Japanese journal of infectious diseases最新文献

Chronic inflammation and persistent immune activation (IA) during HIV infection are associated with non-AIDS complications. We investigated sociodemographic and clinical characteristics influencing IA and exhaustion (IE), and platelet activation (PA) in newly diagnosed people living with HIV (PLHIV) and identified modifiable factors for early interventions. We analysed baseline blood samples from 365 PLHIV participating in a trial investigating the effect of aspirin on IA, IE, and PA. We assessed levels of markers of monocyte activation (soluble CD14), platelet activation (soluble P-selectin), T-cell activation (CD4⁺ and CD8⁺ expressing CD69 and co-expressing CD38 and HLA-DR), and T-cell exhaustion (PD-1). The median (IQR) age of the participants was 37 (28, 45) years, with females comprising 64.7%. Advanced age significantly predicted IA and IE, but not PA. Markers of IA and IE, but not of PA, inversely correlated with CD4 counts, while directly with HIV viral load (HVL). We show that most Tanzanian PLHIV initiating antiretroviral therapy (ART) have low CD4 count, high HVL, with a considerable proportion aged above 50 years, characteristics associated with heightened IA and IE. Adjunctive therapy, when available, should target such population and at ART initiation to prevent morbidity and mortality associated with persistent IA and IE.

Tuberculosis (TB) is an endemic respiratory disease in several countries, including South Korea. The coronavirus disease 2019 (COVID-19) may pose greater risks to individuals with pre-existing respiratory diseases, but there are few reports on how the post-recovery state from TB affects COVID-19 infection and mortality. This study aimed to investigate the susceptibility and mortality of COVID-19 in patients with a history of TB. We retrospectively analyzed data from the National Health Insurance Service of Korea. We extracted individuals with TB from 2011 to 2019 and matched them with a population-based control group. The main outcomes were COVID-19 incidence and death within 30 days of infection. The study included 138,278 matched pairs of individuals with and without a history of TB. COVID-19 incidence was slightly lower in the TB group (38.0% vs. 38.4%, P-value = 0.023). Subgroup analysis showed significantly lower COVID-19 incidence in the pulmonary TB group compared to controls (P-value = 0.001). However, the mortality rate was higher in the TB group (0.9% vs. 0.7%, P-value < 0.001). This study showed that TB has a slightly protective effect against COVID-19 infection but increases the mortality rate. These findings will guide future research on the interaction between TB and COVID-19.

The present study developed a novel nano-structured nasal Bordetella pertussis vaccine candidate using encapsulating filamentous haemagglutinin (FHA) and pertussis toxoid (PTd) into N-trimethyl chitosan (TMC) with the help of CpG as an adjuvant and crosslinker (CpG-adjuvanted TMC/PTd-FHA), followed by physicochemical characterization and immune response evaluation after nasal administration. The TMC/CpG/PTd-FHA nanoparticle (NP) exhibited a particle size and zeta potential of 289.4 nm and +25.7 mV, respectively. The antigen/toxoid-loaded NPs exhibited >80% efficacy for encapsulation into polymer matrices, whereas in vitro antigen/toxoid release was found to be 95.18% after 96 hours. High immunization rates were observed in NP-treated mice with increased IgG and secretory IgA levels and proper capability to induce IFN-γ, IL-4, and IL-17 compared with the control group. Overall, nasal administration of the proposed approach, utilizing CpG as an adjuvant and crosslinker, could elicit humoral and Th1-type cellular immune responses, demonstrating promising potential as a vaccine delivery system.

