Susceptible Persons Research Articles

Mathematical analysis of an epidemic model with direct and indirect transmission modes and two delays

Abstract In this article, we consider an epidemiological model in which we take into account the effects of direct and indirect transmissions. The first mode occurs through direct contact between infectious and susceptible individuals, and the second one will take place through the shedding of virus particles by infectious individuals and their acquisition by susceptible ones. We also study the effect of latency period and time needed for a susceptible person to become infected by indirect transmission mode. By considering the direct and indirect basic reproduction numbers, we define the basic reproduction number R 0 {R}_{0} of the model, which helps us to analyze the stability of equilibria and bifurcation and determine the most sensitive parameters. In conclusion, some numerical simulations are given to confirm the analytical analysis.

Molecular regulation of virulence in Legionella pneumophila.

Legionella pneumophila is a gram-negative bacteria found in natural and anthropogenic aquatic environments such as evaporative cooling towers, where it reproduces as an intracellular parasite of cohabiting protozoa. If L. pneumophila is aerosolized and inhaled by a susceptible person, bacteria may colonize their alveolar macrophages causing the opportunistic pneumonia Legionnaires' disease. L. pneumophila utilizes an elaborate regulatory network to control virulence processes such as the Dot/Icm Type IV secretion system and effector repertoire, responding to changing nutritional cues as their host becomes depleted. The bacteria subsequently differentiate to a transmissive state that can survive in the environment until a replacement host is encountered and colonized. In this review, we discuss the lifecycle of L. pneumophila and the molecular regulatory network that senses nutritional depletion via the stringent response, a link to stationary phase-like metabolic changes via alternative sigma factors, and two-component systems that are homologous to stress sensors in other pathogens, to regulate differentiation between the intracellular replicative phase and more transmissible states. Together, we highlight how this prototypic intracellular pathogen offers enormous potential in understanding how molecular mechanisms enable intracellular parasitism and pathogenicity.

A Population-Based Outcome-Wide Association Study of the Comorbidities and Sequelae Following COVID-19 Infection

BackgroundImmense attention has been given to the outcome of COVID-19 infection. However, comprehensive studies based on large populational cohort with long-term follow-up are still lacking. This study aimed to investigate the risk of various short-term comorbidities (within one month) and long-term sequelae (above one month) after COVID-19 infection.MethodsIn this large prospective cohort study with 14 months follow-up information based on UK biobank, we included 16,776 COVID-19-positive participants and 58,281 COVID-19-negative participants matched for comparison. The risk of each comorbidity and sequela was evaluated by multivariable logistic regression analysis and presented as hazard ratio (HR) and 95% confidence interval (95% CI).ResultsCOVID-19-positive individuals had a higher risk of 47 types of comorbidities within one month following COVID-19 infection, especially those who were older, male, overweight/obese, ever-smoked, with more pre-existing comorbidities and hospitalized. About 70.37% of COVID-19 patients with comorbidities had more than one co-occurring comorbidities. Additionally, only 6 high-risk sequelae were observed after one month of COVID-19 infection, and the incidence was relatively low (< 1%).ConclusionIn addition to long-term sequelae following COVID-19 infection, plenty of comorbidities were observed, especially in patients with older age, male gender, overweight/obese, more pre-existing comorbidities and severe COVID-19, indicating that more attention should be given to these susceptible persons within this period.

Intuitionistic fuzzy multi-objective transportation model during pandemic COVID-19

The given paper discusses an intuitionistic fuzzy discrete time-space optimization model while taking into account the COVID-19 pandemic. The novelty of this study is characterized by the proposal of a distinctive multi-objective intuitionistic fuzzy transportation model in which the demand function varies with time as the number of infected, exposed and susceptible persons increase. Forecasting of demand is executed using the epidemic diffusion model. Also, a new approach to defuzzify triangular intuitionistic fuzzy numbers, depending upon the concept of the golden ratio, is presented. Intuitionistic fuzzy programming approach is used to obtain the pareto-optimal solution. A real-life numerical illustration is explained using the proposed methodology to examine its practical suitability. Outperforming the existing traditional method of solving a transportation problem verifies its proficiency.

