Annual Risk Of Infection Research Articles

Comparison of treatment trains for indirect potable reuse and use of quantitative microbial risk assessment (QMRA) to evaluate reliability of pathogen removal: Zoo Miami case study

Wastewater and reclaimed water contain various microorganisms such as bacteria, viruses, and protozoa that can cause waterborne diseases in humans and animals. Zoos and animal conservation parks utilize reclaimed water for various purposes which may contain pathogens harmful to human and animal health. The goal of this study was to assess the treatment performance of two treatment trains for indirect potable reuse (IPR) and perform quantitative microbial risk assessment (QMRA) to evaluate the reliability of pathogen removal at a proposed advanced water treatment facility at the Zoo Miami. A review of advanced treatment and disinfection technologies relevant for reclaimed water production and pathogen removal was conducted as a part of this study. DPRisk was used to perform QMRA for four reference pathogens selected as model organisms for two IPR treatment trains (TT1 and TT2). Public health risk estimates for pathogens including Adenovirus, Cryptosporidium, Giardia, and enteric viruses indicated that the risk of infection was below the EPA's target daily threshold of 2.7 × 10−7 and annual risk threshold of 10−4 without failure analysis. With failure analysis, both treatment trains met the daily risk goals for each of the reference pathogens approximately 99 % of the time. Adenovirus demonstrated the highest probability of infection with a mean annual risk of infection for TT1 of 6.65 × 10−9 in the absence of failures but reached a maximum of 7.34 × 10−2 with failure analysis. TT2 resulted in higher risk estimates compared to TT1 with a mean annual risk of infection of 2.10 × 10−8 without failure and a maximum of 8.37 × 10−2 with failure analysis. The results of the failure analysis demonstrate the benefit of treatment redundancy in potable reuse system design and highlight the importance of online process monitoring to rapidly identify off-spec or treatment failure events to protect public health. With this information, stakeholders can better understand treatment requirements and microbiological risks to inform potable reuse planning, design, and risk management.

Quantifying microbial risk from drinking water production process under changing climate and socio-economic conditions

Consumption of drinking water containing pathogenic microorganisms may pose serious health risks from waterborne diseases. Quantifying such risks is essential for guiding interventions and policy decisions. Quantitative microbial risk assessment (QMRA) is a very useful method to estimate the public's risk of infection from disease-causing microorganisms in water sources. QMRA of drinking water production process is limited worldwide and so far no such QMRA study has been conducted in Bangladesh. Moreover, climate and socio-economic changes may impact waterborne pathogens and associated health risks, but to what extent remains unclear, because comprehensive QMRA by taking into account combined impact of climatic and socio-economic factors has never been done worldwide so far. In this study, the Swedish QMRA tool was applied to evaluate public health risk from drinking water production process in Dhaka, Bangladesh as a case study. At first, current risk was quantified, and then the potential future risk was projected by taking into account climate and socio-economic factors. The results revealed that the annual infection risks at the current (2020s) baseline condition were below the acceptable risk threshold 10–4 infections per person per year (as proposed by several USEPA scientists) for all three pathogens Salmonella, norovirus and Giardia. However, after extreme events with sewer overflow and agricultural runoff, norovirus violates the acceptable risk thresholds, and the risks for Salmonella and Giardia are in borderline. The selected sustainable future scenario showed some improvement in terms of annual infection risks, while the uncontrolled scenario resulted in substantially higher infection risks both in the near and far future compared to the current scenarios. installment of a UV treatment step as an additional treatment barrier resulted in significant infection risk reduction. According to the sensitivity analysis results, socio-economic factors such as human population, livestock, and pathogen removal in wastewater were found to have greater influence on the infection risks, compared to climate change. The study can help policy makers and water managers to identify interventions to reduce the burden of disease on the population. The tool can be used to assess the health risk associated with drinking water production process in other areas of the world with similar characteristics.

Tuberculosis Immunoreactivity Surveillance in Malawi (Timasamala)-A protocol for a cross-sectional Mycobacterium tuberculosis immunoreactivity survey in Blantyre, Malawi.

