Human papillomavirus (HPV) affects epithelial cells and has a particle diameter of 55 nm. The peculiarity is the proliferation of the skin epithelium as well as the mucous membranes. In the initial stage, the causative agent usually affects the basal cells of the epithelium, penetrating them through microtrauma. Localized papillomas usually appear on the skin of the neck, arms, groin, and genitals (most commonly), on the mucous membranes of the mouth, and on the 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, HPV is prominent, affecting the mucous membranes and skin. Among the large number of papillomaviruses are species with low and high oncogenic risk. It has been proven that oncogenic properties are related to the ability of DNA to integrate into the genome of human cells.
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 cause 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 of the cervix or anus. On the skin side, 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. Men can also become infected with the papilloma virus, which in the worst cases causes cancer of the penis or anus.
Often women are exposed to HPV 16 - this is 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 - benign tumors form first, which after some time develop into cancer. In this case the virions are small (up to 30 nm).
Different types of HPV infections cause:
- Cervical neoplasms;
- Invasive or preinvasive oncology;
- Genital warts of the urinary tract and genitals.
The introduction of the pathogen into the body does not always cause disease. It all depends on predetermined factors: increased sexual activity, vitamin deficiency, pregnancy, hypothermia, endometriosis, smoking, alcohol abuse, and so on. Sh.
Characteristics of infection
Human papillomavirus is highly contagious. It is usually transmitted through direct contact, skin-to-skin or mucous membranes, with an infected person. During 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 beds is also possible, but rarely.
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.
Penetration into the epithelium, disruption of 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 rapidly to others. Warts and warts usually do not cause metastases 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 can go unnoticed for months or years. Even at this point, it is contagious.
Skin warts usually appear in clusters and grow into scratches. The two most common forms of papilloma are grayish, hard, raised with a broken surface (usually a wart) or flat and reddish (with a flat wart). Dropped warts are found on the soles of the feet or heels, grow inward and are therefore often painful.
The causative agents of genital warts are found on moist and warm parts of the body, so they are localized on the folds and mucous membranes. They can cause symptoms such as itching or burning. The incubation period, ie the time between infection and onset of symptoms during genital warts, is 3 weeks to 8 months.
There are several forms of genital warts that are caused by different pathogens:
- Genital warts. Pale or reddish nodules that often stand in clusters and are found on the labia, vagina, penis, urethra, anal canal, and rectum. They are highly contagious.
- Flat warts. They appear in the form of flat nodules and are found mainly on the female genitals. They increase the risk of developing cancer.
- Giant warts (Bushke-Levenstein tumors). They grow in 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 eyes can be affected, resulting in a pink stem growth. It is more difficult to detect an asymptomatic course that a doctor can only see with the help of aids such as acetic acid (which causes warts to fade) or a microscope.
In addition, the virus can also invade cells without altering tissue. Then they talk about latent infection, i. e. 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 enter the cells of the integrated tissue of the skin and mucous membranes, settle in the nuclei of cell structures, and multiply there. Usually, such HPV infections go unnoticed and heal on their own without consequences as the immune system successfully fights the cause.
However, some types of HPV cause skin changes, or growths. Possible forms include genital warts or warts and papillomas that can affect, for example, the face, arms or legs.
Tissue changes are mostly benign, but can also degenerate and cause cancer. For example, cancer can occur with HPV infection decades later. It is also possible cancer of the external genitalia (cancer of the vulva and vagina), anal cancer, cancer of the penis and cancer of the mouth (tumors of the head and neck).
Make a diagnosis
The HPV infection test is performed in women as part of prophylactic visits to the gynecologist. During a gynecological examination, a smear is taken from the cervical mucosa, this is called a Pap smear (cytological examination). The resulting material examines tissue changes to determine the precancerous condition.
Alternatively, an HPV test may be done, during which cell material from a mucosal tampon or tissue sample is tested in a laboratory for certain viruses. However, this allows you to only confirm the infection in the affected area, but do not make any statement about whether tissue changes have occurred. Thus, the HPV test makes sense, especially in conjunction with the 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 the infection does not always cause cancer. Regular examination is recommended to detect tissue changes at an early stage. Conversely, a negative test result does not give us evidence as to whether there was an infection in the past that the body was successfully fighting.
For men, there is no prophylactic examination during which the test would be performed regularly. If there is relevant cancer, a tumor examination can determine if there is HPV infection at the base 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 on pelvic examination.
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 can last longer and last for months or years.
To date, there are no methods of systemic exposure to this virus that would make it possible to eradicate it completely. However, treating warts reduces the number of viruses, so in many cases the immune system can deal with other viruses and thus 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 formulations of salicylic acid.
- Cryotherapy is also a method that is often used for HPV. In this case, the wart was burned using cold, liquid nitrogen.
- Laser or electrocautery is a method to be used in the same way.
Since the frequency of relapses is quite high, it is advisable to check yourself regularly and use a condom even a few months after the lesions disappear so as not to infect your sexual partner.
HPV cancer is much more difficult to treat. In cervical cancer, it is often advisable 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 recurrence. Other tumors caused by HPV are most often treated with targeted therapy, such as radiation or chemotherapy.
It should be remembered that surgery is not a cardinal solution, but only solves a cosmetic problem, since after removal the virus can remain in the surrounding tissues and warts can reappear.
Prevention of infection
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 are vaccinated, are advised to have regular smear examinations.
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.