Humanpapillomaviruses are a group of viruses that infect the mucosal andcutaneous epithelia of higher vertebrates characterized by abnormalskin growths commonly referred to as warts. Various types of wartsaffect the skin they include plantar warts, sublingual /periungualwarts, flat warts and genital warts. Genital warts are of greatconcern because it has been associated with cancers of the urogenitaltract, anal, and cervical cancer. Over 100 types of HPV have beenisolated and about 40 species have been found to infect the genitalskin out of which 13 have been related to cancer. (W.H.O, 2007).
Thesize of HPV virion is small approximately 40-55nm. It is made up ofnon-enveloped, double-stranded DNA viruses which are symmetricallyicosahedral and circular in shape. (Lippincott et al, 2013). Thescientific name of human papillomaviruses is papillomaviridae. Thelife cycle of Human papillomavirus (HPV) begins by infection of thebasal cells of the stratified epithelium. This tissue is composed ofnon-dividing cells which later differentiate into the topmostdifferentiating cells. Within these cells, the HPV genome isreplicated, maintained and passed on from one generation to theother. Affected cell occurs as diplococci and are gram negative (RalfHoffmann, 2006). HPV produces E5, E6, and E7 proteins that interferewith other proteins such as p53 that prevent excessive cell growth.This, in turn, leads to tumor growth. Moist environmental conditions,low temperatures and presence of an injury to the skin surfaces orinfection by another STI causing microbes provide a good niche forthe growth of HPV.(Nardo, D., 2007).
Roughly6.2 million new HPV infections occur in the United States every year,and almost 20 million people are presently infected. (Ault, K. A.,2006) Out of these, 33 percent of women are affected and 15 percentare teenagers (Giuliano, 2011). According to CDC, at least half ofall sexually active individuals acquire HPV in their lifetime,whereas 80% of women acquire an HPV infection at the age of 50. “Inthe United States, it is predicted that 10% of the population has anactive HPV infection. HPV 16 has been linked to cervical cancer in50%, therefore, viable for research studies. According to the WHO,HPV has been ranked as the second leading cause of cancer especiallyin women, therefore, need for regular screening.” (W.H.O, 2007).
HPVis sexually transmitted warts are transmitted through skin to skincontact either the genital or mucosal skin. Genital warts are usuallytransmitted through sexual activities. Other warts could be found onother skin surfaces including the soles of the feet, fingernail,face, and arms. Transmission of HPV can be enhanced by various riskfactors. (Gregory Juckett, 2010). Risk level is increased inindividuals who are immunocompromised, have smoking habits, indulgein sexual activities at an early age and those having multiplepartners. Prolonged use of hormonal contraceptives, high parity, andbacterial vaginosis STD s are other factors (picconi et al., 2015).High-risk human papillomaviruses which are sexually transmittedinclude types 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, 68, 69,and others. These types cause growths that are flat and almostinvisible, as compared with warts caused by types HPV-6 and HPV-11.
Theestimated incubation period from HPV infection to genital wartdevelopment is two weeks to 8 months, with the majority of genitalwarts appearing 2–3 months after an HPV infection. The averageincubation period, which begins immediately after the initial sexualcontact with an infected person, is usually two to three months butcan range from one to 20 months. However, when HPV is transmittedfrom one person to another, the virus infects the top layers of theskin and can remain inactive or latent for months or possibly yearsbefore warts or other signs of HPV infection appear. In couples thathave not had sex partners for many years, the woman may develop anabnormal Pap smear because of the previous contact.
Mostly,HPV is asymptomatic mild infections clear on the own, but persistentinfections may result to warts or cervical cancer. Warts arecharacterized by small or large precancerous lesions on the genitalfacial, arms or other parts of the skin. Cervical cancer, on theother hand, develops when the infection is left untreated andprolonged hence developing complications. Symptoms of cervical cancerthat appear at an advanced stage include
• Irregularmenstrual periods or bleeding after intercourse
• Painthe pelvic, back and leg regions.
• Weightloss, fatigue and lack of appetite
• Vaginaldismay and foul-smelling discharge
• Oneswollen leg.
HPVcan be diagnosed by
• Paptest — whereby a sample of cells is removed from the cervix thenexamined under a microscope for the presence of cytopathic effects
• Colposcopy— in this test a colposcope is used, vinegar is added to the cervixand the infected cells appear white under a colposcope.
• HPVDNA test — the DNA of HPV can be directly detected in the cellsamples by using molecular techniques such as real-time PCR and nextgeneration sequencing. Any HPV can be detected.
Thereis no cure for the virus itself. However, many options exist for theelimination of warts. Topical creams such as Podofilox and Imiquimodare used. Other methods include use of electricity to eradicatewarts, freezing of warts with liquid nitrogen and Loopelectrosurgical excision procedure (LEEP) to remove abnormal cells.(Ramírez-Fort, 2014). Apart from cervical cancer, other diseasesthat could be caused as a result of HPV is included anal, vaginal,penile, vulva and oropharyngeal cancers (Lippincott & Wilkins. ,2013).
A16-year-old girl, Angela presents in a clinic seeking medical adviceon the use of contraceptives since she has an 18 year boyfriend withwhom they intend to be intimate with for the first time. However,along with the discussion she discloses to the medical practitionerthat she is a smoker and has not had any HPV vaccine. Incase you werethe physician, what would you advise Angela?
Basingon the prior knowledge of HPV it is very clear that Angela issusceptible to HPV infections which can cause cervical cancer whichcan be fatal. First of all, she is a teenager, a smoker who intendsto use contraceptives and sexual activities. All this are riskfactors predisposing her to infection. If I were the medicalpractitioner, I would advise her to do a pap smear, get vaccinatedagainst HPV and use protection while having sexual intercourse.Contraceptives should only be used as prescribed by a physician.
Ault,K. A. (Published online 2006 ). Epidemiology and Natural History ofHuman Papillomavirus Infections in the Female Genital Tract. InfectDis Obstet Gynecol.,https://dx.doi.org/10.1155%2FIDOG%2F2006%2F40470.
BoschFX1, d. S. (2007). The epidemiology of human papillomavirus infectionand cervical cancer. DisMarkers., 213-227.
Giuliano,G. M. (2011). Genital HPV infection and related lesions in men. PrevMed,S36-S41.
GregoryJuckett. (2010). Human Papillomavirus: Clinical Manifestations andPrevention. AmFam Physician., 1209-1214.
LippincottWilliams & Wilkins. (2013). Essentials ofRubin`s Pathology.
M.K.Ramírez-Fort, F. K. (2014). HumanPapillomavirus bench to bedside.Karger Medical and Scientific Publishers.
Mongelos,P., Mendoza, l. P., & pic coni, M. A. (2015). Distribution ofhuman papillomavirus(HPV) genotypes and bacterial vaginosis presencein cervical samples from Paraguayan indigenous. Internationaljournal of infectious disease, vol 49:44-49.
Nardo,D. (2007). Humanpapillomavirus (HPV).Detroit: Lucent Books.
RalfHoffmann, 1. B. (2006). DifferentModes of Human Papillomavirus DNA Replication during Maintenance.Journal of Virology, 4431–4439.
WorldHealth Organization, (2007). IARCMonographs on the Evaluation of Carcinogenic Risks to Humans.