Transmission Of Infection Research Articles

Microchip construction for migration assays: investigating the impact of physical confinement on cell morphology and motility during vaccinia virus infection.

Vaccinia virus (VACV)-induced cell migration is thought to be closely related to the rapid transmission of viral infection in the body. The limited studies are mainly based on scratch assay using traditional cell culture techniques, which inevitably ignores the influences of extracellular microenvironment. Physical confinement, inherently presenting in vivo, has proven to be a critical extern cue in modulating migration behaviors of multiple cells, while its impacts on VACV-induced cell motility remain unclear. Herein, we developed a migration assay microchip featuring confined microchannel array to investigate the effect of physical confinement on infected cell morphology and motility during VACV infection. Results showed that different from the random cell migration observed in traditional scratch assay on planar substrate, VACV-infected cells exhibited accelerated directionally persistent migration under confinement microenvironment. Moreover, single-directed elongated dominant lamella appeared to contrast distinctly with multiple protrusions stretched in random directions under unconfined condition. Additionally, the Golgi complex tended to relocate behind the nucleus confined within the microchannel axis compared to the classical reorientation pattern. These differences in characteristic subcellular architecture and organelle reorientation of migrating cells revealed cell biological mechanisms underlying altered migration behavior. Collectively, our study demonstrates that physical confinement acting as a guidance cue has profound impacts on VACV-induced migration behaviors, which provides new insight into cell migration behavior and viral rapid spread during VACV infection.

Sexual healthcare to meet the needs of sexuality and gender diverse aboriginal young people: imagined possibilities

In Australia, Aboriginal young people who are lesbian, gay, bisexual, trans, queer or otherwise sexuality and gender diverse (LGBTQ+) are recognised within several overlapping priority populations in state and federal sexually transmissible infection and HIV strategies. However, limited research has documented their unique sexual health experiences, needs and preferences. In this qualitative study, semi-structured interviews were conducted with 10 LGBTQ+ Aboriginal young people aged 16–24 years in New South Wales. Interviews incorporated questions about service access, positive and negative experiences and self-determined healthcare priorities. We conducted a strengths-based thematic analysis to understand the issues of greatest importance in sexual healthcare for participants. Using the framework of ‘imaginaries’, we explored how participants imagined sexual healthcare that would meet their individual and cultural needs. The dominant imaginary centred on respect, representation and the as-yet-unrealised possibility of sexual healthcare designed by and for people who shared the intersection of Aboriginal and LGBTQ+ experience. We identified individual-level, service-level and societal-level factors influencing this imaginary, including relationships, accessibility and experiences of racism. Analysing the imaginaries constructed by LGBTQ+ Aboriginal young people of empowering, culturally safe sexual healthcare that is ‘for them’ provides insight into potential service design to improve sexual health outcomes for this population.

Evaluation of the antimicrobial effect of a far-uv radiation lamp in a real-life environment

Using far-Ultraviolet-C (UVC) radiation with an emission maximum of 222 nm, has the potential to kill bacteria while not being harmful to humans and can be used continuously in public areas. Elevators pose a high risk of infection transmission, as they are small, crowded spaces with poor ventilation. In such a setting continuous decontamination would be very useful. This study aimed to measure the effectiveness of a far-UVC lamp installed in a frequently used elevator by comparing the bacterial load found in that elevator with the bacterial load in a control elevator. Microbial load was measured by different methods; ATP bioluminescence, surface samples were collected by contact slides, contact plates, and swabbing. Air samples were also collected. No significant differences were found in the microbial content between the control elevator and the UV-lamp elevator, regardless of whether the UV-lamp was always on, or was used with a motion sensor to turn off when someone entered the elevator. The results suggest that the far-UVC requires a longer time to kill the bacteria, while the people traffic were continuously re-contaminating the elevators.

