Histological characteristics of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinases-1 in asthmatic murine model during A(H1N1)pdm09 infection.

Pandemic influenza virus A(H1N1)pdm09 infection occurred in healthy children and young adults, but asthmatic patients presented more rapid progression of respiratory distress and plastic bronchitis. To investigate the pathogenesis of worsening respiratory symptoms after A(H1N1)pdm09 infection, we focused on matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinases-1 (TIMP-1). MMP-9 and TIMP-1 levels in bronchoalveolar lavage fluid and serum from mice with and without asthma were evaluated after A(H1N1)pdm09 or seasonal A(H1N1) infection. MMP-9 levels were more elevated in Asthma/A(H1N1)pdm09-infected mice than in non-Asthma/A(H1N1)pdm09-infected mice on both 3 and 7 days post-infection. Immunohistochemical findings in this pneumonia model showed that MMP-9 and TIMP-1 positive cells were observed in blood vessels and bronchus of lung tissue in severe pathological findings of pneumonia with asthma. Microscopically, shedding cells and secretions were conspicuous in the trachea on days 3 and 7 post-infection, in the A(H1N1)pdm09-infected mice with asthma. Our results suggest that MMP-9 and TIMP-1 expressions are related to severe pneumonia in the A(H1N1)pdm09 infection with asthma, leading to cause epithelial cell shedding.

Multi-season analyses of causative pathogens in children hospitalized with asthma exacerbation.

BACKGROUND: Respiratory viral and mycoplasma infections are associated with childhood asthma exacerbations. Here, we explored epidemiologic profile of causative pathogens and possible factors for exacerbation in a single center over a three-year period. METHODS: Hospitalized asthmatic children with attack aged 6 months-17 years were recruited between 2012 and 2015 (n = 216). Nasopharyngeal mucosa cell samples were collected from the participants and examined by reverse transcription-polymerase chain reaction to detect rhinovirus (RV), respiratory syncytial virus (RSV), enterovirus (EV), parainfluenza virus (PIV), Mycoplasma pneumoniae, and others. Clinical features, laboratory data, asthma exacerbation intensity, and asthma severity were compared among participants. Epidemiologic profile of causative pathogens and possible factors for exacerbation were explored. RESULTS: Viruses and/or Mycoplasma pneumoniae were detected in 75% of the participants. Rhinovirus (48%) was the most commonly detected virus in the participants with single infection, followed by RSV (6%). The median age at admission in the RV group was significantly higher than that in the RSV group. Insufficient asthma control and allergen sensitization were significantly related to RV-associated asthma exacerbation. There was no seasonality of pathogen types associated with asthma exacerbation although a sporadic prevalence of EV-D68 was observehinovirud. Rhinovirus were repeatedly detected in multiple admission cases. CONCLUSION: Our three-year analysis revealed that patients with RV infection were significantly prone to repeated RV infection in the subsequent exacerbation and good asthma control could prevent RV-associated asthma development and exacerbation. Multiple-year monitoring allowed us to comprehend the profile of virus- and/or mycoplasma-induced asthma exacerbation.

Phylogeny and Immunoreactivity of Norovirus GII.P16-GII.2, Japan, 2016-17.

During the 2016-17 winter season in Japan, human norovirus GII.P16-GII.2 strains (2016 strains) caused large outbreaks of acute gastroenteritis. Phylogenetic analyses suggested that the 2016 strains derived from the GII.2 strains detected during 2010-12. Immunochromatography between 2016 strains and the pre-2016 GII.2 strains showed similar reactivity.

Dissemination and genetic analysis of the stealthy vanB gene clusters of Enterococcus faecium clinical isolates in Japan.

