Period Of Infection Research Articles

Effect of copper nanoparticles green-synthesized using Ocimum basilicum against Pseudomonas aeruginosa in mice lung infection model

Abstract The frequency of lung infection induced by multi-drug resistant strains of Pseudomonas aeruginosa has significantly risen, primarily due to the inadequate effectiveness of powerful chemotherapeutic methods. This study demonstrates that the Ocimum basilicum aqueous extract and copper nanoparticles (CuNPs) exhibited significant antioxidant and anti-infectious properties under in vivo conditions. To analyze the characteristics of the CuNPs synthesized from the reaction between copper nitrate solution and the aqueous O. basilicum extract, various techniques such as energy dispersive X-ray analysis, field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis, and transmission electron microscopy were employed. The in vivo study encompasses the assessment of P. aeruginosa lethal dose in mice and the disease manifestation analysis, which comprises reduction in body weight, hypothermia, bacteremia, and other parameters, over a 48 h infection period. The infected mice exhibited a notable decrease in body temperature, measuring at 25°C after 48 h, compared to the initial temperature of 39°C. Additionally, a 30% reduction in weight was seen at the conclusion of the study. To assess the effectiveness of CuNPs on lung infection caused by the calculated lethal dose and bacteremia, histopathology analysis was employed. The bacterial load in the CuNPs group was determined to be 0.5 Log10CFU/mL on Day 8, indicating a notable decrease from the initial measurement of 1.5 Log10CFU/mL on Day 1. The histopathological findings revealed a widespread and sporadic buildup of alveolar space inflammatory cells, with infiltrates observed throughout all lung sections in infected mice. Enhanced lung histology was observed in the group of animal treated with reduced exudates noted at 200 µg/kg. CuNPs demonstrated inhibitory effects on the growth of P. aeruginosa at 8 µg/mL, while at 16 µg/mL, they effectively eradicated P. aeruginosa. The research unequivocally demonstrates the efficacy of CuNPs extract in combating lung infections induced by P. aeruginosa at 200 µg/kg. The recent survey aims to further explore the biomedical characteristics of these CuNPs in order to develop a powerful treatment against this dangerous pathogen.

Emergence and fixation of SARS-CoV-2 minority variants in a chronically infected patient receiving therapy in Denmark.

SARS-CoV-2 variants of concern (VOC), such as Delta and Omicron have harbored mutations, which increased viral infectivity or ability to evade neutralizing antibodies. Immunocompromised patients might be a source of some of these emerging variants. In this study, we sequenced 17 consecutive samples from an immunocompromised patient with a long-term SARS-CoV-2 infection with the pre-VOC era lineage B.1.177.35. We here describe the emergence of 73 nonsynonymous minority variants in this patient and show that 10 of these mutations became dominant in the viral population during the treatment period. Four of these were seen throughout the infection period and had a very low global prevalence, although three of them were also observed later in the Alpha, Delta, and Omicron lineages. We also found that two adjacent nsp12 variants (M785I and S786P) belonged to different quasi-species and competed during the early stages of infection and remdesivir administration. This emphasizes the importance of ongoing genome surveillance of SARS-CoV-2 among immunocpromised patients.

