Targeted next-generation sequencing reveals pathogen spectrum distribution and hematological correlations in children with acute lower respiratory infections.

Hirschsprung-associated enterocolitis (HAEC) remains a major cause of morbidity, with poorly defined triggers and limited modifiable risk factors. Given the roles of immune immaturity and mucosal dysfunction in HAEC pathogenesis, this study evaluated whether age is associated with HAEC risk, and whether seasonal variation consistent with viral exposure is present. A retrospective cohort study was conducted including patients with HD treated at Children's Hospital Colorado (2008-2021). A piecewise exponential Poisson regression model estimated age-specific HAEC incidence rates, adjusting for Trisomy 21 and length of aganglionosis. Seasonal distribution was assessed using an exact binomial test comparing cold (October-March) versus warm months. Among 217 patients, 96 HAEC episodes were identified in 53 patients (24.4%). HAEC incidence was highest in the first year of life and declined progressively with age, with an 88% reduction in patients older than 36 months (RR 0.12, 95% CI 0.07-0.22, p < 0.001). Additionally, 60.4% of episodes occurred during cold months, exceeding expected distribution (p = 0.03). HAEC risk is strongly age-dependent, with a marked reduction after 36 months, supporting a role for immune maturation in disease susceptibility. The observed seasonal pattern suggests that viral exposures may act as triggers in susceptible patients.

Cutaneous leishmaniasis (CL) is a parasitic infection that presents a significant public health concern in the Qassim region of Saudi Arabia. This retrospective observational study aimed to investigate the seasonal patterns and distribution of CL cases in the Al-Qassim region, highlighting the importance of these factors in understanding the disease trends. The present study utilized retrospective observational data from a population cohort to examine reported instances of CL over an 8-year period. The Ministry of Health monitored the CL cases from January 2016 to December 2023. The data were systematically arranged by year, gender, age group, nationality, and season to analyze trends and variations in the disease's distribution at the population level. The chi-square test and analysis of variance were used to analyze the data. A total of 1199 confirmed CL cases were reported during the study period, with significant year-to-year variation (p < 0.005). Males accounted for the majority of cases (72.8%), and the highest burden was observed among individuals aged 15-45 years. Saudi nationals represented most reported cases (76.8%). A consistent seasonal pattern was observed, with higher case numbers during spring and winter, while summer showed the lowest incidence. CL in Al-Qassim displays distinct demographic and seasonal trends, particularly among young adult males and during the spring and winter months. These patterns highlight the importance of targeted preventive measures and health interventions in high-risk populations and peak transmission periods.

Global seasonal distribution of low-frequency ocean soundscapes

Spatial and seasonal distributions of parent, nitrated, and oxygenated PAHs and health risks in a major industrial city in Korea

Seasonal shifts in mercury speciation and relative methylation potential in cold-arid seasonally ice-covered lakes.

Domestic pigeons (Columba livia domestica) are potential reservoirs of opportunistic yeasts that may pose health risks to humans, particularly in urban environments. This study aimed to investigate the prevalence, seasonal distribution, and molecular identification of Candida species in pigeon feces across Riyadh, Saudi Arabia. Fecal samples were collected from 64 pigeons across four regions of Riyadh during all four seasons. Yeasts were isolated using selective Sabouraud dextrose agar and CHROMagar Candida, purified, and preserved. Species-level identification was performed via morphological analysis, MALDI-TOF mass spectrometry (MS), and molecular techniques targeting the ITS1-5.8S-ITS2 region. Phylogenetic analysis was conducted on confirmed Candida albicans isolates. Overall, 20.31% (n=13) of the samples were positive for fungal isolation. The predominant species were C. albicans, Pichia kudriavzevii, and Clavispora lusitaniae. Seasonal analysis revealed the highest prevalence in spring (7.81%), while the central region of Riyadh showed the highest regional prevalence (7.81%). MALDI-TOF MS successfully identified C. lusitaniae and P. kudriavzevii, whereas C. albicans was confirmed via PCR and ITS sequencing (GenBank: OR467467 and OR467468). Phylogenetic analysis placed C. albicans isolates in a well-supported monophyletic clade. Environmental factors such as temperature and humidity influenced fungal prevalence. Cryptococcus neoformans was not detected. Domestic pigeons in Riyadh serve as environmental reservoirs of pathogenic Candida species, highlighting potential public health risks, particularly for immunocompromised individuals. These findings emphasize the need for monitoring urban bird populations to mitigate opportunistic fungal transmission.

Seasonal abundance, distribution patterns and source attribution of n-alkanes in size-segregated aerosols in Delhi, Indo-Gangetic Plain.