Insights of infected Schwann cells extinction and inherited randomness in a stochastic model of leprosy

Investigating disease progression, transmission of infection and impacts of Multidrug Therapy (MDT) to inhibit demyelination in leprosy involves a certain amount of difficulty in terms of the in-built uncertain complicated and complex intracellular cell dynamical interactions. To tackle this scenario and to elucidate a more realistic, rationalistic approach of examining the infection mechanism and associated drug therapeutic interventions, we propose a four-dimensional ordinary differential equation-based model. Stochastic processes has been employed on this deterministic system by formulating the Kolmogorov forward equation introducing a transition state and the quasi-stationary distribution, exact distribution analysis have been investigated which allow us to estimate an expected time to extinction of the infected Schwann cells into the human body more prominently. Additionally, to explore the impact of uncertainty in the key intracellular factors, the stochastic system is investigated incorporating random perturbations and environmental noises in the disease dissemination, proliferation and reinfection rates. Rigorous numerical simulations validating the analytical outcomes provide us significant novel insights on the progression of leprosy and unravelling the existing major treatment complexities. Analytical experiments along with the simulations utilizing Monte-Carlo method and Euler–Maruyama scheme involving stochasticity predicts that the bacterial density is underestimated due to the recurrence of infection and suggests that maintaining a drug-efficacy rate in the range 0.6−0.8 would be substantially efficacious in eradicating leprosy.

A vaccine programme comprising GA08 (GI-27) and Mass (GI-1) strains prevents DMV1639 (GI-17) infectious bronchitis virus transmission among broiler chickens

ABSTRACT Effective control of infectious bronchitis is a challenge in commercial poultry operations due to the high transmissibility of the virus. Although multiple IBV lineages are circulating in the United States, the DMV1639-type IBV strain (GI-17) is currently the major circulating variant, creating production losses in the poultry industry. This study aimed to test whether the combination of a GA08 (GI-27) and a Mass-type (GI-1) IB vaccines could significantly reduce the transmission of a DMV1639-type (GI-17) field IBV strain in 4-week-old commercial broilers. Half of the birds were directly challenged, whereas the other half of the groupmates were put in contact 24 hours later. Two replicates of the same study setup, including 10 directly challenged and 10 contact birds per group, were run. Transmission of the challenge virus was significantly reduced in vaccinates (R = 0.0), whereas all unvaccinated birds became infected (R = 9.6). Reduced transmission of the DMV1639 IB challenge virus by the combined vaccination programme in broiler chickens was also accompanied by clinical protection. These data are important because prevention of IBV transmission by vaccination will result in overall reduced viral replication and consequently in reduced likelihood of genetic changes that can lead to new variants. This is the first published evidence of the successful transmission control of a DMV1639 IBV strain in chickens.

A novel method to select time-varying multivariate time series models for the surveillance of infectious diseases

BackgroundDescribing the transmission dynamics of infectious diseases across different regions is crucial for effective disease surveillance. The multivariate time series (MTS) model has been widely adopted for constructing cross-regional infectious disease transmission networks due to its strengths in interpretability and predictive performance. Nevertheless, the assumption of constant parameters frequently disregards the dynamic shifts in disease transmission rates, thereby compromising the accuracy of early warnings. This study investigated the applicability of time-varying MTS models in multi-regional infectious disease monitoring and explored strategies for model selection.MethodsThis study focused on two prominent time-varying MTS models: the time-varying parameter-stochastic volatility-vector autoregression (TVP-SV-VAR) model and the time-varying VAR model using the generalized additive framework (tvvarGAM), and intended to explore and verify their applicable conditions for the surveillance of infectious diseases. For the first time, this study proposed the time delay coefficient and spatial sparsity indicators for model selection. These indicators quantify the temporal lags and spatial distribution of infectious disease data, respectively. Simulation study adopted from real-world infectious disease surveillance was carried out to compare model performances under various scenarios of spatio-temporal variation as well as random volatility. Meanwhile, we illustrated how the modelling process could help the surveillance of infectious diseases with an application to the influenza-like case in Sichuan Province, China.ResultsWhen the spatio-temporal variation was small (time delay coefficient: 0.1–0.2, spatial sparsity:0.1–0.3), the TVP-SV-VAR model was superior with smaller fitting residuals and standard errors of parameter estimation than those of the tvvarGAM model. In contrast, the tvvarGAM model was preferable when the spatio-temporal variation increased (time delay coefficient: 0.2–0.3, spatial sparsity: 0.6–0.9).ConclusionThis study emphasized the importance of considering spatio-temporal variations when selecting appropriate models for infectious disease surveillance. By incorporating our novel indicators—the time delay coefficient and spatial sparsity—into the model selection process, the study could enhance the accuracy and effectiveness of infectious disease monitoring efforts. This approach was not only valuable in the context of this study, but also has broader implications for improving time-varying MTS analyses in various applications.

