HPV type 18: structure, pathogenesis, prognosis

The appearance on the body of warts and papillomas is associated with the penetration of the papillomatous virus into the body. True, not everyone knows that relatively harmless neoplasms on the skin are not the only manifestation of this far from safe virus. After all, what is united under the name of human papillomavirus (HPV), is a wide variety of types of infection causing various diseases, including cancer, with their characteristic symptoms. Especially dangerous are HPV types 18 and 16. And we can only wish our readers never to get acquainted with them.

[1], [2], [3], [4]

Structure HPV type 18

When scientists after a long search for the truth still managed to identify such a form of life as viruses, they were not surprised that these microparticles remained unnoticed for so long. Small sizes (up to 500 nm) allowed them to pass through various filters. And even sowing in a fertile environment did not yield results, because it was found that viruses outside the living cell can not breed.

Viruses are a non-cellular form of living matter. Although how much this living matter is very difficult to judge. Having microscopic dimensions and the ability to penetrate into a living cell, viruses show activity only within the body of a person or other living organisms, including bacteria (bacteria have their own viruses that cause disease and the death of microorganisms, they are called bacteriophages and used for medicinal purposes). In the environment around us, the viruses are inactive and do not show signs of life.

Papillomavirus affects mainly mammals, which are more than other living things suitable for the introduction and life of viral particles called virions. Skin and the more tender mucous membrane of a person were easily permeable for HPV virions, which is why a high percentage of virus carriers among people. And these are people of different ages, because even a newborn baby can get a papillomavirus infection during the movement of the mother's genital tracts, if there were genital warts on the mucous membrane of her womb or vagina.

HPV 18 is one of 18 types of papilloma virus with a high risk of oncology. Its virions are rounded and very tiny (no more than 30 nanometers). By their size, they approach large protein molecules.

Usually living cells, including bacterial cells, have in their structure 2 kinds of nucleic acids (DNA and RNA), which carry genetic information about hereditary properties. Viruses contain only one species of ND. Papillomavirus belongs to the category of DNA-containing viruses.

The HPV genome is represented as a circular DNA molecule consisting of 2 chains surrounded by a protein coat (capsid). This is the simplest particle that does not have its own energy exchange and is not capable of protein synthesis. The only thing that it can, is to penetrate into the body of a living being with accidental contact with the skin and gain a foothold in the host's cage, feeding on its energy and gradually destroying it.

The genome of papillomavirus encodes two kinds of proteins:

• early (they are characterized by regulatory and reproductive functions, in HPV 18 the same proteins carry a carcinogenic effect and provoke malignant degeneration of the host cells)
• late (it is these proteins that form the envelope of the virion).

The human body is a complex structure, which provides protection from various pathological processes. So the growth and multiplication of cells are controlled by certain genes. Early proteins E6 and E7 virion HPV 18 destroys genes that interfere with the development of the tumor process in the living body.

Virions do not go far. They parasitize in the inner layers of the skin and mucous membrane, affecting young and mature keranocytes of the epidermis. While the virus particle does not penetrate into the cell, it can not reproduce, its behavior is identical to that observed while the virion is outside the living organism. But, penetrating into the living cell, which becomes a source of nutrition and energy for the virion, it resets its protein envelope and integrates into the genome of the cell, changing its properties. Those. Information encoded in the NC of the virion becomes its own genetic information of the cell. And this information is highly destructive in high-cancerous types of HPV, stimulates the constant division of cells, which the immune system can not already control.

In a cell infected with a virus, new DNA and capsids are synthesized, and they are combined into new fully formed virions with the same properties. New virions capture other cells, changing their genetic information like their ancestors.

[5], [6], [7], [8], [9],

Life cycle HPV type 18

The life cycle of papillomavirus is linked to the stages of development of the main cells of the epidermis - keranocytes. It is easiest for the virion to penetrate into the young cell during its active division. Such cells are located near the basement membrane located below the epidermis (under its upper layers). But as they mature, young virus-infected keratocytes rise higher, where new virions are formed.

The incubation period of HPV 18, which causes the appearance of anogenital warts, can last from 1 to 4 months or more. This suggests that a person infected with a virus will not suspect about their virus-carrying for several weeks and months before the appearance of the first symptoms of the disease. But even the appearance of genital warts will not indicate cancer. It will take several more years for a benign tumor, provoked by a virus, to become malignant.

