Human papillomavirus (HPV) affects epithelial cells and has a particle diameter of 55 nm. It is characterized by the proliferation of the skin epithelium as well as mucous membranes. In the initial stage, the pathogen usually affects the basal cells of the epithelium, 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 molecular hybridization methods are used to detect HPV.
Types of human papillomavirus
In humans, they differentiate between HPV, which affects mucous membranes and skin. High numbers of papillomaviruses include low- and high-oncogenic risk species. Oncogenic properties have been shown to be related to their 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 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 at high risk of developing cancerous lesions, especially in the cervix or anus. For the skin, HPV 16 and 18 and HPV 5 and 8 are more common, which can lead to skin cancer. The best known form of HPV-induced cancer is cervical cancer. But men can also get the papilloma virus, which in the worst cases causes cancer of the penis or rectum.
Often, women are exposed to HPV 16 - a form in which introsomal parasitism is observed, i. e. outside the cell chromosome (benign). HPV 18 is characterized by a high risk of developing oncology - first, benign tumors develop that eventually develop into cancer. The virions in this case are tiny (up to 30 nm).
Different types of HPV infections lead to:
- cervical tumors;
- invasive or preinvasive oncology;
- genital warts in the urinary tract and genitals.
Getting 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 viral infection can occur even in a body with a good immune system.
Characteristics of infection
Human papillomavirus is highly contagious. It usually spreads by direct contact, from skin to skin or from mucosa to mucosa, with an infected person. For sexually transmitted infections, this is most common during vaginal or oral sex. The large number of sexual partners or other sexually transmitted infections (sexually transmitted infections) increases the risk. Indirect transfer of objects, soiled clothing or bedding is also possible, but is rare.
In 7% of cases, the virus can be passed from mother to child during childbirth when the infection is active. The risk increases to 40% if you are infected with HPV 16 or 18.
Papillomavirus infection penetrates the epithelium, violates integrity, and 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 others. Warts and warts 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 go unnoticed for months or years. Even at this stage it is contagious.
Skin warts usually occur in clusters and grow with scratches. The two most common forms of papilloma are grayish, hard, with a broken surface (common wart), or flat and reddish (flat wart). Spiky warts are located on the soles of the feet or heels, grow inwards, and are therefore often painful.
The pathogens of genital warts occur on wet and warm parts of the body and are therefore localized in the folds and mucous membranes. They may cause symptoms such as itching or burns. The incubation period, i. e. , 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, often in clusters, occurring in the labia, vagina, penis, urethra, anal canal, and rectum. They are very contagious.
- Flat warts. They appear in the form of flat lumps and are found mainly on the female genitals. They increase the risk of developing cancer.
- Huge 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.
Infection of the mucous membranes of the upper respiratory tract is also possible. The conjunctiva of the eye may be affected, resulting in pink stem growth. It is more difficult to detect an asymptomatic course that the doctor can only see with the help of aids such as acetic acid (which causes the warts to discolor) or a microscope.
In addition, the virus can be located 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
When infected, viruses enter the cells of intact tissue in the skin and mucous membranes, settle in the nucleus of cellular structures and multiply there. In general, 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 cause skin changes, that is, growth. Possible forms include genital warts or warts and papillomas, which can affect, for example, the face, arms, or legs.
The tissue lesions caused are mostly benign, but can degenerate and lead to cancer. For example, cancer can occur decades after HPV infection. Possible cancers of the external female genitals (cancer of the vulva and vagina), anal cancer, cancer of the penis, and cancer of the mouth and throat (cancer of the head and neck).
Establishing the diagnosis
As part of a gynecologist’s preventive visits, testing for HPV infection is performed on women. In a gynecological examination, a swab is taken from the lining of the cervix, this is called the Papanicolaou test (cytological examination). The resulting material is examined for tissue lesions to determine cancerous conditions.
Alternatively, an HPV test can be performed in which cellular material from a mucosal wipe or tissue sample is tested in a laboratory for certain viruses. However, this allows us to prove only infection of the affected area, but we cannot make a statement as to whether tissue lesions have occurred. Thus, HPV testing makes sense, especially when combined with Pap testing, and can help identify cancer precursors in the early stages.
If the test is positive, this is not yet a concern, as infection does not always lead to cancer. Regular testing is recommended for early detection of tissue lesions. In contrast, a negative test result does not make it possible to determine if there has been an infection in the past that the body has successfully fought.
For men, there is no prophylactic examination in which the examination would be performed regularly. If there is a suitable cancer, the tumor can be examined to see if the HPV infection is at the root of the cancer.
Special DNA techniques, such as real-time PCR, are also used in laboratory diagnostics. Anogenital warts caused by HPV types 6 and 11 can be easily detected in a pelvic study.
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 last for months or years.
To date, there are no methods that have a systemic effect on this virus that can completely destroy it. However, treating the resulting warts reduces the number of viruses, so in many cases the immune system is able to fight off other viruses and get rid of them. In some cases, the pathogens survive and can cause symptoms again and 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 commonly used method of treating HPV. In this case, the wart is cold, burnt liquid nitrogen.
- The laser or electrocautery is an equally applicable method.
Because the frequency of relapses is quite high, it is recommended that you check yourself regularly and use a condom a few months after the injuries disappear to avoid infecting your sexual partner.
Treating HPV cancers is much more difficult. In cervical cancer, it is often advisable to remove the uterus and 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 therapy, such as radiation or chemotherapy.
It should be recalled that the operation is not a cardinal solution, but only a cosmetic problem, as after removal the virus is able to remain in the surrounding tissues and the warts may reappear.
Prevention of infection
There are two vaccines: bivalent HPV 16 and 18, and tetravalent HPV 6, 11, 16, and 18. Vaccination is recommended for all girls 14 years of age and older.
The vaccine does not protect against all types of HPV. Therefore, all women between the ages of 25 and 65 should have regular smear tests, even if they are 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 preventing and treating the early stages of the disease caused by infection is a specific multivalent vaccine.