The clinical importance of the nomenclature, evolution and taxonomy of human papillomaviruses

Abstract

Human papillomaviruses (HPVs) are formally described by isolation of their circular double-stranded DNA genomes and establishment and comparison of the nucleotide sequence of these genomes. Alternatives such as serological diagnosis and maintenance of HPVs in culture are neither clinically useful nor consistently feasible. Novel HPV isolates have traditionally been described as "types". The analysis of specific HPV types is of medical importance, because HPV types typically induce type-specific lesions, i.e. they may be specific for cutaneous or mucosal epithelia, or give rise to benign warts or malignant carcinomas. Recently, it was formally decided that papillomaviruses are a virus family separate from the polyomaviruses. Within the papillomavirus family, closely or remotely related types form species or genera. These formal agreements were important as they brought the taxonomy of papillomaviruses in line with that of other viruses, bacteria and higher organisms, although their impact on medical practice and terminology used in clinical studies is limited. Notably, however, HPV types that are closely related (i.e. form "species") are associated with similar lesions. Confusion of the terms "type" and "subtype" should be avoided, as the latter term refers to some specific but rare taxonomic assemblages. In contrast to many RNA viruses, HPV types evolve very slowly, and diverged since the origin of humans only by about 2%. These divergent isolates are called "variants". HPVs evolved together with humankind and Homo sapiens was never without HPVs, and consequently never without warts and cervical cancer. Variants of the same HPV type may have different pathogenicity and may account for part of the worldwide disparities in the occurrence of genital cancers.

Identification of the recently described new type of bovine papillomavirus (BPV-8) in a Brazilian beef cattle herd

“…In addition, it is recognized that the HPV genome evolved with similar frequency to their host genome (De Villiers et al 2004, Bernard 2005. The identification of BPV-8 in Asia (Japan), Europe (Slovakia), and South America (Brazil), within a short period of time, suggests the previous existence of this BPV type in these regions.…”

“…While hundreds of human papillomavirus (HPV) types have been identified, only six BPV types had been characterized until the early 1980s (Jarret et al 1984, Bernard 2005. However, recent studies employing PCR with generic primers FAP59/FAP64 in combination with cloning and sequencing, have described 15 putative new BPV types (Forslund et al 1999, Antonsson & Hansson 2002, Ogawa et al 2004.…”

Infecção pelo papilomavírus humano: etiopatogenia, biologia molecular e manifestações clínicas

“…At the same time, this same genus includes non-mucosal HPV types, such as HPV 7 -associated with cutaneous warts in butchers and handlers of meat, poultry and fish, HPVs found in species 4 (HPVs 2, 27 and 57), and those found in species 2 (HPVs 3 and 10), which cause common warts on the skin. 4,8,10 Beta-papillomavirus (Supergroup B -Subgroup B1) They are divided into five different species. HPVs 5 and 8, which belong to species 1 of this genus, are the most commonly identified in the skin of individuals with epidermodysplasia verruciformis (EV).…”

“…This genus also involves cutaneous HPVs detected in the skin of the population in general without skin lesions, demonstrating the ubiquity and high incidence of asymptomatic infections. 4,5,8,10 Gamma-papillomavirus (Supergroup B -Subgroup B2)…”

The immortalizing and transforming ability of two common human papillomavirus 16 E6 variants with different prevalences in cervical cancer

“…Increased risk of anal cancers has also been reported for certain HPV16 variants (Xi et al, 1998). Genomic variation and a 2 00 000 year evolutionary timeline have been presented as reasons why HPV16 is the most prevalent HPV genotype in cervical and other human cancers (Bernard, 2005).…”