Understanding Human Papillomavirus

Sexually transmitted diseases are a major problem in the world today. Increasing amounts of information are available about these diseases, and talk about the subject is beginning to come to light in the public. People are no longer afraid to talk about this issue, but even still, the numbers are not decreasing. In the few diseases where they are declining, they are not doing so fast enough. Whether the infection is due to a virus or bacteria, people do not understand the severity of the situation. They are not taking as much precaution as they should and it seems as though we are getting nowhere when it comes to eradicating the disease-causing agent.


Human papillomavirus or HPV is one of the most prevalent sexually transmitted diseases today. By the age of 50 at least 80% of women will have had a genital HPV infection (10). Human papillomavirus is caused from a virus known as Papillomaviridae that can cause cancer in the female as well as the male. It can affect the skin of the penis, vulva (area outside the vagina), anus, and the linings of the vagina, cervix, and rectum. As much as this virus focuses around the genital areas it can also affect areas in other places such as the moist folds in skin, underarms, creases of the thighs, under the breasts and even the mouth and throat. Sometimes people actually break out with the warts which are a form of Human papillomavirus but sometimes there are no signs at all. There are over 100 different strains of this virus, 30 of those are known to cause genital warts and more than 15 of those are known to cause cancer. The incubation period for this virus can be anywhere from a month to over a year after initial infection. Some people actually carry the virus for up to a year or more without knowing that they have it and they continue to spread it even more with each new partner. If a person has too many partners within that year, it could very difficult to tell exactly who infected them and who else they have infected. That year only covers those who will actually show any form of symptoms, many people who are infected with HPV never show any symptoms at all. According to the CDC, a person’s body will eliminate the virus all together within two years of infection and it will no longer be detectable in the body (1). One thing to understand is that warts of any type are caused by Human papillomavirus whether they are in the genital area, hands, feet, or anywhere else on the body. The 100 types mentioned also cover planter warts and any other type of wart regardless of the location.


It seems very likely that HPV is currently the most common sexually transmitted disease in young, sexually active individuals (1). In the United States, about 20 million people have HPV at any given time with approximately 5.5 million new cases each year (1). Even though the CDC says that 5.5 million new cases arise each year, the Principals of Anatomy and Physiology by Gerard J. Tortora and Bryan Derrickson published in 2007 says that there are only 1 million new cases each year. Microbiology with Diseases by Taxonomy by Robert Bauman published in 2007 says that only 500,000 new cases arise each year. Not only that, but Bauman also says that the incubation period for this disease is only 3 – 4 months versus the CDC’s report of it sometimes taking over a year. These are just a few examples of how little is truly known about this disease. A graph and table from the CDC shows some statistics for women between the ages 14 – 59 on their initial visit where they found that they were infected with HPV. 14 – 19 year olds were 40% and then 20 – 24 year olds were 50% and then 25 – 29 were at 30%. What can be assumed by the graph is that 14-16 year olds were probably not as sexually active as the 17 – 19 year olds. When the group of 17 – 19 year olds got infected, it took a year or two to show any signs or for the patients to go to the doctor to get checked, by that time, they are in the 20 to 21 year range which is why that range shoots from 40% to 50% (2). Once all of those patients know that they have it then they are no longer in the initial visit stage and that’s the reason for the 30% drop off. Since this virus can be so unpredictable it’s hard to look at the stats for who had it when and think it’s even close to reliable. The only thing we can get close to knowing for sure is an estimate of how many people are actually infected.


To understand Human papillomavirus, we must first know what it is composed of. “The genome constitutes 10-13% of the virion by weight. The genome is not segmented and contains a single molecule of circular; supercoiled, double-stranded DNA. The complete genome is 5300-8000 nucleotides long. The genome has a guanine and cytosine content of 40-50 % (6).” There are no lipids present in this virus on the inside or on the outside because this virus does not have an envelope. Papillomaviridae only infects a single type of eukaryotic organism and that one type is the Homo sapien (6). A virus can not self replicate and in order to take over control within the human it must infect individual cells (4). This particular virus is like a human cell in the way that it has a double strand of DNA, this nucleic acid is the genetic material of the virus known as the genome (6). Some other viruses that have double stands of DNA are herpesvirus and chickenpox virus (6). When this virus replicates, it will attach itself onto a human cell and insert its DNA or fuse with the cell, it takes control of the cells organelles and forces it to create new virus material and translate new proteins. Once the replication is done, the host cell dies and the new viruses are released.


