Mechanisms Of Disease Transmission Research Articles

Analysis of the impact of COVID-19 variants and vaccination on the time-varying reproduction number: statistical methods.

The COVID-19 pandemic has profoundly impacted global health systems, requiring the monitoring of infection waves and strategies to control transmission. Estimating the time-varying reproduction number is crucial for understanding the epidemic and guiding interventions. Probability distributions of serial interval are estimated for Pre-Delta and Delta periods. We conducted a comparative analysis of time-varying reproduction numbers, taking into account population immunity and variant differences. We incorporated the regional heterogeneity and age distribution of the population, as well as the evolving variants and vaccination rates over time. COVID-19 transmission dynamics were analyzed with variants and vaccination. The reproduction number is computed with and without considering variant-based immunity. In addition, values of reproduction number significantly differed by variants, emphasizing immunity's importance. Enhanced vaccination efforts and stringent control measures were effective in reducing the transmission of the Delta variant. Conversely, Pre-Delta variant appeared less influenced by immunity levels, due to lower vaccination rates. Furthermore, during the Pre-Delta period, there was a significant difference between the region-specific and the non-region-specific reproduction numbers, with particularly distinct pattern differences observed in Gangwon, Gyeongbuk, and Jeju in Korea. This research elucidates the dynamics of COVID-19 transmission concerning the dominance of the Delta variant, the efficacy of vaccinations, and the influence of immunity levels. It highlights the necessity for targeted interventions and extensive vaccination coverage. This study makes a significant contribution to the understanding of disease transmission mechanisms and informs public health strategies.

EnduroBone: A 3D printed bioreactor for extended bone tissue culture

Studies of the effects of external stimuli on bone tissue, disease transmission mechanisms, and potential medication discoveries benefit from long-term tissue viability ex vivo. By simulating the in-vivo environment, bioreactors are essential for studying bone cellular activity throughout biological processes. We present the development of an automated 3D-printed bioreactor EnduroBone designed to sustain the ex-vivo viability of 10 mm diameter cancellous bone cores for an extended period. The device is supplied with two critical parameters for maintaining bone tissue viability: closed-loop continuous flow perfusion of 1 mL/min for nutrient diffusion and waste removal and direct mechanical stimulation with cyclic compression at 13.2 RPM (revolutions per minute) to promote cell viability which can lead to improved tissue stability during ex vivo culturing. The bioreactor addresses several limitations of existing systems and provides a versatile open-source platform for bone cancer research, orthopedic device testing, and other related applications. To validate the bioreactor, fresh swine samples were cultured ex-vivo, and their cell viability was determined to be maintained for up to 28 days. Periodic cell viability assessment through live/dead cell staining and confocal imaging at the start (0 days) and at several time points throughout the culture period (7, 14, 21, and 28 days) was used to demonstrate EnduroBone effectiveness in sustaining bone cell health for the extended period tested.

Rearing Protocol for Culex quinquefasciatus

Mosquitoes are vectors capable of transmitting various life-threatening diseases such as dengue, chikungunya, Japanese encephalitis, lymphatic filariasis, malaria, and so on. They are reared in the laboratories for conducting various studies such as vector biology, vector competence, mechanism of disease transmission, to check the efficiency and follow-up of various control methods, insecticide susceptibility, and vaccine trials. Moreover, mass rearing of mosquitoes is required for sterile insect technique (SIT) to control mosquitoes. Successful breeding of mosquitoes requires attention to detail and depends upon various factors such as quality and quantity of larval food, temperature, humidity, population size, mating, blood feeding, and egg laying. Culex quinquefasciatus is a vector of lymphatic filariasis (LF) and a cosmopolitan mosquito, abundant in tropical and subtropical regions. In this study, a simple and convenient rearing protocol for Culex quinquefasciatus has been discussed.