To Study the Carriage and Antimicrobial Sensitivity Profile of MRSA among Nursing Staff of Rural Tertiary Health Care Centre of North India

The present study is carried to determine nasal carriage of MRSA among nursing staff posted in Medicine and allied wards of a rural tertiary healthcare center in North India and antibiotic sensitivity profile of the isolated MRSA strains. Many of the carriers of MRSA harbour pathogen in areas like nares, hand surfaces, axilla and are generally asymptomatic. Colonisation in healthcare workers has increased the incidence of serious nosocomial infection wherein healthcare workers act as vectors for transmission of infection in already immuno-compromised patients. The study undertaken was a cross sectional type where in nursing staff was analysed for nasal carriage of MRSA and antibiotic sensitivity profile of MRSA. A total of A total of 60 nursing staff members posted in medicine and allied wards were recruited in this study. A total of 34 (56.6%) were females and 26 (43.3%) were males. our study showed considerable MRSA carriage among the nurses and also reported a decreased sensitivity to commonly used drugs. Also, no resistance was detected against higher antibiotics like Vancomycin, Teicoplanin and Linezolid which points to their use in eradication of infection caused by MRSA. There is a need to strictly implement and follow the hospital infection control guidelines so as to reduce the spread of MRSA to susceptible persons.

Incidence rate drive the multiple wave in the COVID-19 pandemic

The last three years have been the most challenging for humanity due to the COVID-19 pandemic. The novel viral infection has eventually been able to infect most of the human population. It is now considered to be in the endemic stage, meaning it will remain in our world throughout our lifetime. There will be an intermittent outbreak of the COVID infection from time to time. Therefore, it is necessary to formulate a robust Mathematical model to study the dynamics of disease to have a control mechanism in place. In this article, we suggest a modified MSEIR model to explain the dynamics of COVID-19 infection. We assume that a susceptible person contracting the coronavirus develops a transient immunity to the illness. Further, infectives comprise asymptomatic, symptomatic, hospitalized and quarantined individuals. We assume that the incidence rate is of standard type, and susceptible can only become infective if they come in contact with either asymptomatic or symptomatic individuals. This basic and simple model effectively models the various waves every country has seen during the Pandemic. The simple analysis shows that the model could suggest various waves in future if we carefully select the incidence rate for the infection. In summary, we have discussed the following major points in this article.•We have analysed for local behavior infection-free equilibrium solution. Further, a thorough numerical exploration with various parameter settings has been performed to obtain the different cases of infection dynamics of the coronavirus epidemic.•We have found some interesting scenarios which explain the emergence of multiple waves observed in many countries.

A REVIEW ON IMMUNOPATHOGENESIS OF VTILIGO

Vitiligo is an acquired depigmenting disease of the skin and mucosa caused due to the destruction of the melanocytes. The white patch leads to social stigma in society and psychological stress in vitiligo patients. The etiopathogenesis of vitiligo is complex interplay of multiple genetic risk factors, environmental factors, neural factors, auto cytotoxicity, oxidative stress by reactive oxygen species, immunological factors, anti-melanocytes and organ-specific auto-antibodies mediated by autoreactive T lymphocytes in a genetically susceptible person. Hence, it is termed polygenic and multifactorial. All these factors, either alone or mixed leads to melanocytes death in a susceptible person leading to formation of depigmented patch. This review is an overview of the different pathomechanism involved in vitiligo.

Analysis of the Situation on Anthrax in the World in 2022, the Forecast for the Russian Federation for 2023

The paper provides the results of analysis of the epizootiological and epidemiological situation on anthrax in the world in 2022, also, the forecast of incidence rates for the Russian Federation in 2023 is presented. In 2022, two cases of anthrax in farm animals and two cases of cutaneous form of infection in humans were registered in Russia, in the constituent entities of the North Caucasian Federal District: the Republic of Dagestan and the Stavropol Territory. The tense situation on anthrax was reported in the neighboring countries: Azerbaijan, Georgia, Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan, and Ukraine. Epizootics of infection with the highest number of affected farm and wild animals were recorded in the countries of Africa, Asia, North America and Europe. The incidence of anthrax among people in the far abroad (mainly in Africa and Asia) was mostly associated with consuming the meat of sick and fallen farm animals, contact with infected animals, animal products. The incidence of anthrax in animals and humans in the Russian Federation in 2023 will largely depend on the scale of coverage with specific immunization of susceptible animals and persons at risk of infection and, given the strict implementation of comprehensive surveillance measures, will be limited to the registration of potentially possible single cases of infection.

