Routes Of Disease Transmission Research Articles

Markovian Approach for Exploring Competitive Diseases with Heterogeneity-Evidence from COVID-19 and Influenza in China.

Due to the complex interactions between multiple infectious diseases, the spreading of diseases in human bodies can vary when people are exposed to multiple sources of infection at the same time. Typically, there is heterogeneity in individuals' responses to diseases, and the transmission routes of different diseases also vary. Therefore, this paper proposes an SIS disease spreading model with individual heterogeneity and transmission route heterogeneity under the simultaneous action of two competitive infectious diseases. We derive the theoretical epidemic spreading threshold using quenched mean-field theory and perform numerical analysis under the Markovian method. Numerical results confirm the reliability of the theoretical threshold and show the inhibitory effect of the proportion of fully competitive individuals on epidemic spreading. The results also show that the diversity of disease transmission routes promotes disease spreading, and this effect gradually weakens when the epidemic spreading rate is high enough. Finally, we find a negative correlation between the theoretical spreading threshold and the average degree of the network. We demonstrate the practical application of the model by comparing simulation outputs to temporal trends of two competitive infectious diseases, COVID-19 and seasonal influenza in China.

Dynamical analysis and optimal control of an age‐structured epidemic model with asymptomatic infection and multiple transmission pathways

The diversity of transmission modes and the heterogeneity of populations in the transmission of infectious diseases are issues that have to be faced in the current disease protection. In this paper, an infectious disease model incorporating age structure and horizontal and environmental spread, along with asymptomatic infection, is proposed to describe diversification of disease transmission routes and population heterogeneity. The expression of the basic reproduction number is derived by a linear approximation method, and it is concluded that if , the disease‐free steady state is globally asymptotically stable; if , the model has a unique endemic steady state which is locally asymptotically stable under certain conditions. Further, the uniform persistence of disease is proved using the persistence theory of the infinite‐dimensional dynamical system when . In additional, the issue of optimal control problem according to this model is investigated, and the representation of optimal control with respect to state variables and adjoint variables is obtained which also imply the existence and uniqueness of optimal control. Finally, numerical simulations are carried out to interpret the theoretical results and to discuss the impact of age and control measures in disease transmission.

Evaluation of Knowledge and Attitude of Dental Hygienists and Dental Assistants Regarding People Living with HIV/AIDS and HIV-Associated Oral and Periodontal Lesions in Jeddah, Saudi Arabia.

Oral manifestations serve as important indicators of human immunodeficiency virus (HIV) infection, and dental healthcare practitioners play a pivotal role in preventing and managing HIV. This study aims to assess and compare the knowledge and attitude of dental assistants and dental hygienists concerning people with HIV/acquired Immunodeficiency syndrome (AIDS) patients in Jeddah province of Saudi Arabia. This cross-sectional survey enrolled 160 dental hygienists and assistants practicing in Jeddah. Data was collected using a pretested, self-administered questionnaire comprising 50 questions that investigated knowledge about HIV/AIDS, awareness of HIV-associated oral and periodontal lesions, understanding of HIV transmission routes, and attitudes toward people with AIDS. In the study, 120 (75.0%) participants correctly recognized that individuals with HIV may appear healthy, while 123 (76.9%) participants admitted that HIV carriers have lower resistance to other diseases. Additionally, 126 (78.8%) participants confirmed an association between the virus and oral lesions, and 137 (85.6%) participants were aware of HIV transmission through blood. Moreover, 150 (93.7%) participants expressed their willingness to support, treat, and assist patients with AIDS, while only 10 (6.3%) participants expressed unwillingness. Notably, no statistically significant differences were found between dental assistants and hygienists in their knowledge and attitudes toward HIV/AIDS and people with AIDS. This study demonstrated that dental hygienists and assistants possess good general knowledge regarding HIV/AIDS and are well-informed about the disease's transmission routes. Moreover, a significant majority endorses the importance of treating and supporting AIDS patients.

Evaluating Droplet Survivability on Face Masks with X-ray Microtomography.