P104 Per- and poly-fluoroalkyl substances (PFAS) exposure in early life is associated with intestinal inflammation

Abstract Background Early life environmental exposures are linked with intestinal inflammation and inflammatory bowel disease (IBD) later in life. Per- and poly-fluoroalkyl substances (PFAS) are a large class of fluorinated organic chemicals used widely in consumer products that may be risk factors for IBD; however, the association between exposure to PFAS in early life and intestinal inflammation has not yet been studied. Dried blood spots (DBS) are archived neonatal capillary blood samples collected and stored as part of the New York State neonatal screening program and a cost-effective early life environmental exposure screening resource. Methods We measured 135 PFAS in DBS collected at birth from offsprings of women with and without IBD [n=37 (44%) and 47 (56%), respectively] enrolled in the MEChanisms Of disease traNsmission In Utero through the Microbiome (MECONIUM) cohort between January 2015 and November 2020, using untargeted metabolomics with liquid chromatography high-resolution mass spectrometry. In a subsample (n = 46), we also measured offspring fecal calprotectin (FC) at one year. We fitted exposome-wide regression models to estimate the association between each PFAS signal in the DBS and continuous FC at one year of age. For the significant associations (nominal p-value <0.05), we further explored potential effect modification by stratifying by maternal IBD status. All models were adjusted for relevant confounders. Results The mean (SE) of FC at age one year was 213.9 (23.8) ug/gm. The PFAS chemicals perfluoroundecanoic acid (PFUnDA) and N-ethyl-perfluorooctane sulfonamido acetic acid (N-Et-FOSAA) were significantly associated with increased scaled and log-transformed FC per decile increase in exposures [estimate (95% CI) = 0.52 (0.13,0.91) and 0.34 (0.05,0.63), Figure A]. Associations tended to be stronger in offspring of women with IBD relative to offspring of women without IBD (Figure B). estimate (95% CI) for the associations between PFUnDA and FC were 0.86 (0.34,1.39) and 0.12 (-0.47,0.71), respectively, and between N-Et-FOSAA and FC, these were 0.54 (-0.01,1.08) and 0.31(-0.07,0.68), respectively. Conclusion DBS can be used to measure early life exposure to toxins, and prenatal PFAS exposure is associated with elevated FC, with a slightly stronger effect in the offspring of women with IBD. Larger prospective studies are needed to validate these associations and understand potential underlying mechanisms through which early life PFAS exposures may contribute to IBD etiology.

Review on respiratory infectious disease transmission mechanism: effects of human movement and facemask use

Review on respiratory infectious disease transmission mechanism: effects of human movement and facemask use

JMM Profile: Rift Valley fever: a zoonotic viral haemorrhagic disease.

Rift Valley fever (RVF) is caused by infection with Rift Valley fever virus (RVFV), a mosquito-borne RNA virus that affects both humans and livestock species. Humans can also acquire infection from contact with infected animals and contaminated bodily fluid. Veterinary vaccines are available for use in livestock, but no vaccines have been approved for humans to date. The virus is currently endemic in most sub-Saharan regions of Africa but numerous incursions into Middle Eastern countries and islands in the Indian Ocean, such as Mayotte (an overseas Department of France), have occurred in the past decade. The risk of further geographical expansion is high and therefore additional investigation is warranted to better understand disease transmission and pathogenic mechanisms to develop threat mitigation strategies.

High frame-rate imaging of the shape oscillations and spreading dynamics of picolitre droplets impacting on a surface

The post-impact dynamics and spreading rates of picolitre liquid droplets on surfaces are critical to many practical and industrial applications, as well as respiratory disease transmission mechanisms. Here we use a high framerate imaging method to explore the shape oscillations and spreading of individual ∼10–180 pl volume droplets (corresponding to ∼30–70 μm in initial droplet diameter) impacting on a surface under ambient conditions with 10 μs temporal resolution. The method allows the surface tension to be accurately extracted from the measured frequency of post-impact shape oscillations for sessile droplets in this size range with surface tensions greater than 40 mN m−1 and viscosities up to at least 3.2 mPa s. The Tanner's law model for predicting sessile droplet spreading rates provides an accurate account of the “steady-state” spreading rate for all droplets with surface tensions in the range 22–73 mN m−1 studied here. However, Tanner's law does not account for the delay in the onset of spreading observed for droplets in this size range, caused by competition between shape oscillations and spreading governing the morphology at short time periods, particularly for surface tensions >22 mN m−1.

