Seroepidemiological studies on pertussis, diphtheria and tetanus were performed on 1,540 nursing students enrolled in S-university between 1994 and 2011. Antibody titers against pertussis toxin (PT) and filamentous hemagglutinin (FHA), diphtheria antitoxin titer, and tetanus antitoxin titer were measured using sera taken during enrollment. The antibody-seropositive rates and geometric mean titers (GMTs) were calculated by according to birth year (1975-1993). The pertussis anti-PT and anti-FHA antibody-seropositive rates (seropositive levels were both defined as ?10EU/mL) were 12%-53% and 47%-84%, respectively. The anti-PT antibody-seropositive rate was lower than the anti-FHA rate. The anti-PT antibody GMTs were 2.0-11EU/mL, whereas the anti-FHA antibody GMTs were 10EU/mL or more (8.8-31EU/mL) in almost every group. The diphtheria antitoxin-seropositive rate (?0.1IU/mL) was 49%-79%, and the GMT was nearly 0.1IU/mL. The tetanus antitoxin-seropositive rate (?0.01IU/mL) was 91%-100%, and the GMT was 0.3IU/mL or more for all the groups. While the nursing studentsʼdiphtheria and tetanus antitoxin levels were sufficient to prevent both diseases, the anti-PT antibody-seropositive rate and the GMT were both lower than the level required to prevent pertussis, suggesting that many of the nursing students were pertussis-susceptible. These findings suggest a need for pertussis vaccination in young adults or early adolescents.
Bacillus cereus is a gram-positive rod-type bacterium that forms endospores and is distributed throughout various environments. It rarely causes disease in humans except for cases of food poisoning. However,infection with B. cereus in newborns and immunocompromised individuals can cause severe sepsis. Inappropriate catheter insertion and environmental contamination, including that of linen, are thought to be routes of transmission. Pseudo-outbreaks of B. cereus caused by poor hospital linen management have been reported and are important issues in hospitals. The number of Bacillus spp.-positive blood culture specimens increased in “A”ward of our hospital. Consequently, the hospitalʼs infection control team was asked to determine the cause of the increase. We performed environmental research in the “A”ward and the entire hospital. In addition, we investigated the current status of B. cereus derection in five core hospitals in the North Tohoku region. In our hospital, B. cereus was detected in towels before use. When the timeline of contamination was investigated, we found that the towels had already been contaminated at the time they were delivered to our hospital. The linen washing contractor was unconcerned with laundry disinfection. As a result of our findings, disposable towels were introduced. This resulted in a decrease in Bacillus spp.-positive blood culture specimens. Among the five core hospitals in the North Tohoku region, the hospitals outsourcing laundry to contractors without bacteriological monitoring had a significantly higher rate of B. cereus-positive blood cultures than those of three other hospitals with infection control policies for towel management. The increase in Bacillus spp.-positive blood culture specimens in our hospital was a result of towel contamination. Based on these findings, we suggest that proper linen management（including that of towels）is crucial for infection control as well as the quality control of bacteriological tests.
The influenza vaccine forms the basis of efforts to prevent the occurrence of influenza virus infection. However, vaccine effectiveness (VE) differs every season, which complicates efforts to combat the spread of infection. To develop a robust method to analyse variations in VE, we assessed VE among adult patients with influenza using a test-negative, case-control study design that evaluated vaccination records and the corresponding results of rapid influenza diagnostic tests during the 2013/14 and 2014/15 influenza seasons. During the 2013/14season, the adjusted VEs against influenza A and B viruses were 54.9% (95% confi dence interval [CI] = 24.2% - 73.2%) and 56.6% (95% CI = 19.1% - 76.7%), respectively. In contrast, during the 2014/15season, the adjusted VE against the influenza A (H3N2), virus was -2% (95% CI = -66% - 37.5%). Moreover, only a few patients were infected with the influenza B virus, thus, the VE against influenza B could not be assessed. The low VE during the 2014/15 season could be attributed to antigenic drift in the circulating influenza A (H3N2) viruses and mutations in the egg-adapted vaccine strains. Estimation of the VE against the influenza virus using this test-negative, case-control study design was simple and easy, and this study design had a precision similar to that of a randomized control trial. Therefore, this study design could be employed to predict VE through out the influenza season and may be used as the basis of influenza prophylaxis.