When a person talks, coughs, or sneezes, respiratory droplets are expelled and inevitably land on several surfaces, representing a route for respiratory disease transmission. Here, face masks act as a barrier by obstructing the passage of droplets during exhalation and inhalation. Being constantly exposed to respiratory events and carrying droplet residue, understanding the evaporation and absorption dynamics for tiny droplets on face masks and the fate of viral particle deposition is necessary to analyze the contamination risk. We explore the ideal design for masks from the interaction of mask surfaces with surrogate respiratory droplets by X-ray microscopy and microtomography. We show that the respiratory droplet survivability is significantly reduced in masks with a hydrophilic surface where absorption takes place, leading to a reduction of the postevaporation droplet residue at the mask surface compared with a hydrophobic surface. The results allow us to propose a better mask layer design dependent on wettability, reducing the risk of contamination from respiratory droplets.

Epidemiological and clinical characteristics of Mpox Cases in Serbia in 2022

Abstract Introduction Mpox viral infection, previously known as an endemic zoonosis typical for West and South Africa, appeared in the Republic of Serbia in early summer among young and middle-aged men, particularly Belgrade's citizens. The aim of this study is to evaluate the epidemiological and clinical characteristics of Mpox cases registered in Serbia in 2022. Methods We conducted a national observational study using the national surveillance anonymized data of people who met case definition criteria on Mpox infection and confirmation by the polymerase chain reaction method. Clinical data were collected by standardized case investigation form used for epidemiological and clinical evaluation of cases. Results A total of 43 cases reported from the 17th of June to the 5th of October 2022 were men, aged between 20 and 54 (median age, 35 years), 74,4% living in Belgrade. Three-quarters of cases reported sex with other men as a potential disease transmission route. Out of the total, 15 (34,9%) Mpox cases had HIV co-infection. HIV-positive patients were older than negative cases (p = 0,023). The mean incubation period among patients who reported exposition to a probable or confirmed case was 9,3 (2-22) days. The most common systemic symptoms were fever (86%) and lymphadenopathy (44,2%). Three patients with common symptoms of fever were hospitalized. All cases presented a rash, mostly in pustule form (90,7%). The dominant localization of the skin lesions was the anogenital region (62,5%), whereas 9,3% of the patient's lower extremities were affected. Conclusions In Serbia, the outbreak of Mpox infection affected young and middle-aged men, mainly situated in the capital of Serbia. The disease had a polymorphic presentation, including a characteristical rash of the anogenital region implying the main transmission route. Key messages • Health promotion and community engagement regarding Mpox are very important in large urban settings. • Risk communication should be prioritized to promote safe sexual practices in vulnerable populations.

Application of Data-Driven Building Information Modeling in the Visual Simulation of Disease Transmission and Route with Pipeline System

Currently, preventing epidemics is an extremely critical global topic. Using present data to quickly conduct virus simulations is a difficult but interesting problem, especially when real situations are difficult to experimentally demonstrate. In the past, most studies have used package software for disease transmission simulation, but this approach is limited by availability and software cost. Therefore, we propose a visual simulation of disease transmission using building information modeling data and a 3D model using Unity. The results show that the proposed method can effectively predict the probability and route of disease transmission; it also verifies that the vertical pipeline on the floor plane is conducive to the spread of the virus (90%), and disease transmission on the plane gradually expands outward from the starting room and has a higher probability of spreading (80%) from the opposite room. In addition, a vertical pipeline was simulated using a toilet exhaust air ventilation pipeline, from which it can be observed that the adjacent floors have a higher diffusion probability (70%). It has also been confirmed that distance is the primary factor affecting disease transmission. This framework may provide designers and managers further protection against the spread of future epidemics.

Functional assays to screen and select monoclonal antibodies that target Yersinia pestis