U.S. Small-Scale Livestock Operation Approach to Biosecurity

Agricultural biosecurity is a pressing global issue that must be given continuous attention by researchers, producers, consumers, and government agencies responsible for food security. This article examines the relevant literature specifically related to recommended practices for U.S. small-scale farms and ranches to minimize potential disease susceptibility in animals and humans. Current training and educational resources appear to focus on mechanisms of disease transmission and ecological and/or social factors that support mitigation efforts. Training against biological incursion and knowledge of diseases are typically focused on serving the continuing educational needs of veterinarians, epidemiological groups, and animal health technicians for large-scale facilities. However, there is a gap in the available resources that could be beneficial to keepers of livestock, smaller farmers, and ranchers who lack the financial capability to employ the most proven prevention or mitigation strategies. There have been limited comprehensive reviews in the U.S. of disease control, perception, education, or analysis on current prevention measures among small-scale producers. Findings from a review of the literature were used to formulate disease-prevention training resources and outreach strategies directed at U.S. small-scale farm operators and those likely to be involved in disease outbreak situations (e.g., veterinarians, first responders, and family members). The evaluation of the current types and causes of diseases, along with their respective level of current threat to agriculture, was a fundamental strategy to achieve this goal while reviewing literature focused on U.S. biosecurity and international biosecurity. Developing an evidence-based approach to prevention measures for biosecurity operations will allow for more effective execution and adoption of protocols for small-scale farms.

The formation of bioaerosols in the reopening of an occluded airway

The reopening of an occluded airway can lead to the formation of droplets and aerosols, which can be released during exhalation, providing a possible mechanism of disease transmission. In this study, the flow behavior of airway occlusions (“plugs”) close to their point of rupture is examined using a free-surface model (volume of fluid), such that factors influencing the formation of droplets during their reopening can be identified. The propagation of airway occlusions is highly influenced by recirculating flow at the edge of the front interface, where significant fluctuations of wall shear stresses occur. The resulting drag force causes the rear interface to advance at a greater rate, destabilizing the plug. As the plug thickness decreases, a thin film with uniform thickness forms, resulting in a disk-like structure around the centerline. Rupture occurs around the disk formation largely due to surface tension instability. At lower pressures, smaller disks form causing the rupture to occur through a puncture point (forming no droplets); at higher pressures, a larger disk forms, with rupture occurring along the disk edge and at the center (forming multiple droplets). Upon reopening, a jet of air is produced, causing a temporary increase in shear stress along the wall. However, the magnitude and duration of this increase do not scale directly to the applied pressure, as the formation of droplets and irregularities in airway lining were found to disrupt the flow field and the shear stresses at the wall.

Seroprevalence of Dengue, Chikungunya and Zika at the epicenter of the congenital microcephaly epidemic in Northeast Brazil: A population-based survey.

The four Dengue viruses (DENV) serotypes were re-introduced in Brazil's Northeast region in a couple of decades, between 1980's and 2010's, where the DENV1 was the first detected serotype and DENV4 the latest. Zika (ZIKV) and Chikungunya (CHIKV) viruses were introduced in Recife around 2014 and led to large outbreaks in 2015 and 2016, respectively. However, the true extent of the ZIKV and CHIKV outbreaks, as well as the risk factors associated with exposure to these viruses remain vague. We conducted a stratified multistage household serosurvey among residents aged between 5 and 65 years in the city of Recife, Northeast Brazil, from August 2018 to February 2019. The city neighborhoods were stratified and divided into high, intermediate, and low socioeconomic strata (SES). Previous ZIKV, DENV and CHIKV infections were detected by IgG-based enzyme linked immunosorbent assays (ELISA). Recent ZIKV and CHIKV infections were assessed through IgG3 and IgM ELISA, respectively. Design-adjusted seroprevalence were estimated by age group, sex, and SES. The ZIKV seroprevalence was adjusted to account for the cross-reactivity with dengue. Individual and household-related risk factors were analyzed through regression models to calculate the force of infection. Odds Ratio (OR) were estimated as measure of effect. A total of 2,070 residents' samples were collected and analyzed. The force of viral infection for high SES were lower as compared to low and intermediate SES. DENV seroprevalence was 88.7% (CI95%:87.0-90.4), and ranged from 81.2% (CI95%:76.9-85.6) in the high SES to 90.7% (CI95%:88.3-93.2) in the low SES. The overall adjusted ZIKV seroprevalence was 34.6% (CI95%:20.0-50.9), and ranged from 47.4% (CI95%:31.8-61.5) in the low SES to 23.4% (CI95%:12.2-33.8) in the high SES. The overall CHIKV seroprevalence was 35.7% (CI95%:32.6-38.9), and ranged from 38.6% (CI95%:33.6-43.6) in the low SES to 22.3% (CI95%:15.8-28.8) in the high SES. Surprisingly, ZIKV seroprevalence rapidly increased with age in the low and intermediate SES, while exhibited only a small increase with age in high SES. CHIKV seroprevalence according to age was stable in all SES. The prevalence of serological markers of ZIKV and CHIKV recent infections were 1.5% (CI95%:0.1-3.7) and 3.5% (CI95%:2.7-4.2), respectively. Our results confirmed continued DENV transmission and intense ZIKV and CHIKV transmission during the 2015/2016 epidemics followed by ongoing low-level transmission. The study also highlights that a significant proportion of the population is still susceptible to be infected by ZIKV and CHIKV. The reasons underlying a ceasing of the ZIKV epidemic in 2017/18 and the impact of antibody decay in susceptibility to future DENV and ZIKV infections may be related to the interplay between disease transmission mechanism and actual exposure in the different SES.