Tuberculosis (TB) transmission and prevalence are dynamic over time, and heterogeneous within populations. Public health programmes therefore require up-to-date, accurate epidemiological data to appropriately allocate resources, target interventions, and track progress towards End TB goals. Current methods of TB surveillance often rely on case notifications, which are biased by access to healthcare, and TB disease prevalence surveys, which are highly resource-intensive, requiring many tens of thousands of people to be tested to identify high-risk groups or capture trends. Surveys of "latent TB infection", or immunoreactivity to Mycobacterium tuberculosis (Mtb), using tests such as interferon-gamma release assays (IGRAs) could provide a way to identify TB transmission hotspots, supplementing information from disease notifications, and with greater spatial and temporal resolution than is possible to achieve in disease prevalence surveys. This cross-sectional survey will investigate the prevalence of Mtb immunoreactivity amongst young children, adolescents and adults in Blantyre, Malawi, a high HIV-prevalence city in southern Africa. Through this study we will estimate the annual risk of TB infection (ARTI) in Blantyre and explore individual- and area-level risk factors for infection, as well as investigating geospatial heterogeneity of Mtb infection (and its determinants), and comparing these to the distribution of TB disease case-notifications. We will also evaluate novel diagnostics for Mtb infection (QIAreach QFT) and sampling methodologies (convenience sampling in healthcare settings and community sampling based on satellite imagery), which may increase the feasibility of measuring Mtb infection at large scale. The overall aim is to provide high-resolution epidemiological data and provide new insights into methodologies which may be used by TB programmes globally.

Two-year Monitoring of Microbiological Water Quality in Small Water Supply Systems: Implications for Microbial Risk Management.

Small water supply systems (SWSSs) are often more vulnerable to waterborne disease outbreaks. In Japan, many SWSSs operate without regulation under the Waterworks Law, yet there is limited investigation into microbial contamination and the associated health risks. In this study, the microbiological water quality of four SWSSs that utilize mountain streams as water sources and do not install water treatment facilities were monitored for over 2 years. In investigated SWSSs, the mean heterotrophic plate counts were below 350 CFU/mL, and the total bacterial loads (16S rDNA concentration) ranged from 4.71 to 5.35 log10 copies/mL. The results also showed the consistent presence of fecal indicator bacteria (FIB), i.e., Escherichia coli and Clostridium perfringens, suggesting the potential of fecal pollution. E. coli was then utilized as an indicator to assess the health risk posed by E. coli O157:H7 and Campylobacter jejuni. The results indicated that the estimated mean annual risk of infection and disability-adjusted life years (DALYs) exceeded acceptable levels in all SWSSs for the two reference pathogens. To ensure microbial water safety, implementing appropriate water treatment facilities with an estimated mean required reduction of 5-6 log10 was necessary. This study highlighted the potential microbial contamination and health risk level in SWSSs that utilize mountain streams as water sources, even though the water sources were almost not affected by human activities. Furthermore, this study would also be helpful in supporting risk-based water management to ensure a safe water supply in SWSSs.

Quantitative microbial risk assessment of gastrointestinal illness due to recreational exposure to E. coli and enterococci on the southern coasts of the Caspian Sea

