Prevalence and viral load of 51 genital human papillomavirus types and three subtypes.

Of the 120 known human papillomaviruses (HPV), 51 HPV types infect the genital mucosa. Very little is known about the prevalence and viral load of the majority of these low-risk (Lr-) HPV types in screening populations. We determined the prevalence of 51 HPV types and three subtypes in 999 consecutive BD-SurePath™ liquid-based cervical cytology samples collected during routine gynecological health checks from Belgian women. This series of screening samples was enriched with ASC-US (n = 100), low-grade squamous intraepithelial lesion LSIL (n = 100) and high-grade squamous intraepithelial lesion (HSIL) (n = 97) and analyzed by BSGP5+/6+-PCR/MPG assay for 51 HPV types and three subtypes. In consecutive screening samples, any of the 54 genital HPV (sub)types was found in 37.1%; Hr-HPV types were detected more frequently (26.8%) than the 31 Lr-HPV types (16.4%) and the six possibly high-risk types (6.6%). High viral load infections were present in 17.0% of the screening population. Among the women with cytological abnormalities, the prevalence of high viral loads of Hr-HPV types increased from negative for intraepithelial lesion or malignancy (NIL/M) over ASC-US, LSIL to HSIL (5.3, 47.1, 84.2 and 91.8%, respectively). The prevalence of possibly Hr and Lr-HPV types increased from NIL/M to LSIL but declined to HSIL. From NIL/M to HSIL, Hr-HPV infections showed an increasing frequency of high viral loads compared to total DNA positivity, but the increase between LSIL and HSIL was small. Type-specific analyses revealed substantial differences between individual HPV types in these groups. Our study provides quantitative data for the whole spectrum of genital HPV in a Belgian screening population and in a representative set of women with cervical abnormalities.