Influence of Early Life Factors, including breast milk Composition, on the Microbiome of Infants Born to Mothers with and without Inflammatory Bowel Disease.

Herein we analysed the influence of early life factors, including breast milk composition, on the development of the intestinal microbiota of infants born to mothers with and without IBD. The MECONIUM [Exploring MEChanisms Of disease traNsmission In Utero through the Microbiome] study is a prospective cohort study consisting of pregnant women with or without IBD and their infants. Longitudinal stool samples were collected from babies and analysed using 16s rRNA sequencing and faecal calprotectin. Breast milk proteomics was profiled using Olink inflammation panel. We analysed gut microbiota of 1034 faecal samples from 294 infants [80 born to mothers with and 214 to mothers without IBD]. Alpha diversity was driven by maternal IBD status and time point. The major influencers of the overall composition of the microbiota were mode of delivery, feeding, and maternal IBD status. Specific taxa were associated with these exposures, and maternal IBD was associated with a reduction in Bifidobacterium. In 312 breast milk samples [91 from mothers with IBD], mothers with IBD displayed lower abundance of proteins involved in immune regulation, such as thymic stromal lymphopoietin, interleukin-12 subunit beta, tumour necrosis factor-beta, and C-C motif chemokine 20, as compared with control mothers [adjusted p = 0.0016, 0.049, 0.049, and 0.049, respectively], with negative correlations with baby´s calprotectin, and microbiome at different time points. Maternal IBD diagnosis influences microbiota in their offspring during early life. The proteomic profile of breast milk of women with IBD differs from that of women without IBD, with distinct time-dependent associations with baby's gut microbiome and feacal calprotectin.

Cost assessment of optimal control strategy for brucellosis dynamic model based on economic factors

In recently years, brucellosis between humans and animals in China has shown signs of outbreak again. Brucellosis always takes a heavy toll on human health and profitability of livestock industry, but for farmers, the purpose of breeding is to make profits. Therefore, the optimal control strategy that can maximize the profits of farmers and effectively control brucellosis is needed. It is important to understand the profit mechanism of farmers and disease transmission mechanism in order to design a more effective and reasonable control strategy to maximize the profits of farmers. We propose a dynamic model combining the economic factors, behaviors of livestock farmers and transmission mechanism of brucellosis. Then we investigate the result of the optimal strategy in theory using Pontryagin Maximum Principle and its existence and uniqueness are proved. To verify the accuracy and applicability of the theory, the model are simulated by the least square method based on the price data and infected people data of Ningxia Hui Autonomous Region. The simulation results show that brucellosis is in an outbreak in Ningxia Hui Autonomous Region and the current control policy must be adjusted. Sensitivity analysis indicate economic factors have certain influence on the outbreak of diseases. Under different compositions of three control items (including reduce the contact between susceptible and infected animals, increase the vaccination of susceptible animals, and reduce the discharge of Brucella), we evaluate the optimal control strategy for Ningxia Hui Autonomous Region from profits and infected brucellosis livestock perspectives. The profit results show that the government should increase financial support for disease control and it is effective to implement control by stages.

