High Risk Of Exposure Research Articles

Determination of short- and medium-chain chlorinated paraffins in different components of human blood using gas chromatography-electron capture negative ion-low resolution mass spectrometry

Short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) have attracted significant attention because of their persistence, biotoxicity, bioaccumulation, and long-range migration. Given their worldwide detection in a variety of environmental matrices, concerns related to the high exposure risks of SCCPs and MCCPs to humans have grown. Thus, knowledge of the contamination patterns of SCCPs and MCCPs and their distribution characteristics in the vivo exposure of humans is of great importance. However, little information is available on the contamination of SCCPs and MCCPs in human blood/plasma/serum, mainly because of the difficulty of sample preparation and quantitative analysis. In this study, a new blood sample pretreatment method based on Percoll discontinuous density gradient centrifugation was developed to separate plasma, red blood cells, white blood cells, and platelets from human whole blood. A series of Percoll sodium chloride buffer solutions with mass concentrations of 1.095, 1.077, and 1.060 g/mL were placed in a centrifuge tube from top to bottom to establish discontinuous density gradients. The dosage for each density gradient was 1.5 mL. Human whole blood samples mixed with 0.85% sodium chloride aqueous solution were then added to the top layer of the Percoll sodium chloride solution. After centrifugation, the whole blood was separated into four components. The plasma was located at the top layer of the centrifuge tube, whereas the platelets, white blood cells, and red blood cells were retained at the junction of the various Percoll sodium chloride solutions. The sampling volume of human whole blood and incubation time were optimized, and results indicated that an excessively long incubation time could lead to hemolysis, resulting in a decrease in the recoveries of SCCPs and MCCPs. Therefore, a sampling volume of 1.5 mL and incubation time of 10 min at 4 ℃ were adopted. The cells of the blood components were further broken and extracted by ultrasonic pretreatment, followed by multilayer silica gel column chromatography for lipid removal. The use of 80 mL of n-hexane-dichloromethane (1∶1, v/v) and 50 mL of dichloromethane as the elution solvents (collected together) for the gel column separated the SCCPs and MCCPs from the lipid molecules in the blood samples. Gas chromatography-electron capture negative ion-low resolution mass spectrometry (GC-ECNI-LRMS) was used to determine the SCCPs and MCCPs. Quantification using the corrected total response factor with degrees of chlorination was achieved with linear corrections (R2=0.912 and 0.929 for the SCCPs and MCCPs, respectively). The method detection limits (MDLs) for the SCCPs and MCCPs were 1.57 and 8.29 ng/g wet weight (ww, n=7), respectively. The extraction internal standard recoveries were 67.0%-126.6% for the SCCPs and 69.5%-120.5% for the MCCPs. The developed method was applied to determine SCCPs and MCCPs in actual human whole blood samples. The contents of SCCPs and MCCPs were 10.81-65.23 and 31.82-105.65 ng/g (ww), respectively. Red blood cells exhibited the highest contents of CPs, followed by plasma, white blood cells, and platelets. The proportions of SCCPs and MCCPs in red blood cells and plasma were 70% and 66%, respectively. In all four components, the MCCP contents were higher than the SCCP contents, and the ratios of MCCPs to SCCPs ranged from 1.04 to 3.78. Similar congener patterns of SCCPs and MCCPs were found in the four components of human whole blood. C10-CPs and C14-CPs were predominantly observed in the SCCPs and MCCPs, respectively. In summary, a simple and efficient method was proposed to determine low concentrations of SCCPs and MCCPs in human blood with high sensitivity and selectivity. This method can meet requirements for the quantitative analysis of SCCPs and MCCPs in human blood components, thereby providing technical support for human health risk assessment.

