Differentiating one HPV viral type from another involves detecting different genetic structures. To effectively type an HPV virus, there must be less than 90% DNA base-pairing homology in specific regions (usually coding areas) between the two types. In other words, one viral type has more than a 10% difference in its genetic structure compared to a genome of a different HPV virus type.
Of the more than 100 HPV viral types detected, approximately 100 have been fully identified, and about 40 are known to be associated with sexual transmission. Genital HPV types are divided into low-risk HPV and high-risk HPV categories.