BackgroundGastrointestinal illness refers to a broad range of diseases that affect the digestive system, including infections caused by bacteria, viruses, and parasites. Quantitative Microbial Risk Assessment (QMRA) is a powerful tool used to evaluate the risks associated with microbial pathogens in various environments. The main objective of this study was to conduct a quantitative assessment of gastrointestinal illnesses that occur as a result of exposure to E. coli and enterococci during recreational activities on the southern coasts of the Caspian Sea. MethodsSamples were collected from the recreational beaches along the border line of the Caspian Sea. The samples were analyzed for the presence and enumeration of E. coli and enterococci using the microplate method and membrane filtration techniques. Then, the annual and daily infection risks were computed using the Monte Carlo simulation approach. ResultsThe results revealed that the risk of daily and annual infections on the coasts of Babolsar was higher than that on the coasts of Sari. Also, in the recreational waters of these beaches, the risk of infection by enterococci was higher than that posed by E. coli. In Babolsar, the average annual infection risk caused by E. coli and enterococci was 0.365 and 1 for children and 0.181 and 0.986 for adults. Also, in Sari, the average annual infection risk caused by E. coli and enterococci was 0.060 and 0.908 for children and 0.027 and 0.815 for adults. In addition, children were more likely than adults to become infected. ConclusionIn light of the study's findings, due to the entry of untreated urban wastewater into the southern part of the Caspian Sea (northern Iran) and the high risk of infectious diseases for children, more control and health measures are necessary for children's swimming.

Estimation and evaluation of the risks of protozoa infections associated to the water from a treatment plant in southern Brazil using the Quantitative Microbiological Risk Assessment Methodology (QMRA).

In this study, the Quantitative Microbial Risk Assessment (QMRA) methodology was applied to estimate the annual risk of Giardia and Cryptosporidium infection associated with a water treatment plant in southern Brazil. The efficiency of the treatment plant in removing protozoa and the effectiveness of the Brazilian legislation on microbiological protection were evaluated, emphasizing the relevance of implementing the QMRA in this context. Two distinct approaches were employed to estimate the mechanical removal of protozoa:The definitions provided by the United States Environmental Protection Agency (USEPA), and the model proposed by Neminski and Ongerth.Although the raw water collected had a higher concentration of Giardia cysts than Cryptosporidium oocysts, the estimated values for the annual risk of infection were significantly higher for Cryptosporidium than for Giardia. From a general perspective, the risk values of protozoa infection were either below or very near the limit set by the World Health Organization (WHO). In contrast, all the risk values of Cryptosporidium infection exceeded the threshold established by theUSEPA. Ultimately, it was concluded that the implementation of the QMRA methodology should be considered by the Brazilian authorities, as the requirements and guidelines provided by the Brazilian legislation proved to be insufficient to guarantee the microbiological safety of drinking water. In this context, the QMRA application can effectively contribute to the prevention and investigation of outbreaks of waterborne disease.

Detection and quantitative microbial risk assessment of pathogenic Vibrio cholerae in a river used for drinking, domestic, fresh produce irrigation and recreational purposes

Cholera infection results from the ingestion of water or food contaminated with toxigenic Vibrio cholerae. This study evaluated the occurrence of toxigenic V. cholerae in Asata River, Enugu Metropolis, Nigeria, and estimated V. cholerae infection risks from use of the River water for drinking, domestic and recreational purposes. Vibrio was detected and quantified using membrane filtration technique and thiosulfate–citrate–bile salts–sucrose agar. Isolates were screened by PCR, using specific primers targeting the internal transcribed spacer (its) region between 16 and 23S rRNA and the cholera toxin (ctx) gene. Sequenced 16SrRNA gene amplicons of two selected isolates were used for phylogenetic analysis. Quantitative microbial risk assessment (QMRA) was conducted using the β-Poisson dose–response model. About 81% (58/72) of Asata River samples recorded Vibrio counts above 1.0 ×\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ imes$$\\end{document} 103 cfu/100 mL. Of the fifty Vibrio isolates screened, its was detected in 54% (27/50), out of which 74% (20/27) had the ctx gene of toxigenic V. cholerae. Evolutionary relatedness of the sequenced isolates to V. cholerae was revealed. The estimated risks of cholera infection in persons exposed to untreated Asata River water were above 0.5 for all the exposure scenarios, for both the rainy and dry seasons. The risks were highest (~ 0.9) for exposure via drinking water and annual risk of infection was deduced to have a probability of 1.0. Therefore, dependence on the untreated Asata River water for drinking, recreational, domestic and irrigation purposes may present a potential public health risk of cholera outbreak. We recommend increased monitoring and surveillance of River water for Vibrio abundance and that Asata River be protected from further degradation.