BACKGROUND: VanB-type vancomycin (VAN) resistance gene clusters confer VAN resistances on Enterococcus spp. over a wide range of MIC levels (MIC = 4-1000 mg/L). However, the epidemiology and the molecular characteristics of the VAN susceptible VanB-type Enterococcus still remain unclear. RESULTS: We characterized 19 isolates of VanB-type Enterococcus faecium that might colonize in the gut and were not phenotypically resistant to VAN (MIC = 3 mg/L). They were obtained from two hospitals in Japan between 2009 and 2010. These isolates had the identical vanB gene cluster and showed same multilocus sequence typing (MLST) (ST78) and the highly related profiles in pulsed-field gel electrophoresis (PFGE). The vanB gene cluster was located on a plasmid, and was transferable to E. faecium and E. faecalis. Notably, from these VanB-type VREs, VAN resistant (MIC≥16 mg/L) mutants could appear at a frequency of 10- 6-10- 7/parent cell in vitro. Most of these revertants acquired mutations in the vanSB gene, while the remainder of the revertants might have other mutations outside of the vanB gene cluster. All of the revertants we tested showed increases in the VAN-dependent expression of the vanB gene cluster, suggesting that the mutations affected the transcriptional activity and increased the VAN resistance. Targeted mutagenesis revealed that three unique nucleotide substitutions in the vanB gene cluster of these strains attenuated VAN resistance. CONCLUSIONS: In summary, this study indicated that stealthy VanB-type E. faecium strains that have the potential ability to become resistance to VAN could exist in clinical settings.

Predicting genotype compositions in norovirus seasons in Japan.

Noroviruses cause acute gastroenteritis. Since multiple genotypes of norovirus co-circulate in humans, changing the genotype composition and eluding host immunity, development of a polyvalent vaccine against norovirus in which the genotypes of vaccine strains match the major strains in circulation in the target season is desirable. However, this would require prediction of changes in the genotype composition of circulating strains. A fitness model that predicts the proportion of a strain in the next season from that in the current season has been developed for influenza A virus. Here, such a fitness model that takes into account the fitness effect of herd immunity was used to predict genotype compositions in norovirus seasons in Japan. In the current study, a model that assumes a decline in the magnitude of cross immunity between norovirus strains according to an increase in the divergence of the major antigenic protein VP1 was found to be appropriate for predicting genotype composition. Although it is difficult to predict the proportions of genotypes accurately, the model is effective in predicting the direction of change in the proportions of genotypes. The model predicted that GII.3 and GII.4 may contract, whereas GII.17 may expand and predominate in the 2015-2016 season. The procedure of predicting genotype compositions in norovirus seasons described in the present study has been implemented in the norovirus forecasting system (NOROCAST).

Phylogenetic and Geographic Relationships of Severe Fever With Thrombocytopenia Syndrome Virus in China, South Korea, and Japan.

BACKGROUND: Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne acute infectious disease caused by the SFTS virus (SFTSV). SFTS has been reported in China, South Korea, and Japan as a novel Bunyavirus. Although several molecular epidemiology and phylogenetic studies have been performed, the information obtained was limited, because the analyses included no or only a small number of SFTSV strains from Japan. METHODS: The nucleotide sequences of 75 SFTSV samples in Japan were newly determined directly from the patients' serum samples. In addition, the sequences of 7 strains isolated in vitro were determined and compared with those in the patients' serum samples. More than 90 strains that were identified in China, 1 strain in South Korea, and 50 strains in Japan were phylogenetically analyzed. RESULTS: The viruses were clustered into 2 clades, which were consistent with the geographic distribution. Three strains identified in Japan were clustered in the Chinese clade, and 4 strains identified in China and 26 in South Korea were clustered in the Japanese clade. CONCLUSIONS: Two clades of SFTSV may have evolved separately over time. On rare occasions, the viruses were transmitted overseas to the region in which viruses of the other clade were prevalent.

[Fact-finding survey on regional healthcare services for patients with epilepsy based on a questionnaire administered to public health centers in Japan].

