Seroconversion of anti-Getah virus antibody among Japanese native Noma horses around 2012.

Getah virus (GETV), an arthropod-borne virus transmitted by mosquitoes, has been isolated from several animals. GETV infection in horses shows clinical signs such as fever, rash, and edema in the leg. Noma horses are one of the eight Japanese native horses. The present study aimed to clarify the occurrence of GETV infection in Noma horses. Serum samples collected from Noma horses were analyzed using a virus neutralization test and enzyme-linked immunosorbent assay and showed that the anti-GETV antibody titers in the samples collected in 2017 were significantly higher than those collected in 2012. We concluded that a seroconversion of anti-GETV antibodies was occurred in the Noma horse population around 2012, providing evidence of the GETV epidemic in Japan circa 2012.

A Novel Approach to Surgical Instructions for Scrub Nurses by Using See-Through-Type Head-Mounted Display.

In order to facilitate assists in surgical procedure, it is important for scrub nurses to understand the operation procedure and to share the operation status with attending surgeons. The potential utility of head-mounted display as a new imaging monitor has been proposed in the medical field. This study prospectively evaluated the usefulness of see-through-type head-mounted display as a novel intraoperative instructional tool for scrub nurses. From January to March 2014, scrub nurses who attended gasless laparoendoscopic single-port radical nephrectomy and radical prostatectomy wore the monocular see-through-type head-mounted display (AiRScouter; Brother Industries Ltd, Nagoya, Japan) displaying the instruction of the operation procedure through a crystal panel in front of the eye. Following the operation, the participants completed an anonymous questionnaire, which evaluated the image quality of the head-mounted display, the helpfulness of the head-mounted display to understand the operation procedure, and adverse effects caused by the head-mounted display. Fifteen nurses were eligible for the analysis. The intraoperative use of the head-mounted display could help scrub nurses to understand the surgical procedure and to hand out the instruments for the operation with no major head-mounted-display wear-related adverse event. This novel approach to support scrub nurses will help facilitate technical and nontechnical skills during surgery.

Effective school actions for mitigating seasonal influenza outbreaks in Niigata, Japan.

BACKGROUND: Japan has implemented various school actions during seasonal influenza outbreaks since the 1950's under the School Health Law. However, the effective duration, extent, and timing of closures remain unresolved. MATERIALS AND METHODS: We conducted a retrospective study on the relationship between elementary class closures and influenza outbreak control during four consecutive influenza seasons from the 2004-2005 to 2007-2008 school years in Joetsu, Niigata, Japan. Among a total of 1,061 classes of 72 schools, 624 cases of influenza outbreaks were documented among 61 schools. RESULTS: Class closures were carried out in a total of 62 cases in response to influenza outbreak, which was defined as a student absentee rate of greater than 10% due to influenza or influenza-like illness. Of these cases, two-day class closures were conducted the day after reaching a 10% student absentee rate in 28 cases and other types of closures were initiated in 34 cases. A markedly higher number of outbreak cases ended within one week for two-day class closures compared to the other types of closures (82.1% vs. 20.6%, respectively). The significant association between two-day class closures and interruption of an outbreak within one week was confirmed using a multivariable model adjusted for the season, grade, day of the week of an outbreak start, and absentee rate on the day of an outbreak start (OR, 3.18; 95% CI, 1.12-9.07; p = 0.030). CONCLUSIONS: Our results suggest that a two-day class closure carried out the day after reaching a 10% absentee rate is an effective approach for mitigating influenza outbreaks in elementary schools.

Geodemographics profiling of influenza A and B virus infections in community neighborhoods in Japan.

