Human papilloma viruses produce epithelial tumors of the skin and mucous membranes. More than 100 HPV types have been detected, and the genomes of more than 80 have been completely sequenced. The current classification system, which is based on similarities in their genomic sequences, generally correlates with the three categories used to describe HPV clinically: anogenital or mucosal, non-genital cutaneous, and epidermodysplasia verruciformis. Mucosal HPV infections are classified further as latent, subclinical, or clinical.
Clinical lesions are grossly apparent, whereas latent infections are detected only with tests for viral DNA. Subclinical lesions are identified by application of 3-5% acetic acid and inspection under magnification….

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