Analysis of the genomic diversity of human papillomavirus type 31 in cervical samples reveals the presence of novel sublineages in clade C.

Human papillomavirus 31 (HPV31) is the fourth most frequent high-risk HPV (HR-HPV) genotype identified in cervical cancer (CC) worldwide and in Mexico. It has been recently classified into three lineages (A, B, and C) and eight sublineages (A1, A2, B1, B2, and C1 - C4). Here, we report the complete genomic sequences of 14 HPV31 isolates from cervical samples, and these were compared with viral genome sequences from the GenBank database for phylogenetic and genetic distance analysis. The formation of two novel clades within the C lineage (proposed as C5 and C6) was observed, with a well-defined variant-specific mutational pattern. The smallest average pairwise distance was 0.71% for lineages A and B, 0.94% for lineages A and C, and 1.01% for lineages B and C, and between sublineages, these values were 0.21% for clade A, 0.29% for clade B, and 0.24% for clade C. The isolates were grouped into the sublineages A1, B2, C1-C3, and C6. This is the first report on the whole-genome diversity of HPV31 in Mexico.