OBJECTIVES: Epilepsy is a common chronic neurological disorder characterized by recurrent unprovoked seizures. The prevalence of epilepsy is about 1%, and its incidence is increasing with the aging population. In addition to their medical problems, epilepsy patients face many social problems, including schooling, working, and maintaining their driver's licenses. However, these problems are not fully recognized by the regional healthcare centers (HCCs), and the inadequacy of collaboration between medical services, healthcare, and welfare is sometimes pointed out. Under these circumstances, this fact-finding survey was administered in the form of a questionnaire to HCCs across the nation for the purpose of improving the support system and educational activities for epilepsy in Japan. METHODS: A mail-back survey on regional healthcare services for epilepsy patients was sent out to 490 HCCs across the nation. Public health nurses (PHNs) responded to the self-completed questionnaire on behalf of each HCC. The questionnaire was comprised of the presence or absence of consultations on epilepsy, content of the consultations, and holding of workshops, lectures, or conferences in the community covered by the HCC. RESULTS: We obtained responses from 347 HCCs (response rate 71%). Seventy-three percent of the PHNs had experience with consultations regarding the medical and healthcare issues associated with epilepsy. However, only 10% of the PHNs responded that they could provide appropriate consultation for these issues. The content of the consultations mainly included medical services, clinical symptoms of epilepsy, and anxieties about their social life and their future. Workshops, lectures, or conferences on epilepsy were held for residents or health and welfare professionals in only 8% of the communities. This percentage is lower than those (21-70%) for other intractable or mental disorders that are mainly managed by HCCs (P<0.01). On the other hand, 76% of PHNs in the HCCs felt the need for knowledge about epilepsy, and 60% wanted to join the epilepsy educational programs. CONCLUSION: Although many PHNs belonging to HCCs conduct consultations regarding epilepsy-related issues, many feel they cannot adequately respond to these issues. Furthermore, they feel the need for further knowledge about epilepsy but are not able to gain such knowledge because of financial and geographical restrictions. To improve these situations, regional education programs for epilepsy should be established in each local municipality in the future with support provided by medical facilities, regional medical associations, the Japan Epilepsy Society, and the Government.

Cytokine profile of bronchoalveolar lavage fluid from a mouse model of bronchial asthma during seasonal H1N1 infection.

BACKGROUND: Several studies support the role of viral infections in the pathogenesis of asthma exacerbation. However, several pediatricians believe that influenza virus infection does not exacerbate bronchial asthma, except for influenza A H1N1 2009 pandemic [A(H1N1)pdm09] virus infection. We previously reported that A(H1N1)pdm09 infection possibly induces severe pulmonary inflammation or severe asthmatic attack in a mouse model of bronchial asthma and in asthmatic children. However, the ability of seasonal H1N1 influenza (H1N1) infection to exacerbate asthmatic attacks in bronchial asthma patients has not been previously reported, and the differences in the pathogenicity profiles, such as cytokine profiles, remains unclear in bronchial asthma patients after A(H1N1)pdm09 and H1N1 infections. METHODS: The cytokine levels and viral titers in the bronchoalveolar lavage (BAL) fluid from mice with and without asthma after H1N1 infection (A/Yamagata and A/Puerto Rico strains) were compared. RESULTS: The interleukin (IL)-6, IL-10, tumor necrosis factor (TNF)-α, IL-5, interferon (IFN)-α, IFN-ß, and IFN-γ levels were significantly higher in the BAL fluids from the control/H1N1 mice than from the asthmatic/H1N1 mice. The viral titers in the BAL fluid were also significantly higher in the control/H1N1mice than in the asthmatic/H1N1 mice infected with either A/Yamagata or A/Puerto Rico. CONCLUSIONS: A(H1N1)pdm09 infection, but not H1N1 infection, can induce severe pulmonary inflammation through elevated cytokine levels in a mouse model of asthma.

Analysis of bronchoalveolar lavage fluid in a mouse model of bronchial asthma and H1N1 2009 infection.