Movement shapes biodiversity patterns and ecosystem functioning, and recent advances in animal tracking have improved our ability to quantify space use. Utilization distributions, site fidelity, and habitat use provide complementary perspectives on where animals concentrate their activity and how consistently they reuse key areas, informing conservation and habitat management. Black-tailed Gulls (Larus crassirostris) are abundant in the Yellow Sea, yet their fine-scale seasonal space use and fidelity patterns remain poorly quantified. From 2020 to 2024, we tracked 15 adult Black-tailed Gulls with GPS loggers on the west coast of the Korean Peninsula for 496-850 days per individual. Breeding, non-breeding, and wintering sites were delineated using hierarchical density-based spatial clustering of applications with noise (HDBSCAN). Seasonal utilization distributions were estimated using weighted autocorrelated kernel density estimation (wAKDE). Home range and core area sizes differed among annual stages, with wintering ranges larger than breeding ranges. Ten individuals tracked across consecutive breeding seasons all returned to the same breeding colonies, and inter-annual home-range overlap and habitat-use similarity remained high across stages. Together, strong fidelity and seasonal habitat switching indicate reliance on repeatedly used key areas, while also suggesting potential vulnerability to ecological traps under rapid environmental change in the Yellow Sea.

ENSO-driven distribution shifts in the critically endangered Mustelus whitneyi along the Northern Peruvian Coast.

Seagrass ecosystems as potential reservoirs of antibiotic and metal resistance genes in the Yellow River Delta, China.

PurposeTo analyze the etiological and epidemiological characteristics of acute lower respiratory infection (ALRI) in hospitalized children in Northeast China (Shenyang, Liaoning Province) following the lifting of non-pharmaceutical interventions (NPIs).Patients and MethodsClinical data and test results for 12 respiratory pathogens from 26,721 hospitalized children with ALRI admitted to two hospitals in Shenyang between January 2023 and December 2025 were retrospectively analyzed. Pathogen detection was performed using polymerase chain reaction (PCR) or serological methods. To control for diagnostic heterogeneity, analyses were stratified by PCR and serology as follows: chi-square test for age, gender, and seasonal distributions; multivariate logistic regression for independent factors associated with pathogen positivity; and Spearman’s rank correlation test for associations between meteorological factors and monthly positivity rates.ResultsPCR testing showed that rhinovirus (RV) had the highest positivity rate (13.80%), followed by influenza A virus (IAV) and respiratory syncytial virus (RSV). RSV was most common in infants aged <1 year, while RV and IAV were more common in children aged 3-<6 years. The positivity rate of RV was higher in males than in females (P < 0.001). IAV and RSV peaked in winter and spring, whereas RV peaked in summer. Serological testing showed that Mycoplasma pneumoniae (MP) had the highest positivity rate (37.64%), followed by RSV and adenovirus (ADV). The detection peaks of MP and ADV were concentrated in children aged 6–14 years. The positivity rates of Epstein-Barr virus (EBV), MP, and Chlamydia pneumoniae (Cpn) were lower in males than in females (all P < 0.05). MP peaked in autumn and winter, while IAV peaked in winter. The age and seasonal distribution patterns of RSV were consistent with those from PCR testing. Age, season, and gender were independent influencing factors for pathogen infection. Meteorological factors were significantly correlated with monthly positivity rates of specific pathogens (P < 0.05).ConclusionFollowing the lifting of NPIs, the pathogen spectrum of childhood ALRI in Shenyang presented distinct seasonal, age, and gender differences. Age, season, and gender were independent influencing factors for pathogen infection. Although methodological differences exist between PCR and serological testing, comparisons within the same detection method are generally reliable.

Forest soils play a critical role in regulating heavy metal dynamics; however, the combined influence of seasonal variability and forest type on metal accumulation and ecological risk remains insufficiently understood in subtropical ecosystems. This study investigated the seasonal distribution and ecological risk of six heavy metals (As, Cd, Cr, Hg, Ni, and Pb) across three forest types, monsoon evergreen broadleaf forest (MEBF), pine-broadleaf mixed forest (PBMF), and Pinus massoniana forest (PMF), in Dinghushan, South China. Soil samples were collected during dry and wet seasons and assessed using contamination factor (CF), geoaccumulation index (I_geo), and potential ecological risk index (PERI), complemented by multivariate statistical analyses. Heavy metal concentrations varied significantly among forest types and seasons. MEBF exhibited higher concentrations of most metals, particularly As, Cr, and Hg, likely due to greater organic matter content and enhanced retention capacity typically associated with mature broadleaf forests. In contrast, PMF showed lower overall concentrations but relatively higher Pb and Ni. Several metals displayed elevated concentrations during the wet season, indicating enhanced redistribution under increased soil moisture. Multivariate analyses revealed that Ni and Cr were strongly associated and may reflect lithogenic influences, whereas Hg, As, and Pb showed patterns consistent with possible atmospheric inputs and ecological processes. Arsenic concentrations reached 65.03mg.kg⁻1 in MEBF during the wet season. Overall ecological risk was low to moderate but increased during the wet season. These findings highlight the interactive effects of forest type and seasonal hydrology on heavy metal dynamics in subtropical forest soils.