Nosocomial Transmission of Mycobacterium tuberculosis in an Oncological Setting

Objective: Mycobacterium tuberculosis (MTB) is a contagious airborne disease that is spread from person to person via particles in the air which are expelled when speaking or coughing1. This retrospective observational study aims to assess the nosocomial transmission of pulmonary MTB among inpatient roommates in a high-risk oncological population over a 14-year period. With limited studies on the transmissibility of MTB in such environments, the investigation focuses on evaluating the risk of nosocomial transmission and implementation of appropriate infection control measures. Design: A retrospective analysis from 2010 – April 2023 was conducted in an acute care, 500-bed oncological center. Following exposure workups performed by the Department of Infection Prevention and Control, 17 of 57 identified patients with active pulmonary MTB had inpatient stays with roommates. Source infectivity showed 7 AFB smear positive results, 4 MTB PCR positive results, and 14 MTB culture positive results. Some index patients had a combination of AFB, PCR and/or culture positivity. A high-risk exposure is defined as any patient who shared a room with an index patient for >4 cumulative hours during the infectious period. Infectious period was determined for each index patient based on the onset of symptoms and laboratory results. Workups identified 33 exposed roommates who were notified and advised to undergo testing, employing QuantifERON (QFT-GIT) serum test or Tuberculin skin (TST) PPD test at least 8 weeks following their last day of exposure. The overlap between inpatient roommates and index patients ranged from 1 to 4 days, averaging 1.5 days. Results: Of the 33 high-risk roommates, 14 (42%) patients were unable to provide follow-up testing for various reasons including: patient expiration prior to testing, patient transfer to hospice, and being lost to follow up. Nineteen (58%) patients completed post-exposure testing. 12 patients underwent PPD testing (63%) and 7 patients underwent QuantifERON testing (37%). Zero (0%) were found to have a positive QuantifERON or PPD following their exposure. 15.8% (N=3) of exposed patients had hematologic malignancies, and 84.2% (N=16) of exposed patients had solid tumor malignancies. Conclusion: The risk of active pulmonary MTB transmission in an oncological, inpatient setting was determined to be low. The absence of positive conversions among roommates of confirmed MTB patients underscores the effectiveness of infection control measures, emphasizing the importance of isolating confirmed or suspected cases promptly. Ongoing efforts should continue to focus on these preventive measures to mitigate the risk of MTB transmission in similar high-risk settings.

Post-COVID syndrome: Clinical pattern and impact on health related quality of life

Background COVID-19 management has changed from just dealing with a novel respiratory viral illness to unraveling the mystery of a systemic disease. This study aimed to assess clinical pattern for post-COVID survivors and impact on quality of life. Methods 115 Patients suffering from COVID-19 affection were recruited in this study. The assessment included clinical history with special attention to symptoms attributable to post-COVID manifestations. Evaluation for presence of insomnia, anxiety and depression were done using insomnia severity index (ISI), Hamilton’s anxiety (HAM-A) and depression rating scales (HAM-D), respectively. Laboratory investigations included complete blood count (CBC), kidney function test, liver function test, C-reactive protein (CRP), and inflammatory markers including ESR, CRP and Ferritin level. EQ-5D-5L and EQ visual analogue scale (EQ-VAS) were used to assess participants’ overall health status and quality of life. Results COVID-19 patients suffered from cough (76%), fever (72.9%), fatigue (72.9%), dyspnea (69.8%) and muscle/joint pain (66.1%) as the most distressing symptoms during period of acute infection. Regarding post-COVID syndrome (PCS); Dyspnea (32.2%), fatigue (26.1%), muscle/joint pain (22.6%), loss of taste (16.5%) and loss of smell (15.7%) were the most prevalent at 3 month evaluation. 46.9% patients developed manifestations attributable to post-COVID syndrome. Fever, cough, loss of smell and taste, fatigue, anxiety and insomnia persisted significantly for longer periods among severe cases (Group 2). EQ-5D-5L domains were significantly impaired among severe COVID patients. Significant positive correlation noticed between age and increased duration of dyspnea, muscle/joint pains and depression. Also, CT chest severity scores showed significant correlation with dyspnea, fatigue, muscle/joint pains (P=0.023, 0.012 and <0.001; respectively). Conclusion High prevalence of Post-COVID syndrome is a challenge to health care resources. PCS directly impacts mobility, self-care, usual activities, pain perception and anxiety and therefore is associated with lower quality of life among post-COVID patients.

The 90-Day Risk of Hospitalization in Heart Transplant Recipients After COVID-19 Infection