BACKGROUND: Bronchial asthma is known as a risk factor of admission to the intensive care unit. However, the mechanism by which pandemic 2009 H1N1 (A(H1N1)pdm09) infection increases the severity of symptoms in patients with bronchial asthma is unknown; therefore, we aimed at determining this mechanism. METHODS: Inflammatory cell levels in the bronchoalveolar lavage (BAL) fluid from the non-asthma/mock, non-asthma/A(H1N1)pdm09, asthma/mock, and asthma/A(H1N1)pdm09 groups were determined using BALB/c mice. Cell infiltration levels, cytokine levels, and viral titers were compared among the groups. RESULTS: Neutrophil, monocyte, interleukin (IL)-5, IL-6, IL-10, IL-13, and tumor necrosis factor (TNF)-α levels were significantly higher in the BAL fluid from the non-asthma/A(H1N1)pdm09 and asthma/A(H1N1)pdm09 groups than in the mock groups (p<0.05 for neutrophils and monocytes; p<0.01 for the rest). The number of eosinophils and CD8(+) lymphocytes and the level of transforming growth factor beta 1 (TGF-ß1) in BAL fluid in the asthma/A(H1N1)pdm09 group were significantly higher among all groups (p<0.05 for eosinophils and CD8(+) lymphocytes; p<0.01 for TGF-ß1). The levels of IL-6, IL-10, IL-13, and TNF-α were significantly higher in the asthma/A(H1N1)pdm09 group than in the non-asthma/A(H1N1)pdm09 group (p<0.05 for IL-6 and IL-10; p<0.01 for IL-13 and TNF-α). The level of IFN-γ in the asthma/A(H1N1)pdm09 group was significantly lower than that in the non-asthma/A(H1N1)pdm09 group (p<0.05). The viral titers in the BAL fluids were higher in the asthma/A(H1N1)pdm09 group than in the non-asthma/A(H1N1)pdm09 group (p<0.05). Histopathological examination showed more severe infiltration of inflammatory cells and destruction of lung tissue in the asthma/A(H1N1)pdm09 group than in the non-asthma/A(H1N1)pdm09 group. CONCLUSIONS: Severe pulmonary inflammation induced by elevated levels of cytokines, combined with increased viral replication due to decreased IFN-γ levels, may contribute to worsening respiratory symptoms in patients with bronchial asthma and A(H1N1)pdm09 infection.

Genetic analysis of attachment glycoprotein (G) gene in new genotype ON1 of human respiratory syncytial virus detected in Japan.

We studied the evolution of the G gene in the new genotype ON1 of RSV detected from patients with acute respiratory infection in Japan. Phylogenetic analyses and the evolutionary timescale were obtained by the Bayesian MCMC method. We also analyzed p-distance and positive selection sites. A new genotype ON1 emerged around 2001. The evolution rate was rapid (3.57 × 10(-3) substitutions/site per year). The p-distance was short and no positive selection site was found in the present strains. These results suggested that a new genotype ON1 of RSV-A emerged approximately10 years ago and spread to some countries with a high evolution rate.

[Training programs for staff at local Infectious Disease Surveillance Centers: the needs and usefulness].

OBJECTIVES: The objective of this study was to assess the need for and usefulness of training programs for Local Infectious Disease Surveillance Center (LIDSC) staff. METHODS: A structured questionnaire survey was conducted to assess the needs and usefulness of training programs. The subjects of the survey were participants of a workshop held after an annual conference for the LIDSC staff. Data on demographic information, the necessity of training programs for LIDSC staff, the themes and contents of the training program, self-assessment of knowledge on epidemiology and statistics were covered by the questionnaire. RESULTS: A total of 55 local government officials responded to the questionnaire (response rate: 100%). Among these, 95% of participants believed that the training program for the LIDSC staff was necessary. Basic statistical analysis (85%), descriptive epidemiology (65%), outline of epidemiology (60%), interpretation of surveillance data (65%), background and objectives of national infectious disease surveillance in Japan (60%), methods of field epidemiology (60%), and methods of analysis data (51%) were selected by over half of the respondents as suitable themes for training programs. A total of 34 LIDSC staff answered the self-assessment question on knowledge of epidemiology. A majority of respondents selected "a little" or "none" for all questions about knowledge. Only a few respondents had received education in epidemiology. CONCLUSION: The results of this study indicate that LIDSC staff have basic demands for fundamental and specialized education to improve their work. Considering the current situation regarding the capacity of LIDSC staff, these training programs should be started immediately.

Distribution of Human Sapovirus Strain Genotypes over the Last Four Decades in Japan: a Global Perspective.