ABSTRACT Yersinia pestis is a gram-negative bacterium that causes plague in animals and humans. Depending on the route of disease transmission, the bacterium can cause an acute, often fatal disease that has a narrow window for treatment with antibiotics. Additionally, antibiotic resistant strains have been identified, emphasizing the need for novel treatments. Antibody therapy is an appealing option that can direct the immune system to clear bacterial infections. Advances in biotechnology have made both engineering and producing antibodies easier and more affordable. In this study, two screening assays were optimized to evaluate the ability of antibodies to promote phagocytosis of Y. pestis by macrophages and to induce a cytokine signature in vitro that may be predictive of protection in vivo. We evaluated a panel of 21 mouse monoclonal antibodies targeting either the anti-phagocytic capsule F1 protein or the LcrV antigen, which is part of the type 3 secretion system that facilitates translocation of virulence factors into the host cell, using two functional assays. Anti-F1 and anti-LcrV monoclonal antibodies both increased bacterial uptake by macrophages, with greater uptake observed in the presence of antibodies that were protective in the mouse pneumonic plague model. In addition, the protective anti-F1 and anti-LcrV antibodies produced unique cytokine signatures that were also associated with in vivo protection. These antibody-dependent characteristics from in vitro functional assays will be useful in down-selecting efficacious novel antibodies that can be used for treatment of plague.

A simple and effective aerosol pathogen disinfection test for a flowing air disinfector

Aerosol transmission is an important disease transmission route and has been especially pertinent to hospital and biosafety laboratories during the SARS-CoV-2 pandemic. The thermal resistance of airborne SARS-CoV-2 is lower than that of Bacillus subtilis spores, which are often used to test the effectiveness of SARS-CoV-2 and other pathogen disinfection methods. Herein, we propose a new method to test the disinfection ability of a flowing air disinfector (a digital electromagnetic induction air heater) using B. subtilis spores. The study provides an alternative air disinfection test method. The new test system combined an aerosol generator and a respiratory filter designed in-house and could effectively recover spores on the filter membrane at the air outlet after passing through the flowing air disinfector. The total number of bacterial spores used in the test was within the range of 5 × 105–5 × 106 colony-forming units (CFUs) specified in the technical standard for disinfection. The calculation was based on the calculation method in Air Disinfection Effect Appraisal Test in Technical Standard for Disinfection (2002 Edition). At an air speed of 3.5 m/s, we used a digital electromagnetic induction air heater to disinfect flowing air containing 4.100 × 106 CFUs of B. subtilis spores and determined that the minimum disinfection temperature was 350 °C for a killing rate of 99.99%. At 400 °C, additional experiments using higher spore concentrations (4.700 × 106 ± 1.871 × 105 CFU) and a higher airspeed (4 m/s) showed that the killing rate remained>99.99%. B. subtilis spores, as a biological indicator for testing the efficiency of dry-heat sterilization, were killed by the high temperatures used in this system. The proposed method used to test the flowing air disinfector is simple, stable, and effective. This study provides a reference for the development of test systems that can assess the disinfection ability of flowing air disinfectors.

A Scoping Review of Mathematical Models Used to Investigate the Role of Dogs in Chagas Disease Transmission.

Chagas disease is a zoonotic vector-borne disease caused by the parasite Trypanosoma cruzi, which affects a variety of mammalian species across the Americas, including humans and dogs. Mathematical modeling has been widely used to investigate the transmission dynamics and control of vector-borne diseases. We performed a scoping review of mathematical models that investigated the role of dogs in T. cruzi transmission. We identified ten peer-reviewed papers that have explicitly modeled the role of dogs in Chagas transmission dynamics. We discuss the different methods employed in these studies, the different transmission metrics, disease transmission routes, and disease control strategies that have been considered and evaluated. In general, mathematical modeling studies have shown that dogs are not only at high risk of T. cruzi infection but are also major contributors to T. cruzi transmission to humans. Moreover, eliminating infected dogs from households or frequent use of insecticide was shown to be effective for curtailing T. cruzi transmission in both humans and dogs. However, when insecticide spraying is discontinued, T. cruzi infections in dogs were shown to return to their pre-spraying levels. We discuss the challenges and opportunities for future modeling studies to improve our understanding of Chagas disease transmission dynamics and control.

A Questionnaire Integrated with the Digital Medical Record Improved the Coverage of a Control Program for Congenital Chagas Disease in Tuscany, Italy.

