In-host model for the co-infection dynamics of high-risk human papillomavirus (HPV) and HIV in the presence of immune response

Abstract

HIV/AIDS continues to be a huge global burden having claimed million lives worldwide. It targets the immune system and defence mechanisms against infections such as the human pa- pillomavirus(HPV). HPV can be classifi ed as low-risk or high-risk, with high-risk types (16 and 18) mainly being responsible for cancers, such as cervical cancer in women. HPV is a very common sexually transmitted infection that is given less attention, with many men and women living and spreading infection through unsafe sexual practices. In this thesis we present a mathematical model for the transmission dynamics of HPV in-host in the presence of immune response represented by Cytotoxic T-Lymphocytes cells (CTL). The model presented considers the effects of latent HPV infections and the model dynamics are effectively analysed. The model presents two important reproduction numbers, that is the basic reproduction number R0 and the CTL reproduction number RK. The simulation dynamics of the HPV model are presented. We extend the model to include vaccination and it is established that, while immune response plays an important role in eradicating infection, it is not sufficient in totally eradicating HPV. The immune evasion dynamics of HPV are also analysed and conclusions drawn. Finally we also model the effects of HIV on the dynamics of HPV through the co-infection model. It is established that HIV through, immune-suppression, does make it easy for HPV to progress within the body. Simulations presented indicate the benefits of early initiation of antiretroviral therapy (cART/HAART) in the reduction of HPV prevalence. It is envisaged that the results presented in this thesis will motivate the widespread vaccination of women, girls and also boys, especially in developing countries where the HIV transmission rate is high. The study also aims to promote the uptake of HPV screening by women and girls and the practice of safe sexual practices to reduce infection.