Human papillomavirus subtypes are not uncommon

While both variants and types of human papillomavirus (HPV) are common, subtypes (2–10% sequence divergence in the L1 gene) have been considered to be rare. We searched GenBank and in-house databases using a 440 nt L1 fragment and identified 7, 30 and 10 subtypes/putative subtypes in the HPV genera Alpha, Beta and Gamma, respectively. The number of types/putative types in each genus was 54, 58 and 103. Thus, there appears to exist at least 47 different subtypes/putative subtypes of HPV and they seem to be particularly common in the genus Beta-papillomavirus.