Tomimasa Sunagawa

Reactivation of human herpesvirus 6 by infection of human herpesvirus 7.

We have attempted to reactivate human herpesvirus 6 (HHV‐6) by infection with HHV‐7 using childhood exanthem subitum patients in vitro. Peripheral blood mononuclear cells (PBMCs) were collected from children who had a history of exanthem subitum(ES) by HHV‐6 and were infected by human herpesvirus 7 (HHV‐7) in vitro. The antigen positive rate to HHV‐6 started to increase 7 days after the infection and reached a maximum by Day 15 using an immunofluorescence antibody test. The copy number of HHV‐6 DNA also increased in the samples in 10 days after infection in vitro. No antigen or increase in DNA was detected in PBMCs, that were mock‐infected or infected with supernatant of stock virus after ultracentrifugation, suggesting that an infection by HHV‐7 is necessary to reactivate HHV‐6. In the paired sera samples during the acute and the convalescent phases of ES, seven to ten bands, that were specific for HHV‐6, were recognized in samples from the acute phase, and at least 5 dominant polypeptides were found more intensively after HHV‐7 infection. J. Med. Virol. 60:284–289, 2000.

Identification of a variant B-specific neutralizing epitope on glycoprotein H of human herpesvirus-6

We have identified the human herpesvirus-6 variant B (HHV-6B)-specific neutralizing epitope on glycoprotein H (gH) which is recognized by monoclonal antibody (MAb) OHV3, with complement-independent neutralizing activity. HHV-6 gHs from HHV-6A (strain U1102) and HHV-6B (strain HST) were expressed in a T7-vaccinia virus transient expression system. OHV3 reacted with HST gH, but not with U1102 gH, in an immunoprecipitation assay and an indirect immunofluorescence assay. In addition, OHV3 reacted with chimeric gHs, formed between U1102 gH and HST gH, containing amino acids 272 to 422 of HST gH. Sequence comparison between U1102 and HST showed seven amino acid differences in this region. Site-specific mutations were introduced into these positions and then reactivity against OHV3 was investigated. The arginine at position 389 of HST gH was shown to be a determinant of the HHV-6B-specific reactivity of OHV3.

Ongoing local transmission of dengue in Japan, August to September 2014.

WPSAR Vol 5, No 4, 2014 | doi: 10.5365/wpsar.2014.5.3.007 www.wpro.who.int/wpsar 1 a Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan. b Department of Virology, National Institute of Infectious Diseases, Tokyo, Japan. c Department of Medical Entomology, National Institute of Infectious Diseases, Tokyo, Japan. Submitted: 26 September 2014; Published: 28 October 2014 doi: 10.5365/wpsar.2014.5.3.007 In late August 2014, three autochthonous dengue cases were reported in Japan. Since then, as of 17 September 2014, a total of 131 autochthonous cases have been confirmed. While cases were reported from throughout Japan, the majority were linked to visiting a large park or its vicinity in Tokyo, and the serotype detected has been serotype 1. We report preliminary findings, along with the public health response activities, of the first documented autochthonous dengue outbreak in Japan in nearly 70 years.

Ongoing increase in measles cases following importations, Japan, March 2014: times of challenge and opportunity.

WPSAR Vol 5, No 2, 2014 | doi: 10.5365/wpsar.2014.5.2.001 www.wpro.who.int/wpsar 1 a Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo, Japan. b Department of Virology 3, National Institute of Infectious Diseases, Tokyo, Japan. Submitted: 1 April 2014; Published: 16 May 2014 doi: 10.5365/wpsar.2014.5.2.001 Ongoing increase in measles cases following importations, Japan, March 2014: times of challenge and opportunity

Exposure to H1 genotype measles virus at an international airport in Japan on 31 July 2016 results in a measles outbreak

a Field Epidemiology Training Program, National Institute of Infectious Diseases. b Department of Epidemiology for Infectious Diseases, Graduate School of Medicine, Osaka University, Japan. c Infectious Disease Surveillance Center, National Institute of Infectious Diseases. d Department of Virology III, National Institute of Infectious Diseases. e Division of Global Infectious Diseases, Department of Infection and Epidemiology, Graduate School of Medicine, Tohoku University, Miyagi, Japan. Submitted: 22 December 2016; Published: 07 February 2017 doi: 10.5365/wpsar.2016.7.4.007 Exposure to H1 genotype measles virus at an international airport in Japan on 31 July 2016 results in a measles outbreak

