Human papillomavirus (HPV) affects epithelial cells and has a particle diameter of 55 nm. One feature is the spread of the skin epithelium as well as mucous membranes. In the initial phase, the pathogen usually affects the basal cells in the epithelium and penetrates them through microtrauma. Localized papillomas usually occur on the skin of the neck, armpits, groin and genitals (most often), the oral mucosa and the nasopharynx.
This virus can be asymptomatic for many years. To detect HPV, electron microscopic or molecular hybridized methods are used.
Types of human papillomavirus
In humans, HPV is distinguished, affecting the mucous membranes and skin. Among the large number of papillomaviruses, there are species with low and high oncogenic risk. Oncogenic properties have been shown to be associated with the ability to integrate DNA into the genome of human cells.
The virus is activated in 10-20% of cases. Depending on its type, this can lead to benign or malignant lesions. Some HPVs are not oncogenic. They lead to the appearance of warts and genital warts. The most common are HPV 6 and 11.
HPV oncogenes are those that are at high risk of developing cancerous lesions, especially on the cervix or anus. As for skin, HPV 16 and 18 are more common, as well as HPV 5 and 8, which can lead to skin cancer. The most well-known form of HPV-induced cancer is cervical cancer. But men can also contract papillomavirus, which in the worst case causes cancer of the penis or anus.
Women often face HPV 16 - this is a form in which introsomal parasitism is observed, ie outside the cell chromosome (benign). HPV 18 is characterized by a high risk of developing oncology - first benign tumors form, which after a while degenerate into cancer. Virions in this case are small (up to 30 nm).
Different types of HPV infections lead to:
- neoplasms of the cervix;
- invasive or preinvasive oncology;
- genital warts and genitals.
Ingestion of the pathogen in the body does not always lead to disease. It all depends on the predisposing factors: increased sexual activity, vitamin deficiency, pregnancy, hypothermia, endometriosis, smoking, alcohol abuse, etc. It should be noted that a viral infection can occur even in an organism with a good immune system.
Functions of infection
Human papillomavirus is highly contagious. It is usually transmitted by direct contact, skin to skin or mucous membrane to mucous membrane, with an infected person. In sexually transmitted infections, this most often occurs during vaginal or oral sex. A large number of sex partners or other sexually transmitted diseases (sexually transmitted infections) increase the risk. Indirect transmission through objects, contaminated clothing or bedding is also possible, but occurs infrequently.
In 7% of cases, the mother-to-child transmission of the virus can occur during childbirth when the infection is active. The risk increases to 40% if you are infected with HPV 16 or 18.
Penetrates the epithelium, violates the integrity, papillomavirus infection promotes the growth of the lower layer of epithelial cells in the form of warts or warts. This type of disease is contagious and spreads rapidly to others. As a rule, warts and condyloma do not cause metastases and often disappear spontaneously.
HPV symptoms
The incubation period lasts up to 9 months (average 3 months). HPV can be present in the body without obvious symptoms. The virus can go undetected for months or years. Even at this stage, it is contagious.
Skin warts usually occur in clusters and rise with scratches. The two most common forms of papilloma are either grayish, hard, raised with a broken surface (common wart) or flat and reddish (flat wart). Prickly warts are found on the soles of the feet or on the heels, grow inwards and are therefore often painful.
The causative agents of genital warts occur on moist and hot parts of the body, therefore they are localized in the folds and on the mucous membranes. They can cause symptoms such as itching or burning. The incubation period, ie the time between infection and onset of symptoms, in genital warts varies from 3 weeks to 8 months.
There are several types of genital warts caused by different pathogens:
- Genital warts. Pale or reddish nodules that often appear in clusters and occur on the labia, vagina, penis, urethra, anal canal, and rectum. They are highly contagious.
- Flat warts. They occur in the form of flat nodules and are found mainly on the female genitals. They increase the risk of developing cancer.
- Giant warts (Buschke-Levenshtein tumors). They grow into huge formations and destroy the surrounding tissue. In rare cases, they can degenerate and lead to squamous cell carcinoma.