BACKGROUND: The spread of influenza viruses in a community are influenced by several factors, but no reports have focused on the relationship between the incidence of influenza and characteristics of small neighborhoods in a community. We aimed to clarify the relationship between the incidence of influenza and neighborhood characteristics using GIS and identified the type of small areas where influenza occurs frequently or infrequently. METHODS: Of the 19,077 registered influenza cases, we analyzed 11,437 influenza A and 5,193 influenza B cases that were diagnosed by the rapid antigen test in 66-86 medical facilities in Isahaya City, Japan, from 2004 to 2008. We used the commercial geodemographics dataset, Mosaic Japan to categorize and classify each neighborhood. Furthermore, we calculated the index value of influenza in crude and age adjusted rates to evaluate the incidence of influenza by Mosaic segmentation. Additional age structure analysis was performed to geodemographics segmentation to explore the relationship between influenza and family structure. RESULTS: The observed number of influenza A and B patients in the neighborhoods where young couples with small children lived was approximately 10-40% higher than the expected number (p < 0.01) during all seasons. On the contrary, the number of patients in the neighborhoods of the aging society in a rural area was 20-50% lower than the expected number (p < 0.01) during all seasons. This tendency was consistent after age adjustment except in the case of influenza B, which lost significance in higher incidence areas, but the overall results indicated high transmission of influenza in areas where young families with children lived. CONCLUSIONS: Our analysis indicated that the incidence of influenza A and B in neighborhood groups is related to the family structure, especially the presence of children in households. Simple statistical analysis of geodemographics data is an effective method to understand the differences in the incidence of influenza among neighborhood groups, and it provides a valuable basis for community strategies to control influenza.

New genotypes within respiratory syncytial virus group B genotype BA in Niigata, Japan.

Phylogenetic analysis of respiratory syncytial virus (RSV) group B genotype BA strains from the 2002-2003 to 2009-2010 seasons collected in Niigata, Japan, revealed four distinct clusters, designated new BA genotypes BA7, BA8, BA9, and BA10. These new genotypes were not associated with large outbreaks in the community.

Evidence-based tool for triggering school closures during influenza outbreaks, Japan.

Guidelines available to school administrators to support school closure decisions during influenza outbreaks are usually not evidence-based. Using empirical data on absentee rates of elementary school students in Japan, we developed a simple and practical algorithm for determining the optimal timing of school closures for control of influenza outbreaks.

Molecular evolution of human influenza A viruses in a local area during eight influenza epidemics from 2000 to 2007.

A total of 1,041 human influenza A virus isolates were collected at a clinic in Niigata, Japan, during eight influenza seasons from 2000 to 2007. The H3N2 subtype accounted for 75.4% of the isolates, and the rest were H1N1. Extremely high rates of amantadine-resistant strains of H3N2 subtype were observed in 2005/2006 (100%) and 2006/2007 (79.4%), while amantadine-resistant strains of H1N1 subtype were only detected in 2006/2007 (48.2%). Sequence and phylogenetic analysis of the HA1 subunit of the hemagglutinin (HA) gene revealed a characteristic linear trunk in the case of H3N2 viruses and a multi-furcated tree in the case of H1N1 and showed a higher sequence diversity among H3N2 strains than H1N1 strains. Mutations in the HA1 from both subtypes were mainly found in the globular region, and only one-third of these were retained for two or more successive years. Higher diversity of H3N2 viruses was mainly attributable to a higher fixation rate of non-synonymous mutations and to a lesser extent to a higher nucleotide substitution rate than for H1N1. Our analysis showed evidence of four positively selected sites in the HA1 of H1 and five sites in that of H3, four of which were novel. Finally, acquisition or loss of N-glycosylation sites was shown to contribute to the evolution of influenza A virus, especially in the case of H3N2, which had a higher tendency to acquire new glycosylation sites.

Effectiveness of oseltamivir treatment among children with influenza A or B virus infections during four successive winters in Niigata City, Japan.

Oseltamivir has been used for treatment of influenza A and B infections, but recent reports documented that it was less active against the latter. We compared the effectiveness of oseltamivir in children between laboratory confirmed influenza A and B over 4 influenza seasons from 2001 to 2005 in a pediatric clinic in Japan. Among 1,848 patients screened, 299 influenza A and 209 influenza B patients were administered oseltamivir (treated groups), and 28 influenza A and 66 influenza B patients were assigned as non-treated groups. The duration of fever, defined as period when patients had the maximum temperature higher than 37.5 degrees C in three-time measurements in a day after the clinic visit, was evaluated among the four groups. In uni-variate analysis, the duration of fever was shorter for treated group than non-treated for influenza A (1.8 +/- 0.9 days vs 2.6 +/- 1.3 days, p < 0.01), but it was not significant for influenza B (2.4 +/- 1.3 days vs 2.8 +/- 1.2 days, p = 0.9). The fever duration was longer in treated influenza B than A patients (p < 0.01). Multi-variate analysis indicated younger age (< 6 years old) and higher body temperature at the clinic visit prolonged the duration of fever. Adjusted average duration of fever indicated that oseltamivir was effective for both types, but more effective on influenza A, and the benefit increased for younger children. Our data provide evidence that oseltamivir is beneficial for influenza infections, but the effectiveness is differed by type and age.