BackgroundHeart transplant recipients are at a high-risk of complications from the coronavirus-2019 (COVID-19) infection. Heart transplant recipients are a special group of persistently immunosuppressed people, and COVID-19 may cause them to experience an unpredictable course of infection, with a risk of hospitalization occurring well beyond their initial infection period. The seriousness of COVID-19 disease in heart transplant recipients emphasizes how vital it is to refer patients promptly and early to specialized heart transplant centers. MethodsWe retrospectively reviewed all heart transplant recipients at a single center between March 2019 and October 2021. All recipients with positive nasopharyngeal reverse transcriptase-polymerase chain reaction tests for COVID-19 were included in this study. After IRB approval, we obtained medical records and patient data from electronic medical records. ResultsThis study followed 126 heart transplant patients from March 2019 to October 2021 of which only 49 had COVID-19 infections. The median age at infection was 58 years (49-65), with 41% female. Race distribution was as follows: 59% Caucasian and 39% African American. The median time from transplant to infection was 384 days (237-677). All infected patients had a 50% dose reduction in mycophenolate mofetil per institutional protocol. The majority of symptoms were cough, fatigue, shortness of breath, and fever. Among all patients with COVID-19, 45 (92%) were vaccinated. Of those vaccinated, 27 (60%) patients received Pfizer initial and booster doses, whereas 18 (40%) received Moderna initial and booster doses. Twelve patients (24%) were hospitalized within 90 days of infection, with only two requiring ICU level of care. The median duration of hospitalization was 5 days (4-9). Of the hospitalized patients, 11 (92%) were discharged, and 1 (8%) died in the hospital. Three of the four unvaccinated patients were hospitalized, and one died while hospitalized. The remaining 37 patients were managed as outpatients. ConclusionHeart transplant recipients have an increased risk of contracting COVID-19 and developing severe symptoms due to multiple healthcare contacts, preexisting health conditions, and weakened immune systems. Our data highlight that most vaccinated patients do not require hospitalization within 90 days of infection, and those hospitalized have a high likelihood of survival without needing ICU care.

RANKL-mediated osteoclast formation is required for bone loss in a murine model of Staphylococcus aureus osteomyelitis

Staphylococcus aureus osteomyelitis leads to extensive bone destruction. Osteoclasts are bone resorbing cells that are often increased in bone infected with S. aureus. The cytokine RANKL is essential for osteoclast formation under physiological conditions but in vitro evidence suggests that inflammatory cytokines may by-pass the requirement for RANKL. The goal of this study was to determine whether RANKL-dependent osteoclast formation is essential for the bone loss that occurs in a murine model of S. aureus osteomyelitis. To this end, humanized-RANKL mice were infected by direct inoculation of S. aureus into a unicortical defect in the femur. Mice were treated with vehicle or denosumab, a human monoclonal antibody that inhibits RANKL, both before and during a 14-day infection period. The severe cortical bone destruction caused by infection was completely prevented by denosumab administration even though the bacterial burden in the femur was not affected. Osteoclasts were abundant near the inoculation site in vehicle-treated mice but absent in denosumab-treated mice. In situ hybridization demonstrated that S. aureus infection potently stimulated RANKL expression in bone marrow stromal cells. The extensive reactive bone formation that occurs in this osteomyelitis model was also reduced by denosumab administration. Lastly, there was a notable lack of osteoblasts near the infection site suggesting that the normal coupling of bone formation to bone resorption was disrupted by S. aureus infection. These results demonstrate that RANKL-mediated osteoclast formation is required for the bone loss that occurs in S. aureus infection and suggest that disruption of the coupling of bone formation to bone resorption may also contribute to bone loss in this condition.

New insights into swine dysentery: faecal shedding, macro and microscopic lesions and biomarkers in early and acute stages of Brachyspira hyodysenteriae infection

BackgroundSwine dysentery (SD) is a severe mucohaemorrhagic colitis in pigs caused classically by Brachyspira hyodysenteriae. Although several aspects of B. hyodysenteriae infection dynamic are already described, further research in the early stage of this infection is required. In this study, 7-week-old pigs were orally challenged with B. hyodysenteriae to obtain information about faecal shedding, macro and microscopic intestinal lesions and serum acute phase proteins in pigs at the onset of B. hyodysenteriae shedding (early infection group, n = 8), in pigs with mucohaemorrhagic diarrhoea (acute infection group, n = 8) and in non-infected controls (n = 16).ResultsFirst B. hyodysenteriae detection by q-PCR and first loose stools with blood and mucus occurred both at 8 days post-inoculation. The lapse between a positive q-PCR and observation of mucohaemorrhagic diarrhoea ranged from 0 to 3 days, except in a single pig in which this period lasted 5 days. Macroscopic lesions were observed in the large intestine from both infected groups although more frequent and severe in acute infection group. Microscopic observation of the apex mucosa revealed that in early infection only higher ulceration values were observed compared to healthy controls. In contrast, the acute infection group exhibited higher ulceration, neutrophils infiltration and increased mucosal thickness compared to the other two groups. Among the serum biomarkers tested, only haptoglobin, C-reactive protein, and creatine kinase showed a significant increase in pigs in the acute infection period compared to controls, whereas haptoglobin was the only factor with a significant increase at the early infection compared to non-infected animals.ConclusionsThis study provides new insights about SD and remarks the complex and limited options to perform an early detection of infected animals beyond PCR diagnosis.