Competency level and determinants among infection prevention and control staff in the Middle East and North Africa region

BackgroundCompetency of the staff working in infection prevention and control (IPC) is the cornerstone of successful IPC programs. The objective was to assess competency level and associated factors among IPC staff working in the Middle East and North Africa (MENA) region.MethodsA cross-sectional study was carried out in 2019 among active IPC staff who were members of the Arab Countries Infection Control Network. The questionnaire covered demographic and professional characteristics of IPC staff and characteristics of work facilities and IPC programs. A competency score was created from self-perceived responses to 8 competency domains. The competency score was then transformed into 100-scale and categorized into two groups (≥ median and < median).ResultsA total of 176 participants completed the survey. Participants were mostly female (65.7%), and the mean age was 40.2 ± 8.3 years. The mean competency score was 61.4%. It was slightly variable between domains, being highest with preventing transmission of infection (65%) and lowest with sterilization and disinfection (59%). Higher (≥ median) competency score was associated with having CBIC certification (p < 0.001). It was also associated with facilities having IPC plan (p = 0.005), IPC committee (p = 0.049), regular meetings of IPC committee (p < 0.001), and IPC plan included communications with healthcare workers (p < 0.001). Domain-specific competency scores were significantly associated with receiving same domain-specific training (p < 0.05 for all).ConclusionsThe competency levels of IPC staff in the MENA region is still suboptimal. The current finding calls for more regional and national investment in IPC staff by providing up-to-date customized educational and training opportunities.

Infection prevention and control: understanding the fundamentals.

Infection prevention and control is crucial to prevent patients and healthcare staff from being harmed by avoidable infections, including healthcare-associated infections. This article outlines the main elements of standard precautions for infection prevention and control, as set out by the World Health Organization. Nurses and other healthcare professionals can use this information to refresh their knowledge of infection prevention and control, understand the appropriate practices that should be adopted to reduce the risk of infection transmission, and increase their awareness of the importance of sustainability and education.

Magnitude of Transfusion Transmissible Infections and Associated Factors Among Blood Donors at the Woliso Blood Bank, Oromia, Ethiopia: Across-Sectional Study

&amp;lt;i&amp;gt;Background: &amp;lt;/i&amp;gt;Blood transfusion is an effective treatment for saving millions of lives, even though transfusion-transmissible infections are the major problem. The prevalence of transfusion-transmissible infections varies between different geographical populations. This study aims to assess the prevalence of transfusion-transmissible infections and associated factors among blood donors at Woliso Blood Bank, South West Shewa Zone, Oromia, Ethiopia. &amp;lt;i&amp;gt;Method: &amp;lt;/i&amp;gt;An institutional-based cross-sectional study design was conducted. A structured and pre-tested questionnaire was used to collect data through a face-to-face interview. The data was entered in Epi Data version 3.1, and exported to STATA version 17.0 for data cleaning and analysis. A binary logistic regression analysis was performed to identify factors associated with outcome variables. Odd ratios along with the 95% confidence interval were used to present the finding and statistical significance was reported with a p-value of 0.05. &amp;lt;i&amp;gt;Results: &amp;lt;/i&amp;gt;The overall prevalence of transfusion-transmissible infections was 9.5% (95% CI 6.3-12.9%). Participants without formal education [AOR=4.84; 95% CI= 1.09, 21.46], unprotected sexual intercourse with multiple partners [AOR=4.77; 95% CI= 1.38, 16.44], and participants with a lower frequency of blood donation [AOR=2.85; 95% CI: 1.16, 6.99] were significantly associated with transfusion transmissible infections. &amp;lt;i&amp;gt;Conclusions: &amp;lt;/i&amp;gt;The prevalence of transfusion-transmissible infections was high in this study area. Educational level, unprotected sexual intercourse with more partners, and a number of blood donations were found to be independent predictors of transfusion-transmitted infections. Blood banks and regional health offices should work to mobilize the community and improve health promotion through prevention and control considering the associated factors identified.

