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Epidemiology of Yellow Fever in Nigeria: Analysis of Climatic, Ecological, Socio-Demographic, and Clinical Factors Associated with Viral Positivity Among Suspected Cases Using National Surveillance Data, 2017–2023
Get PDFNagasaki University (長崎大学)博士(医学)Background: Since its resurgence in 2017, Yellow fever (YF) outbreaks have continued to occur in Nigeria despite routine immunization and the implementation of several reactive mass vaccinations. Nigeria, Africa’s most populous endemic country, is considered a high-priority country for implementing the End Yellow fever Epidemics strategy. Methods: This retrospective analysis described the epidemiological profile, trends, and factors associated with Yellow fever viral positivity in Nigeria. We conducted a multivariable binary logistic regression analysis to identify factors associated with YF viral positivity. Results: Of 16,777 suspected cases, 8532(50.9%) had laboratory confirmation with an overall positivity rate of 6.9%(585). Predictors of YFV positivity were the Jos Plateau, Derived/Guinea Savanah, and the Freshwater/Lowland rainforest compared to the Sahel/Sudan Savannah; dry season compared to rainy season; the hot dry or humid compared to the temperate, dry cool/humid climatic zone; 2019, 2020, 2021, 2022, and 2023 epidemic years compared to compared to 2017; first, third, and fourth quarters compared to the second; male sex compared to female; age group > = 15 years compared to < 15 years; working in outdoor compared to indoor settings; having traveled within the last two weeks; being of unknown vaccination status compared to being vaccinated; and vomiting. Conclusion: Ecological, climatic, and socio-demographic characteristics are drivers of YF outbreaks in Nigeria, and public health interventions need to target these factors to halt local epidemics and reduce the risk of international spread. Inadequate vaccination coverage alone may not account for the recurrent outbreaks of YF in Nigeria.長崎大学学位論文 学位記番号:博(医歯薬)甲第1713号 学位授与年月日:令和7年6月4日Author: Stephen Eghelakpo Akar, William Nwachukwu, Oludare Sunbo Adewuyi, Anthony Agbakizua Ahumibe, Iniobong Akanimo, Oyeladun Okunromade, Olajumoke Babatunde, Chikwe Ihekweazu, Mami Hitachi, Kentaro Kato, Yuki Takamatsu, Kenji Hirayama, Satoshi KanekoCitation: Journal of Epidemiology and Global Health, 15, art. no. 2; 2025Nagasaki University (長崎大学), 博士(医学) (2025-06-04)doctoral thesi
Bioflocs-assisted mass culture of Brachionus plicatilis under prolonged zero-water exchange and its application to Pagrus major larviculture
No full textThe sustainable mass production of rotifers is crucial to sufficiently supply marine fish hatcheries. However, maintaining a stable rotifer culture is still a challenge mainly due to unionized ammonia (NH3) toxicity and biological contaminants. This study investigated the effectiveness of single initial inoculation of bioflocs (BF) in addressing the abovementioned problems on rotifer mass culture using Brachionus plicatilis subjected to three treatments for 29 days, namely: 1) water exchange (WE), 2) zero water exchange (ZE), and 3) bioflocs × zero water exchange (BF × ZE). The effects of feeding BF-cultured B. plicatilis and supplementing BF in the rearing water on the survival and growth of red sea bream Pagrus major larvae for 14 days were evaluated. Bacterial composition of BF was determined. BF inoculation resulted in significantly higher rotifer densities from day 14 to day 29 (BF × ZE with 226–434 individuals/mL vs WE and ZE with 69–131 individuals/mL). BF inoculation significantly controlled ciliate contamination (BF × ZE with 7–25 ciliates/mL vs ZE with 421–531 ciliates/mL) from day 21 to day 25. TAN and NH3 concentrations were significantly reduced in the BF × ZE than in ZE and WE treatments on day 29. P. major larvae fed BF-cultured rotifers and reared in BF-supplemented water did not show reduced survival and growth. BF inoculation significantly improves B. plicatilis productivity through the effective removal of NH3 via the ammonia-oxidizing activity of Nitrosomonas nitrosa and bacteria within the phylum Chloroflexota under prolonged zero-water exchange conditions. Furthermore, the study demonstrates the viability of BF in P. major larviculture.Aquaculture, 613, art. no. 743368; 2025journal articl