Effect of ventilation mode and rate on airborne transmission of respiratory disease in indoor environments

Ventilation might play an important role in airborne transmission. By using the computational fluid dynamics (CFD) method, ventilation modes, ventilation rates, and infection source’s face direction were considered in a multi-person indoor environment (10 m*10 m*3 m). The airflow patterns, virus concentration distribution, and infection probability were studied. The results showed that the virus concentration was lower with displacement ventilation (DV, lower in, upper out) than mixing ventilation (MV, top-centre in, upper out) or natural ventilation (NV, upper in, upper out). In 2 air changes per hour (ACH), the infection risk of susceptible persons in MV and NV might be about 2.43-fold and 1.30-fold more than that in DV. Increased ventilation usually reduces viral concentrations and the risk of infection. For the height of breathing zones, the average virus concentration at 12ACH was 49.78%-78.72% lower than that at 2ACH. For susceptible persons at a distance of about 2.8-4.2 m to a COVID-19 infector with 30 min exposure time, the long-range airborne infection probability might be 11.53% (±5.86) (2ACH), 4.96% (±1.82%) (6ACH), and 2.96% (±1.91%) (12ACH).

The Prevalence of Anxiety and Depressive Symptoms Among Patients With Celiac Disease in Jordan.

Background Celiac disease is an immune-mediated intestinal disorder with a global prevalence of 1% that results from gluten sensitivity in a genetically susceptible person. It presents with gastrointestinal symptoms, consequences of malabsorption, and/or extraintestinal manifestations that include neuropsychiatric symptoms. Aim The aim of this study was to measure the frequency of anxiety and depressive symptoms in Jordanian patients with celiac disease. Methods This was a cross-sectional study. A questionnaire was sent electronically to celiac disease patients who were members of the Friends of Celiac Disease Patients Association through WhatsApp using Google Forms (Google, Mountain View, California). The questionnaire contained demographic and disease-related questions, in addition to questions that assessed anxiety and depressive symptoms using validated Arabic versions of the Generalized Anxiety Disorder-7 score and Patient Health Questionnaire-9, respectively. Results A total of 133 patients answered the questionnaires. Of the respondents, 82.7% were females, and the mean age was 33.9 +/- 11.22 years; 31.6% of patients were non-compliant witha gluten-free diet, and 56.4% were symptomatic at the time of the questionnaire. The prevalence of anxiety and depressive symptoms were 85% and 82.7%, respectively. There was no correlation between any of the variables and the presence of anxiety or depressive symptoms. Conclusion A significant proportion of celiac disease patients in Jordan have evidence of anxiety and depressive symptoms. Given this high prevalence and the possible impact on the quality of life, physicians need to screen patients for the presence of psychiatric comorbidities and refer those who have symptoms for further evaluation.

Quantifying the impact of individual and collective compliance with infection control measures for ethical public health policy.

Infectious disease control measures often require collective compliance of large numbers of individuals to benefit public health. This raises ethical questions regarding the value of the public health benefit created by individual and collective compliance. Answering these requires estimating the extent to which individual actions prevent infection of others. We develop mathematical techniques enabling quantification of the impacts of individuals or groups complying with three public health measures: border quarantine, isolation of infected individuals, and prevention via vaccination/prophylaxis. The results suggest that (i) these interventions exhibit synergy: They become more effective on a per-individual basis as compliance increases, and (ii) there is often substantial "overdetermination" of transmission. If a susceptible person contacts multiple infectious individuals, an intervention preventing one transmission may not change the ultimate outcome (thus, risk imposed by some individuals may erode the benefits of others' compliance). These results have implications for public health policy during epidemics.

Determination of Physiological, Biochemical and Anti-oxidative Status in Type 1 Diabetes Mellitus Patients

Type 1 Diabetes Mellitus (T1DM) disorganization of glucose equilibrium distinguishes by autoimmune disruption of the insulin producing pancreatic β-cell that constantly leads to insulin scarcity and resulting hyperglycemia Objective: To determine the physiological, biochemical, and anti-oxidant status in Type 1 Diabetes Mellitus Patients. Methods: It is a comparative study. 60 diabetic patients and 50 Samples of healthy individuals were taken from Nawaz Sharif Hospital. Blood samples (5.0 ml) were obtained and centrifuged at 4000 rpm for 10 minutes to separate the serum. Glutathione (GSH), Catalase (CAT), Superoxide Dismutase (SOD), Malondialdehyde (MDA), Nitric oxide (NO), micronutrients (Vitamin A, Vitamin C and Vitamin E) and Electrolytes was determined. Results: MDA level is progressively higher in T1DM (14.01±0.06) as compared to control group (1.27±0.21) (P- Value 0.000). GSH status is notably reduced in diabetic patients (0.15±.05) as compared to normal (6.24±0.33). Comparable anti-oxidant catalase is reduced (2.82±.04) in affected individuals as compared to normal individuals 4.19±1.09. SOD level was remarkably marked up to (13.52±3.21) in susceptible persons as compared to normal (2.15±0.23). Vitamin A level was markedly reduced to (1.62±0.26) in patients as compared to healthy individuals (7.18±0.33). Conclusions: T1DM patients particularly showed reduced amounts and competency of antioxidant protections due to elevated consumption of specific anti-oxidant components such as low level of intracellular glutathione and Catalase and primarily low levels of vitamin A, vitamin E and vitamin C and exalted level of MDA, SOD and NO.