Impacts of coingesting two tomato-infecting begomoviruses on virus infection in Bemisia tabaci and vector transmission

Impacts of coingesting two tomato-infecting begomoviruses on virus infection in Bemisia tabaci and vector transmission

Limited Emergence of Salmonella enterica Serovar Infantis Variants with Reduced Phage Susceptibility in PhagoVet-Treated Broilers.

Salmonella enterica serovar Infantis (S. Infantis) poses a growing issue in the poultry sector, with phage-based products emerging as a safe and effective control measure. This study investigated the emergence of reduced-phage-susceptibility variants (RPSV) of S. Infantis in PhagoVet-treated broilers, given that RPSV could undermine phage treatment efficacy. The bacteriophages in the PhagoVet product were characterized using transmission electron microscopy (TEM), genome sequencing, and infection profiling. Furthermore, two broiler trials were conducted: a challenge group (T1) and a challenge-and-treated group (T2). The S. Infantis infective dose was set at 104 and 106 colony-forming units (CFUs) per animal, with PhagoVet administration at 106 and 108 plaque-forming units (PFUs) per animal, in Trials 1 and 2, respectively. The results revealed that the four PhagoVet bacteriophages belonged to different genera. PhagoVet evidenced broad-spectrum efficacy against 271 strains representing 18 Salmonella serovars. In Trial 1, PhagoVet reduced bacterial counts in feces to nearly undetectable levels by day 42, with no RPSV detected. However, in Trial 2, three and five RPSVs were detected in feces and ceca, respectively. Consequently, PhagoVet demonstrated efficacy against S. Infantis in broilers, and the potential impact of RPSV is deemed unlikely to compromise its efficacy.

The effectiveness of interventions to reduce the transmission of acute respiratory infections in care homes: a systematic review.

Care home residents are at high risk from outbreaks of respiratory infections, such as influenza and COVID-19. We conducted a systematic review of randomized controlled trials, to determine which interventions (apart from vaccines) are effective at reducing transmission of acute respiratory illnesses (ARIs) in care homes. We searched CINAHL, Medline, Embase and Cochrane for randomized controlled trials (RCTs) of interventions to prevent transmission of ARIs in care homes (excluding vaccines), to April 2023. A total of 21 articles met inclusion criteria. Two infection control interventions significantly reduced respiratory infections. Oseltamivir significantly reduced risk of symptomatic laboratory-confirmed influenza (OR 0.39, 95%CI 0.16-0.94, three trials), and influenza-like illness (OR 0.50, 95%CI 0.36-0.69), even in a vaccinated population. High dose vitamin D supplementation reduced incidence of ARIs (incidence rate ratio 0.60; 95%CI 0.38-0.94, one trial). Nine other RCTs of vitamin, mineral, probiotic and herbal supplements showed no significant effect. Transmission of respiratory infections in care homes can be reduced by educational interventions to improve infection control procedures and compliance by staff, by antiviral prophylaxis soon after a case of influenza has been detected, and by supplementation with high-dose Vitamin D3. Further research is needed to confirm the effect of high-dose Vitamin D3.

Computational Insights for Interactions between nsP2 and nsP3 of CHIKV and Hormones through DFT Computations and Molecular Dynamics Simulations.