The leading route of Chagas disease transmission in nonendemic countries is congenital. However, policies concerning screening, prevention, and management of congenital Chagas disease are rare in these settings. Since 2012, serological screening for Chagas disease should be provided for pregnant women at risk in Tuscany, Italy according to a Regional resolution. Due to difficulties in the implementation, in November 2019, a checklist aimed at identifying pregnant women at risk for Chagas disease was introduced in digital clinical records at Careggi University Hospital, Florence, Italy. In order to evaluate the effectiveness of the "Chagas checklist", data about the number of deliveries by women at risk and their screening coverage between 2012 and June 2022 were collected. Out of 1348 deliveries by women at risk, 626 (47%) Trypanosoma cruzi serology tests were performed during the study period. The annual screening coverage increased from an average of 40.3% between 2012 and 2019 to 75.7% between 2020 and June 2022, underlining the big impact of the checklist. Four Chagas disease serological tests out of 626 (0.6%) resulted positive, corresponding to 2 affected women. No cases of congenital transmission occurred. The study showed that a simple digital tool led to a tangible improvement in the coverage of the screening program; its application in a setting where digital charts are available will contribute to the control and elimination of congenital Chagas disease.

Consequências da pandemia nas práticas odontológicas: revisão de literatura

ABSTRACT SARS-CoV-2 is caused by an RNA virus responsible for the disease known as COVID-19. First diagnosed in 2019, in a human being in the city of Wuhan, China, this disease is classified as a severe respiratory disease. Propagation occurs through coughing, sneezing, inhalation of droplets, or even indirect contact with the nasal, oral, and ocular mucous membranes. Preventive measures involving social distancing, quarantine, and mask use were implemented to prevent its spread. Such measures challenge dental practices, since they depend on proximity and do not allow the use of personal protective equipment, which cover the patient’s oral cavity. This integrative literature review sought to identify articles discussing preventive measures of adequate use in current dental practices, reducing the risk of COVID-19 contamination and spread. Results showed the importance of dentists acting on the disease transmission routes, following care protocols, implementing new dental clinic management practices, such as avoiding crowds, longer time between appointments, use of teledentistry, and adopting preventive measures inside the dental office like hand washing, use of N95 mask, face shield, and air filters. However, oral health professionals must be prepared to face any imminent challenge imposed by infectious diseases in dental practice, following protocol before, during, and after dental care.

Seroprevalence of Hepatitis B Virus Infection and Associated Factors Among Pregnant Women Attending Antenatal Care At Public Hospitals in Borena Zone, Southern Ethiopia.

Hepatitis B virus (HBV) is one of the major threats to global health, affecting millions of people each year and causing morbidity and mortality. The risk of acquiring chronic HVV infection varies with age, with 90% of infections acquired during the perinatal period. Despite many studies, there is little evidence of this virus in the Borena Zone. This study was done to assess seroprevalence HBVinfection and associated factors among pregnant women attending antenatal care at selected Borena Zone public hospitals from June 1 to September 30, 2022. A cross-institutional study was conducted on 368 randomly selected pregnant women who received antenatal care at Yabelo General Hospital and Moyale Primary Hospital. Data on sociodemographic and HBV-related factors were collected using a structured questionnaire. A 5 mL blood sample is then taken and tested using a diagnostic method, the enzyme-linked immunosorbent assay. Finally, data were entered using Epidata version 3.1 and exported to SPSS version 25 and Stata version 14 for analysis. Independent predictors were identified using logistic regression analysis and P < .05 was considered statistically significant. The prevalence of HBV infection was 21 (5.7%) (95% confidence interval [CI], 3.74-8.61). History of hospitalization (adjusted odds ratio [AOR] = 3.44, 95% CI, 1.07-11.09), traditional tonsillectomy (AOR = 4.16, 95% CI, 1.29-13.40), history of sexually transmitted infection (AOR = 5.99, 95% CI, 1.81-19.85), human immunodeficiency virus (HIV) (AOR = 8.28, 95% CI, 1.66-41.41), and alcohol drinking (AOR = 5.08, 95% CI, 1.49-17.31) were independent predictors of HBV infection. The results of this study indicate a moderate prevalence of HBV in selected public hospitals in the Borena Zone. History of hospitalization, traditional tonsillectomy, sexually transmitted infections, HIV, and alcohol use was significantly associated with HBV infection. Therefore, there is a need to conduct health education and more community-based research on disease transmission routes.