HPV can be transmitted through direct skin to skin contact and fomites whether it be casual contact or sexual (4). Some of the inanimate objects that it might be spread through would be moist towels, sharing of undergarments like swim suits, other items that might contain bodily fluids and also although unlikely, toilet seats. There are also some studies that show that it could be spread through blood (7). This disease is somewhat preventable though it is difficult to be certain that one would not be infected. Abstinence seems to be the best method but the use of condoms will reduce the risk. Since HPV can infect areas of the body that can not be covered by a condom such as the scrotum, it is likely that one would still be infected with the virus even if they did use condoms and the partner was infected since it would spread through the uncovered area. There is also a chance that the virus could be airborne. This wouldn’t necessarily affect the average person so much as it would a member of medical staff. “Some physicians have developed warts in their noses after inhaling airborne viruses during laser treatment”(4).
Another thing that has come to light recently is a new vaccine for HPV called Gardasil. There are many websites and books out there with information about HPV but some of the information can be misleading. On the Gardasil website it is said that cervical cancer is caused by a virus. That is a true and false statement in one. While certain types of HPV can cause cervical cancer, it certainly does not cause all types of cervical cancer and it doesn’t always cause cancer at all. Having cervical cancer can be fatal if not detected in time but with regular pap smears and exams it can be caught early and dealt with properly. The vaccine is recommended for girls between the ages of 9 and 26. Getting vaccines can be dangerous and risky, why would the American Medical Association recommend something that could be dangerous to a 9 year child? Since the virus is self limiting and goes away on its own then there probably is not any real concern for receiving this new vaccine but this doesn’t mean that the virus should be taken lightly. A sexually active adult probably already has had the virus and with precaution, those who haven’t had it can reduce their risk. Even if a person does still manage to contract HPV, it will more than likely go away on its own.


Approximately 70% of cervical cancer acquired from HPV is actually caused from strains 16 and 18 (9). There are 270,000 deaths each year from cervical cancer which is the second most common cancer in women worldwide (10). The American Cancer Society has predicted that in the year 2008, there will be 11,070 new cases of invasive cervical cancer and that 3870 women will die from it (11). Some of the signs of cervical cancer include abnormal vaginal bleeding, an abnormal discharge and bleeding or pain during or after sexual intercourse, douching or with pelvic exams (10, 11). There are usually no signs or symptoms until the cancer has reached advanced stages (10).


Early detection is the key and Pap smears and annual exams are a must when it comes to detecting and treating cervical cancer. “Of the women in the United States who develop cervical cancer, about half have never had a Pap test and an additional 10 percent have not had a Pap test in the last five years” (10). There are additional tests that can be done if abnormal cells are found on the cervix during a routine Pap test. The first and most common test is a colposcopy. During a colposcopy the doctor will insert a camera called a colposcope into the vagina to look for abnormal cells on the cervix. If abnormal lesions are found during the colposcopy then a biopsy will be necessary to determine if those lesions are cancerous, pre-cancerous or neither (11). If cancer or pre-cancer is found to be present, there are several treatment options to choose from.


One of the most common treatment options for pre-cancer is cryosurgery, which is freezing of the abnormal cells so that the tissue is destroyed (9). Another treatment option is the loop electrosurgical excision procedure (LEEP). With the LEEP procedure the abnormal cells are removed by using a hot, electric, wire loop (9). Once true cancer has been found, separate treatment options will be used. Sometimes if the cancer is large enough or has spread, a hysterectomy will be performed. Other treatment options include Chemotherapy and radiation treatments. Chemotherapy and radiation can be very hard on the body because of the side effects which include hair loss, nausea, vomiting, vaginal sores, skin changes, early menopause, and sterility (10). Studies show that only 2.6 out of every 100,000 women will die of cervical cancer each year (10). The survival rate with cervical cancer is extremely high. With routine annual exams and Pap tests most women will be able to be treated successfully and go on to live normal, healthy lives.


Sources

1. (2001, April 6). Tracking the hidden epidemics, Trends in STDs in the United States. Retrieved April 21, 2008, from Department of health and human services Centers for Disease Control and Prevention Website:http://www.cdc.gov/std/Trends2000/hpv.htm

2. (2007 November 13). STD surveillance 2006. Retrieved April 21, 2008, from Department of health and human services Centers for Disease Control and Prevention Web site: http://www.cdc.gov/std/stats/tables/table42.htm

3. (2007 August 24). MMWR Weekly. Retrieved April 21, 2008, from Department of
health and human services Centers for Disease Control and Prevention Web site: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5633a5.htm?s_cid=mm5633a5_e

4. Bauman, R. (2007). Microbiology; With diseases by taxonomy. San Francisco, CA: Pearson Benjamin Cummings.

5. Tortora, G., & Derrickson, B. (2007). Principles of anatomy and physiology.Hoboken: John Wiley & Sons.

6. ICTVdB Management (2006). 00.099. Papillomaviridae. In: ICTVdB - The Universal Virus Database, version 4. Büchen-Osmond, C. (Ed), Columbia University, New York, USA Web site: http://www.ncbi.nlm.nih.gov/ICTVdb/ICTVdB/index.htm

7. (2005). New study suggests Human papillomavirus could be spread through blood. Retrieved April 21, 2008, from American society for microbiology Web site: http://www.ictvdb.rothamsted.ac.uk/ICTVdB/00.099.htm

8. (2005 - 2008). Gardasil Human papillomavirus quadrivalent (types 6, 11, 16, and 18) vaccine, recombinant. Retrieved April 21, 2008, from Gardasil Web site: http://www.gardasil.com/

9. Human papillomaviruses and cancer: questions and answers. Retrieved April 27, 2008, from National Cancer Institute Web site: http://www.cancer.gov/cancertopics/factsheet/Risk/HPV

10. Human papillomavirus (HPV) and cervical cancer. Retrieved April 27, 2008, from partnership to end cervical cancer Web site: http://www.nocervicalcancer.org/hpv_cc_faqs.html

11. Learn about cervical cancer. Retrieved April 27, 2008, from American cancer society Web site: http://www.cancer.org/docroot/lrn/lrn_0.asp