Papillomaviruses are small DNA viruses that measure approximately 55 nm in diameter and belong to the family Papovaviridae. HPV is a non-enveloped virus and is composed of an icosahedral-shaped protein capsid (shown in the graphic) enfolding a circular, double-stranded DNA genome of approximately 7,900 base pairs.
Until recently, diagnostic laboratory testing for HPV was impossible since the virus does not grow in tissue cultures or in laboratory animals. Currently, with the recent technologic advancements in molecular biology techniques for HPV testing, scientists have isolated more than 100 different HPV types.