Epidemiology of Domestically Acquired Amebiasis in Japan, 2000–2013

Notifications of amebiasis have been increasing in Japan. Using national surveillance data during 2000-2013, reported cases of amebiasis were analyzed. A case of amebiasis was defined as laboratory-confirmed Entamoeba histolytica infection, regardless of presence of symptoms. We described temporal trends and analyzed correlates of asymptomatic versus symptomatic cases based on odds ratios (ORs) and 95% confidence intervals (CIs) using logistic regression. Of 9,946 cases reported during 2000-2013, 7,403 were domestic cases. During this period, the proportion of domestic cases increased from 63% to 85%. Among male cases, majority were middle aged, and from 2008, the number of cases attributed to heterosexual contact surpassed that of homosexual contact. During 2010-2013, increase in notifications was associated with asymptomatic cases, colonoscopy diagnosis, and males with unknown or heterosexual route of infection. Among males, colonoscopy (OR = 31.5; 95% CI = 14.0-71.0) and cases with unknown route of infection, relative to homosexual contact (OR = 2.2; 95% CI = 1.3-3.9), were associated with asymptomatic infections in multivariate analysis. Although the recent rise may have been due to enhanced detection by colonoscopy or reporting, the large number of asymptomatic cases, with reportedly unknown or heterosexual route of infection, has led to a better understanding of amebiasis in Japan and highlights the potential public health concern.

Epidemiology of vaccine-preventable diseases in Japan: considerations for pre-travel advice for the 2019 Rugby World Cup and 2020 Summer Olympic and Paralympic Games

Introduction In 2019 and 2020, Japan will host two international sporting events estimated to draw a combined 22 million visitors. Mass gatherings like these ones increase the risk of spread of infectious disease outbreaks and international transmission. Pre-travel advice reduces that risk. Methods To assist ministries of health and related organizations in developing pre-travel advice, we summarized national surveillance data in Japan (2000–2016, to the extent available) for rubella, invasive pneumococcal disease, measles, non-A and non-E viral hepatitis, hepatitis A, invasive Haemophilus influenzae disease, tetanus, typhoid fever, invasive meningococcal disease, Japanese encephalitis, influenza, varicella, mumps and pertussis by calculating descriptive statistics of reported cases and reviewing trends. (See Annex A for details of reviewed diseases.) Results Our findings showed notable incidences of rubella (1.78 per 100 000 person-years), influenza (243.5 cases per sentinel site), and mumps (40.1 per sentinel site); seasonal increases for influenza (November–May) and Japanese encephalitis (August–November); and a geographical concentration of Japanese encephalitis in western Japan. Measles cases decreased from 11 013 in 2008 to 35 in 2015, but outbreaks (n = 165 cases) associated with importation occurred in 2016. Though invasive meningococcal disease incidence was only 0.03 per 100 000, international transmission occurred at a mass gathering in Japan in 2015. Discussion Ministries of health and related organizations should use these findings to develop targeted pre-travel advice for travellers to the 2019 Rugby World Cup and the 2020 Summer Olympic and Paralympic Games, especially for mumps, measles, rubella, influenza, and meningitis. Travellers with increased exposure risk should also be advised about hepatitis A and Japanese encephalitis.