Harnessing Soil Diversity: Innovative Strategies for Potato Blight Management in Central-Eastern Poland

Faced with increasing climate challenges, this pioneering study introduces groundbreaking approaches to ensure the resilience of potato crops in east-central Poland. Our research was aimed at developing an innovative, cost-effective system tailored to the diverse local conditions of this region. Conducted between 2018 and 2020, the study analyzed integrated and organic production systems across different soil types and potato varieties. The experiment was conducted using a randomized block design with three replications in two locations. Integrated production systems involve the strategic use of mineral fertilization and chemical protection to optimize crop growth and health, whereas organic production systems rely solely on natural inputs and biological pest control methods. Integrated practices, enhanced by mineral fertilization and chemical protection, notably delayed the onset of late blight by 16 days and extended the critical infection period by 17% compared to their organic counterparts. Remarkably, the integrated systems resulted in a 49% increase in total production and a 52% increase in commercial yields, demonstrating their effectiveness in enhancing crop resilience. Different potato varieties exhibit varied responses to cultivation systems, influencing both yield and disease resistance. Further investigation into these varietal responses can help optimize cultivation practices, leading to improved efficiency and sustainability in potato farming. Location and soil conditions have a significant impact on potato yield and the spread of potato blight. Specific soil properties such as pH levels, organic matter content, soil texture (clay, silt, and sand composition), moisture retention capacity, and nutrient availability are crucial in determining potato productivity and disease dynamics. Further research into these soil properties and the adaptation of varieties to local conditions can contribute to increased productivity and stability in potato production. This study not only paves the way toward sustainable agriculture but also highlights the crucial role of soil diversity in shaping resilient farming practices. Potato producers in the eastern-central region of Poland should implement integrated production systems using mineral fertilization and chemical plant protection, adapted to local soil conditions and potato varieties. These practices can delay the appearance of late blight and increase the total and marketable potato yield. Further research on soil properties and variety adaptation may increase production stability and efficiency. Promoting soil diversity and modern technologies will ensure resilient and sustainable agricultural production in the face of climate change.

Enhanced diabetic wound healing with injectable hydrogel containing self-assembling nanozymes

To build a smart system in response to the variable microenvironment in infected diabetic wounds, a multifunctional wound dressing was constructed by co-incorporating glucose oxidase (GOx) and a pH-responsive self-assembly Cu2−xSe-BSA nanozyme into a dual-dynamic bond cross-linked hydrogel (OBG). This composite hydrogel (OBG@CG) can adhere to the wound site and respond to the acidic inflammatory environment, initiating the GOx-catalyzed generation of H2O2 and the self-assembly activated peroxidase-like property of Cu2−xSe-BSA nanozymes, resulting in significant hydroxyl radical production to attack the biofilm during the acute infection period and alleviate the high-glucose microenvironment for better wound healing. During the wound recovery phase, Cu2−xSe-BSA aggregates disassembled owing to the elevated pH, terminating catalytic reactive oxygen species generation. Simultaneously, Cu2+ released from the Cu2−xSe-BSA not only promotes the production of mature collagen but also enhances the migration and proliferation of endothelial cells. RNA-seq analysis demonstrated that OBG@CG exerted its antibacterial property by damaging the integrity of the biofilm by inducing radicals and interfering with the energy supply, along with destroying the defense system by disturbing thiol metabolism and reducing transporter activities. This work proposes an innovative glucose consumption strategy for infected diabetic wound management, which may inspire new ideas in the exploration of smart wound dressing.