Sapovirus (SaV) infections are a public health problem because they cause acute gastroenteritis in humans of all ages, both sporadically and as outbreaks. However, only a limited amount of SaV sequence information, especially whole-genome sequences for all the SaV genotypes, is publicly available. Therefore, in this study, we determined the full/near-full-length genomic sequences of 138 SaVs from the 2001 to 2015 seasons in 13 prefectures across Japan. The genogroup GI was predominant (67%, n = 92), followed by genogroups GII (18%, n = 25), GIV (9%, n = 12), and GV (6%, n = 9). Within the GI genogroup, four different genotypes were identified: GI.1 (n = 44), GI.2 (n = 40), GI.3 (n = 7), and GI.5 (n = 1). We then compared these Japanese SaV sequences with 3,119 publicly available human SaV sequences collected from 49 countries over the last 46 years. The results indicated that GI.1, and GI.2 have been the predominant genotypes in Japan, as well as in other countries, over at least four decades. The 138 newly determined Japanese SaV sequences together with the currently available SaV sequences, could facilitate a better understanding of the evolutionary patterns of SaV genotypes.

Serum and cerebrospinal fluid cytokine profile of patients with 2009 pandemic H1N1 influenza virus-associated encephalopathy.

PURPOSE: Since April 2009, the number of patients with 2009 pandemic H1N1 influenza virus infection has been increasing in Japan just as in the rest of the world. Patients with 2009 pandemic H1N1 influenza-associated encephalopathy (pIE) have also been reported. The common clinical symptoms of this condition are seizures and progressive coma with high-grade fever. We previously reported the possible association between seasonal influenza-associated encephalopathy (sIE) and proinflammatory cytokines. However, the pathogenesis of pIE remains to be elucidated. RESULTS: In pIE patients with a poor outcome, the serum levels of interleukin (IL)-6, IL-10, and soluble tumor necrosis factor (TNF) receptor (sTNFR1) were significantly higher than those in pIE patients without neurological sequelae. Similarly, the cerebrospinal fluid (CSF) IL-6 levels in pIE patients with a poor outcome were significantly higher than those in pIE patients without neurological sequelae. CONCLUSION: Our results suggest that IL-6, TNF-α, and IL-10 play important roles in pIE, and that the serum levels of IL-6, IL-10, and sTNFR1 and the CSF levels of IL-6 are related to neurological complications.

Characteristics of atopic children with pandemic H1N1 influenza viral infection: pandemic H1N1 influenza reveals 'occult' asthma of childhood.

The number of human cases of pandemic H1N1 influenza viral infection has increased in Japan since April 2009, as it has worldwide. This virus is widespread in the Yamaguchi prefecture in western Japan, where most infected children exhibited respiratory symptoms. Bronchial asthma is thought to be one of the risk factors that exacerbate respiratory symptoms of pandemic H1N1-infected patients, but the pathogenesis remains unclear. We retrospectively investigated the records of 33 children with pandemic H1N1 influenza viral infection who were admitted to our hospital between October and December 2009 and analyzed their clinical features. The percentage of children with asthma attack, with or without abnormal findings on chest radiographs (pneumonia, atelectasis, etc.), caused by pandemic H1N1 influenza infection was significantly higher than that of children with asthma attack and 2008-2009 seasonal influenza infection. Of the 33 children in our study, 22 (66.7%) experienced an asthma attack. Among these children, 20 (90.9%) did not receive long-term management for bronchial asthma, whereas 7 (31.8%) were not diagnosed with bronchial asthma and had experienced their first asthma attack. However, the severity of the attack did not correlate with the severity of the pulmonary complications of pandemic H1N1 influenza viral infection. The pandemic H1N1 influenza virus greatly increases the risk of lower respiratory tract complications such as asthma attack, pneumonia, and atelectasis, when compared to the seasonal influenza virus. Furthermore, our results suggest that pandemic H1N1 influenza viral infection can easily induce a severe asthma attack, pneumonia, and atelectasis in atopic children without any history of either an asthma attack or asthma treatment.

Association between the FTO gene and overweight in Japanese children and adolescents.