The non-structural protein (nsP2 & nsP3) of the Chikungunya virus (CHIKV) is responsible for the transmission of viral infection. The main role of non-structural proteins are involved in the transcription process at an early stage of the infection. In this work, authors have studied the impact of nsP2 and nsP3 of CHIKV on hormones present in the human body using a computational approach. The ten hormones of chemical properties such as 4-Androsterone-2,17-dione, aldosterone, androsterone, corticosterone, cortisol, cortisone, estradiol, estrone, progesterone and testosterone were taken as a potency. From the molecular docking, the binding energy of the complexes is estimated, and cortisone was found to be the highest negative binding energy (-6.57 kcal/mol) with the nsP2 and corticosterone with the nsP3 (-6.47 kcal/mol). This is based on the interactions between hormones and nsP2/nsP3, which are types of noncovalent intermolecular interactions categorized into three types: electrostatic interactions, van der Waals (vdW) interactions, and hydrogen-bonding (H-bonding) interactions. To validate the docking results, additional molecular dynamics simulations and MM-GBSA methods were performed. The change in enthalpy, entropy, and free energy were calculated using MM-GBSA methods. The nsP2 and nsP3 of CHIKV interact strongly with the cortisone and corticosterone with free energy changes of -20.55 & -36.08 kcal/mol, respectively. Methods: The crystal structures of 3TKR and 3GPO proteins of nsP2 and nsP3 were extracted from the RCSB Protein Data Bank. Initially, unnecessary atoms like extra cations or anions and missing explicit hydrogen atoms were removed and added from the native domain of nsP2 and nsP3. The alignment of coordinated in the native domain was performed using Chimera and Notepad++ tools. The molecular docking of protein and ligand was performed usingAutoDock tool; it is essential for the prediction of the orientation of the ligand into the cavity of the target protein based on binding affinity. Based on thermodynamic parameters, MD Simulations were employed to calculate the change in binding free energies of various complexes followed by a change in enthalpy and entropy with time. According to MD production, the CPPTAJ and PTRAJ programs were used to analyse the trajectories, such as dynamic stability (RMSD), residual fluctuation (RMSF), compatibility, and hydrogen bonds of the newly formed complexes. After that, the Density Functional Theory (DFT) were used to calculate the electronic properties of selected molecules by Gaussian 16 on applying the B3LYP method with the 6-311G (d, p) basis set.

Impact of Time and Handwashing on Infection Inference in Scenario‐Based Exposures Among Adults and Children in Japan

ABSTRACTIntroductionThe COVID‐19 pandemic has underscored the importance of preventive measures like handwashing and mask‐wearing. However, preschoolers often struggle to comprehend disease transmission. This study examined how time and handwashing impact adults’ and preschoolers’ inferential processes related to infectious disease transmission.MethodsThirty‐eight Japanese adults aged 18–23 years (8 men; 30 women) and 36 Japanese children aged 5–6 years (15 boys; 21 girls) participated in this study. Participants were presented with scenarios involving an infectious individual who was present (1) at the same time, (2) immediately before, or (3) the previous day. Scenarios were presented via PowerPoint for adults and as a picture‐story for preschoolers, with questions on infection likelihood pre‐ and post‐handwashing.ResultsBoth age groups perceived a significantly higher likelihood of infection for same‐time exposure than for other exposures. Preschoolers estimated a lower likelihood of infection than adults ( = 0.25). Handwashing significantly reduced perceived infection risk, particularly for same‐time ( = 0.34) and immediately after ( = 0.10) exposures.ConclusionThis study highlights the critical need for age‐appropriate communication about infection prevention, particularly for young children. Preschoolers exhibited a more positive perception of infectious disease transmission, which necessitates reinforcing multiple preventive measures beyond handwashing. The findings underscore the importance of considering cognitive development and the influence of contemporary experiences like the COVID‐19 pandemic when educating about disease transmission. Future research should further explore the relationship between cognitive development, individual differences, and infection reasoning to enhance public health strategies for varying age groups.

Causes of pre and post-donation deferrals among blood donors, at Kwale Satellite Blood Transfusion Center, Kwale County, Kenya, 2018–2022

BackgroundBoth pre-donation and post-donation deferrals pose challenges to blood safety and availability. This study delved into the deferral rates before donations and their underlying reasons, as, transfusion transmissible infections (TTIs) leading to post-donation deferrals among potential blood donors at the Kwale Satellite Blood Transfusion Centre (KSBTC) in Kenya.MethodsWe performed a retrospective electronic record review of pre- and post-donation deferrals among blood donors at KSBTC, 2018–2022. The pre-donations deferral rate and reasons for deferral were analyzed. Accepted donations were analyzed to determine the prevalence of HIV, hepatitis B (HBV), hepatitis C (HCV), and syphilis. Descriptive statistics were calculated and both crude odds ratio (COR) and adjusted odds ratio (AOR), and their 95% confidence intervals (CI) were calculated. Variables with p < 0.05 were considered statistically significant.ResultsA review was conducted on 12,633 blood donation records. Among these, individuals 2,729/12,633 (21.60%) were deferred from donating with the primary reason being low hemoglobin levels, constituting 51.86% of deferrals. Around 773/9,904 (7.80%) of blood units, were discarded due to at least one TTI. Among these, HBV accounted for 4.73%, HIV for 2.01%, HCV for 1.21%, and Syphilis for 0.59% of cases. The adjusted odds ratio for male donors were, (aOR = 1.3, 95% CI 1.01–1.57), donors with none or primary education level (aOR = 1.4 95% CI 1.11–1.68), first-timer donors (aOR = 1.2, 95% CI 1.01–1.44), and static strategy for blood collection (aOR = 1.4, 95%CI 1.12–1.63) were independently potentially associated with testing positive for at least one TTI.ConclusionThe study indicates that TTIs continue to pose a risk to the safety of Kenya’s bloodstock, with a notable prevalence of HBV infections. Male donors, individuals with limited education, first-time donors, and utilizing a fixed strategy for blood collection were identified as potential risk factors independently associated with TTIs.

