An outbreak of influenza A(H1N1)pdm09 antigenic variants exhibiting cross-resistance to oseltamivir and peramivir in an elementary school in Japan, September 2024.

An outbreak of influenza A(H1N1)pdm09 viruses exhibiting cross-resistance to oseltamivir and peramivir occurred in Yokohama, Japan, in September 2024. Among 24 students in a class, 11 were diagnosed with influenza or influenza-like illness, and viruses harbouring the NA H275Y and HA Q210H substitutions were isolated from four. Deep sequencing analysis confirmed the clonal spread of these mutants.

Monitoring Influenza C and D Viruses in Patients With Respiratory Diseases in Japan, January 2018 to March 2023.

Background: Influenza viruses can cause zoonotic infections that pose public health risks. Surveillance of influenza A and B viruses is conducted globally; however, information on influenza C and D viruses is limited. Longitudinal monitoring of influenza C virus in humans has been conducted in several countries, but there has been no long-term monitoring of influenza D virus in humans.

[Examination of Analytical Method for Tris(2,3-dibromopropyl)phosphate and Bis(2,3-dibromopropyl)phosphate to Revise the Official Methods Based on "Act on the Control of Household Products Containing Harmful Substances"].

In Japan, the use of frame retardants [tris(2,3-dibromopropyl)phosphate: TDBPP and bis(2,3-dibromopropyl)phosphate: BDBPP] in several household textile products is banned under the "Act on the Control of Household Products Containing Harmful Substances." As the official analytical methods for testing these substances have not been revised for over 42 years, several issues such as the using of harmful reagents, have been pointed out. Therefore, we developed a new method to revise the official method in our previous study.

Determination of lipophilic marine biotoxins (azaspiracids, brevetoxins, and okadaic acid group) and domoic acid in mussels by solid-phase extraction and reversed-phase liquid chromatography with tandem mass spectrometry.

An accurate and efficient method was developed for the determination of azaspiracid shellfish toxins (azaspiracids-1, -2, and -3), neurotoxic shellfish toxins (brevetoxins-2 and -3), diarrhetic shellfish toxins (okadaic acid and dinophysistoxins-1 and -2), and the amnesic shellfish toxin (domoic acid) in mussels (Mytilus galloprovincialis). Lipophilic marine biotoxins (azaspiracids, brevetoxins, and okadaic acid group) were extracted with 0.5 % acetic acid in methanol under heating at 60°C to improve the extraction efficiency of okadaic acid group toxins and then cleaned up with a C18 solid-phase extraction cartridge.

Influence of herd immunity on norovirus: a long-term field study of repeated viral gastroenteritis outbreaks at the same facilities.

Background: Viral acute gastroenteritis (AG) is detected worldwide annually. Outbreaks caused by viruses associated with gastroenteritis have been reported repeatedly at the same facilities in Yokohama, Japan over several years. We investigated the statuses of these repeated outbreaks to consider herd immunity at the facility level.

Analysis and risk assessment of vinyl chloride emitted from aerosol products.

The objectives of this study were to develop a novel analytical method for quantifying vinyl chloride (VC) emitted from aerosol products, to provide analytical data on VC in aerosol products, and to evaluate consumer VC exposure by aerosol products. Our quantitative method involves absorbing VC into dimethyl sulfoxide and analyzing it using headspace gas chromatography/mass spectrometry. The correlation coefficients of the VC calibration curves were ≥ 0.

Nitrite Production by Nitrifying Bacteria in Urban Groundwater Used in a Chlorinated Public Bath System in Japan.

In contrast to pathogens, the effects of environmental microbes on the water quality in baths have not yet been examined in detail. We herein focused on a public bath in which groundwater was pumped up as bath water and disinfected by chlorination. Ammonia in groundwater is oxidized to nitrite, thereby reducing residual chlorine.

Ideal Test Time for Coronavirus Disease 2019 Contact Tracing.

Background: Epidemiological contact tracing is a powerful tool to rapidly detect SARS-CoV-2 infection in persons with a close contact history with COVID-19-affected patients. However, it remains unclear whom and when should be PCR tested among the close contact subjects.

Methods: We retrospectively analyzed 817 close contact subjects, including 144 potentially SARS-CoV-2-infected persons.

[Detection of Residual Solvents in Commercial Supplements Using Headspace (HS)-GC-MS].

In order to understand the actual state of residual solvents contained in commercial supplements, we performed a simultaneous analysis of residual solvents by headspace (HS)-GC-MS with reference to the Japanese Pharmacopoeia's "Residual Solvents", for 29 products selected from among commercial supplements (e.g., revitalizers, weight loss pills) that are deeply colored or contain coating agents and extract powder.

Whole Genome Analysis Detects the Emergence of a Single Serovar Chester Clone in Japan's Kanto Region.

In Japan's Kanto region, the number of serovar Chester infections increased temporarily between 2014 and 2016. Concurrently with this temporal increase in the Kanto region, . Chester isolates belonging to one clonal group were causing repetitive outbreaks in Europe.

[Examination of Analytical Method for Mothproofing Agents to Revise the Official Methods Based on "Act on the Control of Household Products Containing Harmful Substances"].

In Japan, the use of mothproofing agents [dieldrin and 4,6-dichloro-7-(2,4,5-trichlorophenoxy)-2-trifluoromethylbenzimidazole; DTTB] in textiles is regulated by the Act on the Control of Household Products Containing Harmful Substances. Since official analytical methods for these agents have been in place for approximately 40 years, we developed an improved method in a previous study. In the present study, we validated this method.