BACKGROUND: The association between the fat mass- and obesity-associated (FTO) gene and a predisposition to obesity is inconsistent in adult Asian populations. We investigated the association of the FTO gene with weight status in Japanese children and adolescents. DESIGN/SETTING: Nested case-control study and 3-yr longitudinal study - In the Shunan Child Cohort Study, fifth and eighth grade students attending all schools of Shunan completed the questionnaires. Overweight, including obesity, was defined as a percentage of overweight of 20% or in accordance with the International Obesity Task Force. We recruited 133 obese subjects and randomly selected controls from the 2006 cohort. We genotyped three FTO single nucleotide polymorphisms (SNPs): rs3751812, rs9939609, and rs1558902. RESULTS: The three genotyped SNPs were in tight linkage disequilibrium, with the exception of one case. The minor SNP allele of rs3751812 conferred a predisposition to obesity, and its odds ratio was 2.2 [95% confidence interval (CI), 1.5-3.4] in the additive model and 2.7 (95% CI, 1.6-4.4) in the dominant model (p < 0.001). Although blood parameters and some lifestyle behaviors were significantly different between the cases and controls (p < 0.01), these traits were not significantly different among the genotypes. In addition, we did not find an association between the genotypes and body mass index change during the 3 yr. CONCLUSION: The FTO gene is associated with the early onset of overweight in the Japanese population as well as in European populations. The results suggest that obesity-related risk factors in fifth and eighth graders appear because of their overweight status.

Enhanced airway hyperresponsiveness in asthmatic children and mice with A(H1N1)pdm09 infection.

BACKGROUND: Severe asthma exacerbation is an important comorbidity of the 2009 HIN1 pandemic (A(H1N1)pdm09) in asthmatic patients. However, the mechanisms underlying severe asthma exacerbation remain unknown. In this study, airway hyperresponsiveness (AHR) was measured in pediatric asthma patients infected with A(H1N1)pdm09. We also evaluated AHR in asthmatic mice with A(H1N1)pdm09 infection and those with seasonal influenza for comparison. METHODS: AHRs in asthmatic children were defined as the provocative acetylcholine concentration causing a 20% reduction in forced expiratory volume in 1 s (PC20 ). To investigate the pathophysiology using animal models, BALB/c mice aged 6-8 weeks were sensitized and challenged with ovalbumin. Either mouse-adapted A(H1N1)pdm09, seasonal H1N1 virus (1 × 105 pfu/20 µl), or mock treatment as a control was administered intranasally. At 3, 7, and 10 days after infection, each group of mice was evaluated for AHR by methacholine challenge using an animal ventilator, flexiVent. Lung samples were resected and observed using light microscopy to assess the degree of airway inflammation. RESULTS: AHRs in the children with bronchial asthma were temporarily increased, and alleviated by 3 months after discharge. AHR was significantly enhanced in A(H1N1)pdm09-infected asthmatic mice compared to that in seasonal H1N1-infected mice (p < .001), peaking at 7 days postinfection and then becoming similar to control levels by 10 days postinfection. Histopathological examination of lung tissues showed more intense infiltration of inflammatory cells and severe tissue destruction in A(H1N1)pdm09-infected mice at 7 days postinfection than at 10 days postinfection. CONCLUSION: Our results suggest that enhanced AHR could contribute to severe exacerbation in human asthmatic patients with A(H1N1)pdm09 infection.

Use of body mass index and percentage overweight cutoffs to screen Japanese children and adolescents for obesity-related risk factors.

BACKGROUND: Cutoffs based on percentage overweight (POW) are used for screening students in Japan; however, body mass index (BMI) is more common in the rest of the world. To screen for risk factors related to obesity among Japanese primary and secondary school students, we compared fasting and postprandial values, and the receiver operating characteristic (ROC) curves for the POW and BMI criteria. METHODS: The subjects were students aged 10 and 13 years living in Shunan City, Japan between 2006 and 2008 (n = 6566). POW and International Obesity Taskforce (IOTF) BMI criteria were used to screen for obesity-related risk factors. The lower (20%, 18-year-old equivalent: 25 kg/m(2)) and higher (50%, 18-year-old equivalent: 30 kg/m(2)) cutoffs were examined, and ROC curves were drawn. RESULTS: Fasting cholesterol levels were higher than postprandial levels. The prevalences of overweight/obesity were 6.6% to 10.0% using the lower cutoff and 0.6% to 5.0% using the higher cutoff. Among overweight subjects under fasting conditions, dyslipidemia was present in 12% to 52%, hypertriglyceridemia in 29% to 54%, hyperglycemia in 11% to 21%, and hypertension in 15% to 40%. Although the use of the lower and higher POW cutoffs resulted in lower sensitivity and the higher specificity, the POW and BMI ROC curves largely overlapped. However, for girls aged 10 years, the POW curve for >or=3 risks factors was lower than that of the latter (P = 0.013). CONCLUSIONS: For Japanese aged 10 and 13 years, both BMI and POW are useful for risk factor screening. However, subjects may be misclassified with dyscholesterolemia if postprandial blood samples are used.