Airborne transmission risks of tuberculosis and COVID-19 in schools in South Africa, Switzerland, and Tanzania: Modeling of environmental data.

The COVID-19 pandemic renewed interest in airborne transmission of respiratory infections, particularly in congregate indoor settings, such as schools. We modeled transmission risks of tuberculosis (caused by Mycobacterium tuberculosis, Mtb) and COVID-19 (caused by SARS-CoV-2) in South African, Swiss and Tanzanian secondary schools. We estimated the risks of infection with the Wells-Riley equation, expressed as the median with 2.5% and 97.5% quantiles (credible interval [CrI]), based on the ventilation rate and the duration of exposure to infectious doses (so-called quanta). We computed the air change rate (ventilation) using carbon dioxide (CO2) as a tracer gas and modeled the quanta generation rate based on reported estimates from the literature. The share of infectious students in the classroom is determined by country-specific estimates of pulmonary TB. For SARS-CoV-2, the number of infectious students was estimated based on excess mortality to mitigate the bias from country-specific reporting and testing. Average CO2 concentration (parts per million [ppm]) was 1,610 ppm in South Africa, 1,757 ppm in Switzerland, and 648 ppm in Tanzania. The annual risk of infection for Mtb was 22.1% (interquartile range [IQR] 2.7%-89.5%) in South Africa, 0.7% (IQR 0.1%-6.4%) in Switzerland, and 0.5% (IQR 0.0%-3.9%) in Tanzania. For SARS-CoV-2, the monthly risk of infection was 6.8% (IQR 0.8%-43.8%) in South Africa, 1.2% (IQR 0.1%-8.8%) in Switzerland, and 0.9% (IQR 0.1%-6.6%) in Tanzania. The differences in transmission risks primarily reflect a higher incidence of SARS-CoV-2 and particularly prevalence of TB in South Africa, but also higher air change rates due to better natural ventilation of the classrooms in Tanzania. Global comparisons of the modeled risk of infectious disease transmission in classrooms can provide high-level information for policy-making regarding appropriate infection control strategies.

What is the annual risk of infection in congenital midline neck cysts in children? Thyroglossal duct cysts versus dermoid cysts

IntroductionMidline neck lumps in children are mostly found to be thyroglossal duct cysts or dermoid cysts. Thyroglossal duct cysts often have an associated sinus tract which may connect all the way to the foramen caecum on the tongue, while dermoids have no such connection. This study aims to estimate the annual infection risk for midline neck cysts based on our patient series, and to see if this differs between thyroglossal duct cysts and dermoid cysts. MethodsAll children seen at the Royal Hospital for Children, Glasgow who underwent surgical excision of a midline neck cyst between 1st January 2017 and 31st December 2021 were identified. In those whose cyst had been infected prior to surgical excision, the age at which the first episode of infection occurred was recorded and used to calculate a survival curve. ResultsWe identified 53 children (29 male, 24 female) aged 1–16 years (median 4) at the time of surgical excision. There were 26 thyroglossal and 24 dermoid cysts, plus 2 with indeterminate histology and 1 lymph node. Of the 24 dermoids, 4 suffered infection prior to surgery (17%), and 2 of these recurred after surgery (8%). Of the 26 thyroglossal cysts, 16 suffered infection prior to surgery (62%) and 5 of these recurred (19%). 78% of thyroglossal and dermoid cysts had at least 1 episode of infection by age 10 years. DiscussionIn a child with a congenital midline neck cyst that has never been infected, deferring surgery for a year comes with a 7.8% risk that the cyst will get infected.

Annual risk of hepatitis E virus infection and seroreversion: Insights from a serological cohort in Sitakunda, Bangladesh.