Infection of the mucous membranes of the upper respiratory tract is also possible. The conjunctiva of the eye can be affected, resulting in pink stem growths. It is more difficult to detect an asymptomatic course that the doctor can only see using aids such as acetic acid (which causes discoloration of the warts) or a microscope.
In addition, the virus can also take up residence in cells without tissue changes. Then they talk about a latent infection, that is, the presence of pathogens, but without symptoms. After infection, this phase can last from several weeks to several months.
Possible consequences
Once infected, viruses enter the cells of the skin and mucous membranes, settle in the cell structure and multiply there. Usually, such HPV infections go unnoticed and heal themselves without consequences as the immune system successfully fights the pathogen.
However, some of the HPV types cause skin changes, ie. growth. Possible forms include genital warts or warts and papillomas, which may affect the face, arms or legs, for example.
The caused tissue changes are mostly benign, but can also degenerate and lead to cancer. For example, cancer can occur decades after HPV infection. Cancer of the external female genitalia (cancer of the vulva and vagina), anal cancer, cancer of the penis and cancer of the mouth and throat (tumors of the head and neck) are also possible.
Establishment of diagnosis
A test for HPV infection is performed in women as part of a preventive visit to the gynecologist. During a gynecological examination, a cotton swab is removed from the lining of the cervix, this is called a Papanicolaou test (cytological examination). The resulting material is examined for tissue changes to determine precancerous conditions.
Alternatively, an HPV test can be performed in which cell material from a mucosal stick or tissue sample is tested in a laboratory for certain viruses. However, this only allows to prove the infection in the affected area, but not to make statements as to whether the tissue changes have occurred. Thus, an HPV test makes sense, especially when combined with a Pap test, and can help detect cancer precursors at an early stage.
If the test is positive, this is not yet a cause for concern, as infection does not always lead to cancer. Regular examination is recommended to detect tissue changes at an early stage. Conversely, a negative test result does not allow us to claim whether there was previously an infection that the body successfully struggled with.
For men, there is no prophylactic study where the test would be performed regularly. If there is a similar cancer, examination of the tumor can determine if HPV infection is the root of the cancer.
Specialized DNA techniques are also used in laboratory diagnostics, such as real-time PCR. Anogenital warts caused by HPV types 6 and 11 are easily detected during a pelvic examination.
How to cure the human papillomavirus
In most cases, the disease does not require treatment because it goes away on its own and then the virus is no longer detected. However, if this is not the case, the infection can last longer and persist for months or years.
To date, there are no methods of systemic impact on this virus, so it would be possible to destroy it completely. However, the treatment of the resulting warts reduces the number of viruses, so that in many cases the immune system can fight other viruses and thus get rid of them. In some cases, pathogens survive and can cause symptoms over and over again.
Therapeutic tactics depend on the type of HPV and the associated picture of the disease:
- Plantar and genital warts can be treated with topical salicylic acid formulations.
- Cryotherapy is also a method often used for HPV. In this case, the wart is burned with cold using liquid nitrogen.
- Lasers or electrocautery are equally useful methods.
As the frequency of relapses is quite high, it is advisable to check yourself regularly and use a condom even several months after the lesions disappear, so as not to infect the sexual partner.
For HPV cancer, treatment is much more difficult. In cervical cancer, it is often advisable to remove the uterus, the upper part of the vagina and the ovaries, respectively. This can be supplemented with radiation therapy to rule out the likelihood of relapse. Other cancers caused by HPV are most often treated with targeted therapy, such as radiation or chemotherapy.
It must be remembered that the operation is not a cardinal solution, but only solves a cosmetic problem, as the virus after removal can remain in the surrounding tissue and warts can reappear.
Prevention of infection
There are two vaccinations: bivalent HPV 16 and 18 and quadrivalent HPV 6, 11, 16 and 18. Vaccination is recommended for all young girls aged 14 and over.
Vaccination does not protect against all types of HPV. Therefore, all women aged 25 to 65 years, even if they are vaccinated, are advised to undergo regular lubrication.
Early detection and complete removal of genital warts reduces the risk of disease. The effectiveness of using condoms to prevent infection transmission can significantly reduce the risk of developing this condition. The most promising method of preventing and treating the initial stages of the disease caused by this infection is a specific multivalent vaccine.