomial infections of neonates until 1981, when one of them was replaced by a third pattern. Two epidemics of diarrhea in the neonatal wards were associated with an endemic and an exogenic rotavirus strain respectively. The latter was not established as an endemic strain. Three patterns were found exclusively in isolates from infants with nosocomial infection and one pattern was found with a doubled fifth segment, suggesting a double infection. The latter findings support the conjecture that there is reassortment of rotavirus genomic segments in vivo.

Analysis of human rotavirus mixed electropherotypes

Mixed human rotavirus electropherotypes were detected in stool samples from patients with acute gastroenteritis in Santiago, Chile. These electropherotypes accounted for 10% of 149 samples studied. The finding of extra RNA fragments with respect to the regular 11 genome segments suggests the possibility of simultaneous or sequential infection by more than one electropherotype in a single diarrhea event or occurrence of modification in the length of the RNA segments during an infection. These possibilities arose from gel electrophoretic analysis of unique and sequential samples of human rotavirus genome RNA.

Electrophoretic study of the genome of human rotaviruses from Rio de Janeiro, São Paulo and Pará, Brazil

Human rotaviruses from the states of Rio de Janeiro, São Paulo and Pará of Brazil were analysed by RNA electrophoresis. At least some bands characteristic of rotavirus double-stranded RNA were detected in 138 (86.8%) of 159 faecal samples in which the presence of rotavirus had been demonstrated by enzyme immunoassay. Of the RNA-positive samples, 18 (13.0%) were classified as subgroup 1, 94 (68.1%) as subgroup 2, and 26 (18.8%) could not be classified due to absence of visible bands 10 and 11. Subgroup 2 was more frequent in the three states. All strains of subgroup 1 detected in Rio de Janeiro were associated with a single short-lived school outbreak. All strains of subgroup 1 resembled each other in electrophoretic pattern, irrespective of geographical origin, although minor differences could be detected by co-electrophoresis. Subgroup 2, on the other hand, showed a great degree of electrophoretic heterogeneity and could be divided into several sub-categories.

Epidemiology of rotavirus diarrhea in Yogyakarta, Indonesia, as revealed by electrophoresis of genome RNA

Nine different electropherotypes of rotaviruses occurred among 85 children with rotavirus diarrhea in Yogyakarta, Indonesia. Eighty percent of the electropherotypes had a "long" RNA pattern characteristic of human subgroup 2.

Comparison of Rotazyme and direct electron microscopy for detection of rotavirus in human stools

A total of 115 stools were examined for Rotavirus, using direct electron microscopy (EM) and Rotazyme. The overall agreement was 88.7%. Of the negative results, there was 91.95% agreement. Rotazyme reactions of three-plus or more gave a 100% agreement with EM. The Rotazyme test is a useful diagnostic aid in laboratories not capable of performing EM.

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.

Distinctive ribonucleic acid patterns of human rotavirus subgroups 1 and 2

The ribonucleic acid migration patterns of 7 subgroup 1 and 16 subgroup 2 human rotaviruses recovered from four geographic areas were compared. The subgroup 1 ribonucleic acid patterns had strikingly slower-moving segments 10 and 11, suggesting a correlation between the ribonucleic acid pattern and the subgroup specificity.

Comparison of human rotaviruses isolated in Mexico City and in Santiago, Chile, by electrophoretic migration of their double-stranded ribonucleic acid genome segments

During the period October to December 1979, rotaviruses were obtained from infants and young children hospitalized with acute gastroenteritis in Mexico City and were compared by analysis of the migration of their double-stranded ribonucleic acid (RNA) genome segments in gel electrophoresis. Comparison of the results of this analysis and of those of similar studies carried out in 1977 and 1978 showed that the two rotavirus electropherotypes designated 2s and 21 have been continuously present and that the proportion in which these two types have been found in hospitalized patients has varied greatly year to year. The RNAs from rotaviruses 2s and 21 differed in the electrophoretic migraton of at least eight genome segments. However, RNAs from virus assigned to the same electrophoreotypes were not necessarily identical: on the basis of small but significant differences in the migration of segment 7, 8, or 9, isolates of types 2s and 21 could be assigned to two and three different subtypes, respectively. Human rotaviruses obtained in a distant geographical region, Santiago, Chile, in July 1979 had RNA electrophoretic patterns similar to that of electropherotype 21 but different from it in the migration of one or two of the larger RNA segments.

