Добірка наукової літератури з теми "Immuno-Epidemiological"

Epidemiological data on seasonal influenza show that the growth rate of the number of infected individuals can increase passing from one exponential growth rate to another one with a larger exponent. Such behavior is not described by conventional epidemiological models. In this work an immuno-epidemiological model is proposed in order to describe this two-stage growth. It takes into account that the growth in the number of infected individuals increases the initial viral load and provides a passage from the first stage of epidemic where only people with weak immune response are infected to the second stage where people with strong immune response are also infected. This scenario may be viewed as an increase of the effective number of susceptible increasing the effective growth rate of infected.

<abstract><p>In this paper, we introduce a novel multi-scale network model of two epidemics: HIV infection and opioid addiction. The HIV infection dynamics is modeled on a complex network. We determine the basic reproduction number of HIV infection, $ \mathcal{R}_{v} $, and the basic reproduction number of opioid addiction, $ \mathcal{R}_{u} $. We show that the model has a unique disease-free equilibrium which is locally asymptotically stable when both $ \mathcal{R}_{u} $ and $ \mathcal{R}_{v} $ are less than one. If $ \mathcal{R}_{u} &gt; 1 $ or $ \mathcal{R}_{v} &gt; 1 $, then the disease-free equilibrium is unstable and there exists a unique semi-trivial equilibrium corresponding to each disease. The unique opioid only equilibrium exist when the basic reproduction number of opioid addiction is greater than one and it is locally asymptotically stable when the invasion number of HIV infection, $ \mathcal{R}^{1}_{v_i} $ is less than one. Similarly, the unique HIV only equilibrium exist when the basic reproduction number of HIV is greater than one and it is locally asymptotically stable when the invasion number of opioid addiction, $ \mathcal{R}^{2}_{u_i} $ is less than one. Existence and stability of co-existence equilibria remains an open problem. We performed numerical simulations to better understand the impact of three epidemiologically important parameters that are at the intersection of two epidemics: $ q_v $ the likelihood of an opioid user being infected with HIV, $ q_u $ the likelihood of an HIV-infected individual becoming addicted to opioids, and $ \delta $ recovery from opioid addiction. Simulations suggest that as the recovery from opioid use increases, the prevalence of co-affected individuals, those who are addicted to opioids and are infected with HIV, increase significantly. We demonstrate that the dependence of the co-affected population on $ q_u $ and $ q_v $ are not monotone.</p></abstract>

<abstract><p>In this paper, we present a multi-scale co-affection model of HIV infection and opioid addiction. The population scale epidemiological model is linked to the within-host model which describes the HIV and opioid dynamics in a co-affected individual. CD4 cells and viral load data obtained from morphine addicted SIV-infected monkeys are used to validate the within-host model. AIDS diagnoses, HIV death and opioid mortality data are used to fit the between-host model. When the rates of viral clearance and morphine uptake are fixed, the within-host model is structurally identifiable. If in addition the morphine saturation and clearance rates are also fixed the model becomes practical identifiable. Analytical results of the multi-scale model suggest that in addition to the disease-addiction-free equilibrium, there is a unique HIV-only and opioid-only equilibrium. Each of the boundary equilibria is stable if the invasion number of the other epidemic is below one. Elasticity analysis suggests that the most sensitive number is the invasion number of opioid epidemic with respect to the parameter of enhancement of HIV infection of opioid-affected individual. We conclude that the most effective control strategy is to prevent opioid addicted individuals from getting HIV, and to treat the opioid addiction directly and independently from HIV.</p></abstract>

