Human Papilloma Virus is a commonly sexually transmitted disease that is transmitted by direct skin to skin contact with an infected individual by vaginal, oral or anal sex(4,9). HPV is in the family Papovaviridae, it is enveloped, dsDNA and Icosahedral (10). Virulence factors for HPV are E6 protein, E7 protein, and inhibitors of tumor suppressor genes (10). Approximately 5.5 million new cases of HPV occur every year and at least 20 million are already infected(3). "The highest rates of genital HPV infection are found in adults between the ages of 18 and 28 and is prevalent among people with immunosuppressive disorders, such as HIV. HPV is believed to be widespread across racial groups and to have very little variance in prevalence across regions in the U.S." (9). HPV has affected humans for thousands of years, according to Planned Parenthood;ancient Greek and Roman Medical records described genital lesions consistent with genital warts and associated them with sexual activity. No world wide in incidence figures were found.
There are more than 100 different strains of HPV that cause abnormal cell growth and about 1/3 are associated with sexually transmitted genital infections (1,9,3). Ten of the 30 identified can lead to the development of cervical cancer, but mainly in rare instances does this occur (3,8). The usual reservoir for HPV is sexually active people although non-sexual transmission can occur with different strains of HPV. Such as pregnant women passing the infection to a newborn child. The newborn child may develop warts in the larynx during vaginal delivery (2,3,7). HPV affects the skin and mucuous membranes and can cause certain types of warts in various parts of the body including the genital area and also the hands,feet, vocal cords and mouth. (1,9,3). Other types of HPV can cause papillomas which are benign tumors that may lead to cervical, vulvar, anal and penile cancer if left untreated (1,7,4,3). There are 2 kinds of abnormal tissue caused by HPV and they are condyloma, which are warts and dyplasia, which is pre-cancer (1,7).
HPV also leads to abnormal Pap smears and this is how most woman are diagnosed with the infection (3,5). By applying an acetic acid to the suspected area, it whitens when the presence of HPV exists and this is used to identify invisible warts (7). Women might also be diagnosed with symptoms during a pelvic exam by a physician examining the skin of the vulva or vagina with a colposcope used to magnify cervical and vaginal tissue (5). The colposcope can also be used with men to identify areas of infection. Men might be diagnosed by symptoms of a bump that itches, unusual discharge or the need to urinate often or with difficulty (5). In March 1999, the USDA approved the Hybrid Capture II test used when Pap smear tests when inconclusive about whether or not there have been changes in the cells of the cervix (9). But there are no usual signs or symptoms that someone has been infected, infections can be asymptomatic and never cause any recognizable warts (2,3). Genital warts are usually dry and painless, and start as small red or pink swellings that can grow up to 4 inches (2,3,5). Some patients who been known to report a foul odor caused by the warts forming (2).
There is no cure for HPV; usually it does go away on its own but cancer related types are more persistent and can lead to more serious health risks(1,3). There is treatment for warts to solely remove them, but it doesn't cure HPV and there is currently no effective therapy to rid the infection completely. Treatment does vary by location and severity of the infection. There is cryotherapy which is freezing of the warts with liquid nitrogen (2,5). Laser treatment and the slicing with a hot wire or burning are available (2,5). Another treatment is the application of an acid mixture on them called trichloroacetic acid (2).
The use of the antiviral drug called alpha interferon, which is injected directly into the warts, is used to treat warts that reoccur after other means of treatment have failed (7). Imiquimod, which is an immune response cream applied to the affected area, is also available along with 20% podophyllin anti-mitotic solution, 0.5% podofilox solution, and 5% 5-fluorouracil cream (7). Thirty to 40% of warts go away on their own without treatment (6).
There is no information known about how or when people become infected with HPV; people can be exposed and not delevop condyloma or dyplasia for several years (1). According to Planned Parenthood, vaccines against HPV are currently being developed, but are still years aways from being available. "Both prophylactic vaccines that prevent HPV infection and therapeutic vaccines designed to prevent the development of pre-cancerous cells are being developed" (9).
Anyone that has sexual intercourse is at risk of contracting HPV, but there are some prevention tools to decrease your risk. Some suggestions for sexually active women is to have regular Pap smears done to check for abnormalities such as an pre-cancerous conditions or cervical cancerous if already developed (5). Another prevention mechanism for anyone is to not have sexual intercourse with someone who has genital sores or growths that may be unusual in the genital area or anus if they are visible (3). Considering most infections have no visible signs or symptoms this may be hard to see with the naked eye. But probably the most effective prevention tool is to engage in celibacy, if not monogamy can reduce your risk of contracting the infection (1,5). Condoms are effective to a certain extent but don't provide complete protection because HPV can shed beyond the covered area (2,3,5).
References
1. The University of Iowa Health Care, Available from: http://obgyn.uihc.uiowa.edu/Patinfo/Adhealth/hpv.htm. Accessed 2 March 2002.
2. The University of Iowa Health Care, Copyright (c) 1998. HBO & Company, Available from: http://www.uihealthcare.com/topics/sexuallytransmitteddiseases/sexu5272.html. Accessed 2 March 2002.
3. Centers for Disease Control and Prevention, May 2001, Available from: http://www.cdc.gov/nchstp/dstd/Fact_Sheets/FactsHPV.htm. Accessed 2 March 2002.
4. Centers for Disease Control and Prevention, December 2001, Available from: http://www.cdc.gov/nchstp/dstd/Reports_Publications/99HPVReport.htm. Accessed 2 March 2002.
5. Indiana University Health Center, Available from: http://www.indiana.edu/~health/hpv.html. Accessed 2 March 2002.
6. Health and Counseling Services, Garrison-Foster Health Center, Available from: http://www.colby.edu/health.serv/health_matters/hpv.html. Accessed 2 March 2002.
7. National Institute of Allergy and Infectious Diseases, March 2001, Available from: http://www.niaid.nih.gov/factsheets/stdhpv.htm. Accessed 2 March 2002.
8. National Cancer Institute, January 8, 2001, Available from: http://cis.nci.nih.gov/fact/3_20.htm. Accessed 2 March 2002.
9. Planned Parenthood of Amarillo & the Texas Panhandle, December 2001, Available from: http://www.ppatp.org/hpv2.htm. Accessed 2 March 2002.
10. Medical Microbiology and Infectious Diseases, May 11, 1999, Available from: http://www.medinfo.ufl.edu/year2/mmid/bms5300/bugs/hpv.html#AA4. Accessed 18 March 2002.