Different polypeptide composition of two human rotavirus types

Human rotaviruses, which are placed into two groups according to their ribonucleic acid patterns obtained by gel electrophoresis, were characterized both by polypeptide components from purified virions and by polypeptides translated from their denatured ribonucleic acids in rabbit reticulocyte lysates. Viruses assigned to different groups differed in the electrophoretic migration of the second largest of the polypeptides which compose the inner shell; polypeptides that had been synthetized in vitro from ribonucleic acid from each group showed this same difference, thus indicating that this is due to the genomic composition. This study suggests that there are differences in the third largest polypeptide of the inner shell and also in the three smaller polypeptides composing the outer shell. We also demonstrated that there are differences in genomic and polypeptide compositions between simian (SA11) and calf (Nebraska calf diarrhea virus) rotaviruses grown in tissue culture and human rotaviruses.

Shift in the prevalent human rotavirus detected by ribonucleic acid segment differences

Rotavirus was purified from nine patients hospitalized with acute gastroenteritis from October to December, 1978, in Mexico City. Analysis of their ribonucleic acids by gel electrophoresis showed the presence of two distinct patterns (2s and 22) which had been observed in 1977, but which now were found in a very different proportion: the pattern called 2s, observed in only 11% (6 of 52) of the patients in 1977, was found in 90% (8 of 9) of the patients in 1978. Improvements in the electrophoretic method allowed us to observe differences in the migration of up to seven segments between the two patterns and to distinguish small differences in one or two segments within either of the two ribonucleic acid patterns.

Polymorphism of the migration of double-stranded RNA genome segments of reovirus isolates from humans, cattle, and mice

A series of 94 isolates of reovirus from humans, cattle, and mice, showed extensive variability in the patterns of migration of the ten double-stranded RNA genome segments. This variation was found in all three serotypes, and involved all ten genome segments, including the segment responsible for serological specificity. Although a single pattern was present among several samples isolated from individuals and collected at a single time and place, there were often multiple genetic variants of a single serotype present in a population. Samples isolated from widely different geographic origins or different mammalian hosts showed different patterns; samples from a single species from the same area over a period of time showed more limited variations. Among most isolates, the migration of the slowest S segment, the segment that encodes the hemagglutinin and is responsible for serological specificity in laboratory strains, was similar to reference strains for type 1 and type 3 isolates. However, the type 2 isolates showed considerable variation in this segment.

Comparison of electron microscopy, enzyme-linked immunosorbent assay, solid-phase radioimmunoassay, and indirect immunofluorescence for detection of human rotavirus antigen in faeces

Four techniques were compared for their practicability, speed, and sensitivity for the detection of human rotavirus. Radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) were found to be the most sensitive means of identifying rotavirus, and, once processed, up to 40 specimens could be examined daily. Electron microscopy, although less sensitive than these techniques, had the advantage of being able to detect other viral agents present in faecal extracts. Indirect immunofluorescence failed to detect rotavirus as often as the other three methods. In laboratories where routine examination of faecal specimens from patients with gastroenteritis is required, ELISA and RIA are useful alternatives to electron microscopy.

Comparison of the genomes of simian, bovine, and human rotaviruses by gel electrophoresis and detection of genomic variation among bovine isolates

By co-electrophoresis in polyacrylamide gels, the segmented double-standed RNA genome of the simian rotavirus, SA 11, was compared with those of human and bovine rotaviruses. A comparison between SA 11 virus and the Northern Ireland cell culture adapted bovine virus showed that the electrophoretic mobilities of each of the 11 corresponding segments differed. In other comparisons, four to seven segment variations were more common. When the genomes of various bovine rotaviruses were compared, eight different electropherotypes were detected. Four of these electropherotypes were obtained from one property during a single outbreak of disease. In view of such genetic diversity, a scheme for the systematic designation of different rotavirus samples is proposed. The significance of the variations in relation to the molecular epidemiology of bovine rotavirus infections is discussed.

Location of type-specific antigens in calf rotaviruses

Rotavirus antisera with and without neutralizing activity to calf rotavirus were compared for their ability to agglutinate calf rotavirus particles with and without an outer capsid layer. Particles without the outer capsid layer were agglutinated by antisera with immunofluorescent antibody activity and by antisera with immunofluorescent antibody and neutralizing activity. Particles with the outer capsid layer were agglutinated only by antisera with neutralizing activity. The neutralization test appears to be type specific, and it was concluded that type-specific antigens are associated with the outer capsid layer of rotaviruses. Since particles with the outer capsid layer were not agglutinated by antisera lacking neutralizing activity but possessing immunofluorescent antibody activity, it was concluded that in intact particles the group-specific antigen is masked by the outer capsid layer.