Final answer:
HPV infects epithelial cells, especially in the cervix, where it can cause changes indicative of infection. Diagnosis is via Pap smear showing abnormal cells, and high-risk strains can cause cancer, which motivates vaccination.
Step-by-step explanation:
Human papillomavirus (HPV) targets cells in the human epithelium, particularly those in the mucous membranes, such as the cells of the uterine cervix. A diagnostic sign of an HPV infection in a Pap smear includes finding cervical cells that appear larger than normal and with multiple nuclei, which might indicate the presence of the virus. The significance of these cells being infected is that while most HPV infections clear up without causing disease, certain high-risk types of HPV can cause disruptions in normal cellular functions, potentially leading to genital warts or more seriously, cervical cancer, with types HPV 16 and HPV 18 associated with over 70 percent of all cervical cancer cases. The motivation for HPV vaccination is to protect against these high-risk HPV strains that can persist in some individuals and cause precancerous changes or develop into invasive cancer.