Kumiko Sugita

Molecular epidemiology of astroviruses in Japan from 1995 to 1998 by reverse transcription-polymerase chain reaction with serotype-specific primers (1 to 8).

In addition to the serotype‐specific primers described previously (1 to 7), a new serotype 8‐specific primer has been designed, allowing detection of all astrovirus serotypes. A total of 1,382 diarrheal stool samples in 5 regions in Japan were examined by reverse transcription‐polymerase chain reaction (RT‐PCR). The incidence of astrovirus infection in all 5 regions was 5.9% (82 of 1,382 samples) and infection occurred mainly from November to April. Serotypes 1, 3, and 4 were detected in 66, 14, and 2 of the 82 positive samples, respectively. None of the other serotypes was detected. The highest detection rate was from 0 to 1 year old, 39.0%, and the next highest was from 1 to 2 years old, 34.1%. The primers provide a useful approach for study of the epidemiology of astroviruses. J. Med. Virol. 61:326–331, 2000.

Rotavirus infection in children in Japan

Abstract 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.

Detection of human parechovirus in stool samples collected from children with acute gastroenteritis in Japan during 2007–2008

Of 477 stool specimens, which had been screened for rotavirus, adenovirus, norovirus, sapovirus and astrovirus, collected from infants and children with acute gastroenteritis in pediatric clinics encompassing five localities (Sapporo, Tokyo, Maizuru, Osaka, and Saga) in Japan from July 2007 to June 2008, 247 negative samples (51.7%) were subjected to screening for human parechovirus. Human parechovirus (HPeV) was detected by RT‐PCR using a primer pair to amplify 5′UTR region of its genome and was genotyped by sequencing of the VP1 gene. HPeV was detected in 20 of 247 specimens tested, and the detection rate was found to be 8.1%. Seventeen of the 20 strains that tested positive for HPeV were sequenced successfully the VP1 gene. The majority of the HPeV strains (n = 15) could be identified as HPeV1, and the remaining 2 strains could be typed as HPeV3. By phylogenetic and identical matrix analyses of HPeV VP1 sequences, HPeV1 should be divided into two lineages, and all of the Japanese studied HPeV1 strains belong to the lineage 2 accordingly. This is the first report of the circulation of HPeV, especially HPeV1 in Japan. J. Med. Virol. 83:331–336, 2011.

Human bocavirus infection in children with acute gastroenteritis in Japan and Thailand.

A total of 329 fecal specimens, which had been known to be negative for rotavirus, adenovirus, norovirus, sapovirus, and astrovirus, and which were collected from infants and children with acute gastroenteritis in Japan and Thailand during 2005–2008 were screened for human bocavirus (HBoV). HBoV was detected by PCR with a primer pair that amplified the NP1 region of its genome and was genotyped by sequencing of the VP1/VP2 region. Of the 329 samples tested, 6 (1.8%) were positive for HBoV. Of these, five samples were collected from Japan and one sample was from Thailand, and the detection rates of HBoV in each country were 2% and 1.2%, respectively. For the detected HBoV, the capsid VP1/VP2 gene of all HBoV strains was successfully sequenced. Four Japanese HBoV strains studied were clustered into group 1, while the remaining Japanese strain and a unique Thai strain belonged to group 2. No severe acute gastroenteritis associated with HBoV was noted. This study provides better understanding on the epidemiology of HBoV infections in children with acute gastroenteritis in Japan and Thailand. J. Med. Virol. 83:286–290, 2011.

Three clusters of Saffold viruses circulating in children with diarrhea in Japan.

Saffold virus (SAFV) is a newly discovered human virus in the genus Cardiovirus, family Picornaviridae. The virus was first described from fecal specimens of a child with fever of unknown origin in 2007. A total of 454 fecal specimens were collected from children with diarrhea attended clinics in Japan, 2010-2011, 7 (1.5%) were positive for SAFV. Mixed-infections of SAFV and other enteric viruses (rotavirus, norovirus, and bocavirus) were found in four out of seven cases, while monoinfection by SAFV alone was detected in three cases. In addition to diarrhea, fever and vomiting were observed in three children and mild dehydration in one case. No particular symptoms of cough and rhinorrhea were noted. Analysis of partial VP1 nucleotide sequence of 7 Japanese SAFV strains revealed that 5 SAFV sequences were most closely related with SAFV2 reference strains, but separated into SAFV2-A (3 strains) and SAFV2-B (2 strains). In addition, the other two strains were classified as SAFV3. Our results indicated that SAFVs (SAFV2 and SAFV3) were circulated in children with acute gastroenteritis in Japan during 2010 and 2011 epidemic season.