Correlation of viral loads in disease transmission could affect early estimates of the reproduction number.

Early estimates of the transmission properties of a newly emerged pathogen are critical to an effective public health response, and are often based on limited outbreak data. Here, we use simulations to investigate how correlations between the viral load of cases in transmission chains can affect estimates of these fundamental transmission properties. Our computational model simulates a disease transmission mechanism in which the viral load of the infector at the time of transmission influences the infectiousness of the infectee. These correlations in transmission pairs produce a population-level convergence process during which the distributions of initial viral loads in each subsequent generation converge to a steady state. We find that outbreaks arising from index cases with low initial viral loads give rise to early estimates of transmission properties that could be misleading. These findings demonstrate the potential for transmission mechanisms to affect estimates of the transmission properties of newly emerged viruses in ways that could be operationally significant to a public health response.

Stochastic analysis and control for a delayed Hepatitis B epidemic model

Considering the time delay originating from a certain incubation period or asymptomatic state, we propose a delayed epidemic system within the noisy environment of the hepatitis B virus to analyze the mechanism of disease transmission and elucidate how to control it by applying the strategy of vaccinating and treatment. Applying stochastic Lyapunov functional theory, we first construct an integral Lyapunov function coupling the time delay and stochastic fluctuation to investigate whether there exists a unique global solution to the model. Next, we yield the threshold condition for controlling disease extinction, and persistence, as well as its stationary distribution. Governed by these sufficient conditions, we study the existence of optimal control solutions in deterministic and stochastic scenarios to uncover how to accelerate disease extinction through vaccination and treatment. The results indicate that the time delay will prolong the duration of the disease for the original system but suppress the peak value of HBV in the controlled system. Finally, we verify the versatility of theoretical results by numerical simulations. These results will effectively decipher the importance of the time delay in the control of hepatitis B.

Comparing morphological, parasitological, and genetic traits of an invasive minnow between intermittent and perennial stream reaches

Abstract Invasive fishes are a major environmental issue at the global scale, particularly for their impacts on freshwater ecosystems via the mechanisms of hybridisation, competition, predation, and disease transmission. This is of special conservation concern on the Iberian Peninsula due to the high level of endemism. With the aim to improve our knowledge on the invasion process of non‐native fishes, the present study consists of analysing key biological traits potentially related to their colonisation capacity: morphology, parasite communities, and genetic diversity. A non‐native population of Languedoc minnow Phoxinus septimaniae (leuciscid species native to south‐east France) was assessed in Tordera Stream (north‐eastern Iberian Peninsula). Fish were sampled in mid‐May (reproductive period) 2018 and 2019. Biological traits were compared between colonising and resident individuals from stream reaches of intermittent and perennial flow, respectively. After adjusting for fish size/body mass with analysis of covariance, body condition and health status (external and internal examination) tended to be better in the intermittent reach. Parasite load (number) and diversity (Shannon index) were significantly higher in the perennial reach. Fish development was also more stable in colonising minnow, as detected by low levels of fluctuating asymmetry for the eye diameter and the length of pectoral fins (adjusted for bilateral character size). Genetic diversity (microsatellite markers) was lower in resident minnow. Minnow genetic homozygosity (index of internal relatedness) was positively associated with parasite load and developmental instability (high fluctuating asymmetry levels). Our results show that colonising minnows display particular profiles of morphological, parasitological, and genetic traits that apparently allow these individuals to increase their dispersal capacity to survive and reproduce in harsher environmental conditions. The potential mechanisms may be related to a wider physiological tolerance, better immune response, parasite resistance/tolerance, and genetic diversity in colonising specimens. Such information reveals the specific traits of successful fish invaders under a seasonal colonisation dynamic. These data are relevant for environmental managers, to predict and identify areas vulnerable to invasion, in order to establish monitoring programmes for early detection, which will help to reduce the spread of non‐native fish populations.