A mixed-methods study on impact of active case finding on pulmonary tuberculosis treatment outcomes in India

BackgroundTuberculosis (TB) remains a significant public health burden in India, with elimination targets set for 2025. Active case finding (ACF) is crucial for improving TB case detection rates, although conclusive evidence of its association with treatment outcomes is lacking. Our study aims to investigate the impact of ACF on successful TB treatment outcomes among pulmonary TB patients in Gujarat, India, and explore why ACF positively impacts these outcomes.MethodsWe conducted a retrospective cohort analysis in Gujarat, India, including 1,638 pulmonary TB cases identified through ACF and 80,957 cases through passive case finding (PCF) from January 2019 to December 2020. Generalized logistic mixed-model compared treatment outcomes between the ACF and PCF groups. Additionally, in-depth interviews were conducted with 11 TB program functionaries to explore their perceptions of ACF and its impact on TB treatment outcomes.ResultsOur analysis revealed that patients diagnosed through ACF exhibited 1.4 times higher odds of successful treatment outcomes compared to those identified through PCF. Program functionaries emphasized that ACF enhances case detection rates and enables early detection and prompt treatment initiation. This early intervention facilitates faster sputum conversion and helps reduce the infectious period, thereby improving treatment outcomes. Functionaries highlighted that ACF identifies TB cases that might otherwise be missed, ensuring timely and appropriate treatment.ConclusionACF significantly improves TB treatment outcomes in Gujarat, India. The mixed-methods analysis demonstrates a positive association between ACF and successful TB treatment, with early detection and prompt treatment initiation being key factors. Insights from TB program functionaries underscore the importance of ACF in ensuring timely diagnosis and treatment, which are critical for better treatment outcomes. Expanding ACF initiatives, especially among hard-to-reach populations, can further enhance TB control efforts. Future research should focus on optimizing ACF strategies and integrating additional interventions to sustain and improve TB treatment outcomes.

Screening and Isolation of Protease Producing Bacteria from Diabetic Foot Ulcers

This study was conducted to detect bacterial causative pathogens in patients with diabetes foot ulcer infections and determine the protease enzyme. Samples were collected from 75 swabs were collected from patients suffering from diabetic foot ulcers referred to The Diabetic Center /Thi-Qar province. Data collected from patients included: age, gender and Period of infection. The results revealed that positive bacterial growth appeared in 54 (72 %) of diabetic foot ulcer specimen, and the most common isolates were Enterobacter cloaca 15(27.77%), followed by proteus mirabilis 12 (22.22%), Staphylococcus aureus 10 (18.51%), Escherichia coli 8 (14.81%), for each one Klebsiella pneumonia, Pseudomonas aeruginosa and Streptococcus pyogens 3(0.84%). The results of the Protease enzyme test were performed for all 54 isolates to determine the variable ability of these bacterial species isolated from didactic foot ulcers to produce this enzyme. The highest percentage production protease enzyme was 100 % for Pseudomonas aeruginosa, Staphylococcus aureus and 76.92% for proteus mirabilis, while the isolates showed a low production of 20.0 % for Enterobacter cloaca.

Effective intervention of brucellosis prevention in developing countries: A dynamic modelling study

ObjectiveBrucellosis has a considerable impact on human health and the economy in developing countries. In China, the biggest developing country, brucellosis shifted spread of the epidemic from northern to southern regions. Understanding the transmission characteristic of brucellosis on Hunan province, located in central China, is of great significance for successful control. MethodsWe developed a multi-population and multi-route dynamic model (MPMRDM), which is an animal-human-environment coupled model. The model is an extension of the SEIR model, taking into account direct transmission and indirect transmission. We used the model to explore the spread of brucellosis and evaluate the effectiveness of various intervention strategies. ResultsThe animal-to-animal transmission rate was the highest at 5.14 × 10−8, while the environment-to-person transmission rate was the lowest at 9.49 × 10−12. The mean R0 was 1.51. The most effective intervention was taking personal protection, followed by shortening the infection period. Shortening the infection period combined with personal protection is the most effective two-combined intervention strategy. After any comprehensive intervention strategy was implemented, TAR dropped by 90% or more. ConclusionThe results demonstrate that animal transmission route is essential for controlling human brucellosis. Strengthening personal protection, early detection, and early treatment can effectively control the trend of brucellosis. These results can provide an important reference for optimizing brucellosis intervention plans.