To predict how soon this will happen is very difficult, because everything depends on the human immune system and its ability to suppress cell growth. In some patients, malignancy of cells can be detected even after 5 years after infection, others will need 25-30 years, and the body of the third during this time will be able to cope with the virus and remove it away, as it happens with low-coagulant viruses (usually during the year there is a natural death almost all such virions).

[10], [11], [12], [13], [14], [15]

Pathogenesis

Today, more than a hundred types of papillomavirus infection are known. About 80 of them cause a person various diseases. But not all of them are equally dangerous, therefore in virology there is a separation of HPV types into high- and low-oncogene types. Prior to HPV type 16, everything was more or less peaceful, because from 1 to 15 types of viruses caused only the appearance of warts on the body. True, 6, 11 and 13 type are also responsible for the appearance of genital warts on the mucous internal genitalia in women, but they do not carry a particular danger in themselves.

And already, beginning with the 16th type of HPV, problematic viruses begin with a high risk of developing oncological pathologies. All subsequent viruses carry a threat of oncology. In addition to the 16th type, 18, 31, 33, 39, 45 and some other types (18 types in total) are highly coenogenic.

As you can see, there is a type of human papilloma virus of interest to us in this list. Moreover, it is HPV of high oncogenic risk 18, along with HPV 16, which most often appears in gynecological charts as a causative agent of cervical cancer.

HPV 18 and cancer

There are about 40 types of papillomavirus infection, which affects the urogenital organs, causing the appearance on the mucosa of pointed and flat warts. But depending on the type of pathogen, such neoplasms can be a simple cosmetic defect or a cancerous tumor.

Pointed condylomas are convex outgrowths on the skin in the form of papillae, which can hardly differ in color from the skin or be somewhat brighter than it. When the virus is infected with mucous membranes, you can see both single condylomas and multiple condylomas, consisting of several closely located outgrowths. Such neoplasms can be found in the area of the anus and perineum, as well as on the mucosa of internal genital organs in women.

These growths are very contagious. In the presence of such "papillae" the risk of transmission of the virus is close to one hundred percent. How is HPV transmitted? The human papilloma virus is considered one of the most popular urogenital infections. Usually, infection occurs during sexual intercourse, but a contact transmission path is also possible during contact with the affected area.

The presence of genital warts does not mean that a person can develop cancer. These are neoplasms of medium degree of oncogeneity, which do not often lead to oncology. But the appearance of flat warts, which are flush with the surrounding surface of the mucosa, already represents a real risk of a deadly disease.

Flat warts are a more rare phenomenon, which is mainly found in women in the vagina and cervix. In the appearance of such neoplasms, doctors blame precisely the highly-oncogenic types of the virus, including HPV 18.

The appearance of genital warts on women and men still does not speak about cancer. And even the predisposition to oncology is revealed by the laboratory pathway, when the type of the virus will be determined. For example, detection of HPV type 6, 43 or 11 will not cause the doctor special concerns about the patient's health, although he will suggest removing the growths on the mucosa just in case. Another thing if the analysis shows the presence of HPV type 18.

What is so dangerous for HPV 18? We have already said that this type of human papilloma virus belongs to the category of highly oncogenic. Moreover, it is a fairly common infection, which for a long time can hide in the body, destroying healthy cells, changing their genetic information and pushing them to uncontrolled reproduction.

According to different data from 70 to 90% of the world's inhabitants are carriers of various types of papillomavirus infection. Among women who were diagnosed with uterine cancer, 2/3 were carriers of viruses of types 18 and 16, which indicates that these types of HPV are the most dangerous.

It is HPV types 18 and 16 that often lead to the development of cancerous tumors against a background of such diseases that people without a virus do not cause such complications. For example, erosion or dysplasia of the cervix is due to the HPV 16 and 18 types that can suddenly go to cervical cancer. Women who have highly cancerous types of papillomavirus are not identified, can live with these pathologies for many years without much risk to life.

But what kind of parasites are those that do not just live at the expense of a person, but also gradually kill it? Let's try to look at the virus of the papilloma from the point of view of biology.

[16], [17], [18], [19], [20], [21], [22], [23],

Complications and consequences

The human papilloma virus is one of the most common urogenital infections. But while the disease has no external symptoms, it is impossible to detect it without special studies. To say that this is bad, it is impossible, because there are no manifestations yet, it is too early to draw conclusions about possible consequences. There is a possibility that the disease may not manifest at all, which means that its treatment will be meaningless, because even papillomas that have appeared on the body and mucous can disappear after a time.