Hepatitis E virus (HEV) is a major cause of acute jaundice in South Asia. Gaps in our understanding of transmission are driven by non-specific symptoms and scarcity of diagnostics, impeding rational control strategies. In this context, serological data can provide important proxy measures of infection. We enrolled a population-representative serological cohort of 2,337 individuals in Sitakunda, Bangladesh. We estimated the annual risks of HEV infection and seroreversion both using serostatus changes between paired serum samples collected 9months apart, and by fitting catalytic models to the age-stratified cross-sectional seroprevalence. At baseline, 15% (95 CI: 14-17%) of people were seropositive, with seroprevalence highest in the relatively urban south. During the study, 27 individuals seroreverted (annual seroreversion risk: 15%, 95 CI: 10-21%), and 38 seroconverted (annual infection risk: 3%, 95CI: 2-5%). Relying on cross-sectional seroprevalence data alone, and ignoring seroreversion, underestimated the annual infection risk five-fold (0.6%, 95 CrI: 0.5-0.6%). When we accounted for the observed seroreversion in a reversible catalytic model, infection risk was more consistent with measured seroincidence. Our results quantify HEV infection risk in Sitakunda and highlight the importance of accounting for seroreversion when estimating infection incidence from cross-sectional seroprevalence data.

Effectiveness and health risk assessment of drinking water from different sources treated by local household water treatment methods in Bamenda, Cameroon

Abstract This study accessed the efficiency and health risks of drinking water from different sources treated by filtration, boiling, chlorination, flocculation, and solar disinfection. The microbial quality of 45 treated water samples from boreholes, wells, and pipe-borne water was analyzed to determine treatment effectiveness and to quantify risk using quantitative microbial risk assessment. The effectiveness of each treatment method was a function of sampling sources (p < 0.05) and location (p < 0.10), chlorination and boiling being the most efficient methods (100%). Shiegella in well water samples treated by filtration and flocculation had the highest daily infection risk of 69.5 × 10−1 and 67.5 × 10−1 pppd. The annual risk of infection from Salmonella, Shigella, and Staphylococcus ranged from 7.8 × 10−1 to 1.00 pppy, exceeding the U.S. EPA annual infection benchmark (≤10−4 pppy). Salmonella, Shigella, and Staphylococcus had the highest risk of illness of 4.50 × 10−1, 3.30 × 10−1, and 9.80 × 10−1, respectively. All disease burden values exceeded the WHO disease burden benchmark (≤10−6 DALYs/pppy), with Staphylococcus and Salmonella contributing the highest disease burden of 4.71 × 10−2 and 2.13 × 10−2, DALYs/pppy. Therefore, boiling and chlorination are the best disinfection methods for the pathogens tested.

The prevalence of tuberculosis infection among foreign-born Canadians: a modelling study.

The prevalence of tuberculosis infection is critical to the design of tuberculosis prevention strategies, yet is unknown in Canada. We estimated the prevalence of tuberculosis infection among Canadian residents born abroad. We estimated the prevalence of tuberculosis infection by age and year of migration to Canada for people from each of 168 countries by constructing country-specific and calendar year-specific trends for annual risk of infection using a previously developed model. We combined country-specific prevalence estimates with Canadian Census data from 2001, 2006, 2011, 2016 and 2021 to estimate the overall prevalence of tuberculosis infection among foreign-born Canadian residents. The estimated overall prevalence of tuberculosis infection among foreign-born people in Canada was 25% (95% uncertainty interval [UI] 20%-35%) for census year 2001, 24% (95% UI 20%-33%) for 2006, 23% (95% UI 19%-30%) for 2011, 22% (95% UI 19%-28%) for 2016 and 22% (95% UI 19%-27%) for 2021. The prevalence increased with age at migration and incidence of tuberculosis in the country of origin. In 2021, the estimated prevalence of infection among foreign-born residents was lowest in Quebec (19%, 95% UI 16%-24%) and highest in Alberta (24%, 95% UI 21%-28%) and British Columbia (24%, 95% UI 20%-30%). Among all foreign-born Canadian residents with tuberculosis infection in 2021, we estimated that only 1 in 488 (95% UI 185-1039) had become infected within the 2 preceding years. About 1 in 4 foreign-born Canadian residents has tuberculosis infection, but very few were infected within the 2 preceding years (the highest risk period for progression to tuberculosis disease). These data may inform future tuberculosis infection screening policies.