The Extent to which student “Gold Rush” contributes to sexual risky Behaviour amongst students in the spread of HIV/AIDS in higher institutions of learning: A case of Kwame Nkrumah University in Kabwe, Zambia

Transactional sex is very common in institutions of higher learning and has continued to influence high sexual risky behaviours amongst students in Zambian. The terminology that is commonly associated with transactional sex is “gold rush,” a situation where returning students in an institutional of higher learning negotiate for relationships with new students often times with the female first year’s students. The transaction takes place as the senior students negotiate for sexual favours in return for help in terms of money, answering assignments, protection from bullying and other forms of assistance. During transactional sex, there is high sexual risk behaviour as most of the time there is unsafe sex being practiced thereby leading to a high possibility of spreading HIV/AIDS pandemic and other sexually transmitted infections. The study aimed at exploring the vulnerability of students during gold rush. In its approach, the study used a mixed research methodological design. The findings of the study showed that there was high risky sexual behaviours between returning students and the first year’s students on campus leading to high risk exposure to the spread of HIV/AIDS and other related complications. It was recommended that enough sensitizations and well-coordinated awareness programs be engaged in order to mitigate the levels of vulnerability especially amongst female new students who reported on campus.

Effectiveness and resource utilization of hospital-based contact tracing of patients and health care workers with COVID-19 at a tertiary teaching hospital in Thailand

BackgroundThe benefits of contact tracing in health care workers (HCWs) and patients in hospital have rarely been evaluated. This study aimed to assess the yield of contact tracing in order to evaluate the usefulness of resource utilization. MethodsData were collected from 1 April 2021 to 31 March 2022 at teaching hospital in Thailand. The team was notified if any HCW or patient admitted outside COVID-19 designated areas were tested positive. Those with high-risk exposure identified by the team needed to leave from work for 14 days and 2 PCR tests as early as possible and day 14 after the exposure. ResultA total of 4,292 HCWs and 422 patients were exposed to 575 COVID-19 cases and were identified as high-risk contacts, leading to 50,312 days of quarantine and 9,333 PCR tests. The secondary attack rate was 3.42%, which was more common in patients than in HCWs (OR = 1.82, 95%CI = 1.17–2.85, p = 0.0082). Close contact with patients had more secondary attack rates than with HCWs (OR = 1.51, 95%CI:1.01–2.25, p = 0.045). Among those who had close contact with patients, patients but not HCWs had increased risk of infection (OR = 2.86; 95%CI:1.24–6.62; p = 0.0138, OR = 1.06; 95%CI:0.63–1.77; p = 0.834, respectively). The positivity rate of high-risk close contact HCWs was 2.28 per 1,000 person-days after contact, as compared to the positivity rate of low-risk close contact with symptoms at 0.35 per 1,000 person-days during the same period. ConclusionsHospital-based contact tracing could identify more infected HCWs than symptomatic testing alone. Identifying more infected HCWs could potentially prevent infection in both HCWs and patients.

Needlestick Injuries With Insulin Injections: Risk Factors, Concerns, and Implications of the Use of Safety Pen Needles in the Asia-Pacific Region.

Globally, health care workers (HCWs) are at a high risk of occupational exposure to needlestick injuries (NSIs). Needlestick injuries not only are associated with an increased risk of infections caused by bloodborne pathogens but are also a primary source of emotional distress and job burnout for HCWs and patients. Insulin injection-related NSIs are common among HCWs working in hospitals in the Asia-Pacific (APAC) region and impose a significant burden. Insulin pen needles have a high risk of transmitting infections (at both the patient-end and cartridge end of the sharp) after use. Recapping a needle after administering an insulin injection poses a major risk to HCWs. Currently, several safety-engineered needle devices (SENDs) are available with active or passive safety mechanisms. Passive insulin safety pen needles with dual-ended protection and automatic recapping capabilities have resulted in a significant drop in accidental punctures to HCWs while administering insulin to patients with diabetes. In this article, we have reviewed the burden and common causes of NSIs with insulin injections among HCWs in the APAC region. We have discussed current approaches to address the issues associated with NSIs and the benefits of introducing SENDs in health care settings, including long-term care facilities, nursing homes, and home care settings where patients may require assisted insulin injections. This review also summarizes key strategies/recommendations to prevent NSIs in HCWs and patients with diabetes in the APAC region.

COVID-19 Contact Tracing Experience at a Tertiary Healthcare Center in Saudi Arabia.