Read also:

• HPV type 18 in men
• HPV type 18 in women
• HPV type 18 in pregnancy

[24], [25], [26]

Diagnostics

When the symptoms have already appeared and the patient consults a doctor about them or in connection with another problem, a gynecologist or urologist during the physical examination will necessarily pay attention to the appearance of outgrowths in such unusual places as the genitals and anus. If such neoplasms appear in the mouth (larynx and vocal cords), their occurrence may be of interest to both the therapist or the ENT.

When examining women, the suspicion of a papilloma virus can decrease if there is erosion of the cervix (especially if there is a long absence of its treatment), hyperplastic processes at the entrance to the cervical canal, cystic formations that actively increase in size. In men, the urologist or andrologist will pay attention to the appearance of spots and plaques in the region of the head and body of the penis of the patient.

Physical examination of the lesion site allows to suspect (with sufficient accuracy) the papillomavirus infection. But the doctor can not determine by eye what strain of the virus caused the appearance of specific external symptoms. Usually, with HPV type 18 or 16, flat warts appear on the mucosa, but in most cases, several strains of the virus are found in one patient at a time, which means that pointed cannillomas (single or multiple) and anogenital warts can appear on mucous membranes.

In such circumstances, it is very difficult to determine which types of virus the individual patient has. But this must be done, because besides safe low-cancerous strains, types with medium or high oncogeneity can be detected, which can turn an innocuous tumor into a cancer tumor.

Diagnosis of HPV is not only an external examination. To identify the virus in the body and determine its type, practice:

• Study of mucosal tissues of internal genital organs by means of a special microscope (colposcopy). This method allows you to carefully consider lesions and identify not only genital warts (they are usually seen with the naked eye), but also flat. By colposcopy, doctors can carefully examine the tissues with dysplastic processes and their reaction to special reagents (Schiller test): Lugol's solution or vinegar (3% aqueous solution). If there are malignant cells, the affected area acquires a whitish shade.
• Smear microscopy (a cytological study of a biomaterial taken from the surface of the vaginal mucosa, cervical canal or urethra). Cytology in the case of papillomavirus infection does not play a decisive role in the diagnosis of the disease. Nevertheless, it allows us to identify the modified cells (koylocytes and diskuratsity) and by their number to judge the degree of development of the malignant process.
• Histological examination is also a microscopy of tissues, but the biomaterial is already served not by mucus, but by a small piece of affected epidermis and deeper tissues taken during a gynecological or urological examination (biopsy). Such an analysis is carried out if the cytology shows a dubious or positive result. This is the most accurate method for detecting cancer.
• Blood test for antibodies. This study is indicative even in the event that there are no external manifestations of the viral infection yet, but the virus has already entered the human body and can circulate by hematogenous way (by blood). The study allows you to identify the human papilloma virus, but it can not determine the degree of infection (quantitative indicators of virions) and the type of the virus itself with absolute accuracy.
• PAP test. This study is relevant not only for women with suspected cervical cancer, but also for the detection of HPV 18 in men. Like lesions of dysplasia, neoplasms on the penis are lubricated with 3% r-rum acetic acid. A positive test with HPV 18 will show the correct vascular reticulum in the reagent application area.
• HPV Digene test or hybrid capture method. An innovative technique that allows to differentiate high-coagulated strains of the papilloma virus from low-ionogenic ones. There are 2 tests. One (395) identifies types of HPV with low oncogeneity, and the other (394) - with high oncogeneity, including HPV 18 and 16.

Usually this research is carried out in conjunction with a cytological analysis of the smear.

• The PCR analysis  (polymerase chain reaction, PCR test) is no longer a new, widely tested method for detecting highly ionogenic types of human papillomavirus: HPV 18, 16, 31, 33, 56, etc., which allows us to identify dangerous diseases already on early stages. As a biomaterial use a smear with mucous, less often blood or urine.

To date, PCR testing is the most popular and accurate analysis that allows isolating the DNA of a virus. It determines not only the type and type of the virus, but also its quantity.

The structure of the PCR test distinguishes:

• PCR of HPV 16 and 18 qualitative (definition of highly-oncogenic strains of the virus)
• PCR of HPV with genotyping (determination of the genotype of the virus, which is necessary for effective treatment taking into account the resistance of the detected strain to medicinal products),
• PCR of HPV 18 is quantitative (determining the degree of infection or number of virions) and some other variants of the study, including combined ones.