Investigating the Role of Mobility between Rural Areas and Forests on the Spread of Zika

A mathematical model of Zika virus transmission, incorporating human movement between rural areas and nearby forests, is presented to investigate the role of human movement in the spread of Zika virus infections in human and mosquito populations. Proportions of both susceptible and infected humans living in rural areas are assumed to move to nearby forest areas. Direct, indirect, and vertical transmission routes are incorporated for all populations. A mathematical analysis of the proposed model is presented. The analysis starts with normalizing the proposed model. The positivity and boundedness of solutions to the normalized model are then addressed. The basic reproduction number is calculated using the next-generation matrix method and its relation to the three routes of disease transmission has been presented. The sensitivity analysis of the basic reproduction number to all model parameters is investigated. The analysis also includes the existence and stability of disease-free and endemic equilibrium points. Bifurcation analysis is also carried out. Finally, numerical solutions to the normalized model are obtained to confirm the theoretical results and demonstrate human movement's role in disease transmission in human and mosquito populations.

Towards a One Health Food Safety Strategy for Palestine: A Mixed-Method Study.

Introduction: Foodborne diseases, together with increasing antimicrobial resistance (AMR), pose a threat to public health in an era of huge challenges with climate change and the risks of zoonotic epidemics. A One Health approach to foster food safety is a key for improvement, particularly in complex socio-ecological systems such as in Palestine, to examine human–animal-environment interfaces and promote intersectoral action. Objectives: This study aimed to assess food safety from farm to public health toward an operational One Health strategy for Palestine. This study evaluates the food production (broiler production) and monitoring system to better understanding the zoonotic foodborne illnesses transmission and their resistance to antimicrobials. Methods: The transdisciplinary approach included multi-stakeholder discussion groups and field visits to broiler farms, slaughterhouses, and meat stores in the Ramallah and Al-Bireh and Jerusalem districts using a semi-structured observational tool. A survey with 337 poultry producers and workers in slaughterhouses and meat stores was conducted to assess hygiene knowledge, attitudes, and practices during broiler meat production. Results: The stakeholders point out various challenges along the food production chain in Palestine, such as a striking scarcity of public slaughterhouses, insufficient coordination between authorities, a gap between public and private sectors, and inconsistent application of the law. From observations, it appears that, unlike traditional broiler production, the public slaughterhouses and meat markets have effective hygiene, while large-scale farms implement biosecurity measures. Overall, surveyed participants reported that they are aware of zoonotic disease transmission routes and value hygiene standards. Semi-structured observations and survey results are contradictory. Observations indicate poor hygiene practices; however, the vast majority of broiler meat production chain workers claim that hygiene standards are met. Discussion and Conclusions: Our study found that the overuse of antimicrobials, system fragmentation, insufficient infrastructure, a lack of regulations and controls, and poor hygiene practices are among the main obstacles to improving food safety in Palestine. Considering the risk of an important human health burden of food-related illnesses, enhancing food safety in Palestine is required using an integrated One Health approach. It is crucial to develop an integrated quality control system for food production along with promoting on-farm biosecurity and antimicrobial stewardship. Infrastructure, especially slaughterhouses and laboratories, must be built, training and education provided, and consumer awareness raised. As an important added value within a One Health strategy for better food safety in Palestine, research should be reinforced and accompany any future development of the food production monitoring system.

Use of Contact Networks to Estimate Potential Pathogen Risk Exposure in Hospitals