Analyzing the worldwide progression of COVID-19 cases and deaths using nonlinear mixed-effects model.

COVID-19 is an infectious disease that continues to spread worldwide. A precise estimation of the cases and deaths due to COVID-19 would allow for appropriate consideration of healthcare resource allocation, public health response, and vaccination and economic planning, to minimize social damage. In this study, we analyzed the progression of COVID-19 cases and deaths until January 2022 in 156 countries using a nonlinear mixed-effect model based on the SIR framework. Given the major changes in mortality from infection, risk of re-infection and social responses, the analysis was limited to the period before the emergence of the Omicron variant. The impact of infection prevention measures in various countries was assessed, with a specific focus on estimating the effectiveness of lockdowns, where the effect was assumed to change over time. By accounting for excess mortality, our analysis allowed the estimation of unreported cases and deaths, and thus providing a more comprehensive understanding of the impact of pandemic. In the analysis, we identified gross domestic product (GDP), proportion of people aged 65 years or older, latitude of the capital city on transmissibility of infection, and city population and cardiovascular death rate on mortality rate as significant influencing factors. Furthermore, the differences in transmissibility and mortality rates by variants and the effect of vaccination on the mortality rate were assessed. The transmissibility has increased by odds ratios of 1.2 to 1.4 in Beta, Gamma, and Delta variants; mortality rate has increased by odds ratios of 1.7, 2.2, and 1.4 in Beta, Gamma, and Delta variants, respectively; and vaccination decreased the mortality rate by odds ratios of 0.4 and 0.1 in Delta and other variants, respectively.

Optimal operations of gaspers for minimizing the exposure risks of airborne disease transmission in an economy-class aircraft cabin

Overhead gaspers with adjustable open ratios and flow directions can alter the airflow pattern in aircraft cabins and consequently influence airborne infectious diseases transmission. To achieve the optimal operations of gaspers for minimizing the passengers’ exposure risks, this study developed a Bayesian optimization method based on computational fluid dynamics (CFD). A seven-row, single-aisle, fully occupied, economy-class aircraft cabin was used for the numerical investigation. Two air distribution systems, i.e., a mixing ventilation system and a personalized displacement ventilation system, were considered. First, the open ratios of all the gaspers were optimized by the CFD-based Bayesian optimization method. The optimal operations of gaspers were determined with only 20 trials calculated by CFD using the Bayesian optimization. With the optimal open ratios of all the gaspers, the number of relatively high-risk passengers (exposure index over 0.95) was effectively reduced by at least 55% and 86% under the mixing ventilation and the personalized displacement ventilation, respectively, when compared with the results with all the gaspers turned off. Next, the optimal open ratios and flow directions of the gaspers near the index passenger were also determined by the proposed method. With the optimized operations of gaspers, the number of relatively high-risk passengers was effectively reduced by at least 50% and 67% under the mixing ventilation and the personalized displacement ventilation, respectively.

Polysubstance Use and Related Risk Behaviors among People Who Inject Drugs in Kenya Preparing for Hepatitis C Virus Treatment.