Hypoxia- and mechanical stress–induced upregulation of mitochondrial HSP60 is associated with phenotypic switching of pulmonary arterial smooth muscle cells
No full textNagasaki University (長崎大学)博士(医学)Background: Switching from a contractile to a synthetic phenotype of pulmonary arterial smooth muscle cells (PASMCs) is known to play a crucial role in pulmonary arterial hypertension (PAH). We investigated how hypoxia and mechanical stress mediate the phenotypic switching of PASMCs. Methods: Human PASMCs were used for experiments. Hypoxia treatment was done by culturing cells under 1% O₂. Mechanical stress was induced by loading cells to 50 mmHg hydrostatic pressure. We analyzed cell morphology, cell proliferation, phenotypic marker protein expression, cytokine release, and the activation of stress-related pathways at 24 h after treatment. Bulk and single-cell RNA-sequencing datasets were used to analyze heat shock protein family D member 1 (HSPD1) expression in PAH lungs and PASMCs. Heat shock protein 60 (HSP60) was knocked down in PASMCs by transfection of HSPD1-siRNA. Results: Either hypoxia or mechanical stress alone induced the morphology change, increased cell proliferation, and promoted the phenotypic switching and inflammatory cytokines release of PASMCs. Interestingly, all those were dramatically enhanced under the combination of hypoxia and mechanical stress. Mechanistically, we found that the combination of hypoxia and mechanical stress not only significantly enhanced the mitochondrial HSP60 expression but also induced its partial redistribution to the cytosol. Bioinformatic analyses also confirmed the elevated HSPD1 expression in PAH lungs and PASMCs. HSP60 knockdown effectively attenuated the phenotypic switching of PASMCs induced by hypoxia and mechanical stress. Conclusion: Hypoxia- and mechanical stress-induced upregulation of mitochondrial HSP60 is associated with phenotypic switching of PASMCs.長崎大学学位論文 学位記番号:共博(医歯薬)甲第56号 学位授与年月日:令和7年9月19日Author: Geng Liu, Han Nie, Xu Zhang, Zi-Sheng Huang, Koh-Ichiro Yoshiura, Ke-Xiang Liu, Yi Liu, Tao-Sheng LiCitation: Cell Stress and Chaperones, 30(4), art. no. 100089; 2025Nagasaki University (長崎大学), 博士(医学) (2025-09-19)doctoral thesi
Tiger deaths in Vietnam due to infection with H5N1 highly pathogenic avian influenza virus bearing mutations associated with mammalian host adaptation
No full textRecently, infections with the H5N1 subtype of highly pathogenic avian influenza virus (H5N1-HPAIV) in mammals have been reported worldwide, including in cows in the United States and successive human cases in Cambodia. In Vietnam, 47 tigers and three leopards died from H5N1-HPAIV infection between August and October 2024. This study aimed to determine the origin of the H5N1 strains that infect tigers in Vietnam and to identify specific mutations associated with mammalian infection. Specimens were collected from tigers that died of suspected H5N1-HPAIV infection in southern Vietnam in September-October 2024. RNA was extracted and subjected to whole-genome sequencing. Time-stamped phylogenetic analysis was performed using H5N1 sequences recently detected in Vietnam and neighbouring countries. Phylogenetic results revealed that the strain found in tigers (Tiger H5N1 strain) belonged to clade 2.3.2.1e and has been genetically close to the H5N1-HPAIV lineage responsible for ongoing human infections in Cambodia since 2023. Tiger H5N1 strains harboured several amino acid substitutions associated with mammalian host adaptation or transmissibility, such as E627K in polymerase basic protein 2, similar to the Cambodian human H5N1 strains. This mammalian-adapted H5N1 lineage should be continuously monitored in poultry and mammals, including humans, in Vietnam to prevent further transmission.Emerging Microbes and Infections, 14(1), art. no. 2582252; 2025journal articl
とらばさみの規制と販売実態に関する一考察：長崎県を事例として