Objective: To investigate the changes in the positive rate of specific immunoglobulin E (sIgE) for inhalant and ingestive allergens in children at a certain children's hospital in Wuhan City from 2019 to 2024, and to analyze the characteristics of allergen sensitization in different age groups, genders, and seasons, as well as the trend of allergen changes over different years. Methods: A cross-sectional retrospective study was conducted. Clinical data of 64 116 children aged 0-16 years who visited Wuhan Children's Hospital and underwent sIgE testing for 20 common inhalant and ingestive allergens from January 2019 to December 2024 were collected. The patients were divided into the infant group (25 955 cases, 0-3 years old), the preschool group (22 167 cases, 4-6 years old), the school-age group (15 061 cases, 7-12 years old), and the adolescent group (767 cases, 13-16 years old). Non-parametric rank sum test and χ2 were used for analysis and comparison. Results: A total of 64 116 children with suspected allergic diseases from 2019 to 2024 were included. Among them, the overall positive rate of allergen sIgE was 33.2% (21 258/64 116 cases). Comparison of the positive rate of allergens between different years showed statistically significant differences (χ2=987.392, P<0.05), and a significant upward trend was observed after 2020-2022, with 35.8% (5 416/15 122 cases) and 39.2% (4 872/12 433 cases) in 2023 and 2024, respectively. The top 4 inhalant allergens with the highest positive rate of sIgE in suspected allergic disease children from 2019 to 2024 were Dermatophagoides farinae, house dust, Alternaria alternata, and cat epithelium. Milk, eggs, wheat flour, and soybeans were the main top 4 ingestive allergens. The positive rate of allergens in male children was higher than that in female children for house dust mites, house dust, Alternaria alternata, peanuts, soybeans, milk, crabs, shrimp, eggs, codfish, and wheat flour, with statistically significant differences (P<0.05). There were statistically significant differences in the positive rate of inhalant and ingestive allergens among different age groups (except for common ragweed, mugwort, cockroach, crabs, beef, and mutton), and the positive rate of multiple allergens was higher in the preschool group, such as 33.5% (7 437/22 167 cases) for eggs, 33.1% (6 903/22 167 cases) for Dermatophagoides farinae, and 26.5% (5 876/22 167 cases) for milk. The detection rate of multiple sensitizations increased year by year (The χ2 trend test value is 2 796.539 7, P<0.05), and the proportion of quadruple or more (i.e., detection of 4 or more positive allergens) sensitization reached 12.1% (1 504/12 433 cases) in 2024. The comparison of the positive rate of inhalant and ingestive allergens between seasons showed statistically significant differences (P<0.05). Conclusion: There are distinct gender, age and seasonal distribution characteristics of allergens in children in Wuhan area.

Microplastics in coastal surface waters of Northern Vietnam: Characteristics, seasonal distribution, APCS-MLR-based source apportionment, and ecological risks.

BACKGROUNDFire-related deaths are a significant global public health concern. Although most cases are accidental, some may involve suicide or homicide, making forensic autopsy essential for determining the cause of death. Variations in mortality rates between countries, along with the presence of soot residues and heat-related artifacts, can complicate postmortem interpretation. The classic cherry-pink skin discoloration is not consistently observed; therefore, detection of soot in the upper respiratory tract provides important evidence. This study aimed to evaluate the demographic, forensic, and pathological characteristics of fire-related deaths.METHODSThis retrospective study analyzed fire-related deaths subjected to autopsy at the Morgue Specialization Department of the Erzurum Group Presidency of the Forensic Medicine Institution between 2018 and 2024. Parameters assessed included age, sex, origin of the incident, seasonal distribution, location of the event, degree of burns, and indicators of vitality.RESULTSThe majority of fire-related deaths were accidental and occurred predominantly in adult males. Most incidents took place in residential settings, with a higher frequency observed during the fall and winter seasons. Autopsy findings commonly revealed third- and fourth-degree burns, as well as soot deposition in the respiratory tract and associated pulmonary pathologies. In cases involving prolonged hospitalization, complications emerged as a major contributing factor to mortality.CONCLUSIONFire-related mortality is influenced not only by the extent and severity of burns but also by associated complications and characteristics of vulnerable populations. From a forensic medicine perspective, there is a need to develop fire safety policies and comprehensive strategies to reduce fire-related deaths.

Enhanced per- and polyfluoroalkyl substances (PFAS) exposure in a large estuary-coastal sea continuum shortly after a spring flood event.