Methicillin-resistant Staphylococcus aureus (MRSA) with decreased susceptibility to daptomycin (DAP) were isolated from 4 patients receiving DAP from November 2013 to May 2014. These patients were treated with DAP for more than 7 days in all the cases. The pulsed-field gel electrophoresis (PFGE) patterns for MRSA isolates recovered from each patient pre- and post- DAP therapy were identical. Sequencing of mprF detected 2 amino acid substitutions (T345I or L826F) in 2 of the isolates. These results suggest that in vivo MRSA was resistant to DAP during DAP therapy. Furthermore, the MICs for DAP can vary by±1 di lution depending on the susceptibility test. When testing DAP susceptibility, there is a need to monitor reproducibility using different susceptibility tests, including the CLSI method.
The Ebola virus disease (EVD) outbreak that occurred in West Africa in 2014 was the largest ever in the world. In Sierra Leone, the number of cases reported peaked in December 2014 and gradually declined. However, the outbreak was not immediately terminated. To support the response of the World Health Organization (WHO) to EVD, the WHO Western Pacific Regional Office established the Western Pacific Ebola Support Team (WEST) with the aim of eliminating EVD in Port Loko District, where a certain number of new cases were still being reported in March 2015. We were dispatched to join WEST as WHO short term consultants in epidemiology for about six weeks from March to June 2015. Here, we describe our activities in the field as epidemiologists to show how Japan can contribute in the area of epidemiology during infectious disease outbreaks of international concern. The analysis suggested that the surveillance data for all the deaths and suspected EVD cases were underreporting the actual number of EVD cases in Port Loko District. Although contact tracing was con ducted, new EVD cases were often found among untraced contacts because of inadequate information from residents or insufficient investigation by the contact tracing team. In addition, incomplete monitoring of the health status of close contacts resulted in secondary transmission of the disease. Data managers established a database by centralizing data from the surveillance and contact tracing teams, laboratories, and healthcare facilities. The number of deaths per week recorded by these data sources was lower than the number of deaths per week that would be expected from the national mortality statistics. The team strengthened surveillance and social mobilization in the regions with wide disparities between the actual and reported numbers of deaths. For the on-the-ground activities, the field coordinator, epidemiologists, and social mobilizers, as well as the logistic and administrative support personnel, were all indispensable in supporting the field investigation of these infectious disease outbreaks of public health concern. A field coordinator, in particular, requires outstanding knowledge, experience and skills to lead team operations in liaison with international and local partners and to build confidence among local residents. The development of these human resources and the maintenance of a response team are required for potential future outbreaks, and this is an important area that Japan could prepare for and then contribute to future outbreaks. This report does not represent an official view of the WHO or our affiliates.
Objective：This study sought to clarify how laboratory testing of human mastadenovirus (adenovirus) is conducted in local public health institutes (LPHI) as part of Japanese adenovirus surveillance. Methods：Questionnaires on adenovirus surveillance were distributed to LPHIs (n=77) between February and May, 2014. Results：The participation response rate was 100%. During this period, adenoviral cultures were conducted at 65 institutes (84%) while 49 (64%) used neutralization testing. PCR diagnoses were conducted at 58 institutes (75%). The national adenovirus diagnosis manual (http://www.nih.go.jp/niid/ja/labo-manual.html),which includes methods of viral culture and PCR for penton, hexon, and fiber-coding regions, was used in 68% of the LPHIs. Ocular samples were diagnosed at 36 (47%) LPHIs. Conclusion：Most LPHIs conduct adenovirus surveillance in accordance with the national diagnosis manual. Both PCR and viral cultures were used for adenovirus surveillance in the majority of LPHIs during the surveyed period.
We report a case of a 63-year-old HIV-positive Japanese male with a CD4 cell count of 127/μL who was admitted to our hospital because of suspected malignant lymphoma. Initial blood tests revealed anemia,thrombocytopenia, hypoalbuminemia, and hypergammaglobulinemia. Imaging tests revealed a lung nodule,bilateral pleural effusion, hepatosplenomegaly and generalized lymphadenopathy. No evidence of malignant lymphoma or multicentric Castlemanʼs disease was noted on biopsy specimens；however, Kaposi sarcomaassociated herpesvirus (KSHV)-encoded latency-associated nuclear antigen-1-positive cells were observed as well as an elevated interleukin (IL)-6, IL-10 and KSHV viral load. He fulfilled the novel diagnostic criteria for KSHV-associated inflammatory cytokine syndrome (KICS). After initiating antiretroviral therapy, his symptoms and radiological abnormalities drastically improved. After 1-year follow-up, his HIV was well controlled without any relapsing symptoms.