A current challenge for disease modeling and public health is understanding pathogen dynamics across scales since their ecology and evolution ultimately operate on several coupled scales. This is particularly true for vector-borne diseases, where within-vector, within-host, and between vector–host populations all play crucial roles in diversity and distribution of the pathogen. Despite recent modeling efforts to determine the effect of within-host virus-immune response dynamics on between-host transmission, the role of within-vector viral dynamics on disease spread is overlooked. Here, we formulate an age-since-infection-structured epidemic model coupled to nonlinear ordinary differential equations describing within-host immune-virus dynamics and within-vector viral kinetics, with feedbacks across these scales. We first define the within-host viral-immune response and within-vector viral kinetics-dependent basic reproduction number [Formula: see text] Then we prove that whenever [Formula: see text] the disease-free equilibrium is locally asymptotically stable, and under certain biologically interpretable conditions, globally asymptotically stable. Otherwise, if [Formula: see text] it is unstable and the system has a unique positive endemic equilibrium. In the special case of constant vector to host inoculum size, we show the positive equilibrium is locally asymptotically stable and the disease is weakly uniformly persistent. Furthermore, numerical results suggest that within-vector-viral kinetics and dynamic inoculum size may play a substantial role in epidemics. Finally, we address how the model can be utilized to better predict the success of control strategies such as vaccination and drug treatment.

Leishmaniasis is a neglected and emerging disease prevalent in Mediterranean and tropical climates. As such, the study and development of new models are of increasing importance. We introduce a new immuno-epidemiological model of visceral leishmaniasis in dogs. The within-host system is based on previously collected and published data, showing the movement and proliferation of the parasite in the skin and the bone-marrow, as well as the IgG response. The between-host system structures the infected individuals in time-since-infection and is of vector-host type. The within-host system has a parasite-free equilibrium and at least one endemic equilibrium, consistent with the fact that infected dogs do not recover without treatment. We compute the basic reproduction number R0 of the immuno-epidemiological model and provide the existence and stability results of the population-level disease-free equilibrium. Additionally, we prove existence of an unique endemic equilibrium when R0 > 1, and evidence of backward bifurcation and existence of multiple endemic equilibria when R0 < 1.