A simulation-based method to inform serosurvey design for estimating the force of infection using existing blood samples.

The extent to which dengue virus has been circulating globally and especially in Africa is largely unknown. Testing available blood samples from previous cross-sectional serological surveys offers a convenient strategy to investigate past dengue infections, as such serosurveys provide the ideal data to reconstruct the age-dependent immunity profile of the population and to estimate the average per-capita annual risk of infection: the force of infection (FOI), which is a fundamental measure of transmission intensity. In this study, we present a novel methodological approach to inform the size and age distribution of blood samples to test when samples are acquired from previous surveys. The method was used to inform SERODEN, a dengue seroprevalence survey which is currently being conducted in Ghana among other countries utilizing samples previously collected for a SARS-CoV-2 serosurvey. The method described in this paper can be employed to determine sample sizes and testing strategies for different diseases and transmission settings.

Patient Preferences for Ulcerative Colitis Treatment in the Middle East Region: A Discrete-Choice Experiment

Treatments for ulcerative colitis (UC) differ in safety, efficacy, and route of administration; patient preferences for treatment attributes should be considered in treatment decisions. No study to date has explored patient preferences for moderate-to-severe UC treatment in Middle Eastern countries. A discrete-choice experiment aimed to quantify treatment preferences in patients with moderate-to-severe UC in 5 Middle Eastern countries (Saudi Arabia, Kuwait, Jordan, the United Arab Emirates, and Lebanon). Respondents chose between experimentally designed profiles for hypothetical UC treatments with varying efficacy (time until UC symptoms improve and chance of UC symptom control after 1 year), side effects (annual risk of serious infection, 5-year risk of malignancy), mode and frequency of administration, and need for occasional steroid use. A random-parameters logit model was used to estimate preference weights for these attributes, from which conditional relative importance estimates and maximum acceptable increases in risks of serious infection and malignancy were derived. Among 365 adults with moderate-to-severe UC who completed the survey (mean age, 36 years; 50% female), 5-year risk of malignancy and symptom control after 1 year had the greatest conditional relative importance. Respondents were generally willing to accept statistically significant increases in annual risk of serious infection and 5-year risk of malignancy in exchange for better efficacy, changes in mode of administration and dosing schedule, and avoiding occasional steroid use. Of the attributes evaluated, individuals with UC in Middle Eastern countries most value avoiding 5-year risk of malignancy and a higher probability of symptom control, on average.

APPLICATION OF QMRA TO EVALUATE THE POTENTIAL HEALTH RISKS ASSOCIATED WITH BACTERIAL CONTAMINATION OF WATERS IN ROYAL BELUM STATE PARK, MALAYSIA

Temenggor Lake located in Royal Belum State Park is an important water resource for indigenous people, an ecosystem for aqua organisms and a place for water recreational activities for visitors. The aim of this research was to use a quantitative microbial risk assessment (QMRA) approach to calculate the probability of potential pathogen infection risk to the visitors and the indigenous community. Thirty-six water samples were collected from the surface waters of Temenggor Lake from recreational water activity and indigenous people activity sites from November 2020 till December 2021. Membrane filtration technique was used for bacterial quantification. The risk was estimated using the calculation of the daily risk of infection, annual risk of infection, and risk of illness per annum and per event. The water quality during sampling periods at year-end showed higher bacterial concentrations related to rainfall events. Bacterial concentrations at visitor water activity areas were within Category A allowing for recreational activities with full body contact while water quality at indigenous people water activity areas were classified as Category B to be used mainly for secondary body contact and hence not allowed for swimming and bathing. Notably, indigenous people's settlement areas recorded a higher risk of illness for both E. coli and Salmonella spp., mainly at station A03 (Kg. Sungai Tiang). It has been revealed that water quality in indigenous people and visitor water activity areas were significantly different due to being affected by different types of human activity and other factors such as geohydrological conditions, topography, land use, environmental conditions and events. This study provides baseline data to help in future management strategies to ensure the conservation of the natural landscape and economic viability, in addition to the protection of the local community.