The qualitative type of research allows us to determine only the presence of a specific strain of the virus in the body. Decoding results for HPV 18 or another type of virus will contain one of the words: "positive" or "negative". For example, HPV 16 18 positive (+) if the DNA fragments of the virus were detected in the biomaterial, or HPV 16 18 negative (-), if none were found.

To find out how serious the situation is in the detection of highly co-genic strains of the virus, additional quantitative analysis is needed. Here, everything will depend on the human immunity (both general and local). The weaker the immune system, the more virions in the biomaterial will be detected.

The PCR test analyzer allows detecting more than 0.3 copies of HPV DNA per ml, which is considered the norm for HPV 18, since fewer copies are no longer clinically important and can not cause serious pathology.

In itself, the detection of a minimum number of DNA from the papilloma virus indicates good immunity. But we can not exclude the fact that the infection could have occurred quite recently (in this case, the result of PCR will be declared doubtful), therefore, after a time, on the recommendation of a doctor, it is necessary to pass a second analysis.

When it comes to cervical cancer, 16 and 18 types of papillomavirus infection most often appear in the research results. What is the difference between HPV 16 and HPV 18, because both types of virus are considered highly coenotic and are accused of developing uterine cancer? It must be said that the degree of oncogenicity in these strains of the virus is not the same. According to some Internet sources, HPV 16 is the most dangerous, not accounting for 50% of oncology detection cases, while HPV 18 becomes the culprit of this dangerous disease in only 10% of cases.

However, foreign scientists, after conducting a series of studies, came to the conclusion that the cause of the development of invasive adenocarcinomas (this type of cervical cancer is detected by doctors in most patients) is in most cases still HPV-18, and in cases when both strains are detected virus, the 18th type contributes to the rapid progression of the disease. In the case of non-invasive species of glandular cancer, affecting not only the reproductive system, but also other organs, the leading role belongs to HPV-16.

The emergence of early dysplastic processes in the uterus during studies in some cases was observed even before the introduction of the genome of HPV 16 into the cell, and it says that the integration of this type of virus into the cells of a living organism is not a necessary condition for the development of the disease. The pathological process begins even before its first signs appear.

But the development of severe grade 3 dysplasia of the cervix, often turning into an invasive adenocarcinoma, in most cases implied the integration of HPV 18 and other types of papillomavirus infection that cause pathological processes in the uterus (highly oncogenic HPV 31, 33, 52b, 58 and low-oncogenic HPV 6 and 11 ), inside the cell. This is necessary to transfer her genetic information, the information that will later change its properties and turn into a cancerous tumor.

But even the introduction of highly ionogenic virus into the cell does not always cause cancer. Only 1 in 100 women with dysplasia subsequently diagnosed with cervical cancer. It all depends on the length of the virus's stay in the body and its ability to express carcinogenic genes E6 and E7 (inserting them into the genome of the host cell and transmitting information causing mutations), activating the mechanisms of converting the female sex hormone estradiol to 16α OH steron, the presence or absence of multiple mutational damage to the chromosomes of a living cell. Thus, oncological diseases against the background of papillomavirus infection develop only when several factors interact simultaneously, creating fertile soil for the initiation of malignant cell degeneration.

[27], [28], [29]

Prevention HPV type 18

Palillovirus infection is a problem that is close to many people. And in favor of this, say the relevant Internet resources, where those who have high-coagulant types of virus are identified, share their troubles and ask for advice on how to proceed further, how to deal with this small parasite that can cause a terrible disease.

No less concerned are those people in the family or among close friends of whom the carriers of the virus have been identified. In their posts, there is a concern for the lives of relatives and friends, but at the same time they are concerned about their health, understanding that the virus is quite contagious. And although the main way of transmission of the virus is considered sexual (and, moreover, in the presence of external manifestations), which means that the danger is mainly for sexual partners, people understand that HPV virions can be found in blood or other physiological fluids and allocation of the patient. This is what frightens many, forcing them to restrict communication with the virus carrier.

In fact, the risk of transmission of infection by contact is minimal. There is no exact evidence that the contact-household way is generally relevant in this case, therefore doctors generally do not take it into account. At kisses the virus can be transferred only under condition that one of the partners has papillomavirus neoplasms in the throat, but also there it usually happens as a result of oral sex. That is, everything again is reduced to sexual contacts: oral, vaginal and rectal, which can settle the virus in the rectum.