Recurrence and persistence of fever in children who developed amantadine-resistant influenza viruses after treatment.

In recent years, a dramatic increase of amantadine-resistant influenza A has occurred globally, but limited data have been available on the clinical course of patients developed amantadine-resistant viruses. We compared fever reduction between patients who developed resistance or remained sensitive in a pediatric clinic in Niigata, Japan, from 2000 to 2006. A total of 2,802 clinical samples were collected from patients who visited the pediatric outpatient clinic with influenza like illness during the seven influenza epidemic seasons. Patients were divided into 4 groups and analyzed for the fever reduction after amantadine treatment: emerged amantadine-resistant (n = 15); amantadine-sensitive (n = 35); patients administered no antiviral drugs (n = 42); and oseltamivir-treated patients (n = 320), which served as references. All 4 groups showed alleviation of fever up to day 3. The amantadine-resistant group had a significant recurrence of fever on day 4 and/or 5, and as a consequence, the course of illness was prolonged. Considering the pattern of fever, recurrent and persistent patterns were found significantly at higher rates in children with emerged resistant virus compared to other groups, and the age tended to be younger in amantadine-resistant compared to amantadine-sensitive group (3.9 +/- 3.0 vs 6.7 +/- 4.1 years old, n.s.). Therefore, we concluded that younger children were prone to develop amantadine-resistance after treatment and showed a significant recurrence of fever on day 4 and/or 5, and the course of illness was consequently prolonged.

Measles outbreaks in high schools closely associated with sporting events in Niigata, Japan.

OBJECTIVES: Due to high vaccine coverage in Niigata, we had no outbreaks of measles from 1997 to 2003 but an opportunity to study the role of sporting events in the propagation of an epidemic was experienced in the spring of the latter year. METHODS: Mandatory measles case reports were requested from all high schools in Niigata, which covered a school year, date of onset, club activity, vaccination status, and hospitalization. RESULTS: With national marathon and kendo (Japanese fencing) meetings for high school students, measles outbreaks occurred at 27 high schools with 192 patients (186 students and 6 teachers) in Niigata. Of 64 unvaccinated patients, 14 (21.9%) were hospitalized and 6 (6.2%) of 97 vaccinated patients. Mostly single cases were encountered at high schools in which index cases had a vaccination history, whereas at a high school in which index cases had no vaccination history, the total number of cases per school increased, mostly within more than 3 cases (p<0.05). CONCLUSION: We conclude that sporting events, even if outdoors, might be a risk factor for measles infections. Appropriate actions to control outbreaks should be performed promptly in collaboration with related personnel and institutions.

Antibody response to influenza vaccination in nursing home residents and healthcare workers during four successive seasons in Niigata, Japan.

OBJECTIVE: To evaluate the antibody response to influenza vaccines in nursing home residents and healthcare workers (HCWs) and its relation to residents' functional and chronic disease status during four successive seasons. DESIGN: Before-after study. SETTING: Nine nursing homes during the 1998-1999 season and two during the 1999-2000, 2000-2001, and 2001-2002 seasons. PARTICIPANTS: Two hundred fifty-nine residents and 79 HCWs during the 1998-1999 season; 180 and 71, respectively, during the 1999-2000 season; 162 and 71, respectively, during the 2000-2001 season; and 153 and 79, respectively, during the 2001-2002 season. RESULTS: Multivariate analysis indicated that the mean fold increase in the geometric mean titers (GMTs) of hemagglutination inhibition (HI) antibodies and the response rate (the proportion of vaccinees resulting in a significant, at least fourfold increase in antibody titer) were good and no significant differences occurred for almost all strains in both residents and HCWs. The GMTs of HI antibodies and the protection rate (the proportion of participants with HI antibody titers > or = 40) were increased in both residents and HCWs, but were significantly lower for almost all strains in residents than in HCWs. Furthermore, multivariate analysis indicated that subdivision of residents into three groups by level of daily activities and into four groups according to underlying diseases revealed only minor differences in immune responses. CONCLUSIONS: Antibody responses to the influenza vaccine were lower in residents than in HCWs. However, residents showed similar antibody responses regardless of their level of daily activity or underlying diseases.

