a. HPV infections are graphed by risk type comparing worldwide and Zambian HPV distributions. The worldwide HPV distribution data was adapted from Clifford et al. (2005) and Peyton etal. (2001)   [See Additional file 1]. High-risk (HR; blue) and Low-risk (LR; red) HPV distributions among Zambian and worldwide populations. 1b. HPV infections by risk type in relation to HIV status. High-risk (HR; blue) and Low-risk (LR; red) HPV distributions are graphed as a function of HIV status for Zambian study participants. The distribution of HR and LR HPVs is displayed as the percent of HPV infections in participants. Positive HIV status is associated with a higher prevalence of HR HPV infections.