Simultaneous determination of ten paralytic shellfish toxins and tetrodotoxin in scallop and short-necked clam by ion-pair solid-phase extraction and hydrophilic interaction chromatography with tandem mass spectrometry.

Paralytic shellfish toxins and tetrodotoxin (puffer-fish toxin), the latter of which was recently found in bivalves from Europe, Japan, and New Zealand, are potent neurotoxins. A simple and effective clean-up procedure was developed for the simultaneous determination of ten paralytic shellfish toxins (gonyautoxins 1-6, decarbamoylgonyautoxins 2 and 3, and N-sulfocarbamoylgonyautoxins 2 and 3) and tetrodotoxin in the scallop, Mizuhopecten (Patinopecten) yessoensis, and the short-necked clam, Ruditapes philippinarum. To reduce matrix effects, 1% aqueous acetic acid extracts of the bivalves were cleaned up by ion-pair solid-phase extraction using a graphite carbon cartridge with tridecafluoroheptanoic acid as the volatile ion-pair reagent, followed by fourfold dilution.

Highly specific monoclonal antibodies and epitope identification against SARS-CoV-2 nucleocapsid protein for antigen detection tests.

The ongoing coronavirus disease 2019 (COVID-19) pandemic is a major global public health concern. Although rapid point-of-care testing for detecting viral antigen is important for management of the outbreak, the current antigen tests are less sensitive than nucleic acid testing. In our current study, we produce monoclonal antibodies (mAbs) that exclusively react with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and exhibit no cross-reactivity with other human coronaviruses, including SARS-CoV.

Subtype Screening of bla Genes Using Bipartite Primers for DNA Sequencing.

Genes conferring carbapenem resistance have spread worldwide among gram-negative bacteria. Subtyping of these genes has epidemiological value due to the global cross-border movement of people. Subtyping of bla genes that frequently detected in Japan appears to be important in public health settings; however, there are few useful tools for this purpose.

Influenza vaccine effectiveness against influenza A in children based on the results of various rapid influenza tests in the 2018/19 season.

During influenza epidemics, Japanese clinicians routinely conduct rapid influenza diagnostic tests (RIDTs) in patients with influenza-like illness, and patients with positive test results are treated with anti-influenza drugs within 48 h after the onset of illness. We assessed the vaccine effectiveness (VE) of inactivated influenza vaccine (IIV) in children (6 months-15 years old, N = 4243), using a test-negative case-control design based on the results of RIDTs in the 2018/19 season. The VE against influenza A(H1N1)pdm and A(H3N2) was analyzed separately using an RIDT kit specifically for detecting A(H1N1)pdm09.

Increased risk of rhinovirus infection in children during the coronavirus disease-19 pandemic.

Background: Coronavirus disease (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first detected in Japan in January 2020 and has spread throughout the country. Previous studies have reported that viral interference among influenza virus, rhinovirus, and other respiratory viruses can affect viral infections at the host and population level.

Methods: To investigate the impact of COVID-19 on influenza and other respiratory virus infections, we analyzed clinical specimens collected from 2244 patients in Japan with respiratory diseases between January 2018 and September 2020.

[Examination of Analytical Methods for Methanol, Trichloroethylene, and Tetrachloroethylene to Revise the Official Methods Based on the Act on the Control of Household Products Containing Harmful Substances].

In Japan, the use of methanol, trichloroethylene, and tetrachloroethylene in aerosol household products is banned under the Act on the Control of Household Products Containing Harmful Substances. As the official analytical methods for testing for these substances have not been revised for over 35 years, several issues have been pointed out. Thus, we developed a new method to revise the official method in our previous study.

Cost-effectiveness analysis of influenza vaccination during pregnancy in Japan.

Background: Pregnant women and infants are known as high risk groups for influenza. WHO recommend pregnant women be vaccinated with inactivated influenza vaccine. In Japan, some municipalities started to give subsidy to encourage pregnant women to receive a shot on their own accord, which has made the introduction of seasonal antepartum maternal vaccination program (AMVP) into the routine vaccination list a current topic in health policy and has raised the need to evaluate the value for money of such possibility.

Recent Molecular Evolution of Human Metapneumovirus (HMPV): Subdivision of HMPV A2b Strains.

Human metapneumovirus (HMPV) is a major etiological agent of acute respiratory infections in humans. HMPV has been circulating worldwide for more than six decades and is currently divided into five agreed-upon subtypes: A1, A2a, A2b, B1, and B2. Recently, the novel HMPV subtypes A2c, A2b1, and A2b2 have been proposed.

Influenza A(H1N1)pdm09 virus exhibiting reduced susceptibility to baloxavir due to a PA E23K substitution detected from a child without baloxavir treatment.

Human-to-human transmission of PA I38 mutant influenza A(H3N2) viruses with reduced baloxavir susceptibility has been reported in Japan. In December 2019, we detected a PA E23K mutant A(H1N1)pdm09 virus from a child without baloxavir treatment. The PA E23K mutant virus exhibited reduced baloxavir susceptibility but remained susceptible to neuraminidase inhibitors.

Early combination treatment with baloxavir and peramivir for hospitalized adults with influenza A in Yokohama, Japan.

Baloxavir marboxil is a new anti-influenza drug, but data on the clinical efficacy of a combination treatment of baloxavir and peramivir is scarce. We conducted a single-center retrospective analysis comparing the mortality of a combination of baloxavir and peramivir (B & P, n = 10) and peramivir without baloxavir (P-mono, n = 132) in hospitalized adults with influenza A between 2011 and 2019 in Yokohama City, Japan. Sequencing analysis was conducted in the B & P group to check the I38 mutation in polymerase acidic protein which is associated with baloxavir resistance.