No full textThis study examines the legal status of steel-jaw leghold traps (torabasami) used for capturing wildlife, focusing on the regulatory framework and sales practices in Nagasaki Prefecture, Japan. Although the Act on the Protection and Management of Wildlife, and the Optimization of Hunting prohibits the use of steel-jaw leghold traps, accidental captures involving such traps have been reported nationwide, raising public concern. However, academic studies on the subject remain limited, and no prior legal or empirical research has been conducted specifically in Kyushu or Nagasaki. From a legal-policy perspective, this study analyzes the development of relevant legal provisions through statutory interpretation and Diet records. This study further investigates the regulatory practices in two municipalities: Tsushima City and Nagasaki City. Tsushima City has adopted a policy banning the use, possession, and sale of steel-jaw leghold traps in order to protect the endangered Tsushima leopard cat. In contrast, Nagasaki City permits applications for the use of such traps within the legal framework, although no permits have been granted in the past five years. To assess actual sales practices, this study conducted both telephone and field surveys of retailers in Nagasaki City. The findings revealed that approximately 15 traps were sold annually. This suggests that a certain number of individuals may be using such traps either legally—under exemptions for agricultural, forestry, or environmental sanitation purposes without permit requirements—or illegally, in violation of existing prohibitions. Given this uncertainty, further investigation into how these traps are actually used may help clarify their legal and ecological implications. Ultimately, this study highlights the regulatory challenges associated with the diverse purposes and contexts in which such traps are employed, suggesting the need for more context-sensitive legal responses.長崎大学総合環境研究, 28(1), pp.25-36; 2025departmental bulletin pape
Conformationally flexible ellagitannins: conformational analysis of davidiin and punicafolin by DFT-based 1H–1H coupling constant calculations
No full textMany ellagitannins with various conformations of their glucose moiety have been isolated from natural plant sources. Herein, we performed a conformational analysis using density functional theory (DFT) calculations of 1H–1H coupling constants. In solution, davidiin was found to exist as an equilibrium mixture of the BO,3 (boat) and 1C4 (chair) conformations, whereas punicafolin is an equilibrium mixture of the 3S1 (skew-boat) and 1C4 conformations. Their conformational equilibria vary depending on solvent and temperature. Such conformational flexibility may be important for the biosynthesis of ellagitannins with diverse structures.New Journal of Chemistry, 49(26), pp.11068-11079; 2025journal articl
A noninvasive test for human prion disease using hair roots and scalp
No full textInvasive tests like cerebrospinal fluid (CSF) examination are highly effective for diagnosing human prion disease (HPD). Real-time quaking-induced conversion (RT-QuIC) CSF assay demonstrates 80–90% sensitivity for HPD diagnosis. To establish a minimally invasive diagnostic approach, we evaluated RT-QuIC testing on hair root and scalp samples. We collected scalp samples from 22 HPD and 5 non-HPD patients during pathological examinations and analyzed them using RT-QuIC assay and neuropathological methods. In our prospective study, hair root and CSF samples from 300 patients were tested using RT-QuIC assay along with other biomarkers, including 14-3-3 protein, total tau protein, RT-QuIC CSF assay, and MRI findings. All 22 HPD patients demonstrated positive prion seeding activity in scalp and hair root RT-QuIC assays. Neuropathological examination in one HPD patient revealed abnormal prion protein in scalp tissue. Among 177 HPD patients diagnosed by Japan Prion Surveillance Committee and 123 non-HPD patients, RT-QuIC assay of hair roots demonstrated sensitivity and specificity of 45.8% and 100%, respectively. Sensitivities of 14-3-3 protein, total tau protein, RT-QuIC CSF assay, and MRI findings were 83.1%, 86.4%, 74.6%, and 100%, respectively, with specificities of 65.0%, 65.0%, 100%, and 56.1%, respectively. RT-QuIC assays could be developed into novel diagnostic methods for neurodegenerative diseases.Scientific Reports, 15(1), art. no. 41492; 2025journal articl
Mitigation of polystyrene microplastic-induced hepatotoxicity in human hepatobiliary organoids through bile extraction