Molecular epidemiology of rotavirus gastroenteritis in Japan during 2014‐2015: Characterization of re‐emerging G2P[4] after rotavirus vaccine introduction

Rotavirus vaccines have been available in Japan since 2011. This study conducted to monitor the trend of group A rotavirus (RVA) genotypes 3 years after vaccine introduction. A total of, 539 fecal samples were collected from children with acute gastroenteritis in six regions during July 2014‐June 2015. Among them, 178 samples (33.0%) were positive for RVA. The most predominant genotype was G1P[8] (35.9%) followed by G2P[4] (26.4%), G9P[8] (21.3%), G3P[8] (4.5%), and G3P[9] (4.5%). The detection rate of G2P[4] was increased soon after vaccine introduction. Sequence analyses of VP7 and VP4 genes of the representative G2P[4] strains were found to be clustered in sub‐lineage IVa of lineage IV. It is noteworthy that one amino acid substitution in the antigenic epitope (Q114P) of VP4 gene was found in representative G2P[4] strains of the current study. However, it is unclear whether the change in antigenic epitope is due to the effect of vaccination or due to natural variation, warranting further continuous monitoring of rotavirus evolution after vaccine introduction.

Molecular Epidemiological Traits of Group A Rotaviruses in Japanese Children During Transitional Period of Rotavirus Vaccine Implementation, 2011 - 2014

BACKGROUND Group A rotavirus (RVA) vaccines have been introduced in Japan since 2011. To investigate the molecular epidemiological traits of RVA during the transitional period of rotavirus vaccine implementation in Japan, this study was undertaken by following up three-decade long surveillance conducted in the same regions. METHODS RVA were screened and genotyped by RT-PCR from diarrheal samples collected from non-hospitalized patients in six localities (Hokkaido, Tokyo, Shizuoka, Osaka, Kyoto, and Saga) during 2011 - 2014. Selected samples were sequenced to elucidate the evolutionary trend. RESULTS Among 1858 specimens, the detection rate of RVA declined to 4.0% in 2013 - 2014 from 17.9% in 2011 - 2012 and 22.1% in 2012 - 2013. G1P[8] was the most predominant genotype in the first two years accounting for more than half, and G9P[8] showed the highest detection rate as 35.0% in the last year. Interestingly, the proportional rate of G2 strains in the studied period increased from 0% to 25%. VP6 genotyping revealed that DS-1 like reassortant G1P[8] strains were detected all over Japan and their prevalence fluctuated greatly from 35.0% to 89.5%. Sequence analysis of VP6 showed that strains in the current strains were closely related but distinct from the original reference strains, namely Wa and DS-1. CONCLUSIONS The detection rates of RVA, their GP combinations, prevalence of reassortant strains varied greatly after the introduction of rotavirus vaccines in Japan. Continuous monitoring is warranted to refine future vaccine strategy.

1141526807 Expression of inducible microsomal prostaglandin E synthase in local endometriosis lesions

Recently, an inducible microsomal human prostaglandin E synthase (mPGES) was identified. This enzyme converts the cyclooxygenase (COX) product prostaglandin (PG) H2 to PGE2, an eicosanoid that has been linked to carcinogenesis. Increased amounts of PGE2 have been observed in many tumor types including colorectal adenomas and cancers. We have already reported increased expression of COX‐2 mRNA in local lesions of endometriosis. To further elucidate the mechanism responsible for increased levels of PGE2 in endometriosis, we investigated the expression of mPGES. Formalin fixed and paraffin embedded 15 samples were examined with immunohistochemistry. Immunostaining was carried out with a rabbit mPGES‐1 anti‐human polyclonal antiboby. In selected cases, expression of mPGES mRNA was examined by RT‐PCR using total RNA extracted from frozen samples. Immunohistochemistry revealed increased mPGES immunoreactivity in endometriosis samples compared with eutopic endometria. Immunoreactivity of mPGES was observed in both epithelia and stromal or inflammatory cells. Increased expression of mPGES‐1 mRNA was detected in most of endometriosis samples. Taken together, our results suggested that overexpression of mPGES in addition to COX‐2 contributes to possible increased PGE2 production in endometriosis patients.

Mycoplasma pneumoniae respiratory tract infection prevailing among infants at a nursery school

Mycoplasma pneumoniae (M. pneumoniae) infection in infants had been considered to be very rare, but recently some clinical cases have been reported. We experienced an epidemic of M. pneumoniae infection in a nursery school, and compared M. pneumoniae infection in infants with that in preschool and school children to investigate the features of infantile M. pneumoniae infection. We obtained the following clinical findings in 15 infantile patients with M. pneumoniae infection: The maximum body temperature scarcely increased to 38.5 degrees C or more and the period of high temperature and cough was shorter in infant patients than in preschool and school aged patients. Stridor occurred in 4 patients but skin disorder was not observed. In the laboratory findings, the white blood cell count tended to increase with no changes in neutrophil/lymphocyte ratio and CRP increased slightly. M. pneumoniae antibody was negative in all the patients except 3 and old hemagglutination tests were positive in only 4 patients. The chest X-ray examinations showed a mild increase in the hilar shadow. However, the sequentially located homogeneous shadow which is commonly seen in preschool and school aged patients was not detected. M. pneumoniae antibody scarcely increased in infantile patients but M. pneumoniae was isolated by throat culture from 14 of the 15 patients who were diagnosed as having M. pneumoniae infection.