After lifting travel bans imposed during the coronavirus 2019 pandemic, the number of reported measles cases in Japan started rising, culminating in 11 cases in Osaka Prefecture in 2024. We investigated the molecular epidemiology of these cases using 450 nucleotides of the C-terminal region of the nucleoprotein gene (N-450) and the noncoding region located between the matrix and fusion protein genes (MF-NCR). N-450 analysis revealed eight cases of genotype D8 and three of B3. Seven of the D8 cases were closely related to strains from Central Asia and Europe, harboring mutations in the primer binding region targeted by real-time PCR assays for measles virus. The remaining D8 case matched a strain from Thailand. All three B3 cases were identical to the strain detected in Vietnam in 2024. MF-NCR analysis of D8 cases revealed similar trends to those observed in the N-450 analysis. However, the B3 viruses from Vietnam differed by several bases from the closest related sequence and included a 6-base insertion. Given the resurgence of measles in Vietnam since 2024, the potential risk of continuous measles importation remains. Attention should focus on measles surveillance under circumstances of increased international human interactions, specifically the Exposition 2025 Osaka, Kansai in Japan.

Since we reported the first parechovirus A3-associated myalgia (PeVA3-M) outbreak in Yamagata in 2008 as an emerging disease, we have investigated PeVA3 infections as part of the National Epidemiological Surveillance of Infectious Diseases, Japan in sentinel hospitals/clinics and also performed a specific symptomatic surveillance targeting PeVA3-M. As PeVA3-M has only been reported from Japan, it is necessary to continue the above surveillance. In our surveillance from July 2022 to December 2023, we found 31 PeVA3 infections including three PeVA3-M and suspected cases using PCR and a virus isolation method. Further next-generation sequencing (NGS) analysis was performed for the representative isolates and their original specimens between 2022 and 2023 as well as those between 2003 and 2019. The NGS analysis showed that 7,245~7,309 and 7,118~7,287 nucleotides (98.7~99.8% and 97.1~99.4% compared with the reference strains) were available from 25 representative isolates and from 6 clinical specimens, respectively. This study indicated that the recombinant PeVA3 strains, which appeared in 2019, remained in circulation in Yamagata between 2022 and 2023. Furthermore, a NGS method is useful for the molecular epidemiological surveillance of PeVA3 infections, although improvements of the method used for the clinical specimens are required.

Incompletely resolved immune dysfunction in people living with HIV (PLWH) on antiretroviral treatment (ART) could differentially impact CD4+ and CD8+ T cell subsets. In this study, we investigated SARS-CoV-2 vaccine-induced CD4+ and CD8+ T cell responses in 26 PLWH on ART following third-dose mRNA vaccination. Spike-specific CD4+ and CD8+ T cell responses were assessed based on the expression of activation markers, CD137/OX40 and CD137/CD25, respectively, in response to stimulation with overlapping peptides spanning the spike protein. All participants showed spike-specific T cell responses, with CD8+ responses at a higher median frequency than CD4+. Interestingly, 5 participants who showed a higher frequency of spike-specific CD4+, relative to CD8+ T cells, were significantly younger and had higher CD4 counts pre-ART, in comparison to other participants. Further multivariate analysis revealed that only CD4 count pre-ART was an important predictor of elevated spike-specific CD4+ T cell responses; whereas no association was observed with neutralizing antibody (nAb) potency towards SARS-CoV-2 spike. Our results highlight heterogeneous immune functionality of vaccine-induced, SARS-CoV-2 spike-specific CD4+ and CD8+ T cells in PLHW on ART.

The potencies of domestic influenza virus reference antigens were initially calibrated using a single radial immunodiffusion (SRID) assay using primarily prepared international reference antigens. The SRID potency should not be affected when using another reference antigen calibrated with the same international antigen. However, the SRID potency of the test antigens can vary, although the causes of these discrepancies remain unclear. Here, we calibrated two candidate reference antigens (LotA and LotB) in the A(H3N2) subtype with various pairs of reference reagent sets (antigen and antiserum). The potencies of LotA and LotB varied depending on the reagent pair used, with a more pronounced effect in LotA (CV = 5.4% vs. 3.8%). To explore the cause of these divergences, we analyzed the dissociation constant of each reagent pair and scored them based on the hypothesis that pairs exhibiting stronger antigen-antibody binding would have smaller precipitin rings. Comparing these scores with the respective potency scores, we observed a strong correlation between the Binding score (relative BLI-K_D) and potency score in LotA (r = 0.8464, p = 0.0001) but not in LotB (r = 0.4000, p = 0.1408). These data suggest that antigen-antibody binding strength is an influencing factor of SRID potency.