Introduction As of May 2023, the end of the pandemic, the cumulative number of COVID-19 cases reached more than 841,000 cases. Healthcare workers (HCWs) especially have been at the frontline during this pandemic and are at a higher chance of contracting COVID-19. Approximately half of all high-risk exposures were to healthcare personnel with COVID-19. While several tools for contact tracing were developed for the general public, contact tracing for infectious diseases in the healthcare setting is limited, and global testing of HCWs, or in-hospital digital tracing, is not performed in most facilities. The King Faisal Specialist Hospital and Research Center (KFSH&RC) collaborated with the Infection Control and Health Information Technology Affairs (HITA)to create an automated COVID-19 contact tracing tool specifically for HCWs who worked at the institute. This study aims to describe the contact tracing experience at KFSH&RC. Methods A retrospective study was conducted to describe the use of an automated tool that was developed to assist in the contact tracing process and that was to be used by KFSH&RC employees who had been in contact with a COVID-19-positiveindividual. This tool is utilized for the early identification of possible COVID-19 cases and risk stratification of the exposed individuals. The tool can be accessed through the KFSH&RC website; it also collects information about the COVID-19 exposure rate among the different departments such as administration, capital projects/facilities, and healthcare at a tertiary care hospital in Riyadh, Saudi Arabia Results The tool has been utilized 7,353 times by contact cases. Approximately 7% of those tested later developed a COVID-19 infection. When assessing the positivity rates per department, The Environmental Services Department had the highest positivity rate of 28.21%, followed by Health Information Technology and Analytics (HITA), and then the Central Transportation Department. Conclusion This study acts as the first of its kind to describe the successful use of the healthcare contact tracing system in one of Saudi Arabia's largest hospitals (KFSH&RC) and describe the infection trends in different departments of the hospital. Through the tracing system, the departments with the highest COVID-19 infection occurrences at the hospital were identified in a timely manner, and safety protocols were implemented.

Developing high-resolution PM2.5 exposure models by integrating low-cost sensors, automated machine learning, and big human mobility data

Introduction: Traditional methods to estimate exposure to PM2.5 (particulate matter with less than 2.5 µm in diameter) have typically relied on limited regulatory monitors and do not consider human mobility and travel. However, the limited spatial coverage of regulatory monitors and the lack of consideration of mobility limit the ability to capture actual air pollution exposure.Methods: This study aims to improve traditional exposure assessment methods for PM2.5 by incorporating the measurements from a low-cost sensor network (PurpleAir) and regulatory monitors, an automated machine learning modeling framework, and big human mobility data. We develop a monthly-aggregated hourly land use regression (LUR) model based on automated machine learning (AutoML) and assess the model performance across eight metropolitan areas within the US.Results: Our results show that integrating low-cost sensor with regulatory monitor measurements generally improves the AutoML-LUR model accuracy and produces higher spatial variation in PM2.5 concentration maps compared to using regulatory monitor measurements alone. Feature importance analysis shows factors highly correlated with PM2.5 concentrations, including satellite aerosol optical depth, meteorological variables, vegetation, and land use. In addition, we incorporate human mobility data on exposure estimates regarding where people visit to identify spatiotemporal hotspots of places with higher risks of exposure, emphasizing the need to consider both visitor numbers and PM2.5 concentrations when developing exposure reduction strategies.Discussion: This research provides important insights for further public health studies on air pollution by comprehensively assessing the performance of AutoML-LUR models and incorporating human mobility into considering human exposure to air pollution.

A fluorescent method for bisphenol A detection based on enzymatic oxidation-mediated emission quenching of silicon nanoparticles

As a common raw material of industrial products, bisphenol A (BPA) is widely used in the production of food contact materials, and there is a high risk of exposure in food. However, BPA is a well-known endocrine disruptor and poses a serious threat to human health. Herein, a fluorescent sensing platform of BPA based on enzymatic oxidation-mediated fluorescence quenching of silicon nanoparticles (SiNPs) is established and used to the detection of BPA in food species. The SiNPs are prepared with a facile one-step synthesis and emit bright green fluorescence. BPA can be oxidized by horseradish peroxidase (HRP) and hydrogen peroxide (H2O2) to form a product which can quench the fluorescence of SiNPs through electron transfer. There is a good linear relationship between the fluorescence intensity and BPA concentration in the range of 1–100 μM. Therefore, a fluorometry of BPA is established with a low limit of detection (LOD) of 0.69 μM. This method has been applied to the determination of BPA in mineral drinking water, orange juice, and milk with satisfactory results. The fluorescent sensor of BPA based on SiNPs has favorable application foreground in the field of food safety analysis.

Portrait of Montréal healthcare workers infected with SARS-CoV-2 during the first wave of the pandemic: a cross-sectional study.