Les arboviroses, transmises par les moustiques Aedes et Culex, continuent de menacer la santé et la vie des populations des zones où elles sont endémiques et représentent des risques d’émergence dans nouveaux territoires colonisés par ces vecteurs. L’objectif principal de nos travaux était i) d’évaluer le niveau d’exposition des populations aux piqûres des Aedes aegypti et Ae. albopictus et le risque de transmission des maladies qu’ils transmettent, en milieu urbain en Afrique de l’Ouest et au Sud de la France métropolitaine et ii) d’évaluer et valider les réponses IgG anti-EGS et anti-protéine recombinante de 30 kDa de Culex quinquefasciatus comme biomarqueur d’exposition potentiel des Hommes aux piqûres des Culex. Nous avons dosé dans les sérums des individus exposés, les réponses anticorps : i) IgG anti-Nterm-34 kDa et les IgG anti- antigènes d’arbovirus (LUMINEX) chez les enfants d’Anoumabo, de Bromakoté et de Petit-Bassam, à d’Abidjan, , ii) IgG et IgM anti-Nterm-34 kDa d’Ae. aegypti à l’’Auvergne, de Corse, d’Occitanie et de PACA, en France, et iii) IgG anti-EGS et la protéine recombinante 30 kDa chez les enfants de Dar-es-Salam, N’Gattakro, Kennedy à Bouaké.A Abidjan, les IgG anti-Nterm-34 kDa étaient significativement différentes entres les quartiers d’étude avec un fort niveau à Bromakoté. Les IgG spécifiques étaient associées aux données des pièges collants. Selon la technique LUMINEX les arbovirus circulaient dans les quartiers, avec à une détection majoritaire de DENV3. Petit-Bassam était le plus affecté. L’ensemble de ces résultats démontraient que l’exposition aux Aedes et ainsi le risque de transmission étaient variables entre quartiers au sein d’une même ville africaine.En France métropolitaine, les IgG spécifiques étaient plus élevées dans les régions colonisées que dans la région non colonisée. La réponse IgG spécifique était plus élevée en Occitanie et en PACA par rapport à la Corse. Les IgM anti-peptide salivaire, indiquait une différence significative entre les régions exposées. En Occitanie, les niveaux médians des réponses IgG anti-peptide des départements 30 et 34, étaient plus élevés que celles des départements 31 et 66. En PACA, une différence significative du niveau des IgG spécifique était détectée entre le département 04 et 13 et entre les départements 05 et 13. Les IgG des départements 13 et 83 plus élevées que ceux des autres départements. Les départements colonisés entre 2010 et 2012 présentaient un taux d’IgG anti-peptide statiquement plus élevés que celui des départements non colonisés. Les IgM entre les individus des 4 régions était pratiquement nul. Ces résultats indiquaient la pertinence du biomarqueur IgG anti-peptide salivaire pour discriminer les régions et les départements les plus exposés aux piqûres d’Ae. albopictus et ainsi d’évaluer l’hétérogénéité des risques de transmission des arboviroses en France métropolitaine.Pour les Culex, les réponses IgG anti-EGS et anti-30 kDa étaient significativement plus élevées chez les enfants vivant dans les sites de forte densité de Culex quinquefasciatus. Les IgG anti-30 kDa étaient significativement plus élevées chez les enfants ne dormant pas sous les moustiquaires imprégnées d’insecticide par rapport à ceux dormant dessous. De plus, une corrélation positive a été observée entre les réponses IgG anti-EGS et les Ac IgG anti 30 kDa au sein de la population totale.Cette étude a montré que l’utilisation des biomarqueurs d’exposition aux piqûres des Aedes pourraient un outil pertinent pour l’évaluation de l’hétérogénéité d’exposition aux vecteurs d’arbovirus dans le contexte urbain africain et entre les départements d’une même région dans le Sud de la France métropolitaine. Les réponses IgG anti-EGS et anti-protéine 30 kDa représenteraient des candidats biomarqueurs potentiels aux piqûres de Culex. Toutefois, leur validation comme de ce biomarqueur d’exposition aux Culex, des études complémentaires sont nécessaires
Arboviruses, transmitted by the Aedes and Culex mosquitoes, continue to threaten the health and lives of populations in areas where they are endemic and represent risks of emergence in new territories colonised by these vectors. The main objective of our work was i) to assess the level of exposure of populations to the bites of Aedes aegypti and Ae. albopictus and the risk of transmission of the diseases they transmit, in an urban environment in West Africa and in the South of metropolitan France and ii) to evaluate and validate the anti-EGS IgG and anti-recombinant 30 kDa protein responses of Culex quinquefasciatus as a potential biomarker of human exposure to Culex bites. We measured in the sera of exposed individuals, the antibody responses: i) IgG anti-Nterm-34 kDa and IgG anti arbovirus antigens (LUMINEX) in children from Anoumabo, Bromakoté and Petit-Bassam, in Abidjan, ii) IgG and IgM anti-Nterm-34 kDa of Ae. aegypti in Auvergne, Corsica, Occitania and PACA, France, and iii) anti-EGS IgG and recombinant 30 kDa protein in children from Dar-es-Salam, N'Gattakro, Kennedy in Bouaké.In Abidjan, anti-Nterm-34 kDa IgG was significantly different between the study districts with a high level in Bromakoté. Specific IgG was associated with sticky trap data. According to the LUMINEX technique, arboviruses were circulating in the districts, with a majority detection of DENV3. Petit-Bassam was the most affected. All these results showed that exposure to Aedes and thus the risk of transmission varied between neighbourhoods within the same African city.In metropolitan France, specific IgG was higher in the colonised areas than in the uncolonised area. The specific IgG response was higher in Occitania and PACA compared to Corsica. The anti-salivary peptide IgM, indicated a significant difference between the exposed regions. In Occitanie, the median levels of anti-peptide IgG responses in departments 30 and 34 were higher than those in departments 31 and 66. In PACA, a significant difference in the level of specific IgG was detected between departments 04 and 13 and between departments 05 and 13. IgG levels in departments 13 and 83 were higher than in the other departments. Departments colonised between 2010 and 2012 had statically higher anti-peptide IgG levels than non-colonised departments. IgM between individuals in the 4 regions was practically zero. These results indicated the relevance of the salivary anti-peptide IgG biomarker to discriminate the regions and departments most exposed to Ae. albopictus bites and thus to assess the heterogeneity of arbovirosis transmission risks in metropolitan France.For Culex, anti-EGS and anti-30 kDa IgG responses were significantly higher in children living in sites of high Culex quinquefasciatus density. Anti-30 kDa IgG was significantly higher in children not sleeping under insecticide-treated nets compared to those sleeping under them. In addition, a positive correlation was observed between anti-EGS IgG responses and anti-30 kDa IgG Ac in the total population.This study showed that the use of biomarkers of exposure to Aedes bites could be a relevant tool for the assessment of heterogeneity of exposure to arbovirus vectors in the African urban context and between departments of the same region in southern France. Anti-EGS IgG and anti-30 kDa protein responses would represent potential biomarker candidates for Culex bites. However further studies are needed, to validate them as a biomarker of Culex exposure