Phytochemical and Proximate Analysis of Sweet Potato (Ipomea batatas) Leaves Aqueous Extract and Its Prophylatic Effects on Pseudomonas aeruginosa Infected Catfish (Clarias gariepinus)

The phytochemical and proximate analysis of sweet potato (Ipomea batatas) leaves were carried out to ascertain its bio-active compounds and proximate composition, and their importance in aquaculture. Subsequently, four different feeds were produced from a thirty-five (35) percent crude protein feed using I. batatas aqueous leaves extracts as follows: Do (Oml/kg); D1 (50ml/kg); D2 (100ml/kg) and D3 (150ml/kg). One hundred and fifty (150) sub-adult Clarias gariepinus were distributed to five groups in triplicate and designated as: D+ve (positive control); D-ve (negative control); D1; D2 and D3. While D+ve and D-ve were fed Do, D1 – D3 were fed 50ml/kg – 150ml/kg respectively. After eight weeks of feeding ten (10) fish from D-ve, D1 – D3 were infected intraperitoneal, with 1.5ml of 15 x 1010cfu/ml over night grown Pseudomonas aeruginosa and the fish in D+ve was not infected. After one week post infection period, the prophylactic effects of the I. batatas leaves extract were evaluated on the experimental fish following assessments on survival rate, disease resistance, condition factor and physicochemical parameters of the experimental waters. The results indicates as follows: proximate composition of I. batatas leaves contains fat, crude protein, crude fibre, ash and carbohydrate at different percentages, but they were higher in content in the dried leaves, but reverse was the case for moisture content. Phytochemical content of I. batatas leaves contains high percentage of alkaloids, phenols, flavonoids and Saponins with noticeable quantities of tannins, anthraquinones and coumarins; the survival rate and disease resistance indicates that D-ve recorded 46.66+11.54% and 0+0.00% respectively, while D+ve and D1 – D3 had 100+0.00% in both parameters; there were no significant difference in the dissolve oxygen, temperature and pH D+ve, D-ve and D1 – D3 but the value in D-v were lower compared to the rest. The values for conductivity and total dissolve solids (TDS) were significantly higher in D1-D3 compared to D+ve and D-ve, but the value of TDS was significantly lower in D+ve.

Within-Host Viral Growth and Immune Response Rates Predict Foot-and-Mouth Disease Virus Transmission Dynamics for African Buffalo.

AbstractInfectious disease dynamics operate across biological scales: pathogens replicate within hosts but transmit among populations. Functional changes in the pathogen-host interaction thus generate cascading effects across organizational scales. We investigated within-host dynamics and among-host transmission of three strains (SAT-1, -2, -3) of foot-and-mouth disease viruses (FMDVs) in their wildlife host, African buffalo. We combined data on viral dynamics and host immune responses with mathematical models to ask the following questions: How do viral and immune dynamics vary among strains? Which viral and immune parameters determine viral fitness within hosts? And how do within-host dynamics relate to virus transmission? Our data reveal contrasting within-host dynamics among viral strains, with SAT-2 eliciting more rapid and effective immune responses than SAT-1 and SAT-3. Within-host viral fitness was overwhelmingly determined by variation among hosts in immune response activation rates but not by variation among individual hosts in viral growth rate. Our analyses investigating across-scale linkages indicate that viral replication rate in the host correlates with transmission rates among buffalo and that adaptive immune activation rate determines the infectious period. These parameters define the virus's relative basic reproductive number (ℛ0), suggesting that viral invasion potential may be predictable from within-host dynamics.

Limited data on infectious disease distribution exposes ambiguity in epidemic modeling choices

Traditional disease transmission models assume that the infectious period is exponentially distributed with a recovery rate fixed in time and across individuals. This assumption provides analytical and computational advantages, however, it is often unrealistic when compared to empirical data. Current efforts in modeling nonexponentially distributed infectious periods are either limited to special cases or lead to unsolvable models. Also, the link between empirical data (the infectious period distribution) and the modeling needs (the definition of the corresponding recovery rates) lacks a clear understanding. Here we introduce a mapping of an arbitrary distribution of infectious periods into a distribution of recovery rates. Under the Markovian assumption to ensure analytical tractability, we show that the same infectious period distribution at the population level can be reproduced by two modeling schemes that we call and , depending on the individual response to the infection, and aggregated empirical data cannot easily discriminate the correct scheme. Besides being conceptually different, the two schemes also lead to different epidemic trajectories. Although sharing the same behavior close to the disease-free equilibrium, the scheme deviates from the expected epidemic when reaching the endemic equilibrium of a susceptible-infectious-susceptible transmission model, while the scheme turns out to be equivalent to assuming a homogeneous recovery rate. We show this through analytical computations and stochastic epidemic simulations on a contact network, using both generative network models and empirical contact data. It is therefore possible to reproduce heterogeneous infectious periods in network-based transmission models, however, the resulting prevalence is sensitive to the modeling choice for the interpretation of the empirically collected data on the length of the infectious period. In the absence of higher resolution data, studies should acknowledge such deviations in the epidemic predictions. Published by the American Physical Society 2024