During the first wave of COVID-19 in Québec, healthcare workers (HCWs) represented 25% of the cases in Montréal. A study was conducted to describe SARS-CoV-2-infected HCWs in Montréal, and certain workplace and household characteristics. Secondary objectives included estimating the associations between having had access to personal protective equipment (PPE) and training, and following self-isolation recommendations, and certain sociodemographic and workplace characteristics. A cross-sectional study was conducted, based on a stratified random sample, among Montréal HCWs who tested positive for SARS-CoV-2 between March and July 2020. A total of 370 participants answered a telephone-administered questionnaire. Descriptive statistics were conducted, followed by log binomial regressions to estimate the associations. Study participants were mostly female (74%), born outside of Canada (65%), and identified as Black, Indigenous, and People of Colour (BIPOC; 63%). In terms of healthcare positions, most were orderlies (40%) or registered nurses (20%). Half (52%) of the participants reported having had insufficient access to PPE and 30% reported having received no training related to SARS-CoV-2 infection prevention, with large proportions being BIPOC women. Working evening or night shifts decreased chances of having had sufficient access to PPE (OR 0.50; 0.30-0.83). This study describes the profile of the HCWs who were infected during the first wave of the pandemic in Montréal. Recommendations include collecting comprehensive sociodemographic data on SARS-CoV-2 infections and ensuring equitable access to infection prevention and control training and PPE during health crises, particularly those at highest risk of exposure.

Recent progress in analytical strategies of arsenic-binding proteomes in living systems.

Arsenic (As) is one of the most concerning elements due to its high exposure risks to organisms and ecosystems. The interaction between arsenicals and proteins plays a pivotal role in inducing their biological effects on living systems, e.g., arsenicosis. In this review article, the recent advances in analytical techniques and methods of As-binding proteomes were well summarized and discussed, including chromatographic separation and purification, biotin-streptavidin pull-down probes, in situ imaging using novel fluorescent probes, and protein identification. These analytical technologies could provide a growing body of knowledge regarding the composition, level, and distribution of As-binding proteomes in both cells and biological samples, even at the organellar level. The perspectives on analysis of As-binding proteomes are also proposed, e.g., isolation and identification of minor proteins, in vivo targeted protein degradation (TPD) technologies, and spatial As-binding proteomics. The application and development of sensitive, accurate, and high-throughput methodologies of As-binding proteomics would enable us to address the key molecular mechanisms underlying theadverse health effects of arsenicals.

Low-level ambient sulfur dioxide exposure and genetic susceptibility associated with incidence of idiopathic pulmonary fibrosis: A national prospective cohort study

BackgroundThe association between long-term air pollution exposure and the development of idiopathic pulmonary fibrosis (IPF) has been established, but the evidence regarding the effect of low levels of air pollution, especially ambient sulfur dioxide (SO2), is limited. Besides, the combined effect and interaction between genetic susceptibility and ambient SO2 on IPF remain uncertain. MethodsThis study retrieved data from 402,042 participants who were free of IPF at baseline in the UK Biobank. The annual mean concentration of ambient SO2 was estimated for each participant based on their residential addresses using a bilinear interpolation method. Cox proportional hazard models were used to examine the relationship between ambient SO2 and incident IPF. We further generated a polygenic risk score (PRS) for IPF and estimated the combined effects of genetic susceptibility and ambient SO2 on incident IPF. ResultsAfter a median follow-up of 11.78 years, 2562 cases of IPF were identified. The results indicated that each 1 μg/m3 increase in ambient SO2 was associated with a hazard ratio (HR) (95% confidence interval [CI]) of 1.67 (1.58, 1.76) for incident IPF. The study found statistically significant synergistic additive interaction between genetic susceptibility and ambient SO2. Individuals with high genetic risk and high ambient SO2 exposure had a higher risk of developing IPF (HR = 7.48, 95% CI:5.66, 9.90). ConclusionThe study suggests that long-term exposure to ambient SO2, even at concentrations lower than current air quality guidelines set by the Word Health Organization and European Union, may be an important risk factor for IPF. This risk is more pronounced among people with a high genetic risk. Therefore, these findings emphasize the need to consider the potential health effects of SO2 exposure and the necessity for stricter air quality standards.

