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 early stages, pathogens usually affect 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 often), oral mucosa, and nasopharynx.
The virus can be asymptomatic for years. To detect HPV, electron microscopic methods or molecular hybridization are used.
Types of human papillomavirus
In humans, HPV is differentiated, affecting mucous membranes and skin. Among a large number of papillomavirus viruses, 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, this can cause 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 oncogens 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 are HPV 5 and 8, which can cause 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 are confronted with HPV 16 - this is a form in which introsomal parasitism is observed, i. e. outside the chromosome of the cell (benign). HPV 18 is characterized by a high risk of developing oncology - first, a benign tumor is formed, which after a while degenerates into cancer. The virus in this case is small (up to 30 nm).
Various types of HPV infections lead to:
- cervical neoplasm;
- invasive or pre-invasive oncology;
- genital warts of the urinary tract and genitals.
The uptake 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, and others. It should be noted that viral infections can occur even in organisms with good immune systems.
Characteristics of infection
Human papillomavirus is highly contagious. It is usually spread through direct contact, skin to skin or mucous membranes to mucous membranes, with infected people. In genital infections, this most often occurs during vaginal or oral sex. A large number of sexual partners or other STIs (sexually transmitted infections) increase the risk. Indirect spread through contaminated objects, clothing or bedding is also possible, but rare.
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 into the epithelium, violating its integrity, papillomavirus infection induces 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 others. As a rule, warts and condylomas do not cause metastasis 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 goes undetected for months or years. Even at this stage, it is contagious.
Skin warts usually occur in groups and increase with scratches. The two most common forms of papilloma are gray, hard, enlarged with a broken surface (common warts) or flat and reddish (flat warts). Pointed warts are found on the soles of the feet or on the heels, grow inwards and are therefore often painful.
The causative agent of genital warts occurs on moist and warm parts of the body, therefore it is localized on the folds and mucous membranes. They can cause symptoms such as itching or burning. The incubation time, that 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 clusters and occur in the labia, vagina, penis, urethra, anal canal, and rectum. They are highly contagious.
- Flat warts. They appear in the form of flat knots and are found mainly on the female genitals. They increase the risk of cancer.
- Giant warts (Buschke-Levenshtein tumor). They grow into large formations, 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 the growth of pink stems. It is more difficult to detect an asymptomatic course, which can only be seen by a doctor with the help of an aids, such as acetic acid (which causes discoloration of warts) or a microscope.
In addition, the virus can also settle in cells without tissue changes. Then they discuss a latent infection, i. e. 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 integumental tissue cells of the skin and mucous membranes, settles at the core of the cell structure and multiplies there. Usually, such HPV infections go unnoticed and heal on their own without consequences, as the immune system successfully fights the pathogen.
However, some types of HPV make skin changes, i. e. growths. Possible forms include genital warts or warts and papillomas, which can affect, for example, the face, arms, or legs.
The resulting tissue changes are mostly benign, but can also degenerate and lead to cancer. For example, cancer can occur decades after HPV infection. External female genital cancer (vulvar and vaginal cancer), anal cancer, penile cancer, and mouth and throat cancer (head and neck tumors) may also occur.
Establish a diagnosis
Testing for HPV infection is done in women as part of a preventive visit to a gynecologist. During the gynecological examination, a broom is taken from the lining of the cervix, this is called the 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 mucosal tissue or tissue samples is tested in a laboratory for a specific virus. However, this can only prove infection in the affected area, but does not make a statement as to whether tissue changes have occurred. Therefore, HPV testing makes sense, especially if 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 concern, as infection does not always lead to cancer. Periodic examinations are 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 has been an infection in the past that the body has successfully dealt with.
For men, there are no prophylactic examinations where tests will be performed periodically. If there is a suitable cancer, examination of the tumor can determine if HPV infection is the cause of the cancer.
Specific 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 testing.
How to treat human papillomavirus
In most cases, the disease does not require treatment because the disease goes away on its own and then the virus can no longer be detected. However, if this does not happen, the infection can last longer and persist for months or years.
To date, there is no method of systemic effect on this virus, as it is likely to completely destroy it. However, treating the resulting warts can reduce the amount of virus, so in many cases the immune system can fight off other viruses and thus get rid of them. In some cases, the pathogen persists and can cause recurrent symptoms.
Therapeutic tactics depend on the type of HPV and the picture of the associated disease:
- Plantar and genital warts can be treated with topical salicylic acid formulations.
- Cryotherapy is also a commonly used method for HPV. In this case, the warts are burned cold, using liquid nitrogen.
- Laser or electrocautery is the same method.
Since the frequency of recurrences is quite high, it is recommended to check yourself regularly and use a condom even a few months after the lesion disappears, so as not to infect the sexual partner.
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 ovaries. This can be supplemented with radiation therapy to rule out the possibility of relapse. Other cancers caused by HPV are most often treated with targeted therapies, such as radiation or chemotherapy.
It should be noted that the operation is not a cardinal solution, but only solves a cosmetic problem, because after removal of the virus can persist 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 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 they have been vaccinated, are advised to undergo regular smear examinations.
Timely detection and removal of genital warts can reduce the risk of disease. The effectiveness of condom use 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 early stages of the disease caused by this infection is a specific multivalent vaccine.