To investigate the relative frequency of individual human rotavirus serotypes prevailing in Japan, 562 stool specimens collected from patients with rotavirus gastroenteritis between November 1986 and March 1988 in seven districts were examined by an enzyme-linked immunosorbent assay (ELISA) with serotype 1-, 2-, 3-, and 4-specific monoclonal antibodies. Serotype 1 was the predominant serotype in the winter of 1986-1987; however, both serotypes 1 and 2 were detected frequently in the winter of 1987-1988. The results showed the relative frequency of individual serotypes by locale and the yearly change in the prevalence of each serotype in the same area. The result of subgroup specificity of rotavirus obtained by using ELISA with subgroup I- and II-specific monoclonal antibodies confirmed the general finding that rotavirus strains having subgroup I specificity are serotype 2 and those having subgroup II specificity are either serotype 1, 3, or 4. Unusual strains having both subgroup I and II specificity or neither specificity and strains presumed to represent new serotypes were also found.

In 1993, mumps with a high incidence of aseptic meningitis became prevalent in Akita prefecture, Japan. Three mumps virus isolates obtained from the nonvaccine-associated cases lacked the B amHI restriction cleavage site of the P gene, like the Urabe strain (Yamada, A. et al,. However, four additional nucleotide substitutions were found in the determined region of 157 bp. Fourteen of 19 cases from which mumps virus showing the Urabe-like RFLP profile was detected were complicated with symptomatic meningitis, whereas there were only four cases of meningitis among 23 individuals infected with the wild type showing no Urabe-like RFLP profile (non-"Urabe-like" wild-type). The incidence of meningitis was over 70% among patients infected with the "Urabe-like" wild-type virus. The "Urabe-like" wild-type disappeared after February 1994 in the epidemic area and was replaced by the non-"Urabe-like" wild-type. Patients infected with the "Urabe-like" wild-type lived in a closed colony, in which there were two instances of transmission between siblings. Thus this outbreak was transient and narrowly localized.

BackgroundA newly developed fetal movement acceleration measurement recorder has made it possible to count gross movements for hours. The purpose of this study was to determine the normal reference values for such movements.MethodsOne hundred and six pregnant women recorded fetal movements by themselves when they slept at home weekly from 28 weeks to term. The normal reference values were determined based on the data that could be recorded for more than 4 h per night.ResultsA total of 2,458 h of data from 385 recordings from 64 women was available. The median ratio of 10-s periods in which fetal movements occurred to the total time interval was 17% at 28 gestational weeks, decreasing to ∼6% at term. The number of fetal movements was 74 times/h, decreasing to 29 times at term. The number, the mean, and the longest durations of periods with no fetal movement, meaning no fetal movements were found for more than 5 min, were 1.56 times/h, 7.95 and 14.25 min, respectively, at 28 weeks, and increasing to 2.54 times, and 9.63 and 19.67 min, respectively, at term.ConclusionsThis study provides normal reference values for gross fetal movement count using the fetal movement acceleration measurement recorder.

The Yuri strain of small round structured virus (SRSV) was cloned from a fecal specimen in which virus particles were observed by electron microscopy. The most common RT-PCR protocol in Japan, however, using 35/36 and NV81/NV82/SIV182 nested primer pairs, could not detect the SRSV genome in this specimen. Nucleotide and amino acid sequence analysis revealed that the Yuri strain is genetically close to the genotype II of SRSV. A novel procedure using primer sets designed from the nucleotide sequence of the Yuri strain was applied to the screening of 119 stool samples obtained from subjects with sporadic diarrhea and 46 samples obtained during seven foodborne gastroenteritis outbreaks. Using this novel procedure, PCR bands were detected in 44% and 52% of the samples, respectively. These detection rates were approximately twice those obtained with the 35/36 and NV81/NV82/SM82 nested primers. In particular, more than 40% of positive samples could be detected by using only the Yuri primer sets. Furthermore, three improvements were made in the RNA preparation, cDNA synthesis, and amplification steps to save materials and time. The background, or extra bands, in the amplification reaction resulting from DNA in the fecal specimens was completely removed by DNase I treatment just before cDNA synthesis. Random nonamers were used as universal primers in the reverse transcription. No difference in sensitivity or specificity was noted in the final results when either random nonamers or specific primers were used. The use of a preamplification step under low stringent conditions before standard amplification under highly stringent conditions compensated for any mismatched bases in the primers with respect to the target sequences. Thus our novel procedure using Yuri primer sets may be useful for the screening of SRSV in the recent SRSV outbreaks in Japan.

cDNA clones of the mumps virus wild-type strain, associated with a high incidence of aseptic meningitis (ODATE-1 strain), were isolated and analyzed from genomic nucleotide position 22 to 8520 containing the NP, P, M, F, SH and HN protein coding region. The ODATE-1 strain exhibited a RFLP profile identical to that of the Urabe vaccine strain in spite of the fact that the virus was isolated from non-vaccinated cases. However, a comparison of nucleotide and amino acid sequences among the ODATE-1 strain, Urabe strain and Miyahara strain revealed that the ODATE-1 strain was not related to the Urabe strain. The mumps virus (MV) is one of the medically important paramyxoviruses within the paramyxovirus family. In 1993, mumps associated with a high incidence of aseptic meningitis became prevalent in Akita Prefecture, Japan. We have previously reported that two types of MV distinguishable by their restriction fragment length polymorphism (RFLP) profiles were isolated in the outbreak (5). One type (the "Urabe-like" wild-type) lacked the B amHI restriction cleavage site of the P gene, like the Urabe vaccine strain (12), in spite of the fact that the virus was isolated from non-vaccinated cases. Moreover, the incidence of meningitis among patients infected with the "Urabe-like" wild-type strain was over 70%, compared with 17% in those infected with the other "non -Urabe-like" wild-type strain (5) . A partial nucleotide sequence analysis revealed that the "Urabe-like" wildtype strains (ODATE strains) were not identical to the Urabe vaccine strain. Although the possibility that the Urabe strain had reverted to the wild-type cannot be completely ruled out, no evidence of this was obtained from the result of our previous study. This molecular information prompted us to analyze other genomic regions of the ODATE strain.The MV is composed of unsegmented negative-sense