Global assessment of marine plastic exposure risk for oceanic birds

Plastic pollution is distributed patchily around the world’s oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species.

Identifying the Blood Lead Reference Value Based on the Advisory Committee on Childhood Lead Poisoning Prevention Guidelines and Factors Associated with Elevated Blood Lead Levels among Preschool Children in Thailand, 2019

The blood lead reference value (BLRV) is used for guiding lead prevention and control measures. It is usually defined as the 97.5th percentile of the population-based blood lead level in each country. This study aims to determine the BLRV and factors associated with elevated (≥5 µg/dL) blood lead levels among children aged 1–5 years in Thailand. A cross-sectional study was conducted using secondary data extracted from a national survey, implemented in 171 hospitals during October 2018–September 2019. Demographic characteristics and potential risk factors including lead-related industries were collected. Multilevel logistic regression was used. Of 3,184 children included in the survey, the BLRV was 6.9 µg/dL. Three significant risk factors were identified: living near a lead factory (adjusted odds ratio (AOR) 2.09, 95% CI 1.27–3.42), exposure to the manufacture of fishing tackle (AOR 4.39, 95% CI 1.54–12.50), and exposure to the manufacture of shot and ammunition (AOR 6.30, 95% CI 1.81–21.93). Despite a calculated BLRV of 6.9 µg/dL, we propose a BLRV of 5 μg/dL in Thailand based on guidelines from the United Kingdom. Surveillance of blood lead levels should be established among children at high risk of lead exposure.

Lead precipitation on the gingival tissue of Iraqi workers in some fuel stations in Baghdad

Abstract Background: Lead usually is precipitated at the gingiva of the fuel station workers. Lead interacts with different molecules, thereby interfering with their function. An excess of lead contents could be toxic to the human body. Objectives: This proposed study was conducted for the evaluation of salivary lead level effect and the severity of gingival pigmentation in Iraqi fuel station workers. Materials and Methods: This study involves 40 individuals, who were asked to answer a questionnaire. The case sheet questions involve the personal details of participants such as gender, age, marital status, and working experience. It was filled by the participants. This is followed by an oral examination to assess the oral hygiene status and color of gingiva, then divided into three groups according to working period. To evaluate the level of lead within the saliva, it was estimated in teaching laboratories in Medical City by using atomic absorption spectrophotometer as well as clinical evaluation of the intensity of gingival discoloration according to the gingival surface and dental sites. Data were analyzed using IBM SPSS Statistics and descriptive statistics to calculate the absolute and relative frequencies. Result: It was shown that gingival discoloration was noticed in 40% of the total sample with light brown to mixed brown/pink (average lead level = 5.74 mg/dL). In addition, 30% of the sample had a mixed brown/pink pigmentation (average lead level = 6.75 mg/dL) and the rest (30%) presented with mixed brown/pink to dark brown (average lead level = 10 mg/dL). The working periods range from 3 months to 10 years, the lowest value and the highest of lead in saliva were 8.3 and 11.8 mg/dL, respectively. The average of these values is 10.00 mg/dL. Conclusion: The intensity and severity of gingival pigmentation are directly associated with the level of salivary lead. Occupational safeties are essential for workers who are at high risk of exposure to avoid adverse effects of this metal on general health.

CANINE DISTEMPER VIRUS ECOLOGY: INSIGHTS FROM A LONGITUDINAL SEROLOGIC STUDY IN WILD RACCOONS (PROCYON LOTOR).

Increasing reports of canine distemper virus (CDV) in a variety of hosts, and changing CDV dynamics, have led to renewed interest in the ecology of CDV infections in wildlife. Longitudinal serologic studies provide insights into intrapopulation and intraindividual pathogen dynamics, but few studies in wildlife have been conducted. We used data from 235 raccoons (Procyon lotor) captured on more than one occasion between May 2011 and November 2013 to investigate CDV dynamics in Ontario, Canada. Using mixed multivariable logistic regression, we found that juvenile raccoons were more likely to be seronegative from August to November than from May to July. Using paired titers from CDV-exposed individual raccoons, we determined that the winter breeding season, when there is high intraspecific contact and an increase in susceptible juveniles, may be a period of high risk for CDV exposure. Interestingly, CDV seropositive adult raccoons had nondetectable titers ranging from 1 mo to 1 yr later. Based on our preliminary investigation using two different statistical approaches, CDV exposure was associated with a decrease in parvovirus titer. This result raises important questions about whether virus-induced immune amnesia occurs after CDV exposure, which has been described for measles virus, a closely related pathogen. Overall, our results provide significant insights into CDV dynamics. Further research is needed to investigate whether CDV-induced immune amnesia occurs in raccoons and to determine the potential impacts of a reduced population immunity that may occur secondary to CDV exposure, particularly as it relates to rabies control efforts.

