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In this paper, a dynamic HIV model with cell-to-cell transmission, two immune responses, and induced apoptosis is proposed and studied. First, the non-negativity and boundedness of the solutions of the model are given, and then the exact expression of the basic reproduction number R0 is obtained by using the next generation matrix method. Second, criteria are obtained for the local stability of the disease-free equilibrium, immune response-free equilibrium, and the infected equilibrium with both humoral and cellular immune responses. Furthermore, the threshold conditions are also derived for the global asymptotic stability of the disease-free equilibrium, immune responsefree equilibrium, and the infected equilibrium with both humoral and cellular immune responses by constructing the suitable Lyapunov function. Finally, some numerical simulations are conducted to verify the theoretical results; the numerical simulation results show that the increase of apoptosis rate had a positive role in the control of viral infection. [ABSTRACT FROM AUTHOR]

In this paper, a fractional order HIV/HTLV co-infection model with HIV-specific antibody immune response is established. Two cases are considered: constant control and optimal control. For the constant control system, the existence and uniqueness of the positive solutions are proved, and then the sufficient conditions for the existence and stability of five equilibriums are obtained. For the second case, the Pontryagin's Maximum Principle is used to analyze the optimal control, and the formula of the optimal solution are derived. After that, some numerical simulations are performed to validate the theoretical prediction. Numerical simulations indicate that in the case of HIV/HTLV co-infection, the concentration of CD4+T cells is no longer suitable as an effective reference data for understanding the development process of the disease. On the contrary, the number of HIV virus particles should be used as an important indicator for reference. [ABSTRACT FROM AUTHOR]

Human immunodeficiency virus (HIV) infection is a major public health concern with 1.2 million people living with HIV in the United States. The role of nutrition in general, and albumin/globulin in particular in HIV progression has long been recognized. However, no mathematical models exist to describe the interplay between HIV and albumin/globulin. In this paper, we present a family of models of HIV and the two protein components albumin and globulin. We use albumin, globulin, viral load and target cell data from simian immunodeficiency virus (SIV)-infected monkeys to perform model selection on the family of models. We discover that the simplest model accurately and uniquely describes the data. The selection of the simplest model leads to the observation that albumin and globulin do not impact the infection rate of target cells by the virus and the clearance of the infected target cells by the immune system. Moreover, the recruitment of target cells and immune cells are modeled independently of globulin in the selected model. Mathematical analysis of the selected model reveals that the model has an infection-free equilibrium and a unique infected equilibrium when the immunological reproduction number is above one. The infection-free equilibrium is locally stable when the immunological reproduction number is below one, and unstable when the immunological reproduction number is greater than one. The infection equilibrium is locally stable whenever it exists. To determine the parameters of the best fitted model we perform structural and practical identifiability analysis. The structural identifiability analysis reveals that the model is identifiable when the immune cell infection rate is fixed at a value obtained from the literature. Practical identifiability reveals that only seven of the sixteen parameters are practically identifiable with the given data. Practical identifiability of parameters performed with synthetic data sampled a lot more frequently reveals that only two parameters are practically unidentifiable. We conclude that experiments that will improve the quality of the data can help improve the parameter estimates and lead to better understanding of the interplay of HIV and albumin-globulin metabolism. [ABSTRACT FROM AUTHOR]

The difficulty in accessing hard-to-reach populations as men who have sex with men presents a dilemma for HIV surveillance as their omission from surveillance systems leaves significant gaps in our understanding of HIV/AIDS epidemics. Several methods for recruiting difficult-to-access populations and collecting data on trends of HIV prevalence and behavioural factors for surveillance and research purposes have emerged. This paper aims to critically review different sampling approaches, from chain-referral and venue-based to respondent-driven, time-location and internet sampling methods, focusing on its main advantages and challenges for conducting HIV research among key populations, such as men who have sex with men. The benefits of using these approaches to recruit participants must be weighed against privacy concerns inherent in any social situation or health condition. Nevertheless, the methods discussed in this paper represent some of the best efforts to effectively reach most-at-risk subgroups of men who have sex with men, contributing to obtain unbiased trends of HIV prevalence and HIV-related risk behaviours among this population group. [ABSTRACT FROM AUTHOR]

Recently different definitions of fractional derivatives are proposed for the development of real-world systems and mathematical models. In this paper, our main concern is to develop and analyze the effective numerical method for fractional order HIV/AIDS model which is advanced approach for such biological models. With the help of an effective techniques and Sumudu transform, some new results are developed. Fractional order HIV/AIDS model is analyzed. Analysis for proposed model is new which will be helpful to understand the outbreak of HIV/AIDS in a community and will be helpful for future analysis to overcome the effect of HIV/AIDS. Novel numerical procedures are used for graphical results and their discussion. [ABSTRACT FROM AUTHOR]

This work investigated a piecewise immunosuppressive infection model that assessed the effectiveness of implementing this therapeutic regimen once the effector cell count falls below a specific threshold level by introducing a threshold strategy. The sliding mode dynamics, global dynamics, and boundary equilibrium bifurcations of the Filippov system were examined based on the global dynamics of the two subsystems. Our primary findings indicate that the HIV viral loads and effector cell counts can be stabilized within the required predetermined level. This outcome depends on the threshold level, immune intensity, and the initial values of the system. Therefore, properly combining these key factors makes it possible to effectively curb the abnormal increase of virus and keep the effector cells at a reliable level. This approach maximizes the controllable range of the HIV. The proposed switching system incorporating pseudo-equilibrium exhibits three types of equilibriums that could be bistable or tristable. It means there is a possibility of controlling the virus after administering therapy if the immune intensity c is limited within the range of the post-treatment control threshold and the elite control threshold when R0 > Rc1 > Rc2 > 1. [ABSTRACT FROM AUTHOR]

Objective: Despite existing evidence about the benefits of nutrition, physical activity (PA) and sport to the overall health and wellbeing of children, knowledge gaps remain on this relationship in children living with chronic conditions like HIV/AIDS. Such knowledge should inform context specific programs that could enhance the quality of life of children. The purpose of this study was to examine the effects of integrating a nutrition intervention (culturally tailored food supplement) into antiretroviral therapy (ART) on psychosocial outcomes and physical activity among HIV-positive children in Botswana. Method: 201 HIV-positive children (6-15 years; M = 9.44, SD = 2.40) were recruited and randomly assigned (stratified by age and gender) to two groups. The intervention group (n = 97) received a high protein (bean-sorghum plus micronutrients) food supplement, while the control group (n = 104) received a sorghum plus micronutrients supplement. Participants were followed over 12 months. Anthropometric measures, PA, motor performance, and health related quality of life (HRQL) were collected at baseline, 6 and 12 months. Results: Mixed repeated-measures ANOVA revealed a significant time effect of the food supplement on target variables except body fat percentage, speed, and school functioning. Time × treatment interaction was found for physical functioning, psychosocial functioning and total quality of life score. Scores on physical functioning and total of quality life in the intervention group significantly increased from baseline to 6 months compared with the control group (p = 0.015). Conclusion: A combination of ART and nutritional intervention had a positive effect on physical functioning and total quality of life of HIV-positive children in this study. There were also improvements to physical activity and motor performance tests over time. More research is needed on long term effects of nutrition and PA interventions on HRQL in children living with HIV. [ABSTRACT FROM AUTHOR]