Human papillomavirus (HPV) affects epithelial cells and has a particle diameter of 55 nm. Its feature is the proliferation of the epithelium of the skin, as well as the mucous membranes. At the initial stage, the pathogen usually affects the basal cells of the epithelium, penetrating into them through microtrauma. Localized papillomas usually occur on the skin of the neck, armpits, groin and genitals (most commonly), oral mucosa, and nasopharynx.
This virus can be asymptomatic for years. To detect HPV, electron microscopy or molecular hybridization methods are used.
Types of human papilloma virus
In humans, HPV is distinguished, which affects the mucous membranes and skin. Among the large number of papillomaviruses, there are species with low and high oncogenic risk. It has been shown that oncogenic properties are associated with the ability to integrate DNA into the genome of human cells.
The virus is activated in 10-20% of cases. Depending on the type, these can cause benign or malignant lesions. Some HPVs are not oncogenic. They cause the appearance of warts and genital warts. The most common are HPV 6 and 11.
HPV oncogenes are those who have a 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 most well-known form of HPV-induced cancer is cervical cancer. But men can also catch the papilloma virus, which in the worst cases causes cancer of the penis or anus.
Often women are exposed to HPV 16 - this is the form in which introsomal parasitism is observed, that is, outside the chromosomes of cells (benign). HPV 18 is characterized by a high risk of developing oncology - first, a benign tumor is formed, which after a while turns into cancer. The virions in this case are small (up to 30 nm).
Different types of HPV infection cause:
- cervical neoplasms;
- invasive or pre-invasive oncology;
- genital warts on the urinary tract and genitals.
The entry of pathogens into the body does not always cause disease. It all depends on predisposing factors: increased sexual activity, vitamin deficiency, pregnancy, hypothermia, endometriosis, smoking, alcohol abuse, etc. It should be noted that viral infections can occur even in organisms with a good immune system.
Symptoms of infection
The 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 genital infections, it most commonly occurs during vaginal or oral sex. A large number of sex partners or other STIs (sexually transmitted infections) increase the risk. Indirect transmission through contaminated objects, clothing or bedding is also possible, but is rare.
In 7% of cases, mother-to-child transmission of the virus can occur during delivery when the infection is active. The risk increases to 40% if you are infected with HPV 16 or 18.
Penetrating into the epithelium, violating its 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 rule, warts and condyloma do not cause metastases and often disappear spontaneously.
HPV symptoms
The incubation period lasts up to 9 months (mean 3 months). HPV can be present in the body without obvious symptoms. Viruses can go undetected for months or years. Even at this stage, it's contagious.
Skin warts usually occur in clusters and increase with scratching. The two most common forms of papillomas are grayish, hard, raised with a cracked surface (common warts) or flat and reddish (flat warts). Pointy 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 warm 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, which is the time between infection and the onset of symptoms, in genital warts ranges from 3 weeks to 8 months.
There are several forms of genital warts caused by different pathogens:
- Genital warts. Pale or reddish nodules that often stand 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 tumor). They grew into a huge formation, destroying the surrounding tissue. In rare cases, they can degenerate and cause squamous cell carcinoma.
Infections of the mucous membranes in the upper respiratory tract are also possible. The conjunctiva of the eye may be affected, resulting in a pinkish stem growth. It is more difficult to detect an asymptomatic course, which can only be seen by a doctor with the help of an assistive device, such as acetic acid (which causes wart discoloration) or a microscope.
In addition, viruses can also stay in cells without any tissue changes. Then they talk about latent infection, that is, the presence of a pathogen, but without symptoms. After infection, this phase can last from a few weeks to several months.
Possible consequences
When infected, the virus penetrates into the cells of the integumentary tissue of the skin and mucous membranes, settles in the nucleus of the cell structure and multiplies there. Usually, such an HPV infection goes unnoticed and resolves on its own without consequences, as the immune system successfully fights off the pathogen.
However, some types of HPV cause skin changes, namely 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 can also degenerate and cause cancer. For example, cancer can occur decades after HPV infection. Cancers of the female external genital organs (cancer of the vulva and vagina), cancer of the rectum, cancer of the penis, and cancer of the mouth and throat (tumor of the head and neck) are also possible.
Establish a diagnosis
Tests for HPV infection are performed on women as part of a preventative visit to a gynecologist. During a gynecological examination, a swab is taken from the lining of the cervix, this is called the Papanicolaou test (cytology examination). The resulting material is examined for tissue changes to determine precancerous conditions.
Alternatively, an HPV test may be performed, in which cell material from a mucosal swab or tissue sample is tested in a laboratory for specific viruses. However, this makes it possible to prove only infection of the affected area, but does not make any statements about whether tissue changes have occurred. So 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 cause cancer. Routine examination is recommended to detect tissue changes at an early stage. On the other hand, a negative test result does not allow us to confirm whether there was an infection in the past that the body managed to overcome.
For men, there is no prophylactic examination where tests will be performed regularly. If there is a suitable cancer, examination of the tumor can determine whether HPV infection is at the root of the cancer.
Special 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, this disease does not require treatment because it will go away on its own and then the virus is no longer detectable. However, if this does not happen, the infection may persist longer and persist for months or years.
To date, there is no method of systemic impact on this virus, which makes it possible to completely destroy it. However, treating the resulting wart reduces the number of viruses, so in most cases the immune system can fight off other viruses and thus get rid of them. In some cases, the pathogen persists and can cause repeated symptoms.
Treatment tactics depend on the type of HPV and the associated disease features:
- Plantar and genital warts can be treated with a topical formulation of salicylic acid.
- Cryotherapy is also a frequently used method for HPV. In this case, the wart is burned cold, using liquid nitrogen.
- Laser or electrocautery are equally applicable methods.
Because the frequency of recurrence is quite high, it is advisable to have regular check-ups and use a condom even a few months after the lesions have disappeared, so as not to infect sexual partners.
For HPV cancer, treatment is much more difficult. In cervical cancer, it is often recommended to remove the uterus, respectively, the upper part of the vagina and the ovaries. It can be supplemented with radiation therapy to rule out a relapse. Other cancers caused by HPV are most often treated with targeted therapy, such as radiation or chemotherapy.
It should be borne in mind that surgery is not the ultimate solution, but only solves cosmetic problems, because after removal the virus can remain in the surrounding tissues and warts may appear again.
Infection prevention
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 years and over.
Vaccination does not protect against all types of HPV. Therefore, all women between the ages of 25 and 65, despite being vaccinated, are advised to have regular smears.
Timely detection and complete removal of genital warts reduces the risk of the disease. Effective use of condoms to prevent transmission of infection can significantly reduce the risk of developing this condition. The most promising method for the prevention and treatment of the early stages of the disease caused by this infection is a specific multivalent vaccine.