Predicting Directions of Changes in Genotype Proportions Between Norovirus Seasons in Japan.

The norovirus forecasting system (NOROCAST) has been developed for predicting directions of changes in genotype proportions between human norovirus (HuNoV) seasons in Japan through modeling herd immunity to structural protein 1 (VP1). Here 404 nearly complete genomic sequences of HuNoV were analyzed to examine whether the performance of NOROCAST could be improved by modeling herd immunity to VP2 and non-structural proteins (NS) in addition to VP1. It was found that the applicability of NOROCAST may be extended by compensating for unavailable sequence data and observed genotype proportions of 0 in each season. Incorporation of herd immunity to VP2 and NS did not appear to improve the performance of NOROCAST, suggesting that VP1 may be a suitable target of vaccines.

The Association Between Documentation of Koplik Spots and Laboratory Diagnosis of Measles and Other Rash Diseases in a National Measles Surveillance Program in Japan.

Koplik spots are considered a disease-specific sign for measles, although comprehensive virological studies have not been conducted to date. In Japan, a national survey of 3023 measles and measles-suspected cases was conducted between 2009 and 2014 using polymerase chain reaction (PCR) or reverse transcription PCR (RT-PCR) to detect various rash/fever-associated viruses. Koplik spots were observed in 717 of 3023 cases (23.7%). Among these, the measles virus was detected in 202 cases (28.2%), while the rubella virus was detected in 125 cases (17.4%). Other viruses were detected in 51 cases having the spots (7.1%). In some of the cases with spots, two or three viruses, such as the rubella virus, parvovirus, and human herpesvirus type 6 were also detected. The sensitivity and specificity of Koplik spots as a diagnostic marker for measles were 48 and 80%, respectively. The results suggested that Koplik spots might appear not only in measles but also in other viral infections, such as rubella, as a clinical sign.

Nationwide Molecular Epidemiology of Measles Virus in Japan Between 2008 and 2017.

Genotyping evidence that supports the interruption of endemic measles virus (MV) transmission is one of the essential criteria to be verified in achieving measles elimination. In Japan since 2014, MV genotype analyses have been performed for most of the measles cases in prefectural public health institutes nationwide. With this strong molecular epidemiological data, Japan was verified to have eliminated measles in March, 2015. However, even in the postelimination era, sporadic cases and small outbreaks of measles have been detected repeatedly in Japan. This study investigated the nationwide molecular epidemiology of MV between 2008 and 2017. The 891 strains in the total period between 2008 and 2017 belonged to seven genotypes (D5, D4, D9, H1, G3, B3, and D8) and 124 different MV sequence variants, based on the 450-nucleotide sequence region of the N gene (N450). The 311 MV strains in the postelimination era between 2015 and 2017 were classified into 1, 7, 8, and 32 different N450 sequence variants in D9, H1, B3, and D8 genotypes, respectively. Analysis of the detection period of the individual N450 sequence variants showed that the majority of MV strains were detected only for a short period. However, MV strains, MVs/Osaka.JPN/29.15/ [D8] and MVi/Hulu Langat.MYS/26.11/ [D8], which are named strains designated by World Health Organization (WHO), have been detected in many cases over 2 or 3 years between 2015 and 2017. The WHO-named strains have circulated worldwide, causing outbreaks in many countries. Epidemiological investigation revealed repeated importation of these WHO-named strains into Japan. To demonstrate the elimination status (interruption of endemic transmission) in situations with repeated importation of the same strains is challenging. Nevertheless, the detailed sequence analysis of individual MV strains and chronological analysis of these strains provided sufficient evidence to show that Japan has still maintained its measles elimination status in 2017.