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Statistical analysis of viral dynamics in HIV-1 infected patients undergoing structured treatment interruptions were performed using a novel model that accounts for treatment efficiency as well as total CD8+ T cell counts. A brief review of parameter estimates obtained in other studies is given, pointing to a considerable variation in the estimated values. A Bayesian approach to parameter estimation was used with longitudinal measurements of CD4+ and CD8+ T cell counts and HIV RNA. We describe an estimation procedure which uses spline approximations of CD8+ T cells dynamics. This approach reduces the number of parameters that must be estimated and is especially helpful when the CD8+ T cells growth function has a delayed dependence on the past. Seven important parameters related to HIV-1 in-host dynamics were estimated, most of them treated as global parameters across the group of patients. The estimated values were mainly in keeping with the estimates obtained in other reports, but our paper also introduces the estimates of some new parameters which supplement the current knowledge. The method was also tested on a simulated data set. [ABSTRACT FROM AUTHOR]

Human T-cell Leukaemia Virus Type 1 (HTLV-I) is a retrovirus that causes Adult T-cell Leukaemia (ATL). The transmission routes of HTLV-I are (i) from infected mothers to their newborn babies, (ii) from infected males (husbands) to females (their wives) by long-term sexual intercourse, and (iii) from infected females (wives) to males (their husbands). Eshima et al. (2001) analysed a continuous-time HTLV-I model with no age structure in the population. In this paper, we consider the population dynamics of HTLV-I infection in a discrete-time mathematical model incorporating an age structure. The necessary and sufficient condition for the extinction of HTLV-I is derived from the mathematical model. A simulation of the HTLV-I infection based on the model demonstrates a rapid reduction of the HTLV-I infection proportion in Japan. [ABSTRACT FROM AUTHOR]