Emerging Non-Antibiotic Options Targeting Uropathogenic Mechanisms for Recurrent Uncomplicated Urinary Tract Infection.

Urinary tract infections (UTIs) are the most frequent bacterial infections in the clinical setting. Even without underlying anatomic or functional abnormalities, more than 40% of women experience at least one UTI in their lifetime, of which 30% develop recurrent UTIs (rUTIs) within 6 months. Conventional management with antibiotics for rUTIs may eventually lead to the development of multidrug-resistant uropathogens. Targeting of the pathogenicity of rUTIs, the evolution of uropathogenic Escherichia coli (UPEC), and inadequate host defenses by immune responses should be explored to provide non-antibiotic solutions for the management of rUTIs. The adaptive evolution of UPEC has been observed in several aspects, including colonization, attachment, invasion, and intracellular replication to invade the urothelium and survive intracellularly. Focusing on the antivirulence of UPEC and modulating the immunity of susceptible persons, researchers have provided potential alternative solutions in four categories: antiadhesive treatments (i.e., cranberries and D-mannose), immunomodulation therapies, vaccines, and prophylaxis with topical estrogen therapy and probiotics (e.g., Lactobacillus species). Combination therapies targeting multiple pathogenic mechanisms are expected to be a future trend in UTI management, although some of these treatment options have not been well established in terms of their long-term efficacy. Additional clinical trials are warranted to validate the therapeutic efficacy and durability of these techniques.

Studying and Simulating the Fractional COVID-19 Model Using an Efficient Spectral Collocation Approach

We give a theoretical and numerical analysis of a coronavirus (COVID-19) infection model in this research. A mathematical model of this system is provided, based on a collection of fractional differential equations (in the Caputo sense). Initially, a rough approximation formula was created for the fractional derivative of tp. Here, the third-kind Chebyshev approximations of the spectral collocation method (SCM) were used. To identify the unknown coefficients of the approximate solution, the proposed problem was transformed into a system of algebraic equations, which was then transformed into a restricted optimization problem. To evaluate the effectiveness and accuracy of the suggested scheme, the residual error function was computed. The objective of this research was to halt the global spread of a disease. A susceptible person may be moved immediately into the confined class after being initially quarantined or an exposed person may be transferred to one of the infected classes. The researchers adopted this strategy and considered both asymptomatic and symptomatic infected patients. Results acquired with the achieved results were contrasted with those obtained using the generalized Runge-Kutta method.

Emergence of zoonotic Brugia pahangi parasite in Thailand.

Zoonotic Brugia pahangi parasite infections in humans have emerged over two decades in Southeast Asia (SEA), including Malaysia and Thailand. The species is commonly found in domestic cats and dogs as the natural reservoir hosts. The sporadic transmission pattern of B. pahangi zoonosis causes childhood infections in Thailand and adulthood infections in Malaysia. It is crucial to understand the vulnerability in how zoonotic B. pahangi parasite is transmitted to susceptible persons in receptive settings and the exposure to the infection under impoverished environment to which the human-vector-animal interactions are related. This acquisition of knowledge will help multiple health science professions to apply One Health approach to strengthening the capacity in diagnosis and surveillance, and hence detecting and monitoring the "lingering" zoonotic B. pahangi infections present in vulnerable populations in Thailand and elsewhere in SEA. In this review article, the authors focused on articulating the concepts of plantation-related zoonotic B. pahangi filariasis by updating current knowledge of B. pahangi life cycle, vector's life cycle and current state of research on the epidemiology and ecology of B. pahangi zoonosis.

FERMENTATION ENHANCED NUTRITIONAL QUALITY OF FOOD- A REVIEW

Among the earliest processed food products, fermented foods are those ingested by humans. Through fermentation techniques different semi-digested and reactive meals can sometimes be converted into functional foods which have a beneficial effect on health. Generally, fermentation helps to eliminate numerous unwanted microbes and toxins from food particles while also introducing helpful microbes to help with digestion, these bacteria also help to develop new enzymes. Fermentation also enhances the quality of different food products such as soybeans, dairy products, cereals, etc. by including their nutritional status. Thereby quality of functional foods can be increased through fermentation which generally improves the GI Tract health, acts as immune system enhancer, improving the bio-availability of nutrients, lowering the lactose intolerance habitat, reducing the appearance of allergic symptoms in susceptible persons and also sometimes decreasing the risk of certain diseases including cancer. Basically fermented foods contain probiotic organisms which may be the probable agents to enhance the health benefits of individuals. In this article, emphasis has been given to the beneficial effect of fermented foods on the general health of the human being.