Proteome-wide analysis of lysine 2-hydroxyisobutyrylation in Frankliniella occidentalis

BackgroundLysine 2-hydroxyisobutyrylation (Khib) is a novel and conserved post-translational modification (PTM). Frankliniella occidentalis are economically important agricultural pests globally and also notorious for vectoring destructive plant viruses. To better study the disease transmission mechanism of F. occidentalis, it is necessary to conduct in-depth analysis of it. So far, no Khib modification of insects has been reported.ResultsIn this study, a proteome-wide analysis of Khib modifications in F. occidentalis was analyzed for the first time through the combination of high performance liquid chromatography fractionation technology and 2-hydroxyisobutyrylated peptide enrichment and other advanced technologies, 4093 Khib sites were identified on 1125 modified proteins. Bioinformatics and functional enrichment analyses showed that Khib-modified proteins were significantly enriched in many cell compartments and pathways, especially related to various cellular components and biological processes, and were more concentrated in ribosomes and proteasome subunits, involved in energy metabolism, protein synthesis and degradation, compared to the other nine species including Japonica rice, Homo sapiens, P. patens, Botrytis, Ustilaginoidea virens, Saccharomyces cerevisiae, T. gondii, C. albicans, and F. oxysporum. And Khib sites on virus-interacting insect proteins were discovered for the first time, such as cyclophilin and endoCP-GN.ConclusionsAfter three repeated experiments, we found a total of 4093 Khib sites on 1125 proteins. These modified proteins are mainly concentrated in ribosomes and proteasome subunits, and are widely involved in a variety of critical biological activities and metabolic processes of F. occidentalis. In addition, for the first time, Khib modification sites are found on the proteome of F. occidentalis, and these sites could be acted as for the virus interaction, including cyclophilin and endoCP-GN. The global map of 2-hydroxyisobutyrylation in thrips is an invaluable resource to better understand the biological processes of thrips and provide new means for disease control and mitigation of pest damage to crops.

P050 A comparison of the Gut Microbiota in Pregnant Women with and without Inflammatory Bowel Disease and Their Offspring in Hong Kong and United States

Abstract Background Data on the impact of geographic location on the gut microbiota of pregnant women with and without inflammatory bowel disease (IBD) and their infants are lacking. Methods 420 pregnant women with or without IBD and 331 infants were prospectively enrolled in the MECONIUM (Exploring MEChanisms Of disease traNsmission In Utero through the Microbiome) study in Hong Kong (HK) and United States (US). Of these individuals, the fecal microbiota compositions from 105 mothers (47 from HK and 58 from US) at third trimester and 54 babies (26 from HK and 28 from US) at 1 month were surveyed using 16s rRNA sequencing. Results The birthweight of infants in HK was significantly lower compared to that of infants in the US (p-value<0.001), while other baseline characteristics were comparable (Table 1). We observed differential gut microbiome beta-diversity between pregnant women without IBD (PERMANOVA test, p-value<0.05) and their infants (p<0.05) from HK and the US (Figure 1A). At the genus level, compared to pregnant women without IBD in the US, those in HK had a higher abundance of 15 taxa including Bifidobacterium, Faecalibacterium and Bacteroides and lower abundance of 6 taxa including Blautia and Turicibacter (Figure 1B). Compared to infants born to women without IBD in the US, those in HK had higher abundance of 3 taxa including Klebstella and Escherichia/Shigella and lower abundance of Enterococcus (Figure 1B). When comparing the gut microbiome alpha-diversity of women with and without IBD (Figure 1C), and that of their infants, both were lower in HK, (p-values= 0.077, 0.13, respectively) and in the US (p-values=0.0024, 0.019, respectively). Conclusion Our results suggest the impact of geographic location on the gut microbiome diversity and composition irrespective of IBD status. Maternal IBD is associated with reduced microbiome diversity in infants in both the US and HK.

