By Lisa Horth

In 1818, Thomas Jefferson said to Joseph Cabell, "If the children are untaught, their ignorance and vices will in future life cost us much dearer in their consequences than it would have done in their correction by a good education." While Jefferson was not specifically referring to education regarding sexually transmitted disease in that conversation, the essence of his message is fitting for such subject matter. 

Sexually transmitted diseases, or STDs are caused by an assortment of microscopic infectious agents, which include viruses, bacteria, protozoan, and fungi. 

Some STD’s, like syphilis, are easily curable, if detected in the early stages. Others, like herpes, can last a lifetime. This is because syphilis is a bacterial infection that can be treated with antibiotics, whereas herpes is a surreptitious virus. After initial infection with herpes, the viral particles go latent (do not replicate) in the nervous system for days or even years. Hidden away in the nervous system it is difficult for the immune system to remove the viral particles. Later on, when a person’s immune system is compromised by, say, the flu or stress, the herpes viral particles travel down the nerves and back to the skin, or mucus membranes, and replicate rapidly, forming painful blisters that are literally bursting with viral particles.  This is why sexual contact with another person with herpes may subject you to catching the virus, though it is also true that someone may not appear to have sores, and may not even realize that they are infected with the herpes virus, but can still transmit the virus upon sexual contact, when shedding it, invisibly.

The recent headline-making sexually transmitted disease is human papillomavirus (HPV), now the most common STD in the U.S. HPV is presently the only known, definitive cause cervical cancer. There are over 100 different strains of HPV. Some of these simply cause common conditions such as hand, or foot (plantar) warts. However, just over 40 strains of HPV infect the genito-anal region. These HPV strains are subdivided into ‘high-risk’ and ‘low-risk’ strains. High-risk strains can cause cervical and other cancers, and low-risk strains tend to cause genital warts. There are 23 high-risk strains, with HPV strains 16 and -18 being the most common. These two strains are associated with 70% of cervical cancers worldwide. There are 20 low-risk strains, with strains 6 and 11 being associated with 90% of genital warts, worldwide. 

Most folks do not develop any symptoms or major health problems if they contract HPV sexually. Such infections generally clear the body naturally, through the work of the immune system, and this tends to occur within one to two years (though high-risk strains may persist longer). However, persistent HPV infection for over six months is the most important risk factor for precancerous cervical lesions. It is important to recognize that these lesions may appear symptomless to the person with the HPV and therefore being monitored by a doctor during this stage is important. 

Having multiple sexual partners is the dominant risk factor associated with HPV infection. Additional risk factors that may increase susceptibility to HPV infections include a history of smoking, long-term oral contraceptive use, and the presence of other sexually transmitted infections, such as herpes, and Chlamydia. There is some evidence that condoms lower the risk of contracting HPV, however sexual contact with an infected person may still result in infection since the HPV may fall outside of the region covered by the condom.

In the United States, men are not currently tested for HPV and women are tested for HPV following an abnormal PAP. This is because women have a definitive risk of cervical cancer from HPV. A positive HPV test indicates that the virus is found on the cervix but this does not necessarily mean that cancer has arisen. The assay used most often by medical laboratories to determine whether HPV is present in a sample can detect 13 high-risk strains simultaneously. Unfortunately, this means that the test results returned from a laboratory to the doctor and patient indicate that the test is either ‘positive’ or ‘negative’ for the presence of the virus but the report does not indicate which HPV strains, or how many strains, the individual is infected with. One problematic issue of test-results being reported this way is that co-infection of multiple HPV strains (or infection by more than one strain simultaneously) may affect up to 60% of people infected with HPV and co-infection is associated with an increased risk of pre-cancerous lesions on the cervix. For women, follow-up doctor visits after abnormal PAP smears are important for identifying cancer early, if it arises. More, general information can be found at the Department of Health and Human Services Center for Disease Control and Prevention’s website (http://www.cdc.gov/STD/HPV/).

There are now two HPV vaccines available commercially (Gardasil and Ceravix), one of which is available in the United States. This vaccine (Gardasil) is intended for young women never exposed to the four, common sexually transmitted strains (16, 18, 6 and 11) that the vaccine contains. Vaccines are now thought to afford some protection against some other HPV strains, as well. However, it is important to recognize that only two of the 23 or so cancer-causing strains are found in the vaccine that is available in the U.S.  Vaccines are administered only to women who have not yet been exposed to the specific strains of HPV in the vaccine, which is the reason the vaccine is advertised primarily for very young women. Post-vaccination immunity is thought to last at least five years.

While the primary focus of-late has been on HPV in women, this is because of its clear and strong association with cervical cancer. HPV infections are now also being associated with many other types of cancer, including oral and anal, and are found in men and women. In fact, the highest frequency of HPV-related oral cancers is found in ~54 year old, white, married, college educated men and women with incomes exceeding $50,000. Dentists can detect these oral cancers once they have formed by evaluating abnormal cells in the mouth and throat. As is true for many types of cancer, radiation and surgery are the methods of removal for these oral cancers.

For men, sexually related cancers (e.g. penile and anal) may be symptomless, or may cause symptoms such as swollen lymph nodes in the groin, genital skin color changes, and bleeding in the region of the cancer. More information on this can be found at the Health and Human Services Center for Disease Control and Prevention’s website (http://www.cdc.gov/std/hpv/stdfact-hpv-and-men.htm). Gay and bisexual men should be aware that they are 17 times more likely to develop anal cancer than heterosexual men. 

Quite recently, a link between multiple cancer-types has also been identified. For example, individuals with anogenital cancers have a 4.3 fold greater risk for tonsillar cancer than other people. 

While not always pretty, education trumps ignorance, be it the year 1818, or 2009. Let us not leave the children untaught, or anyone else in our community for that matter, regarding the consequence of untreated HPV and other STDs.  Perhaps this will minimize some of the consequences that might be of concern to Thomas Jefferson, were he alive today, and contemplating the value of education as it relates to sexually transmitted diseases.

Lisa Horth is an assistant professor of biology at Old Dominion University.