タイ国に浸淫しているヒトおよび動物ロタウイルスの血清学的並びに遺伝学的研究

This series of studies used antigenic and genetic analysis to examine rotavirus strains prevailing in humans and animals in Thailand. The results are summarized as follows: 1) A number of fecal specimens were collected from humans (patients with diarrhea), cattle (young calves with diarrhea) and pigs (piglets with diarrhea) in Thailand. These were screened for rotavirus by polyacrylamide gel electrophoresis (PAGE) of segmented viral genome and enzyme-linked immunosorbent assay (ELISA) with group A-specific monoclonal antibodies. Group A rotaviruspositive specimens were then examined for their subgroup and G serotype specificity using subgroup (I-and II-) specific monoclonal antibodies and G serotype (1-, 2-, 3-, 4- and occasionally 6-) specific monoclonal antibodies, respectively. G serotype specificity of the specimens untypable by ELISA was then examined by polymerase chain reaction (PCR) using serotype-specific primers, which showed very high sensitivity in serotype determination. 2) The rate of rotavirus detection in pediatric diarrhea was calculated at 36.9% on the basis of the examination of diarrhea specimens collected in Bangkok in 1991-94. Rotavirus gastroenteritis was shown to occur most frequently in infants and young children equal to or less than 2 years of age with a peak at 6-11 months of age. The male to female ratio was calculated at 1.36. Monthly distribution of the occurrence of rotavirus gastroenteritis in Bangkok indicated that the illness tends to cluster in September through January. 3) Although as a whole G serotype 1 was the most often detected in this series, the frequency of detection of individual serotypes differed greatly by year. While in the 1983-84 survey G serotype 4 was the most frequent, both G serotypes 1 and 2 dominated in the 1987-88 survey. In the following two years of 1988-89 and 1989-90, G serotype 1 predominated, while in 1990-91 survey G serotype 3, which had been detected only rarely until then, surpassed other G serotypes 1 and 2. G serotype 1 was the most frequent in 1991-92, second to G serotype 2 in 1992-93 and again predominant in 1993-94. 4) It was unexpected that all bovine rotavirus strains found in the present studies were antigenically non-G serotype 6, since most bovine rotaviruses reported until then belonged to G serotype 6. The RNA patterns of these strains were grouped into the three electropherotypes a, b and c. Sequence analysis of the VP7 gene of strain 61A (representing the electropherotype c) indicated that it does not belong to G serotype 1, 2, 3, 4, 5, 6, 8, 9, or 11. These results formed the basis of our subsequent antigenic and genetic studies showing that while the G serotype of strains A44 (electropherotype a) and 61A is 10, that of strain A5 (electropherotype b) is 8, which is discussed in this paper. ?5) Serotyping by ELISA showed that the majority of porcine rotavirus strains (7/13) detected in 1987 was G serotype 3. Twenty-three group A rotavirus strains detected in 1990-91 were grouped by RNA PAGE into six electropherotypes a-f. The G serotypes assigned to these by ELISA and PCR were as follows: G serotype 3 (three strains of electropherotypes a and c), G serotype 10 (14 strains of electropherotype d) and undetemined serotype (6 strains). The presence of G serotype 10 porcine rotavirus, a finding unreported to date, has been further confirmed by serologic and genetic analysis in this laboratory (Pongsuwanna et al., submitted), which is discussed in this paper. 6) On the basis of the findings indicating the close genetic relationship among rotaviruses of humans and various animal species, the possibility of interspecies transmission and subsequent genome reassortment in the recipient host and the significance of these events in the mechanisms of evolution and diversification of rotavirus in nature are discussed

First Report from the Asian Rotavirus Surveillance Network

Rotavirus remains the most common cause of severe, dehydrating diarrhea among children worldwide. Several rotavirus vaccines are under development. Decisions about new vaccine introduction will require reliable data on disease impact. The Asian Rotavirus Surveillance Network, begun in 2000 to facilitate collection of these data, is a regional collaboration of 36 hospitals in nine countries or areas that conduct surveillance for rotavirus hospitalizations using a uniform World Health Organization protocol. We summarize the Network's organization and experience from August 2001 through July 2002. During this period, 45% of acute diarrheal hospitalizations among children 0–5 years were attributable to rotavirus, higher than previous estimates. Rotavirus was detected in all sites year-round. This network is a novel, regional approach to surveillance for vaccine-preventable diseases. Such a network should provide increased visibility and advocacy, enable more efficient data collection, facilitate training, and serve as the paradigm for rotavirus surveillance activities in other regions

Molecular and antigenic analyses of serotypes 8 and 10 of bovine rotaviruses in

Antigenic and genomic properties of non-serotype 6 bovine rotaviruses isolated in Thailand and Japan were studied by cross-neutralization tests, nucleotide sequence determination of the VP7 gene, and RNA-RNA hybridization. Two Thai strains (61A and A44) were serologically related to a Japanese isolate KK3 which has been assigned to serotype 10. In contrast, strain A5 was found to be antigenically similar to human strain 69M with serotype 8 specificity, although strain A5 showed a one-way cross-reaction with serotype 6 strain NCDV. VP7 sequence analysis confirmed these results. High degrees of similarity in nucleotide and amino acid sequences (92-5 to 98.2% and 96.3 to 97.9%, respectively) were found among the VP7 genes of the four serotype 10 bovine strains (61A, A44, KK3 and B223). The VP7 amino acid sequence of strain A5 was similar to those of serotype 8 human strains (91-7 % and 94-8 % for strains B37 and 69M, respectively). In RNA-RNA hybridization experiments, a high level of overall relatedness was found among the three serotype 10 bovine strains (61 A, A44 and KK3), and strains A5 and NCDV were also moderately related to the three serotype 10 viruses. All the bovine rotaviruses tested in this study, regardless of their serotype specificity, exhibited a moderate geneticrelatedness to strain 69M of serotype 8, and, to a lesser extent, to serotype 2 human rotavirus strains