Temperature-Dependent Sporulation of the Fungus Coniella diplodiella, the Causal Agent of Grape White Rot.

White rot, caused by the fungus Coniella diplodiella, can severely reduce grapevine yields worldwide. Currently, white rot control mainly relies on fungicides applied on a calendar basis or following hailstorms that favor disease outbreaks; however, the control achieved with this strategy is often inconsistent or otherwise unsatisfactory. Realizing more rational control requires an improved understanding of white rot epidemiology. To this end, we conducted experiments with grapevine berries of two Vitis vinifera cultivars (either injured or not before artificial inoculation with a conidial suspension of C. diplodiella) to determine the effect of temperature on the length of latency (i.e., the time between infection and onset of mature pycnidia on berries) and the production of pycnidia and conidia. Sporulation occurred between 10 and 35°C, with the optimum detected at 20°C. The latency period (LP) was shorter at 25 to 35°C than at lower temperatures; the shortest LP was 120 h at 30°C on injured berries. Affected berries produced abundant conidia at 15 to 30°C (the optimum was 20°C) for more than 2 months following inoculation. Mathematical equations were developed that fit the data, with strong associations with temperature for the LP (R2 = 0.831) and for the production dynamics of secondary conidia (R2 = 0.918). These equations may contribute to the development of a risk algorithm to predict infection periods, which can inform risk-based disease control strategies rather than calendar-based disease control strategies.

A comprehensive analysis of non-pharmaceutical interventions and vaccination on Ebolavirus disease outbreak: Stochastic modeling approach.

Ebolavirus disease (EVD) outbreaks have intermittently occurred since the first documented case in the 1970s. Due to its transmission characteristics, large outbreaks have not been observed outside Africa. However, within the continent, significant outbreaks have been attributed to factors such as endemic diseases with similar symptoms and inadequate medical infrastructure, which complicate timely diagnosis. In this study, we employed a stochastic modeling approach to analyze the spread of EVD during the early stages of an outbreak, with an emphasis on inherent risks. We developed a model that considers healthcare workers and unreported cases, and assessed the effect of non-pharmaceutical interventions (NPIs) using actual data. Our results indicate that the implementation of NPIs led to a decrease in the transmission rate and infectious period by 30% and 40% respectively, following the declaration of the outbreak. We also investigated the risks associated with delayed outbreak recognition. Our simulations suggest that, when accounting for NPIs and recognition delays, prompt detection could have resulted in a similar outbreak scale, with approximately 50% of the baseline NPIs effect. Finally, we discussed the potential effects of a vaccination strategy as a follow-up measure after the outbreak declaration. Our findings suggest that a vaccination strategy can reduce both the burden of NPIs and the scale of the outbreak.

Destruction of the brush border by Salmonella enterica sv. Typhimurium subverts resorption by polarized epithelial cells.

Salmonella enterica serovar Typhimurium is an invasive, facultative intracellular gastrointestinal pathogen that destroys the brush border of polarized epithelial cells (PEC). The brush border is critical for the functions of PEC because it resorbs nutrients from the intestinal lumen and builds a physical barrier to infecting pathogens. The manipuation of PEC during infection by Salmonella was investigated by live-cell imaging and ultrastructural analysed of the brush border. We demonstrate that the destruction of the brush border by Salmonella significantly reduces the resorption surface of PEC along with the abrogation of endocytosis at the apical side of PEC. Both these changes in the physiology of PEC were associated with the translocation of type III secretion system effector protein SopE. Additionally, the F-actin polymerization rate at the apical side of PEC was highly altered by SopE, indicating that reduced endocytosis observed in infected PEC is related to the manipulation of F-actin polymerization mediated by SopE and, to a lesser extent, by effectors SopE2 or SipA. We further observed that in the absence of SopE, Salmonella effaced microvilli and induced reticular F-actin by bacterial accumulation during prolonged infection periods. In contrast to strains translocating SopE, strains lacking SopE did not alter resorption by PEC. Finally, we observed that after engulfment of Salmonella, ezrin was lost from the apical side of PEC and found later in early endosomes containing Salmonella. Our observations suggest that the destruction of the brush border by Salmonella may contribute to the pathogenesis of diarrhea.