Person-to-person contact is important for the transmission of health care-associated pathogens. Quantifying these contact patterns is crucial for modeling disease transmission and understanding routes of potential transmission. To generate and analyze the mixing matrices of hospital patients based on their contacts within hospital units. In this quality improvement study, mixing matrices were created using a weighted contact network of connected hospital patients, in which contact was defined as occupying the same hospital unit for 1 day. Participants included hospitalized patients at 299 hospital units in 24 hospitals in the Southeastern United States that were part of the Duke Antimicrobial Stewardship Outreach Network between January 2015 and December 2017. Analysis was conducted between October 2021 and February 2022. The mixing matrices of patients for each hospital unit were assessed using age, Elixhauser Score, and a measure of antibiotic exposure. Among 1 549 413 hospitalized patients (median [IQR] age, 44 [26-63] years; 883 580 [56.3%] women) in 299 hospital units, some units had highly similar patterns across multiple hospitals, although the number of patients varied to a great extent. For most of the adult inpatient units, frequent mixing was observed for older adult groups, while outpatient units (eg, emergency departments and behavioral health units) showed mixing between different age groups. Most units mixing patterns followed the marginal distribution of age; however, patients aged 90 years or older with longer lengths of stay created a secondary peak in some medical wards. From the mixing matrices by Elixhauser Score, mixing between patients with relatively higher comorbidity index was observed in intensive care units. Mixing matrices by antibiotic spectrum, a 4-point scale based on priority for antibiotic stewardship programs, resulted in 6 major distinct patterns owing to the variation of the type of antibiotics used in different units, namely those dominated by a single antibiotic spectrum (narrow, broad, or extended), 1 pattern spanning all antibiotic spectrum types and 2 forms of narrow- and extended-spectrum dominant exposure patterns (an emergency room where patients were exposed to one type of antibiotic or the other and a pediatric ward where patients were exposed to both types). This quality improvement study found that the mixing patterns of patients both within and between hospitals followed broadly expected patterns, although with a considerable amount of heterogeneity. These patterns could be used to inform mathematical models of health care-associated infections, assess the appropriateness of both models and policies for smaller community hospitals, and provide baseline information for the design of interventions that rely on altering patient contact patterns, such as practices for transferring patients within hospitals.

IL-31 expression in HIV-infected patients with different routes of disease transmission.

Acquired immunodeficiency syndrome (AIDS) is caused by the human immunodeficiency virus (HIV). AIDS is characterized by an impaired immune system and low cellular immunity. The main manifestation of AIDS is a reduction in the number of CD4+ T cells and alteration in cytokine concentration. The present work aimed to explore the expression of IL-31 in HIV infection and disease progression.Serum samples were collected from HIV-infected patients with different routes of disease transmission. The subjects included 24 patients who were infected with HIV upon blood transmission and 36 patients who had acquired the disease through sexual transmission (21 cases of homosexual transmission and 15 cases of heterosexual transmission). In addition, 20 normal healthy individuals were included to serve as the control group. The levels of IL-31 in the collected serum samples were estimated using the human IL-31 Platinum ELISA kit.The serum analysis results revealed that the concentration of IL-31 in the serum samples for the blood transmission, sexually transmission, and normal group patients was 4.07 ± 1.63 pg/L, 7.43 ± 1.15 pg/L, and 2.87 ± 1.04 pg/L, respectively. The statistical analysis revealed that the concentration of IL-31 in HIV-1 infection was higher than that in the normal control. In addition, the expression of IL-31 was significantly higher in the sexual transmission group compared to the blood transmission group (P < .05).IL-31 could have an important role in HIV infection, although the role of IL-31 in disease progression in HIV-infected individuals requires further research.

Evaporation dynamics of a surrogate respiratory droplet in a vortical environment

HypothesisVortex droplet interaction is crucial for understanding the route of disease transmission through expiratory jet where several such embedded droplets continuously interact with vortical structures of different strengths and sizes. ExperimentsA train of vortex rings with different vortex strength, quantified with vortex Reynolds number (Re′=0,53,221,297) are made to interact with an isolated levitated droplet, and the evolution dynamics is captured using shadowgraphy, particle image velocimetry (PIV), and backlight imaging technique. NaCl-DI water solution of 0, 1, 10 and 20 wt% concentrations are used as test fluids for the droplet. FindingsThe results show the dependence of evaporation characteristics on vortex strength, while the crystallization dynamics was found to be independent of it. A reduction of 12.23% and 14.6% in evaporation time was seen in case of de-ionized (DI) water and 1% wt NaCl solution respectively in presence of vortex ring train at Re′=221. In contrast to this, a minimal reduction in evaporation time (0.6% and 0.9% for DI water and 1% wt NaCl solution, respectively) is observed when Re′ is increased from 221 to 297. The mechanisms for evaporation time reduction due to enhancement of convective heat and mass transfer from the droplet and shearing away of vapor layer by vortex ring interaction are discussed in this work.

Microbial activity and community structure in PM2 .5 at different heights in ground boundary layer of Beijing atmosphere under various air quality levels.

