Human papillomavirus (HPV) affects epithelial cells and has a particle diameter of 55 nm. One 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 microtrauma. Localized papillomas usually occur on the skin of the neck, armpits, hips, and genitals (most commonly), the oral mucosa, and the nasopharynx.
This virus can be asymptomatic for many years. Hybridized electron microscopic or molecular methods are used to detect HPV.
Types of human papillomavirus
In humans, HPV is distinguished, which affects the mucosa and skin. Among the large number of papillomaviruses, 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 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 have a high risk of developing cancerous lesions, especially in the cervix or anus. In terms of skin, HPV 16 and 18 are the most common, as well as HPV 5 and 8, which can lead to skin cancer. The most common form of cancer caused by HPV is cervical cancer. But men can also contract the papilloma virus, which in the worst cases causes cancer of the penis or anus.
Women are often exposed to HPV 16 - this is a form in which introsomal parasitism is observed, ie outside the cellular (benign) chromosome. HPV 18 is characterized by a high risk of developing oncology - first, benign tumors form, which over time degenerate into cancer. The virions in this case are small (up to 30 nm).
Different types of HPV infections lead to:
- neoplasms of the cervix;
- invasive or pre-invasive oncology;
- genital warts of the urinary tract and genitals.
Ingestion of the pathogen in the body does not always lead to disease. It all depends on predisposing factors: increased sexual activity, lack of vitamins, pregnancy, hypothermia, endometriosis, smoking, alcohol abuse, etc. It should be noted that a viral infection can also occur in an organism with a good immune system.
Characteristics of the infection
Human papillomavirus is highly contagious. It is usually transmitted through direct contact, skin-to-skin or mucous-to-mucosal contact, with an infected person. 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 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 at birth 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, 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 others. As a rule, warts and warts do not cause metastasis 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 may not be detected for months or years. Even at this stage, it is contagious.
Skin warts usually occur in groups and grow with itching. The two most common forms of papilloma are either gray, hard, raised with a broken surface (common warts) or flat and reddish (flat warts). Spiked warts are found on the soles of the feet or on the heels, grow inside and are therefore often painful.
The causative agents of genital warts occur in wet and warm parts of the body, therefore they are localized in the folds and in the mucosa. They can cause symptoms such as itching or burning. The incubation period, i. e. the time between infection and the onset 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 often stay in groups and occur in the labia, vagina, penis, urethra, anal canal and rectum. They are very sticky.
- Flat warts. They appear in the form of flat nodes and are found mainly in the female genitals. They increase the risk of developing cancer.
- Giant warts (Buschke-Levenshtein tumors). They grow into large formations, destroying surrounding tissues. In rare cases, they can degenerate and lead to squamous cell carcinoma.
Infection of the mucous membranes in the upper respiratory tract is also possible. The conjunctiva of the eyes can be affected, resulting in increased pink stalk. 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 wart stain) or a microscope.
In addition, the virus can also take up space in cells without any tissue changes. Then they talk about a hidden infection, namely the presence of pathogens, but without symptoms. After infection, this stage can last from a few weeks to several months.
Possible consequences
When infected, the viruses penetrate the cells of the integrative tissue of the skin and mucosa, settle in the nuclei of cellular structures, and multiply 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 cause skin changes, 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 can also degenerate and lead to cancer. For example, cancer can occur decades after being infected with HPV. External female genital cancer (vulvar and vaginal cancer), anal cancer, penile cancer, and mouth and throat cancer (head and neck tumors) are also possible.
Establishing the diagnosis
A test for HPV infection is performed on women as part of preventive visits to the gynecologist. During a gynecological examination, a swab is taken from the cervical lining, this is called a Papanicolaou test (cytological examination). The resulting material is examined for tissue changes to determine precancerous conditions.
Alternatively, an HPV test may be performed, in which cellular material from a mucosal swab or tissue sample is tested in the laboratory for certain viruses. However, this allows you to try only the infection of the affected area, but not to make any statement if tissue changes have occurred. Thus, an HPV test makes sense, especially when combined with a Pap test, and can help detect precursors of cancer 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. Regular examination is recommended to detect tissue changes at an early stage. Conversely, a negative test result does not allow us to ascertain whether there has been an infection in the past with which the body successfully fought.
For men, there is no prophylactic examination in which the test would be performed regularly. If there is a relevant cancer, the 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 a pelvic examination.
How to cure human papillomavirus
In most cases, the disease does not require treatment because it passes 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 of systemic impact on this virus, due to which it would be possible to completely destroy it. However, treating the resulting warts reduces the number of viruses, so in many cases the immune system can fight off other viruses and thus get rid of them. In some cases, pathogens survive and can cause incessant symptoms.
Therapeutic tactics depend on the type of HPV and the picture associated with the disease:
- Plantar warts and genital warts can be treated with topical salicylic acid formulations.
- Cryotherapy is also a method often used for HPV. In this case, the wart is burned cold, using liquid nitrogen.
- Lasers or electrocautery are equally applicable methods.
Since the frequency of recurrences is quite high, it is advisable to check yourself regularly and use condoms for several months after the lesions disappear, so as not to infect your sexual partner.
For HPV cancers, treatment is much more difficult. In cervical cancer, removal of the uterus, ie the upper part of the vagina and ovaries, respectively, is often advised. 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 remembered that surgery is not a cardinal solution, but only solves a cosmetic problem, as after removal the virus is able to remain in the surrounding tissues and warts may reappear.
Prevention of infection
There are two vaccines: HPV bivalent 16 and 18 and HPV bivalent 6, 11, 16 and 18. Vaccination is recommended for all young girls aged 14 years 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 staining examinations.
Timely detection and complete removal of genital warts reduces the risk of disease. The effectiveness of using condoms 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 this infection is a specific multivalent vaccine.