papillomvirus

Papillomvirus refers to a large group of non-enveloped, double-stranded DNA viruses in the family Papillomaviridae. These small viruses target keratinocytes in stratified squamous epithelium and have a circular genome of about 8 kilobases, organized into early (E) and late (L) gene regions that regulate replication and virion assembly.

There are more than 200 identified types, divided into mucosal and cutaneous categories. Each HPV type tends to infect a specific epithelial site and is associated with distinct clinical outcomes, ranging from benign warts to lesions that may progress to cancer in certain high-risk types.

The life cycle begins in basal epithelial cells, where the virus establishes episomal DNA. Productive replication occurs in differentiating cells. High-risk types express oncogenes E6 and E7 that can disrupt p53 and Rb pathways, contributing to cellular transformation and, with other factors, potential cancer development.

Transmission occurs mainly through skin-to-skin contact and sexual contact; vertical transmission can occur in some cases. Most infections are asymptomatic and are cleared by the immune system within one to two years, but persistent infection with high-risk types increases cancer risk.

Diagnosis relies on cytology and HPV DNA testing, with clinical evaluation for warts. There is no general antiviral cure for established HPV infection. Treatment targets lesions or precancerous changes, using cryotherapy, surgical excision, topical agents, or ablation; vaccination reduces acquisition of common oncogenic and wart-causing types.

Prevention centers on vaccination, including Gardasil 9 and Cervarix, administered before exposure. Screening programs for cervical cancer remain essential in reducing disease burden.