Public Health Impact and Cost-Effectiveness of Screening for Active Tuberculosis Disease or Infection Among Children in South Africa.

Although tuberculosis disease is a leading cause of global childhood mortality, there remain major gaps in diagnosis, treatment, and prevention in children because tuberculosis control programs rely predominantly on presentation of symptomatic children or contact tracing. We assessed the public health impact and cost-effectiveness of age-based routine screening and contact tracing in children in South Africa. We used a deterministic mathematical model to evaluate age-based routine screening in 1-year increments from ages 0 to 5 years, with and without contact tracing and preventive treatment. Screening incorporated symptom history and tuberculin skin testing, with chest x-ray and GeneXpert Ultra for confirmatory testing. We projected tuberculosis cases, deaths, disability-adjusted life years (DALYs), and costs (in 2021 U.S. dollars) and evaluated the incremental cost-effectiveness ratios comparing each intervention. Routine screening at age 2 years with contact tracing and preventive treatment averted 11 900 tuberculosis cases (95% confidence interval [CI]: 6160-15 730), 1360 deaths (95% CI: 260-3800), and 40 000 DALYs (95% CI: 13 000-100 000) in the South Africa pediatric population over 1 year compared with the status quo. This combined strategy was cost-effective (incremental cost-effectiveness ratio $9050 per DALY; 95% CI: 2890-22 920) and remained cost-effective above an annual risk of infection of 1.6%. For annual risk of infection between 0.8% and 1.6%, routine screening at age 2 years was the dominant strategy. Routine screening for tuberculosis among young children combined with contact tracing and preventive treatment would have a large public health impact and be cost-effective in preventing pediatric tuberculosis deaths in high-incidence settings such as South Africa.

Performance analysis of interactive cascade ventilation combined with solar energy for the epidemic prevention and control

Increasing low-grade and renewable energy sources in the HVAC systems has become necessary to reduce heating energy consumption. Hence, seeking a new air conditioning system that can be combined with renewable energy is significant to maintain a healthy and comfortable indoor environment with a low cost. This paper proposes a novel air source heat pumps assisted solar hot water with interactive cascade ventilation system (shortened as SWAP-ICV). Taking the traditional air source heat pumps with mixing ventilation system (AP-MV) as a reference, the virus control performance and energy efficiency of SWAP-ICV is investigated through CFD and TRNSYS simulations. The results demonstrate that interactive cascade ventilation under full-fresh air operation mode and normal-epidemic linkage mode can make the annual infection risk reduce by 41.16% and 9.33% compared with mixing ventilation under full-fresh air operation mode. Meanwhile, the proposed system can reduce energy consumption by 59.92% and 69.8% during the normal period and epidemic period by introducing solar energy. The average system COP during the heating season indicates that SWAP-ICV can improve the system efficiency by 1.9–2.58 times than AP-MV system. The conclusions obtained from this research can provide new ideas for the design and operation of air conditioning systems in the post-epidemic era.

Non-potable water reuse and the public health risks from protozoa and helminths: a case study from a city with a semi-arid climate.

The study estimated the risk due to Cryptosporidium, Giardia, and Ascaris, associated with non-potable water reuse in the city of Jaipur, India. The study first determined the exposure dose of Cryptosporidium, Giardia, and Ascaris based on various wastewater treatment technologies for various scenarios of reuse for six wastewater treatment plants (WWTPs) in the city. The exposure scenarios considered were (1) garden irrigation; (2) working and lounging in the garden; and (3) consumption of crops irrigated with recycled water. The estimated annual risk of infection varied between 8.57 × 10-7 and 1.0 for protozoa and helminths, respectively. The order of treatment processes, in decreasing order of annual risk of infection, was found to be: moving-bed bioreactor (MBBR) technology > activated sludge process (ASP) technology > sequencing batch reactor (SBR) technology. The estimated annual risk was found to be in this order: Ascaris > Giardia > Cryptosporidium. The study also estimated the maximum allowable concentration (Cmax) of pathogen in the effluent for a benchmark value of annual infection of risk equal to 1:10,000, the acceptable level of risk used for drinking water. The estimated Cmax values were found to be 6.54 × 10-5, 1.37 × 10-5, and 2.89 × 10-6 (oo) cysts/mL for Cryptosporidium, Giardia, and Ascaris, respectively.

