# ****İrem Aktaş - Papillomaviruses**** Papillomavirus is an 8 kb circular double-stranded DNA virus. Papillomaviruses, non-enveloped and icosahedral, were first discovered to cause warts in cottontail rabbits. The papillomavirus seen in cows is called bovine papillomaviruses (BPV) and seen in humans is called Human papillomaviruses (HPV). Low-risk HPVs are subclinical and cause benign lesions, while high-risk HPVs can cause cancer along with infections. In this chapter, HPV is focused on. --- **1. Features of Papillomaviruses** ![](https://i.imgur.com/TqYs9Ns.png) --- **2. Human Papillomaviruses (HPV)** ![](https://i.imgur.com/otcSRxG.png) *Figure 1: Structure of HPV* After it was proven that cervical cancer is a sexually transmitted disease, Harold zur Hausen turned to researching the viruses that cause it. Since papillomavirus causes genital warts, he started studies to solve the relationship between HPV and cervical carcinoma. As a result of his studies, he analyzed the HPV-16 and HPV-18 genotypes that are constantly involved in cervical carcinoma. There are more than 150 subtypes of HPV. Most HPVs manifest as warts. It can be benign or malignant. Benign tumor warts can be cured by freezing and burning treatments. It appears more common in men but can be more dangerous for women. HPV warts in the vagina are difficult to notice and can lead to cervical cancer in the future. HPV-16 and 18 subtypes constitute the majority of cervical cancers. With the discovery of HPV vaccines, cervical cancer death rates have decreased. The prevalence of HPV among healthy people is increasing. According to the latest research, 61.3% of HPV settles in the skin, 41.5% in the vagina, 30% in the mouth and 17.3% in the intestine. --- **2.1. Transmission of HPVs**