Polysubstance use (PSU), injection drug use (IDU), and equipment sharing are associated with bloodborne infection (BBI) transmission risk, particularly Hepatitis C Virus (HCV), yet data on PSU in low- and middle-income countries (LMICs) is limited. We report on baseline PSU, medication-assisted treatment (MAT) engagement, and motivation to reduce IDU among 95 people who inject drugs (PWID) who accessed needle and syringe programs (NSP) in Nairobi and Coastal Kenya prior to HCV treatment. Bivariate and multivariate logistic regression were used to examine the associations between PSU and behaviors that confer HCV transmission and acquisition risks. Most participants (70.5%) reported PSU in the last 30 days, and one-third (35.8%) reported PSU exclusive to just heroin and cannabis use. Common combinations were heroin and cannabis (49.3%), and heroin, cannabis, and bugizi (flunitrazepam) (29.9%). Participants at baseline were receiving MAT (69.5%), already stopped or reduced IDU (30.5%), and were HIV-positive (40%). PSU was significantly associated with IDU (p = 0.008) and the number of times (p = 0.016) and days (p = 0.007) injected in the last 30 days. Participants reported high PSU and equipment sharing, despite high MAT engagement. While co-locating BBI treatment within existing harm reduction services is necessary to promote uptake and curb re-infection, tailored services may be needed to address PSU, particularly in LMICs.

Utilizing large language models in infectious disease transmission modelling for public health preparedness

IntroductionOpenAI's ChatGPT, a Large Language Model (LLM), is a powerful tool across domains, designed for text and code generation, fostering collaboration, especially in public health. Investigating the role of this advanced LLM chatbot in assisting public health practitioners in shaping disease transmission models to inform infection control strategies, marks a new era in infectious disease epidemiology research. This study used a case study to illustrate how ChatGPT collaborates with a public health practitioner in co-designing a mathematical transmission model. MethodsUsing natural conversation, the practitioner initiated a dialogue involving an iterative process of code generation, refinement, and debugging with ChatGPT to develop a model to fit 10 days of prevalence data to estimate two key epidemiological parameters: i) basic reproductive number (Ro) and ii) final epidemic size. Verification and validation processes are conducted to ensure the accuracy and functionality of the final model. ResultsChatGPT developed a validated transmission model which replicated the epidemic curve and gave estimates of Ro of 4.19 (95 % CI: 4.13- 4.26) and a final epidemic size of 98.3 % of the population within 60 days. It highlighted the advantages of using maximum likelihood estimation with Poisson distribution over least squares method. ConclusionIntegration of LLM in medical research accelerates model development, reducing technical barriers for health practitioners, democratizing access to advanced modeling and potentially enhancing pandemic preparedness globally, particularly in resource-constrained populations.

Diversity of Free-Living Amoebae in New Zealand Groundwater and Their Ability to Feed on Legionella pneumophila.

Free-living amoebae (FLA) are common in both natural and engineered freshwater ecosystems. They play important roles in biofilm control and contaminant removal through the predation of bacteria and other taxa. Bacterial predation by FLA is also thought to contribute to pathogen dispersal and infectious disease transmission in freshwater environments via the egestion of viable bacteria. Despite their importance in shaping freshwater microbial communities, the diversity and function of FLA in many freshwater ecosystems are poorly understood. In this study, we isolated and characterized FLA from two groundwater sites in Canterbury, New Zealand using microbiological, microscopic, and molecular techniques. Different methods for groundwater FLA isolation and enrichment were trialed and optimized. The ability of these isolated FLA to predate on human pathogen Legionella pneumophila was assessed. FLA were identified by 18S metagenomic amplicon sequencing. Our study showed that Acanthamoeba spp. (including A. polyphaga) and Vermamoeba veriformis were the main FLA species present in both groundwater sites examined. While most of the isolated FLA co-existed with L. pneumophila, the FLA populations in the L. pneumophila co-culture experiments predominantly consisted of A. polyphaga, Acanthamoeba spp., Naegleria spp., V. vermiformis, Paravahlkampfia spp., and Echinamoeba spp. These observations suggest that FLA may have the potential to act as reservoirs for L. pneumophila in Canterbury, New Zealand groundwater systems and could be introduced into the local drinking water infrastructure, where they may promote the survival, multiplication, and dissemination of Legionella. This research addresses an important gap in our understanding of FLA-mediated pathogen dispersal in freshwater ecosystems.