Epidemiological Characteristics of Congenital Rubella Syndrome Cases during Rubella Epidemic in Japan, 2012-2014

Abstract Background Rubella infection during the first 20 weeks of pregnancy can cause congenital rubella syndrome (CRS). The main defects of CRS are known as classic triads; hearing impairment, congenital heart disease, and cataract. In Japan from 2011 to 2013, rubella outbreak occurred mainly among adults in their 20s to 40s, and consequently notification of CRS cases increased. Methods We collected information of epidemiological characteristics regarding all reported CRS cases and their mothers retrospectively by questionnaire to the physicians and interview to the several members of patients’ association of CRS. We conducted descriptive analysis to evaluate public health impact on CRS in Japan. Results A total of 45 CRS cases were reported from October 2012 to October 2014. Majority of cases (96%: 43/45) were diagnosed at less than three months old, except for two cases whose diagnoses at 9 months old and 13 months old due to late onset of cataract and hearing impairment. Males accounted for 56% (25/45). The median gestational week at birth was 38 weeks (range: 31 to 41 weeks) and mean birth weight was 2,171 g (standard deviation: ± 626 g). Frequencies of clinical manifestations at the time of diagnosis revealed that 67% (30/45) of cases had hearing impairment, 58% (26/45) had congenital heart disease, and 16% (7/45) had cataract. The most frequent heart diseases was patent ductus arteriosus (77%: 20/26), followed by pulmonary stenosis (15%: 4/26), and atrial septal defect (15%: 4/26). Only 7% (3/45) had classic triads. Thrombocytopenia which accounted for 73% (33/45) was the most frequent manifestation developed other than classic triads. Eleven cases died at the time of investigation, indicating 24% of case fatality proportion of reported CRS cases in this outbreak. Among ten cases died before 6 months old, nine were complicated by congenital heart disease. None of the mothers of reported CRS cases had two doses of Rubella Containing Vaccine (RCV) before pregnancy; meanwhile 24% (11/45) of mothers had one dose of RCV. Conclusion High case fatality proportion of CRS pointed out obvious high public health impact in Japan. Vaccination of two doses of RCV before pregnancy is necessary to preventing CRS. Disclosures All authors: No reported disclosures.

First mumps outbreak in a decade: measuring impact of mumps among naïve population - Tokunoshima Island, Japan

Abstract Background Currently, mumps vaccine is not included in the routine vaccination program in Japan and consequently, nationwide mumps outbreak is observed approximately every 4 years. Tokunoshima Island, located in the southern part of Japan with population of 25,000, experienced island-wide mumps outbreak since July 2015. This outbreak was unique because unlike the rest of the country, the Island was not hit by mumps virus for last 10 years. Island being in an inconvenient location, and with less than 2% mumps vaccine coverage rate among one year old children every year, we considered that the population, especially less than 10 years old, is basically naïve to mumps virus. We conducted a comprehensive outbreak investigation to analyze the disease burden of mumps among mumps naïve Island population. Methods We collected information of epidemiological characteristics for all mumps cases which visited medical facility in the Island from July 1, 2015 to June 30, 2016. In addition, to capture those who developed mumps but not sought medical care, we conducted questionnaire survey targeting all students and their family members. We conducted descriptive analysis to evaluate public health impact of mumps among mumps naïve population. Results From chart review, we found 1,191 mumps cases. Median age was 6 years old (range: 0–77). Among them, six cases were tested positive by RT-PCR and its genotype was type G. Genome sequence of the all collected viruses matched 100%. This result indicated that 5.1% of the population developed mumps by a single strain. If we focus on under 10 years old population, the incidence rate is 37,824 cases per 100,000 person-years. We also found 24 (2%) cases of aseptic meningitis and 2 (0.2%) cases of deafness. This disease burden is under-estimated as we captured 35 additional cases with symptoms but did not visited medical facility with 61% questionnaire collection rate. Conclusion We investigated large mumps outbreak which took place in an island with high mumps susceptible population. This disease burden clearly indicates that mumps vaccine should be included in routine vaccination and maintain high coverage rate to prevent periodic outbreaks. Disclosures All authors: No reported disclosures.

Prospective Case-Control Study of Risk Factors for Incident Syphilis Infection Among Men Who Have Sex With Men in Tokyo, Japan

Western Pacific Surveillance and Response (WPSAR) is an open access journal dedicated to the surveillance of and response to public health events. The goal of the journal is to create a platform for timely information sharing both within our region and globally to enhance surveillance and response activities. WPSAR is a continuous publication which means articles will be published online as soon as they have completed the review and editing process. Every three months articles will be batched for a print issue. It is a publication managed by the World Health Organization Regional Office for the Western Pacific. IN THIS ISSUE