No full textBackground & Aims; Polystyrene microplastics (PS-MPs) are pervasive in our daily life and can be ingested by the human body through bioaccumulation, causing organ damage, especially liver damage. However, the effect of PS-MPs bioaccumulation on human hepatotoxicity and their metabolism remains unclear. Recent studies have demonstrated that PS-MPs cause lipid and bile acid metabolism disorders. The human hepatobiliary organoids (HBOs) regenerated from chemically induced liver progenitor cells converted by mature hepatocytes and the bile duct provides a bioengineering model for liver disease and hepatic metabolism. Approach & Results; Exposure of HBOs to PS-MPs with a diameter of 1 µm for 48 h causes hepatotoxicity, hepatocyte damage, and changes in bile acid metabolism. PS-MPs could be accumulated into the bile ducts of HBOs, which can be promoted by ursodeoxycholic acid, increasing bile flow and volume by activating the bile transporter of BSEP in a dose-dependent manner along with MRP-2. The accumulation of PS-MPs in the bile duct was able to be inhibited by the bile transporter inhibitor of troglitazone that could inhibit the transporters of BSEP and MRP-2, which increased the hepatotoxicity caused by PS-MPs. Conclusions; This study provides insights into the metabolic pathways of PS-MPs in the liver and suggests potential therapeutic strategies to reduce MP-induced liver damage.Ecotoxicology and Environmental Safety, 288, art. no. 117330; 2024journal articl
九州西部におけるグンバイヒルガオの開花個体の分布と平戸島の新産地
No full textSeedlings and young plants from sea-borne seeds of Ipomoea pes-caprae have been recorded on the coasts of Japanese mainland beyond the distribution area. Most of them are washed away caused by the storm surge from a typhoon and occasionally withered in the cold. The distribution of flowering individuals of the species in Kyushu was clarified and the new locality was recorded on Hirado Island, Nagasaki Prefecture, where is the northern limit locality of this species in Kyushu.長崎県生物学会誌, 97, pp.22-24; 2025journal articl
Association between smartphone glances during application-based navigation and pedestrian navigation performance: a real-world experimental study
No full textBackground: The percentage of people owning smartphones is rapidly increasing due to the digitalization of modern society. Among the smartphone’s features, route guidance using navigation applications establishes spontaneous and independent outdoor mobility, and can potentially support people’s health. Despite some known concerns regarding smartphone use while walking, navigation performance and eye-tracking behavior while walking with navigation applications in real-world environments are unclear. This study aimed to investigate the association between gaze behavior, particularly glancing at smartphones, and navigation performance among adult users of navigation applications while walking. Methods: This cross-sectional experimental study involved 33 healthy adults aged 20 years and older (20–81 years, 66.7% female) not requiring assistance with walking or activities of daily living. A route navigation task (RNT) of approximately 1,300 m was performed in a real outdoor environment. The participants were required to complete the route as quickly as possible, following the instructions of the navigation application. Simultaneously, the fixation time, number of fixations, number of saccades, total saccade angle, and number of glances at the smartphone were recorded using a wearable eye-tracking device. After checking the distribution of the obtained outcomes and performing correlation analysis, a generalized linear model (GLM) was created to investigate the relationship between the number of glances at the smartphone and the participants’ navigation performance and gaze behavior. To confirm the validity of the estimates for each GLM, a bootstrap sample of 2,000 iterations was used to evaluate the estimates. Results: Correlation analysis showed that the number of stops and route errors were moderately and positively correlated with the number of times participants glanced at their smartphones (P<0.05). In the original GLM, the number of stops and route errors showed a significant positive association with the number of glances at the smartphone (P<0.05). This significant positive relationship persisted even after examining the bootstrap sample. Conclusions: In healthy adults, frequent screen glances while walking with a navigation application may interfere with navigation performance. Establishing an alternative navigation system that does not rely on screen-checking may help pedestrians move more efficiently and safely.mHealth, 11, art. no. 63, pp.1-11; 2025journal articl