Metastrongyloid Infection with Aelurostrongylus abstrusus, Troglostrongylus brevior, Oslerus rostratus and Angiostrongylus chabaudi in Feral Cats from the Canary Islands (Spain)

Lungworms are a major cause of feline respiratory disease, frequently underdiagnosed due to its presentation of symptoms being similar to that of other feline respiratory pathologies. Epidemiological data about these nematodes are scarce in the Canary Islands (Spain). Given the veterinary importance of these parasites, the aim of the present study was to improve the current epidemiological knowledge of the lungworm species that could be affecting feral cats in this archipelago. A total of 29 feral cats from La Gomera were analyzed. The respiratory tract of each animal was inspected and the nematodes obtained were identified by morphological keys and molecular techniques. Metastrongylids were detected to be widely distributed throughout the island with a prevalence of 55.2% (16/29). The species Aelurostrongylus abstrusus, Troglostrongylus brevior, Oslerus rostratus and Angiostrongylus chabaudi were identified. Also, coinfections with A. chabaudi and O. rostratus were detected in two animals. The present study shows a high diversity of lungworms in feral cats in La Gomera, with the first report of A. chabaudi and T. brevior for the Canary Archipelago and the first citation of A. chabaudi in cats for Spain. The wide distribution and high prevalence found in this study indicate a high risk of exposure to pulmonary infections in cats.

THE EFFECT OF RADIATION PROTECTION ON THE DEVELOPMENT OF THYROID NODULES AMONG RADIOGRAPHERS IN MALANG

The use of radiation technology in Indonesia is mostly applied in the medical world and is immensely beneficial, but radiation exposure also has negative effects on health in the form of deterministic and stochastic effects. The thyroid gland is at a high risk of radiation exposure, which leads to the development of thyroid nodules. To prevent that, there must be safety measures in the use of radiation technology by implementing radiation protection, such as a thyroid shield. This study aims to examine the effect of the compliant use of a thyroid shield on the development of thyroid nodules among radiographers in Malang. This study is an observational study with the use of secondary data, where the primary data were previously gathered cross-sectionally in April 2021. The data from 40 subjects were then analyzed using a T-test with the result of the t-value = 4.299 and α = 0.000. With the result of α < 0.05 and t-value > t-distribution, this study concludes that the use of a thyroid shield has an effect on the development of thyroid nodules among radiographers in Malang, and compliant use can lower the incidence of thyroid nodules. Keywords: Radiation exposure, radiographer, thyroid nodule, thyroid

Hepatitis A seroprevalence, vaccination status and demographic determinants in children and adolescents in Germany, 2014–2017, a population-based study

Children play an important role in hepatitis A virus (HAV) transmission but, due to frequent asymptomatic or mild courses, these infections are underrecognized in routine surveillance. Here, we analyzed hepatitis A (HA) seroprevalence, vaccination status and demographic determinants and estimated previous HAV infections in a cross-sectional population-based study of children and adolescents with residence in Germany 2014–2017, performing weighted univariable and multivariable logistic regression. Of 3567 participants aged 3–17 years, serological results were available for 3013 (84.5%), vaccination records for 3214 (90.1%) and both for 2721 (76.3%). Of 2721 with complete results, 467 (17.2%) were seropositive, thereof 412 (15.1%) with and 55 (2.0%) without previous HA vaccination, indicating previous HAV infection. Seropositivity was associated with age, residence in Eastern states, high socioeconomic status and migration background with personal migration experience. Participants with migration background and personal migration experience also had the highest odds ratios for previous HAV infection. Germany remains a country with very low HA endemicity. The current vaccination recommendations focusing on individuals with a high risk for HAV exposure (e.g. travelers to endemic countries) or severe disease appear appropriate. Migration and travel patterns as well as the endemicity in other countries influence the domestic situation, warranting further monitoring.