Tick-borne viruses are primarily transmitted to vertebrates by infected ticks during blood feeding and cause various diseases in humans and animals. Haemaphysalis longicornis is one of the main tick species responsible for human tick bites and is thought to be the primary vector of severe fever with thrombocytopenia syndrome, an important tick-borne viral disease in Japan. Although H. longicornis ticks pose a potential risk to humans in Japan, studies on tick-borne viral prevalence of this tick species in Japan are limited. In this study, we conducted RNA virome analysis of H. longicornis ticks collected in Toyooka City, Hyogo Prefecture, Japan. Two known viruses, Dabieshan tick virus and Hubei sobemo-like virus 15, and putative novel quaranjavirus-like sequences were detected. Additionally, assessments of endogenous viral elements (EVEs) related to the virus and virus-like sequences suggested putative novel quaranjavirus-like sequences existed in both RNA and DNA forms. However, we could not determine whether this quaranjavirus-like sequence was of viral origin and could not conclude whether the DNA forms of the quaranjavirus-like sequence existed as EVEs in ticks. This study provides new insights into the prevalence of tick-associated viruses in ixodid ticks and serves as a reference for future approaches to prevent tick-borne diseases.

Necrotizing fasciitis (NF) is rapidly progressive soft tissue infection with a high mortality rate. Identifying the predisposing factors for NF is critical for enabling diagnosis and medical treatment. This study aimed to identify the factors associated with NF in a hospital located in rural Thailand. In total, 167 NF and 147 cellulitis cases were compared between 2019 and 2021. Among the NF cases, 13.17% required amputation and 7.69% were fatal. The study identified male sex, farming occupation, S. pyogenes infection, and comorbidities, including diabetes mellitus (DM), chronic kidney disease, and hypertension, as significant predisposing factors for NF. DM was statistically significantly associated with an increased risk of amputation. For pathogen-specific NF, advanced age (≥ 60 years) was the only statistically significant predisposing factor for S. pyogenes-associated NF. Conversely, NF caused by Staphylococcus aureus is significantly associated with farming occupation, DM, and hypertension. For NF caused by Enterobacterales, male sex, farming occupation, DM, and chronic kidney disease were statistically significant predisposing factors. These may not be risk factors that can be generalized, but may be the only risk factors for NF in Thailand. However, these findings may inform the development of guidelines for nursing care and pathogen-specific prevention of NF.

Mpox is a viral zoonosis caused by the monkeypox virus (MPXV), a double-stranded DNA virus mostly transmitted by direct contact, respiratory droplets, and contaminated fomites. Immunodeficiency, younger age, chronic diseases, and lack of immunization are all associated with severe illness. Mpox was declared by the World Health Organization a Public Health Emergency of International Concern on May 20, 2022. This report aimed to provide a detailed histopathological and immunohistochemical findings of a fatal case of an immunosuppressed patient infected with MPXV, reported in Colombia in September 2022. A description of the clinical findings was made, followed by histopathological, immunohistochemical, and molecular studies to confirm the presence of MPXV genomes and viral antigens in different tissues. MPXV viral DNA of the clade IIb was identified, and MPXV genomes were found in the liver, lung, heart, and brain. Interestingly, MPXV antigens were observed in the skin and lung, mainly in necrotic areas surrounded by active inflammatory cell markers. The simultaneous use of several diagnostic tools, as histopathological, molecular and Next Generation Sequencing in fatal cases involving a variety of viral agents, provide relevant information to understand the pathogenesis and clarify the cause of death of this emerging infectious disease.