Cnaphalocrocis medinalis, a major migratory rice pest in Asia, shows significant variation in female sex pheromone composition across geographical regions. This study investigated the distribution and seasonal dynamics of two distinct sex pheromone strains in populations across China to improve monitoring accuracy and understand migration patterns. Chemical analysis identified two pheromone types: an aldehyde-alcohol blend (AA) dominated by Z13-18:Ald (4.30 ± 2.68 ng per female), and an acetate ester blend (AE) dominated by Z11-16:Ac (5.04 ± 0.72 ng per female). Among 339 females examined, the AE strain was substantially more prevalent (80-97%) in most regions. Ovarian development ranged from levels 2 to 4, with mating frequencies of 0-5 times, indicating the prevalence of the AE strain in natural populations. Large-scale pheromone trapping monitoring across 106 sites outlined distinct geographical and seasonal distributions in males. Southern regions exhibited higher AE proportions in July-August, whereas northern areas, particularly the middle-lower Yangtze provinces, were dominated by the AA strain in August-September, often accounting for 60-90% of captures. For example, AA was >90% in Nantong, whereas AE remained at >80% in Jingzhou. Seasonal shifts occurred in some southern locations, such as Chongzuo, where AE surpassed AA by September. Two pheromone strains of C. medinalis co-occur across China with geographically and seasonally structured distributions. The AE strain predominates overall, but both strains must be used concurrently for accurate population monitoring. This pheromone polymorphism is likely to reflect different geographical origins of migratory populations and provides a foundation for region-specific pest management strategies. © 2026 Society of Chemical Industry.

Febrile infants ≤ 90 days are at increased risk of serious and invasive bacterial infections (SBIs/IBIs), although viral illnesses account for most febrile episodes. Current management algorithms prioritize bacterial risk stratification, while viral epidemiology is inconsistently integrated into pathways. Aim of this study is to describe age-specific bacterial and viral etiologies, seasonality, temporal trends, and co-infections in febrile infants presenting to a tertiary paediatric emergency department. Retrospective observational study including infants ≤ 90 days evaluated between 2018 and 2025. Infants were stratified into three age groups (≤ 28, 29-60, 61-90 days). Bacterial and viral etiologies, co-infections, seasonal distribution, and temporal trends were analysed. Among 1529 infants, SBI represented 15% of cases. IBI was age-dependent, peaking in neonates ≤ 28 days, whereas viral infections predominated across all groups. Approximately 10% of SBIs occurred with documented viral co-infection. Bacterial infections showed no seasonal pattern, while viral infections demonstrated seasonality, with winter respiratory peaks and summer enterovirus/parechovirus circulation. Viral detections declined during 2020-2021 and rebounded in 2022 whereas bacterial rates remained stable. Viral etiologies display pronounced seasonality, whereas bacterial infections remain non-seasonal. Viral positivity does not exclude SBI and urinalysis should remain routine. An epidemiology-aware approach may support without replacing bacterial risk stratification.

The COVID-19 pandemic and associated public health measures disrupted the circulation of respiratory viruses worldwide. However, the long-term impact of these changes on pediatric respiratory tract infections (ARTIs) remains incompletely understood. We conducted a prospective study in children under 14years hospitalized for ARTIs in Severo Ochoa Hospital (Spain) from January/2006 to September/2023. The cohort was divided into three periods: pre-pandemic (T1), pandemic (T2), and post-pandemic (T3). Clinical and virological results were compared. 6048 children were included (T1:5,101; T2:122; T3:825). Viral detection increased in T3 (91%) compared to T1 (78.7%) and T2 (69.5%), p < 0.001, with higher rate of coinfections, p < 0.001, and pneumonia diagnoses, p < 0.001. HRV and RSV were the most frequent viruses across periods, with HRV maintaining year-round circulation and RSV showing marked seasonal disruption in T2, followed by return to its typical winter pattern in T3. Detection of PIV and HMPV increased in T3, with altered seasonal peaks and a shift toward older age groups. Influenza infections, nearly absent in T2, re-emerged in T3 with delayed seasonal peaks and higher median ages. HBoV circulation declined and became more evenly distributed throughout the year. Clinically, children in T3 were older, with more hypoxia, radiological infiltrates, and pneumonia, while bronchiolitis cases decreased. Most pneumonia cases in T3 had a viral etiology, with HRV, RSV, HMPV, and PIV as the main contributors. Post-pandemic shifts in viral circulation and disease profiles among children with ARTIs highlight the ongoing impact of COVID-19 on pediatric respiratory health. The increased burden of viral pneumonia and the change in seasonal distribution of infections underscore the need for updated surveillance, diagnostic strategies, and prevention programs tailored to the post-pandemic context.