OP02 The breastmilk proteomics of women with Inflammatory Bowel Disease (IBD) and its impact on fecal calprotectin and microbiota composition in their babies

Abstract Background Breastmilk (BM) is a complex fluid that contributes to shaping the immune system of the offspring. BM composition depends on stage of lactation, maternal health status and diet, environment, and genetics. Limited data exists on the composition of the BM from women with IBD and its potential impact on the newborn’s microbiome composition. Methods The MECONIUM (Exploring MEChanisms Of disease traNsmission In Utero through the Microbiome) study is a prospective cohort study including pregnant women with IBD, pregnant healthy control (HC), and their offspring. BM samples were collected 2 weeks post-delivery. Stool samples from the offspring were collected throughout the first 3 years of life and used to assess faecal calprotectin (fCal) and gut microbiota composition (16S). Targeted proteomics of the BM samples was performed with the Olink inflammation panel (92 protein biomarkers). Correlations between specific proteins in the BM, fCal and 16S were assessed using non-parametric tests. Multiple testing correction was performed with false discovery rate (FDR). MaAsLin2 R package was used for multivariate testing. Results 236 BM samples were analysed: 174 from HC, 37 Crohn’s disease (CD), 25 ulcerative colitis (UC). Thymic stromal lymphopoietin (TSLP), a cytokine with an important role in the maturation of T cells, was significantly lower in BM of women with IBD vs HC (FDR p=0.0017). The levels of TSLP in the BM of the mothers correlated negatively with infant fCal at year1 (rho=-0.20, p=0.01), and with the relative abundance of Cronobacter (MaAsLin2 FDR 0.1) of the offspring at month 1. Chemokine (C-C motif) ligand 20 (CCL20), which acts in chemotaxis of dendritic cells and T-cells and B-cells, was also significantly lower in women with CD vs HC (FDR 0.013) and in women with CD vs UC (p=0.014). Matrix metalloproteinase-1 (MMP-1), a collagenase involved in the breakdown of extracellular matrix, was also lower in BM of women with CD (p=0.009) and a negative correlation was observed between the levels of MMP1 and fCal at 3 months and 1 year (rho=-0.20 and -0.18, p=0.01 and 0.02, respectively). Osteoprotegerin (OPG), higher in BM of women with UC (p=0.018), was positively correlated with Streptococcus (MaAsLin2 FDR p=0.2) and negatively correlated with Bacteroides and Parabacteroides (MaAsLin2 FDR p=0.03 and 0.1) in the offspring at month 1. Conclusion The proteomic profile of BM of women with IBD is distinct from that of women without IBD. BM composition may influence offspring’s’ gut microbiome signatures and fCal level at different timepoints. These findings suggest that BM composition may impact the offspring’s intestinal immune system maturation and microbiome development, and warrant further research.

Minimising exposure to respiratory droplets, ‘jet riders’ and aerosols in air-conditioned hospital rooms by a ‘Shield-and-Sink’ strategy

ObjectivesIn COVID-19, transfer of respiratory materials transmits disease and drives the pandemic but the interplay of droplet and aerosol physics, physiology and environment is not fully understood. To advance understanding...

SIRS epidemiological model with ratio‐dependent incidence: Influence of preventive vaccination and treatment control strategies on disease dynamics

In this paper, we study an SIRS epidemic model with ratio‐dependent incidence rate function describing the mechanisms of infectious disease transmission. Impacts of vaccination and treatment on the transmission dynamics of the disease have been explored. The treatment rate is constant when the number of infected individuals is greater than the maximal capacity of treatment and proportional to the number of infected individuals when the number of infected individuals is less than the maximal capacity of treatment. Analysis shows that (1) the sufficiently large value of the preventive vaccination rate can control the spread of disease, and (2) a threshold level of the psychological (or inhibitory) effects in the incidence rate function is enough to decrease the infective population. It is also obtained that model undergoes transcritical and saddle‐node bifurcations with respect to disease contact rate. Moreover, in the presence of treatment strategy, the model has multiple endemic equilibria and undergoes a backward bifurcation. The maximal capacity of treatment plays important roles on the disease dynamics of the model. The number of infected individuals decreases with respect to the maximal capacity of treatment, and the disease completely dies out from the system for the large capacity of the treatment when constant treatment strategy is applied. Further, it is also found that the spread of disease can be suppressed by increasing treatment rate. From sensitivity analysis, we have observed that the transmission and treatment rates are most sensitive parameters. The effects of different parameters on the disease dynamics have also been investigated via numerical simulation.