The pandemic of the new coronavirus infection has spread to more than 200 countries. To date, over 130 million people have been affected and over 2.8 million have died. COVID-19 infection has a number of specific epidemiological and clinical features. In severe cases of the disease, acute respiratory distress syndrome develops, which is often fatal. The SARS-CoV-2 virus is susceptible to mutations, which alarms the scientific community all over the world. Therefore, scientific research in the field of COVID-19, the search for new diagnostic tools, methods for nonspecific and specific prevention and treatment are central topics today.This collection contains abstracts submitted by leading experts in the field of epidemiology, clinics of infectious diseases, molecular diagnostics, young researchers and medical practitioners. Published materials contain data on the methods of molecular diagnostics of COVID-19, se-quencing of the SARS-CoV-2 genome, epidemiology of new coronavirus infection, immuno-pathogenesis of COVID-19, clinical features of infection and treatment options, as well as the study of post-infectious and post-vaccination immunity and examples of complex measures for nonspecific prevention of COVID-19.The materials of the Congress are of interest to doctors and researchers of all specialties, teachers of secondary and higher educational institutions.

Cancer is the consequence of the recalcitrant multiplication of the transformed cells. Cancer cells grow and proliferate at a fast pace and do not follow normal regulation of cell division. Breast cancer is a heterogeneous group of diseases, which is the second leading cause of death among women. Although androgen is primarily considered a male steroid hormone, it also has an important role in the female reproductive system. The literature evidence suggests the role of androgen receptors (AR) in the normal development of the breast. At puberty, the expression of AR is even more than ER, suggesting its importance during the process of sexual development; its activity maintains the ER-induced cell proliferation and normal development of the breast. Epidemiological studies have suggested a positive correlation between high endogenous androgens and the risk of breast cancer in both pre- and postmenopausal women. In both ER and PR-positive breast cancers, AR is expressed in 60-70% of the cases. AR is also reported to be co-expressed with ER in around 80-90% of breast cancer cases and is considered an independent prognostic factor of ER-positive breast cancers. Tumor-microenvironment has a complex role in tumor initiation, progression, and metastasis. Tumor-infiltrating and resident cells secretes a variety of inflammatory and anti-inflammatory cytokines, which in turn either inhibit or promote tumor growth. Immunosuppressive and immuno-inductive effects of androgen have been reported in various studies. Androgens have been reported to influence the adaptive immune system more than the innate immune system in many ways. Crosstalk of androgen and cytokine signaling has many effects in breast cancer epidemiology. So, in this chapter, we will discuss the various immune-endocrine perspectives of breast cancers.