Human papilloma virus (HPV) affects epithelial cells and has a particle diameter of 55 nm. A feature is the proliferation of skin epithelium as well as mucous membranes. In the initial stage, the pathogen usually affects the basal epithelial cells, penetrating them through microtraumas. 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 many years. Electron microscopic or molecularly hybridized methods are used to detect HPV.
Types of human papilloma virus
In humans, HPV is different that affects the mucous membranes and skin. Among the large number of papilloma viruses, there are species with low and high oncogenic risk. Oncogenic properties have been shown to be related to the ability to integrate DNA into the human cell genome.
The virus is activated in 10-20% of cases. Depending on the type, it 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 who have a high risk of developing cancerous lesions, especially on the cervix or anus. As for the skin, HPV 16 and 18 are more common, as are HPV 5 and 8, which can lead to skin cancer. The most well-known form of cancer caused by HPV is cervical cancer. But men can also be infected with the papilloma virus, which in the worst cases causes cancer of the penis or anus.
Often women face HPV 16 - 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 are formed which after some time degenerate into cancer. The virions are tiny in this case (up to 30 nm).
Different types of HPV infections lead to:
- cervical neoplasms;
- invasive or preinvasive oncology;
- genital warts of the urinary tract and genitals.
The introduction of pathogens into the body does not always lead to disease. It all depends on 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.
Features of infection
The human papilloma virus is highly contagious. It is usually transmitted by direct contact, skin to skin or mucosa to mucosa, with an infected person. In genital infections, this most often occurs during vaginal or oral sex. A large number of sexual partners or other sexually transmitted diseases (sexually transmitted infections) increases the risk. Indirect transmission through objects, contaminated 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.
By penetrating the epithelium, violating the integrity, the papilloma virus infection stimulates 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 rapidly to others. Warts and condyloma usually do not cause metastases 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 remain undetected for months or years. Even at this stage it is contagious.
Warts on the skin usually appear in clumps and increase with scratching. The two most common forms of papilloma are either grayish, hard, raised with a broken surface (ordinary wart) or flat and reddish (flat wart). Pointed warts are located 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, so they are localized in the folds and on the mucosa. They can cause symptoms such as itching or burning. The incubation period, ie the time between infection and the appearance 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 appear on the labia, vagina, penis, urethra, anal canal, and rectum. They are very contagious.
- Straight nipples. They appear in the form of straight 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, destroying the surrounding tissues. In rare cases, they can degenerate and lead to squamous cell carcinoma.
Mucosal infection in the upper respiratory tract is also possible. Conjunctiva of the eyes may be affected, resulting in pink growths on the stem. 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 a change in the color of the nipples) or a microscope.
In addition, the virus can also settle in cells without any changes in the tissue. Then they talk about latent infection, ie the presence of pathogens, but without symptoms. After infection, this phase can last from a few weeks to several months.
Possible consequences
When infected, the viruses penetrate the cells of the integumentary tissue of the skin and mucous membranes, deposit in the nuclei of cellular structures and multiply there. Usually, such HPV infections go unnoticed and treat themselves without sequelae, as the immune system successfully fights the pathogen.
However, some types of HPV create changes in the skin, ie. Outgrowths. 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 degenerate and lead to cancer. For example, cancer can occur decades after HPV infection. Cancers 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.
Diagnosis
The test for HPV infection is performed in women as part of preventive visits to the gynecologist. During the gynecological examination, a swab is taken from the mucous membrane of the cervix, which is called the Papanicolaou test (cytological examination). The resulting material is examined for tissue changes to determine the precancerous condition.
Alternatively, an HPV test may be performed in which cellular material from a mucosal swab or tissue sample is laboratory tested for specific viruses. However, this makes it possible to prove only the infection of the affected area, but not to make any statements as to whether changes in the tissue have occurred. Therefore, the HPV test makes sense, especially in combination with the Pap test, and can help detect cancer precursors at an early stage.
If the test is positive, that is not yet a cause for concern, because the infection does not always lead to cancer. Regular examination is recommended to detect tissue changes at an early stage. In contrast, a negative test result does not allow us to determine whether there has been an infection in the past that the body has successfully fought.
For men, there is no prophylactic examination in which the test would be performed regularly. If there is a corresponding cancer, a tumor examination can determine if the 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 pelvic examination.
How to cure human papilloma virus
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 can last longer and last for months or years.
To date, there are no methods of systemic influence on this virus, due to which it would be possible to completely destroy it. However, treating warts reduces the number of viruses, so in many cases the immune system can fight other viruses and 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 preparations.
- Cryotherapy is also a method often used for HPV. In this case, the wart is burned in the cold, using liquid nitrogen.
- Lasers or electrocautery are equally applicable methods.
Since the recurrence rate is quite high, it is advisable to check yourself regularly and use condoms even a few months after the lesions disappear, so as not to infect your sexual partner.
For HPV cancer, treatment is much more difficult. In cervical cancer, it is often advisable to remove the uterus, ie the upper part of the vagina and ovaries. This can be supplemented with radiotherapy to rule out the possibility of recurrence. Other tumors 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 a cardinal solution, but only solves a cosmetic problem, because after removal the virus can remain in the surrounding tissues and warts can reappear.
Infection prevention
There are two vaccines: bivalent HPV 16 and 18 and tetravalent HPV 6, 11, 16 and 18. Vaccination is recommended for all girls over 14 years of age.
Vaccination does not protect against all types of HPV. Therefore, a regular swab check-up is recommended for all women between the ages of 25 and 65, even if they have been vaccinated.
Timely detection and complete removal of genital warts reduces the risk of disease. The effectiveness of using a condom to prevent the transmission of infection 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.