This document discusses the epidemiology and pathogenesis of HIV. It begins with global epidemiology statistics, including that there are 35.3 million people living with HIV worldwide. It then provides more specific statistics on new infections, deaths, at-risk groups, and prevalence by region. Regarding pathogenesis, it explains that HIV primarily attaches to CD4 receptors on cells and integrates its genetic material, leading to infection. It also discusses the body's immune response and how HIV evades detection through high mutation rates. Prevention methods discussed include behavior change, condoms, testing, and antiretroviral treatment and prophylaxis.