Human papillomavirus (HPV) affects epithelial cells and has a particle diameter of 55 nm. One feature is the proliferation of the skin epithelium, as well as the mucous membranes. In the initial stage, the pathogen usually affects the basal cells of the epithelium, penetrating them through microtrauma. Localized papillomas usually appear on the skin of the neck, armpits, groin, and genitals (most commonly), the oral mucosa, and the nasopharynx.
This virus can be asymptomatic for many years. To detect HPV, electron microscopy or molecular hybridization 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. In terms of skin, HPV 16 and 18 are more common, as well as HPV 5 and 8, which can cause skin cancer. The best known form of HPV-induced cancer is cervical cancer. But men can also get the papillomavirus, which in the worst case causes cancer of the penis or anus.
Often women are faced with HPV 16; this is a form in which introsomic parasitism is observed, that is, outside the cellular chromosome (benign). HPV 18 is characterized by a high risk of developing oncology: first, benign tumors are formed, which after some time degenerate into cancer. Virions in this case are tiny (up to 30 nm).
Various types of HPV infections lead to:
- neoplasms of the cervix;
- invasive or preinvasive oncology;
- genital warts of the urinary tract and genitalia.
Ingestion of the pathogen into 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.
Characteristics of the infection
The human papillomavirus is very contagious. It is usually transmitted by direct contact, skin to skin or mucosa to mucosa, with an infected person. In genital infections, this occurs most often during vaginal or oral sex. A large number of sexual partners or other STIs (sexually transmitted infections) increase the risk. Indirect transmission through contaminated objects, clothing, or bedding is also possible, but rarely occurs.
In 7% of cases, 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.
Penetrating the epithelium, violating the integrity, papillomavirus infection promotes the growth of the lower layer of epithelial cells in the form of warts or warts. This form of the disease is contagious and spreads quickly to other people. As a general rule, warts and condylomas do not metastasize and often disappear spontaneously.
Symptoms of HPV
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 appear in groups and increase when scratched. The two most common forms of papilloma are grayish, hard, raised with a broken surface (common wart), or flat and reddish (flat warts). Pointed warts are found on the soles of the feet or on the heels, grow inward, and are therefore often painful.
The causative agents of genital warts occur in humid and warm parts of the body, therefore, they are located in the folds and mucous membranes. They can cause symptoms like itching or burning. The incubation period, that is, the time between infection and the appearance of symptoms, in genital warts varies from 3 weeks to 8 months.
There are several forms of genital warts caused by different pathogens:
- Genital warts. Pale or reddish nodules that are often found in groups and occur on the labia, vagina, penis, urethra, anal canal, and rectum. They are very contagious.
- Flat warts. They appear in the form of flat knots and are found mainly on the female genital organs. They increase the risk of developing cancer.
- Giant warts (Buschke-Levenshtein tumors). They grow in huge formations, destroying the surrounding tissues. 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 eyes can be affected, resulting in pink stem growths. It is more difficult to detect an asymptomatic course, which the doctor can only see with the help of aids, such as acetic acid (which causes discoloration of warts) or a microscope.
In addition, the virus can also establish itself in cells without tissue changes. Then we 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
When infected, viruses penetrate the cells of the integumentary tissue of the skin and mucous membrane, settle in the nuclei of cell structures and multiply there. These HPV infections generally go unnoticed and heal on their own without consequences, as the immune system successfully fights off the pathogen.
However, some of the HPV types create changes in the skin, that is, growths. Possible forms include genital warts or warts and papillomas, which can affect, for example, the face, arms or legs.
The tissue changes caused are mostly benign, but they can also degenerate and lead to cancer. For example, cancer can occur decades after HPV infection. Cancer of the external female genital organs (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.
Establish the diagnosis
An HPV infection test is performed in women as part of preventive visits to the gynecologist. During a gynecological exam, a swab is taken from the lining of the cervix, this is called a Pap test (cytology exam). The resulting material is examined for tissue changes to determine precancerous conditions.
Alternatively, an HPV test can be performed, in which cellular material from a mucosa swab or tissue sample is analyzed in a laboratory for certain viruses. However, this allows testing only for infection of the affected area, but not making statements about whether tissue changes have occurred. Therefore, 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 still not a cause for concern, as infection does not always lead to cancer. A regular examination is recommended to detect changes in the tissues at an early stage. In contrast, a negative test result does not allow us to say whether there was an infection in the past that the body successfully fought with.
For men, there is no prophylactic exam where the test is done regularly. If there is a corresponding cancer, examination of the tumor can determine whether HPV infection is at 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 exam.
How to cure human papillomavirus
In most cases, the disease does not require treatment because it goes away on its own and then the viruses are no longer detected. However, if this is not the case, the infection may 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, treating the resulting warts reduces the amount of virus, so in many cases the immune system can fight other viruses and thus get rid of them. In some cases, the 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 formulations of salicylic acid.
- Cryotherapy is also a method that is often used for HPV. In this case, the wart is burned with cold, using liquid nitrogen.
- Lasers or electrocautery are equally applicable methods.
Since the frequency of relapses is quite high, it is recommended that it be monitored regularly and use condoms even several months after the lesions disappear, so as not to infect the sexual partner.
For HPV cancers, treatment is much more difficult. In cervical cancer, it is often advisable to remove the uterus, respectively, the upper part of the vagina and the ovaries. 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 should be remembered that the operation is not a cardinal solution, but only solves a cosmetic problem, since after removal the virus can remain in the surrounding tissues and warts can appear again.
Infection prevention
There are two vaccines: HPV 16 and 18 bivalent and HPV 6, 11, 16 and 18 quadrivalent. Vaccination is recommended for all girls 14 years of age and older.
Vaccination does not protect against all types of HPV. Therefore, all women between the ages of 25 and 65, even if vaccinated, are advised to have regular smears.
Timely detection and complete removal of genital warts reduces the risk of disease. The effectiveness of using condoms to prevent the transmission of infections can significantly reduce the risk of developing this condition. The most promising method for the prevention and treatment of the initial stages of the disease caused by this infection is a specific multivalent vaccine.