Outcome of Single Stage Anterior and Posterior Surgery for Tuberculous Paraplegia.

Morbidity and mortality from tuberculosis, a significant infectious illness, are expected to rise worldwide. The projected number of new cases rose from 7.5 million in 1990 to 11.9 million in 2005, a 58.6% increase in 2011. The widespread belief that TB is no longer a public health concern is unfounded; on the contrary, the link between HIV/AIDS and antibiotic resistance has further exacerbated the crisis that already existed. Similar to the nations in sub-Saharan Africa, India is now considered a Group IV country, with an annual risk of infection between 1% and 2.5%. 2. Although 60% of TB cases occur in people who are HIV-positive, only 3-5% of cases in HIV-negative individuals are skeletal. The most frequent type of articuloskeletal tuberculosis is spinal tuberculosis. 1. The goal of this study is to evaluate the neurological outcome of anterior debridement, fusion, posterior instrumentation, and early rehabilitation in individuals with spinal cord injuries. 2. The goal of this study is to determine the prevalence of pressure ulcers, hypostatic pneumonia, and urinary tract infections urinary tract infections (UTIs) among these individuals. 3. The goal of this study is to determine the frequency of graft-related problems. 4. See how well these individuals are able to keep their corrected deformities from returning. Patients who had simultaneous anterior (anterior debridement and bone grafting) and posterior (posterior instrumentation and fusion) procedures were followed prospectively. Thirty patients' films were examined. In addition, cord edema was suggested in 13 of the patients based on the presence of strong signal intensities there. Myelomalacia signs were seen in one patient, but he or she went on to make a complete neurological recovery. The average duration of operation was 355 minutes, and this included the time needed to position the patient for the two separate procedures. There was an 89.5% rate of neurological recovery with an average corrected loss of 6.98 degrees (0.20 degrees to 35.90 degrees), and the complication rate was acceptable in the group analyzed.

Evaluation of Seasonal Variation on the Health Risks Using the Quantitative Microbial Risk Assessment Approach in a Wastewater Treatment Plant in Hamadan, Iran.

Wastewater treatment plants (WWTPs) are a source of airborne bacterial contamination that can pose health risks to staff. The aim of this study was to evaluate seasonal variations in the health risks of exposure to Staphylococcus aureus bioaerosols using the quantitative microbial risk assessment (QMRA) approach in a WWTP in Hamadan, Iran. This was a descriptive cross-sectional study. This study determined the emission concentrations of S. aureus bioaerosols in summer and winter. Then, the health risks of three exposure scenarios (the worker, field engineer, and laboratory technician) were evaluated using the QMRA approach. The bioaerosol samples were collected every 12 days in both summer and winter of 2021 with a nutrient agar using a single-stage cascade impactor (Quick Take 30, SKC Inc.) in both outdoor and indoor environments. The results demonstrated that in both seasons, S. aureus bioaerosol concentrations in outdoor and indoor environments were below the standard established by the American Conference of Governmental Industrial Hygienists (500 CFU/m3 ). While in summer, the annual infection risks and the disease burden for the three exposure scenarios in both outdoor and indoor environments were higher than the United States Environmental Protection Agency (≤10-4 pppy) and the World Health Organization (WHO) (≤10-6 DALYs pppy-1) benchmarks, respectively. The findings provided high health risks for staff in the three exposure scenarios of an indoor environment, which should not be ignored, as well as emphasizing the use of the QMRA approach to estimate health risks caused by occupational exposure to bioaerosols and taking executive measures to protect staff working in the WWTPs.