Salivary Cortisol and Anxiety in Canadian Dentists over 1 Year of COVID-19

The dental profession has endured unprecedented disruption amid COVID-19. Novel stressors have included a high risk of occupational exposure to COVID-19, financial losses, and stricter infection prevention and control requirements. The present study investigated the longitudinal impact of COVID-19 on the stress and anxiety levels of a cohort of Canadian dentists (N = 222) between September 2020 and October 2021. Salivary cortisol was selected as a biomarker of mental stress, and 10 sets of monthly saliva samples (2,131 in total) were self-collected, sent to our laboratory in prepaid courier envelopes, and analyzed by enzyme-linked immunosorbent assay. To assess COVID-19 anxiety, 9 monthly online questionnaires were administered, comprising a general COVID-19 anxiety instrument and 3 items regarding the impact of dentistry-related factors. Bayesian log-normal mixed effect models were fitted to estimate the longitudinal trajectory of salivary cortisol levels and their association with the disease burden of COVID-19 in Canada. After accounting for age, sex, vaccination status, and the diurnal rhythm of cortisol secretion, a modest positive association was found between dentists’ salivary cortisol levels and the count of COVID-19 cases in Canada (96% posterior probability). Similarly, the self-reported impact of dentistry-related factors, such as fear of getting COVID-19 from a patient or coworker, was greatest during peaks of COVID-19 waves in Canada; however, general COVID-19 anxiety decreased consistently throughout the study period. Interestingly, at all collection points, the majority of participants were not concerned about personal protective equipment. Overall, participants reported relatively low rates of psychological distress symptoms in relation to COVID-19, a result that should be reassuring for the dental community. Our findings strongly suggest a link between self-reported and biochemical measurements of stress and anxiety in Canadian dentists during the COVID-19 pandemic.

Exposure risk and emergency evacuation modeling of toxic gas leakage in urban areas under the influence of multiple meteorological factors

Frequent toxic gas leakage accidents in urban environments cannot be timely controlled and often cause great harm due to the many factors affecting gas diffusion. In this study, based on the coupling method of the Weather Research and Forecasting Model (WRF) and the open source OpenFOAM software platform, the chlorine gas diffusion process at different temperatures, wind speeds, and wind directions in a chemical laboratory and nearby urban areas in Beijing was studied numerically. A dose-response model was used to calculate chlorine lethality and assess exposure risk at the pedestrian level. To predict the evacuation path, an improved ant colony algorithm, a greedy heuristic search algorithm based on the dose-response model, was applied. The results demonstrated that the combination of WRF and OpenFOAM could consider the effects of various factors such as temperature, wind speed, and wind direction on the diffusion of toxic gases. The direction of chlorine gas diffusion was affected by wind direction, and the range of chlorine gas diffusion was affected by temperature and wind speed. The area of high exposure risk (fatality rate above 40%) at high temperatures was 21.05% larger than that at low temperatures. When the wind direction was opposite the building, the high exposure risk area was 78.95% smaller than that under the building direction. The present work provides a promising approach for exposure risk assessment and evacuation planning for the emergency response to urban toxic gas leakage.

Outdoor Health Risk of Atmospheric Particulate Matter at Night in Xi'an, Northwestern China.

The deterioration of air quality via anthropogenic activities during the night period has been deemed a serious concern among the scientific community. Thereby, we explored the outdoor particulate matter (PM) concentration and the contributions from various sources during the day and night in winter and spring 2021 in a megacity, northwestern China. The results revealed that the changes in chemical compositions of PM and sources (motor vehicles, industrial emissions, coal combustion) at night lead to substantial PM toxicity, oxidative potential (OP), and OP/PM per unit mass, indicating high oxidative toxicity and exposure risk at nighttime. Furthermore, higher environmentally persistent free radical (EPFR) concentration and its significant correlation with OP were observed, suggesting that EPFRs cause reactive oxygen species (ROS) formation. Moreover, the noncarcinogenic and carcinogenic risks were systematically explained and spatialized to children and adults, highlighting intensified hotspots to epidemiological researchers. This better understanding of day-night-based PM formation pathways and their hazardous impact will assist to guide measures to diminish the toxicity of PM and reduce the disease led by air pollution.