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This study represents the first analysis of the bacterial community in chickens affected by swollen head syndrome, utilizing 16S rRNA gene sequencing. Samples were obtained from clinical laying chickens and were examined for the presence of Avibacterium paragallinarum (APG) and Ornithobacterium rhinotracheale (ORT) using conventional polymerase chain reaction (PCR). From the samples, five APG-positive (APG) and APG-negative (N-APG) samples were chosen, along with five specific pathogen-free chickens, for 16S rRNA gene sequencing. Results showed that APG and ORT were widely detected in the chicken samples with swollen head syndrome (SHS, 9/10), while APG was detected in all five specific pathogen-free (SPF) samples. In contrast, conventional PCR sensitivity was found to be inadequate for diagnosis, with only 35.7% (5/14) and 11.1% (1/9) sensitivity for APG and ORT, respectively, based on 16S rRNA gene sequencing data. Furthermore, 16S rRNA gene sequencing was able to quantify the bacteria in the samples, revealing that the relative abundance of APG in the APG group ranged from 2.7 to 81.3%, while the relative abundance of APG in the N-APG group ranged from 0.1 to 21.0%. Notably, a low level of APG was also detected in all 5 SPF samples. The study also identified a significant number of animal and human common bacterial pathogens, including but not limited to Gallibacterium anatis, Riemerella columbina, Enterococcus cecorum, Mycoplasma synoviae, Helicobacter hepaticus, and Staphylococcus lentus. In conclusion, 16S rRNA gene sequencing is a valuable tool for bacterial pathogen diagnosis and the discovery of novel bacterial pathogens, while conventional PCR is not reliable for diagnosis., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

This study investigated the determinants of personal exposures (PE) to coarse (PM 2.5-10 ) and fine particulate matter (PM 2.5 ) for elderly communities in Hong Kong. The mean PE PM 2.5 and PM 2.5-10 were 23.6 ± 10.8 and 13.5 ± 22.1 μg/m 3 , respectively during the sampling period. Approximately 76% of study subjects presented statistically significant differences between PE and ambient origin for PM 2.5 compared to approximately 56% for PM 2.5-10 , possibly due to the coarse-size particles being more influenced by similar sources (road dust and construction dust emissions) compared to the PM 2.5 particles. Individual PE to ambient (P/A) ratios for PM 2.5 all exceeded unity (≥1), suggesting the dominant influences of non-ambient particles contributed towards total PE values. There were about 80% individual P/A ratios (≤1) for PM 2.5-10 , implying possible effective infiltration prevention of larger size particulate matter particles leading to dominant influences from the outdoor sources. The higher concentration of NO 3 - and SO 4 2- in PM 2.5-10 compared to PM 2.5 suggests possible heterogeneous reactions of alkaline minerals leading to the formation of NO 3 - and SO 4 2- in PM 2.5-10 particles. The PE and ambient OC/EC ratios in PM 2.5 (8.8 ± 3.3 and 10.4 ± 22.4, respectively) and in PM 2.5-10 (6.0 ± 1.9 and 3.0 ± 1.1, respectively) suggest possible secondary formed OC from surrounding rural areas. Heterogeneous distributions (COD >0.2) between the PE and ambient concentrations were found for both the PM 2.5 and PM 2.5-10 samples. The calibration coefficient as the association between personal and surrogate exposure measure of PE to PM 2.5 (0.84) was higher than PM 2.5-10 (0.52). The findings further confirm that local sources were the dominant contributor to the coarse particles and these coefficients can potentially be used to estimate different PE to PM 2.5 and PM 2.5-10 conditions. A comprehensive understanding of the PE to determinants in coarse particles is essential to further reduce potential exposure misclassification., Competing Interests: Declaration of competing interest We have declared no financial interests/personal relationships which may be considered as potential competing interests Prof. Kin Fai HO reports financial support was provided by The Chinese University of Hong Kong. Prof. Kin Fai HO reports a relationship with The Chinese University of Hong Kong that includes: employment and funding grants. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Ambient fine particulate matter (PM 2.5 ) is a leading environmental risk factor globally, and over half of the associated disease burden are caused by cardiovascular disease. Numerous randomized controlled trials (RCT) have investigated the short-term cardiovascular benefits of indoor air purifiers (IAPs), but major knowledge gaps remain on their longer-term benefits. In this 1-year, randomized, double-blinded, parallel controlled trial of 47 elderly (n true-purification  = 24; n sham-purification  = 23) aged ≥70 years, true-purification reduced household PM 2.5 levels by 28% and maintained lower exposure throughout the year compared to the sham-purification group. After 12 months of intervention, a significant reduction of diastolic blood pressure was found in the true-purification versus sham-purification group (-4.62 [95% CI: -7.28, -1.96] mmHg) compared to baseline measurement prior to the intervention, whereas systolic blood pressure showed directionally consistent but statistically non-significant effect (-2.49 [95% CI: -9.25, 4.28] mmHg). Qualitatively similar patterns of associations were observed for pulse pressure (-2.30 [95% CI: -6.57, 1.96] mmHg) and carotid intima-media thickness (-10.0% [95% CI: -24.8%, 4.7%]), but these were not statistically significant. Overall, we found suggestive evidence of cardiovascular benefits of long-term IAPs use, particularly on diastolic blood pressure. Evidence on other longer-term cardiovascular traits is less clear. Further trials with larger sample sizes and long-term follow-up are needed across diverse populations to evaluate the cardiovascular benefits of IAPs., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Ka Hung Chan reports financial support was provided by BHF Centre of Research Excellence. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

To investigate the characteristics of oxygenated volatile organic compounds (OVOCs) and their potential contribution to ozone (O 3 ) generation, we conducted 3-h high-resolution observations during the summertime of 2022 and the wintertime of 2021. This study focused on a total of 28 OVOCs in five different chemical classes, which were encompassed at two representative sites in Hong Kong, including a roadside and an urban area. During the summertime, the total concentrations of quantified OVOCs (∑ OVOCs ) were 45 ± 12 and 63 ± 20 μg m -3 at the roadside and urban sites, respectively, whereas the ∑ OVOCs decreased by 31 ± 11 % and 38 ± 13 %, respectively, during the wintertime. Among the classes of OVOCs, carbonyls and alcohols were the two predominant at both sites, with relatively higher concentration levels of acetone, methanol, butanaldehyde, and acrolein. The sources of OVOCs have significant spatial and temporal characteristics. Spatially, OVOCs were predominately attributed to primary emission and background at the roadside site, whereas they were a combination of primary emission, secondary formation, and background at the urban site. Temporally, background sources dominated the summertime OVOCs, while the contribution of primary emissions increased for the wintertime OVOCs. The O 3 formation potential (OFP) for the OVOCs was calculated. The OFPs were 67 ± 16 and 119 ± 31 μg m -3 at the roadside and urban sites during the summertime, whereas the winter OFPs declined 30 % at the roadside and 38 % at the urban site. The background sources of carbonyls and alcohols at the roadside and of carbonyls and acrylates in the urban area were the major contributors to the summer OFP. Controlling the OVOC sources from local non-combustion sources such as gasoline-fuel evaporation and volatile chemical-containing products could lead to a reduction of OVOCs in the background and subsequently mitigate the OFP. This is beneficial for local O 3 reduction in Hong Kong and surrounding regions., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2023 Elsevier B.V. All rights reserved.)