The human papillomavirus (HPV) affects epithelial cells and has a particle diameter of 55 nm. A feature is the proliferation of the skin epithelium as well as the mucous membranes. In the initial stage, the pathogen usually affects the basal epithelial cells, penetrating them through microtraumas. Local papillae usually occur on the skin of the neck, armpits, groin and genitals (most commonly), in the oral mucosa, and in 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 seen, which affects the mucous membranes 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 of DNA to integrate 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 that have a high risk of developing cancerous lesions, especially in the cervix or anus. As for the skin, HPV 16 and 18 are more common, as well as 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 papillomavirus, which in the worst cases causes cancer of the penis or anus.
Women often experience HPV 16 - this is a form in which endosomal parasitism is observed, ie outside the chromosome of the cells (benign). HPV 18 is characterized by a high risk of developing oncology - first, benign tumors form, which after a while degenerate into cancer. The virions in this case are tiny (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, vitamin deficiency, pregnancy, hypothermia, endometriosis, smoking, alcohol abuse, etc.
Characteristics of the infection
The human papillomavirus is highly contagious. It is usually transmitted through direct contact, skin-to-skin or mucous membrane, with an infected person. In genital infections, this is more common during vaginal or oral sex. A large number of sexual partners or other STDs (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 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, 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 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 may not be detected for months or years. Even at this stage, it is contagious.
Skin warts usually appear in groups and increase with scratching. The two most common forms of papilloma are either grayish, hard, raised with a broken surface (common wart) or flat and reddish (flat warts). Ants appear on the soles of the feet or on the heels, develop inwards and are therefore often painful.
The causative agents of genital warts occur in wet and hot parts of the body, so they are located in the folds and mucous membranes. They can cause symptoms such as itching or burning. The incubation period, ie the time between infection and the onset of symptoms, in genital warts ranges from 3 weeks to 8 months.
There are different types of genital warts caused by different pathogens:
- Genital warts. Pale or reddish nodules that often stand in groups and appear on the lips, vagina, penis, urethra, anal canal and rectum. They are very contagious.
- 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 in huge formations, destroying the surrounding tissues. In rare cases, they can degenerate and lead to squamous cell carcinoma.
It is also possible to infect the mucous membranes of the upper respiratory tract. The conjunctiva of the eyes can be affected, resulting in pink stems. 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 warts to discolor) or a microscope.
In addition, the virus can also settle in cells without tissue changes. Then they talk about a latent infection, ie the presence of pathogens, but without symptoms. After infection, this phase can last from several weeks to several months.
Possible consequences
When infected, the viruses penetrate the cells of the whole tissue of the skin and mucous membranes, settle in the nuclei of the 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 changes in the skin, that is, growths. Possible forms include genital warts or warts and papillomas, which can affect, for example, the face, hands or feet.
The tissue changes that are caused are mostly benign, but they can also degenerate and lead to cancer. For example, cancer can occur decades after being infected with HPV. External female genital cancer (cancer of the vulva and vagina), rectal cancer, penile cancer, and cancer of the mouth and neck (tumors of the head and neck) are also possible.
Establishment of a diagnosis
A test for HPV infection in women is performed as part of preventive visits to the gynecologist. During a gynecological examination, a swab is taken from the lining of the cervix, this is called a Pap smear (cytological examination). The resulting material is examined for tissue changes to determine precancerous conditions.
Alternatively, an HPV test may be performed, in which cell material from a mucosal plug or tissue sample is tested in a laboratory for certain viruses. However, this only proves the infection of the affected area to be proven, but not to make statements about whether tissue changes have occurred. Thus, an HPV test makes sense, especially when combined with a Pap test and can help detect precancerous cancers at an early stage.
If the test is positive, this is not a cause for concern, as the infection does not always lead to cancer. Regular screening is recommended to detect tissue changes at an early stage. Conversely, a negative test result does not allow us to claim whether there has been an infection in the past with which the body has successfully fought off.
For men, there is no screening test during which the test would be performed regularly. If there is a corresponding cancer, the tumor test can determine if the HPV infection is at the root of the cancer.
Specialized DNA techniques are also used in laboratory diagnosis, such as real-time PCR. Genital warts caused by HPV types 6 and 11 are easily detected during the pelvic exam.
How to cure human papillomavirus
In most cases, the disease does not require treatment because it disappears on its own and then viruses are no longer detected. However, if this does not happen, the infection can last longer and persist for months or years.
To date, there are no methods of systemic exposure to 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 other viruses and thus get rid of them. In some cases, the pathogens survive and can cause symptoms over and over again.
Treatment regimens depend on the type of HPV and the relative picture of the disease:
- Plantar warts and genital warts can be treated with topical salicylic acid preparations.
- Cryotherapy is also a commonly used method for HPV. In this case, the warts are burned with cold, using liquid nitrogen.
- Lasers or electrocautery are equally applicable methods.
As the frequency of relapses is quite high, it is recommended to check yourself regularly and use condoms even 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, it is often recommended to remove the uterus, respectively, the upper part of the vagina and the ovaries. This can be supplemented with radiotherapy to rule out the possibility of recurrence. Other cancers caused by HPV are more often treated with targeted therapy, such as radiation or chemotherapy.
We must remember that surgery is not a basic solution, but only solves a cosmetic problem, since after removal the virus is able to remain in the surrounding tissues and warts can reappear.
Prevention of infection
There are two vaccinations: bivalent HPV 16 and 18 and quadruple HPV 6, 11, 16 and 18. Vaccination is recommended for all young girls aged 14 and over.
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 smear tests.
Early detection and complete removal of genital warts reduces the risk of disease. The effectiveness of using condoms to prevent the transmission of the 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 special multivalent vaccine.