The outbreak of the COVID-19 epidemic is a reminder that aerosols have important health effects as a potential route for disease transmission. Biological components in aerosols (especially PM2.5 ) may pose potential threats to humans as pathogens and allergens. Research on PM2.5 and biological components currently focuses mainly on polluted conditions, with less emphasis on clean environments. Sampling has also been primarily based on a single point with a lack of data at different positions. In this study, a modified fluorescein diacetate hydrolysis method was used to measure microbial activity in PM2.5 at different altitudes over a year in Beijing, China. A high-throughput sequencing method was used to study the microbial community. Results showed that microbial activity 1.5m (0.0465 ng m-3 ) above the ground was higher than 31.5m (0.0348 ng m-3 ). There was higher microbial activity at both heights during spring. Furthermore, a positive correlation was observed between microbial activity and relative abundance of dominant species. Microbial activity increased during autumn and winter increased alongside the pollution level, but in spring higher levels of microbial activity were observed in excellent or good weather conditions. The results from this study are valuable for further research regarding the biological components of atmospheric PM, the prevention of biological pollution, and establishing a comprehensive air quality evaluation system.

HIV/AIDS KNOWLEDGE AND UTILISATION OF HCT UPTAKE AMONG MUSLIM YOUTH IN SOUTH WEST NIGERIA

Nigeria has the third highest population of people living with human immunodeficiency virus (HIV). Despite this, the knowledge of HIV/AIDS and uptake of voluntary counselling and testing (VCT) is still low, especially in the rural areas. This study assessed knowledge of HIV/AIDS and uptake of VCT among Muslim youths in a community in Oyo State, Nigeria. A pretested questionnaire was administered on a cross-section of 309 Muslim youth attending a religious programme in Iseyin town, Nigeria. Information about knowledge of HIV/AIDS and uptake of VCT was elicited among respondents. The majority of respondents did not know the need to assess and why VCT; however, knowledge of route of disease transmission was high, with majority mentioning sexual activity and unscreened blood transfusion, respectively, as possible transmission routes. Respondents listed avoidance of premarital sex, outlawing prostitution, and screening of blood before transfusion as protective measures respectively. Reasons for rejection of VCT included fear of stigma, marital disharmony, incurable nature of the disease and Islamic belief that HIV is most common among youth that are not religious because Islam is already against sexual intimacy before marriage.

Improved contact tracing using network analysis and spatial-temporal proximity

PurposeContact tracing is a crucial tool in infection prevention and control (IPC), which aims to identify outbreaks and prevent onward transmission. What constitutes a contact is typically based on strict binary criteria (i.e., being at a location at the same time). Missing data, indirect contacts and background sources can however substantially alter contact-tracing investigations. Here, we present StEP, a Spatial-temporal Epidemiological Proximity model that accounts for imperfect data by introducing a network-based notion of contact based on spatial-temporal proximity derived from background flows of patient movement.Methods & MaterialsWe showcase StEP by analysing outbreaks of multidrug-resistant bacteria and COVID-19 within a large hospital Trust in London (UK).StEP utilises spatial-temporal patient trajectories and the background hospital movement flows to recover enhanced contact networks. Firstly, we study a well-characterised outbreak of carbapenemase-producing Enterobacteriaceae (CPE) involving 116 hospitalised patients where genetic sequencing is used to learn model parameters. Secondly, our trained model is deployed in an unsupervised manner on three unseen outbreaks involving 867 patients of related CPE-types. Thirdly, we test application to an altogether novel pathogen by analysing a hospital outbreak of COVID-19 among 90 hospital patients, and demonstrate the power of StEP when characterising newly emerging diseases, even when there is a lack of sequencing data.ResultsIn addition to recovering core contact structures, StEP identifies missing contacts that link seemingly unconnected infection clusters, revealing a larger extent of transmission than conventional methods. Via genomic analyses we confirm that the additional contacts detected through StEP lead to improved alignment to the plasmid phylogeny (the major outbreak driving force). Hence the StEP contact network is most aligned to the transmission structure.ConclusionBy considering spatial-temporal information in a continuous manner, StEP tackles several challenges associated with traditional contact-tracing. StEP allows both direct and indirect contacts as possible routes of disease transmission and is tuneable to a pathogen's epidemiological characteristics. Such flexible use of heterogeneous data in uncertain situations can significantly enhance IPC.