An Early Dengue Virus Fever Diagnostic Tool

The dengue virus is a persistent and very prevalent pathogenic threat in underdeveloped nations such as India. In order to create effective management and treatment plans, it is necessary to continuously monitor the spread and diagnosis of dengue infections due to their variable types and frequencies. The dengue virus is a very complicated illness that presents in many ways. Using standard laboratory techniques to define the dengue virus infection is challenging. NS1, however, might be a useful diagnosis in the initial several days of fever. In this study, the presence of the dengue-specific NS1 antigen was examined in 88 patients from the Raipur regions of Chattisgarh who had been ill for one to thirty days.A kit based on ELISA was used. The collected data was analyzed and the percentage frequency of both IgM positive and negative and NS1 positive and negative results were expressed for each dengue fever patient. Notably, 36.3% of the population had dengue infection. Early in the infection period, the NS1 antigen was effectively measured. In every participant who tested positive for NS1 on the second day of fever, IgM was negative. Nevertheless, when the temperature increased, this correlation became less strong. It was determined through analysis that leuckocytopenia and thrombocytopenia were random states unrelated to NS1 positive. It is clear that diagnosing dengue is extremely difficult and that the antigenic profile drastically shifts as the fever progresses over a period of days.By using a diagnostic approach based on a thorough examination of the subjects, clinicians can reduce the possibility that dengue shock syndrome would cause hemorrhage. Key Words: India's dengue outbreak, dengue virus fever, or virally transmitted diseases

Cardiovascular Autonomic Dysfunction in Hospitalized Patients with a Bacterial Infection: A Longitudinal Observational Pilot Study in the UK.

A temporal reduction in the cardiovascular autonomic responses predisposes patients to cardiovascular instability after a viral infection and therefore increases the risk of associated complications. These findings have not been replicated in a bacterial infection. This pilot study will explore the prevalence of cardiovascular autonomic dysfunction (CAD) in hospitalized patients with a bacterial infection. A longitudinal observational pilot study was conducted. Fifty participants were included: 13 and 37 participants in the infection group and healthy group, respectively. Recruitment and data collection were carried out during a two-year period. Participants were followed up for 6 weeks: all participants' cardiovascular function was assessed at baseline (week 1) and reassessed subsequently at week 6 so that the progression of the autonomic function could be evaluated over that period of time. The collected data were thereafter analyzed using STATA/SE version 16.1 (StataCorp). The Fisher Exact test, McNemar exact test, Mann-Whitney test and Wilcoxon test were used for data analysis. 32.4% of the participants in the healthy group were males (n = 12) and 67.6% were females (n = 25). Participants' age ranged from 33 years old to 76 years old with the majority being 40-60 years of age (62.1%) (Mean age 52.4 SD = 11.4). Heart rate variability (HRV) in response to Valsalva Maneuver, metronome breathing, standing and sustained handgrip in the infection group was lower than in the healthy group throughout the weeks. Moreover, both the HRV in response to metronome breathing and standing up showed a statistically significant difference when the mean values were compared between both groups in week 1 (p = 0.03 and p = 0.013). The prevalence of CAD was significantly higher in the infection group compared to healthy volunteers, both at the beginning of the study (p = 0.018) and at the end of follow up (p = 0.057), when all patients had been discharged. CAD, as assessed by the HRV, is a common finding during the recovery period of a bacterial infection, even after 6 weeks post-hospital admission. This may increase the risk of complications and cardiovascular instability. It may therefore be of value to conduct a wider scale study to further evaluate this aspect so recommendations can be made for the cardiovascular autonomic assessment of patients while they are recovering from a bacterial infectious process.