Papillomaviruses are double-stranded DNA viruses with a particle diameter of
about 55 nanometers (nm). They can infect the skin as well as the epithelium in all vertebrates including humans. Warts are a common form of HPV infection. Certain types of HPV can also cause carcinomas including those of the male (penis) and female (cervix) genitalia.
There are about 200 types of HPVs known and, according to the World Health Organization (WHO), they cause about 5% of all cancers globally, with an estimated 626, 600 women and 67, 000 men getting such cancers annually. Women co-infected with the human immunodeficiency virus (HIV) are 6 times more prone to developing cervical cancers compared to women without HIV. While currently there is no specific chemotherapy against HPV-related cancers, more than one type of prophylactic and highly effective vaccines are now available. Prescreening of women (Pap test) is another time-honored preventive strategy against cervical cancers.
Figure 1. Virion of a papillomavirus
Two types of prophylactic vaccines (Gardasil® and Cervarix®) are approved for use in Canada. The vaccination of girls and boys before they become sexually active can prevent the development of about 90% of HPV-related genital cancers.
In view of the remarkable success of prophylactic vaccination against HPV-related cervical cancers, the WHO has launched a program to eliminate cervical cancers by the year 2030, mainly via vaccination of eligible girls.
It should be noted here that science in general and ‘virology’ in particular are indebted to cells derived from cervical (HPV-induced) cancer. In 1953, cancer cells removed during a biopsy from Henrietta Lacks, a 31-year-old American, became the first ever immortalized cell line (HeLa cells) making possible numerous breakthroughs in biology, virology, and vaccine development. HeLa cells continue to be a mainstay in research even today.
HPVs in general remain refractory to in vitro culture, thus limiting the generation of information for their environmental survival and inactivation. However, Simian virus 40 (SV40), a polyomavirus of monkeys has been used as a surrogate for HPVs when testing the virucidal activity of chemical disinfectants, by evaluation of the susceptibility of HPV16 pseudovirus and SV40 to seven active biocidal substances using Quantitative Suspension Tests. SV40 was shown to be a reliable surrogate virus for HPV when testing isopropanol-, GTA-, QAC-, and OPA-based disinfectants (7).
CREM Co Labs has recently developed a quantitative method to assess the decontamination of high-touch environmental surfaces (HITES) by wiping and spraying in a field-relevant manner (8). The method is suitable for work with all major classes of human pathogens as well as common types of environmental surfaces. It can also assess the transfer of pathogen contamination to clean surfaces during wiping. This method, named Tier 3 of quantitative carrier test (QCT-3), builds on the two tiers (QCT-1 and QCT-2) we had developed earlier (9). QCT-3 can be used to assess the efficacy of sprays and wipes in a field-relevant manner against the surrogate of HPV (SV40).
References:
1)Government of Canada. Public health services. Human papillomavirus (HPV).
2) Christy M Hebner, Laimonis A. (2006). Human papillomaviruses: basic mechanisms of pathogenesis and oncogenicity. Rev Med Virol. 2006 Mar-Apr;16(2):83-97.
3) Okunade KS. (2020).Human papillomavirus and cervical cancer. J Obstet Gynaecol. 2020 Jul;40(5):602-608.
4) Araldi RP,Assaf SMR and Carvalho RF et all.,(2017). Papillomaviruses: a systematic review. Genet Mol Biol. 2017 Jan-Mar; 40(1): 1–21.
5) WHO. Human papillomavirus and cancer. 23 August 2023.
6) Centers for Disease Control and Prevention (CDC) HPV Fact Sheet.
7) Hufbauer, M. et al. (2021). Inactivation of polyomavirus SV40 as surrogate for human papillomaviruses by chemical disinfectants. Viruses. 2021 Nov 2;13(11):2207.
8) Zargar B, Sattar SA. Decontamination of high-touch environmental surfaces (HITES) by wiping: quantitative assessment of a carrier platform simulating pathogen removal, inactivation and transfer in the field. Lett Appl Microbiol. 2023 Feb.
9) Sattar, S.A., Springthorpe, V.S., Adegbunrin O., Zafer, A.A. & Busa M. (2003). A disc-based quantitative carrier test method to assess the virucidal activity of chemical germicides. J. Virol. Methods. 112: 3-12.