A CFD approach to reduce the risk of Covid-19 airborne transmission in a typical office

The Covid-19 virus can spread rapidly in the air and cause the epidemic to rage around the world. This study takes a typical office as the research object and proposes four different partition settings to suppress the spread of the virus in the air based on displacement ventilation. And these strategies are verified by DPM model simulations of two daily situations of indexed person for coughing and talking. This study then employed a modified Wells-Riley model to evaluate the effectiveness of these strategies in mitigating the risk of viral infection. As expected, in the absence of a partition, a susceptible person at the other end of the seat greatly increased the risk of infection. Partitions can significantly reduce the risk of infection (100% → 20%), while partitions with a full-wrapped structure can reduce the risk of infection to less than 1%. For the instantaneous release scenario of coughing, the barrier can capture a large particle diameter (&gt;50 μm) particles, and the smaller particle diameter can be discharged out of the room with the thermal plume. The strategies provided in this study can provide recommendations for indoor epidemic prevention and control in the context of the Covid-19 pandemic.

Analysis Of Local Stability Of The Model On COVID-19 Spread In DKI Jakarta Province

The province of DKI Jakarta in Indonesia has an advanced amount of COVID-19 incidents. Hence its dispersion must be restrained. The SEAIQHRD (Susceptible, Exposed, Asymptomatic, Infected, Quarantined, Hospitalized, Recovery, Deceased) model for the dispersion of COVID-19 was evolved in this article. Next, using NGM method to compute basic reproduction number and employing Routh-Hurwitz criterion method to analyze its local stability. Further, two equilibrium points, namely: endemic and disease-free equilibrium points, are obtained. The value of basic reproduction number is used to determine stability analysis. If basic reproduction number less than one, then the endemic equilibrium point is considered asymptotically stable. Based on the sensitivity analysis, the recovery rate of those who are symptomatic subpopulations can help stop the propagation of COVID-19 illness. This article employs data from the DKI Jakarta Province in numerical simulations to depict the dynamics of the COVID-19 dispersion model. According to the analysis's findings, the COVID-19 dispersion model is asymptotically stable at the endemic equilibrium point with ℜ0=2,1966. This indicate that the average of each infected individual can infect two susceptible persons so that the number of infected person will increase over time and cause an outbreak, which means that COVID-19 will remain in the community.

Stability and Hopf bifurcation of an epidemiological model with effect of delay the awareness programs and vaccination: analysis and simulation

The present research is concerned with studying the media coverage delay impact and vaccine impact to control outbreaks the infectious disease in the population, we suggested that our mathematical modeling divide the population into three classes: susceptible persons S(t), vaccinated person V(t) and infected persons I(t). The susceptible individuals are also divided due to media programs into awareness and unawareness of disease danger and its mode of transmission. We studied the influence of time delay in response to the media program on awareness of the epidemic. We first discussed the existence of the equilibrium points of the system and obtain sufficient conditions for the local asymptotic stability of all equilibrium points. Further, the existence of Hopf bifurcation is shown near endemic equilibrium. It is interesting to note that there exists at least one limit cycle around the unstable endemic equilibrium. In particular, sufficient conditions for a unique stable limit cycle have been presented. Finally, we verified the feasibility of the results by numerical simulation and give a brief conclusion to generalize that the delay effect of media and vaccination can cause unexpected dynamic predictions for interacting populations.

Invasive listeriosis in Finland: surveillance and cluster investigations, 2011-2021.

Foodborne pathogen Listeria monocytogenes may cause serious, life-threatening disease in susceptible persons. We combined data from Finnish national listeriosis surveillance, patient interview responses, and laboratory data of patient samples and compared them to listeria findings from food and food production plants collected as part of outbreak investigations during 2011-2021. The incidence of invasive listeriosis in Finland (1.3/100000 in 2021) is higher than the EU average (0.5/100000 in 2021), and most cases are observed in the elderly with a predisposing condition. Many cases reported consuming high-risk foods as well as improper food storage. Since ongoing patient interviews and whole genome sequencing were introduced, several listeriosis outbreaks were detected and food sources identified. Recommendations about high-risk foods for listeriosis and proper food storage should be better communicated to susceptible people. In Finland, patient interviews and typing and comparing listeria isolates in foods and patient samples are crucial in solving outbreaks and determining measures to control invasive listeriosis.