Prevalence of human metapneumovirus and influenza virus infections among Japanese children during two successive winters.

BACKGROUND: Human metapneumoviruses (hMPVs) are recognized as a leading cause of respiratory infections in young infants in many countries. The objective of this study was to identify links between hMPV and influenza virus infections among children with influenza-like illness. METHOD: This study was conducted in 2 influenza seasons (2002-2003 and 2003-2004) at 2 pediatric outpatient clinics in Niigata city, Japan. Nasopharyngeal swabs or aspirates were collected from influenza-like illness patients, and hMPV and influenza were detected by reverse transcription-polymerase chain reaction (RT-PCR). A nucleotide sequence of 352 nucleotides segment of the F gene was performed. RESULTS: A total of 765 influenza viruses and 84 hMPV were identified from 1498 nasopharyngeal swabs or aspirates by virus isolation and RT-PCR, respectively. hMPV-positive rates in patients with influenza-like illness were 5.7 and 5.2% in the 2002-2003 and 2003-2004 seasons, respectively. Epidemic curves of influenza and hMPV patients showed similar patterns with peaks in February in 2 influenza seasons. hMPV infections occurred frequently in infants and school children. Approximately 46% of hMPV patients were coinfected with influenza A viruses, but those coinfected cases were not clinically distinct from the others. No coinfection with influenza B viruses was found. Phylogenetic analysis of the hMPV fusion gene sequences revealed that 2 distinct hMPV cocirculated and that completely identical strains in subgroup A were observed over 2 years. CONCLUSIONS: HMPV plays an important pathogenic role in patients with influenza-like illness in winter seasons, often in coinfections with influenza A viruses.

Molecular epidemiology of respiratory syncytial virus infections among children with acute respiratory symptoms in a community over three seasons.

To study the molecular epidemiology of respiratory syncytial virus (RSV) in a community, children with acute respiratory symptoms at a pediatric outpatient clinic in Niigata, Japan, were analyzed over three seasons from November 2001 to July 2004. Of 499 nasopharyngeal aspirate specimens, 185 (37.1%) were RSV positive, and only 8 (4.5%) of 177 patients were shown by the reverse transcription (RT)-PCR method to be reinfected. RSV infection occurred beginning in the early winter, and the rates declined in the spring. The predominant subgroup changed from A to B and returned to A over the three seasons. Phylogenetic analysis also revealed that multiple genotypes cocirculated each year, with genotype GA5 of subgroup A predominating in the 2001-2002 and the 2003-2004 seasons. A new genotype of subgroup B (named BA, according to the nomenclature for viruses) with a 60-nucleotide insertion in the second variable region of the attachment glycoportein protein was predominant as an emerging strain in the 2002-2003 season, but this was not associated with new epidemiological or clinical features, unlike the cases of disease caused by other genotypes in the other seasons. In conclusion, our molecular analysis of RSV confirms that multiple genotypes cocirculate each year and that the genotype predominating may shift with the season. Support for determination of the genotype by RT-PCR as an effective tool for characterization of RSV circulation patterns in the community is provided.

Geographic and temporal trends in influenzalike illness, Japan, 1992-1999.

From 1992 to 1999, we analyzed >2.5 million cases of influenzalike illness (ILI). Nationwide influenza epidemics generally lasted 3-4 months in winter. Kriging analysis, which illustrates geographic movement, showed that the starting areas of peak ILI activity were mostly found in western Japan. Two spreading patterns, monotonous and multitonous, were observed. Monotonous patterns in two seasons featured peak ILI activity that covered all of Japan within 3 to 5 weeks in larger epidemics with new antigenic variants of A/H3N2. Multitonous patterns, observed in the other five seasons, featured peak ILI activity within 12 to 15 weeks in small epidemics without new variants. Applying the kriging method allowed better visualization and understanding of spatiotemporal trends in seasonal ILI activity. This method will likely be an important tool for future influenza surveillance in Japan.