And again, the presence of a virus in the body is not an indication that a person will later become a client of an oncological clinic. One need only recall the fact that among women with HPV 16 or 18 only 1% develops cancer of the cervix, so do not particularly get killed about getting infected with the virus and put a cross on your life in advance. Depression and unnecessary worries can only exacerbate the situation.

It is much more logical to regularly visit a gynecologist or dermatovenerologist, undergo the prescribed course of treatment and be more selective in choosing a sexual partner.

What preventive measures can be advised to those who have no papillomavirus infection, so that it is not found in the future:

• Once a year, or better in half a year, you need to undergo an examination with a gynecologist (woman) or a urologist / andrologist (men), even if there are no symptoms of the disease. Especially important is an examination of those who have already had cases of cancer in the family, which indicates a predisposition to them.
• We recommend to be more careful about choosing a sexual partner. Let it be one, but a reliable partner who will not run to the side, than a lot of questionable. It must be remembered that a person may not even suspect about his illness, but already be a source of danger, being a virus carrier. For example, women can not visualize the condition of the mucosa of the internal genital organs, which means that even the appearance of internal condylomas can go unnoticed for a long time. A man, even in the absence of external manifestations, should understand that for a partner with weakened immunity, he is still a risk factor for infection, because even 1 virion is able to subsequently reproduce a huge number of clones.
• If one of the sexual partners has been diagnosed with HPV 18 or 16, but during an exacerbation of infection, he should limit sexual contact until the symptoms disappear. In the future it is recommended to use such a reliable protection against various infections, such as a condom. It remains a question of whether a condom can fully delay the spread of infection, but the risk of infection is much less, which is also important.
• Intimate hygiene before and after intercourse is also considered a preventative measure of infection. And this applies not only to viruses, but also to no less dangerous infections that cause sexually transmitted diseases.
• Strong immunity is the main condition for the health of the body, because our immune system, if adequately operated, can protect us from various adversities. And even if the high-coagulant types of papillomavirus can penetrate into the tissues of the body, the immune system will not allow them to multiply and provoke pathological processes. Any infection can show active activity in the body only against a background of reduced immunity. So, we must first take care of the health of the immune system.

Proper nutrition, healthy and active way of life, rejection of bad habits, hardening procedures, timely treatment of any diseases to prevent their transition to a chronic odds, striking on the immune system - that is the guarantee of strong immunity and prevention of viral diseases of any etiology.

• Since stress is considered to be a strong factor that weakens the defenses of the body, it is necessary to learn to react correctly to stressful situations. If a person can not cope with his feelings and emotions on his own, it's never a shame to turn to a specialist psychologist for help, which has long been practiced in foreign countries, but still will not become fashionable in our homeland.
• Vaccination is one of the most reliable ways to prevent a variety of infections. Nowadays, many vaccines have been invented from various diseases, and papillomavirus infection is no exception. And if before the vaccine acted mainly from HPV types 6 and 11, today there are already several vaccines capable of preventing infection with highly-concomitant HPV types 16 and 18 as well.

Let's talk more about vaccination, which should be understood not as a curative measure, but as a preventive measure of a viral infection. In foreign countries, this practice has already been set on a broad scale. For example, in Finland, the vaccine against HPV is considered mandatory for all girls who are 10 years old.

Vaccination is voluntary in our country. Doctors can only offer such a measure of prevention, and the person is already watching whether he can afford to purchase a vaccine, the cost of which is from 750 hryvnia and above.

To date, our compatriots doctors mainly offer 2 types of vaccine, which can prevent infection with the main types of papillomavirus, which cause the appearance of tumors on the mucous of the genital organs (6,11, 16 and 18). This vaccine is "Gardasil" and its cheaper analogue "Cervarix".

The preventive course consists of 3 injections. The interval between the first and second vaccination is 1 month. The third injection is done six months after the first. The duration of the procedure is about an hour, during which the doctors make an injection and observe the reaction of the patient's body. Vaccination of children under the age of 18 is carried out only in the presence of parents. After the full course of vaccination, the patient remains protected for 3-6 years, regardless of age.

Vaccine manufacturers recommend that vaccination begin at the age of 9-10 years, as described in the instructions to the drugs. But doctors believe that such a measure will be relevant for all girls, girls and young women aged 9 to 26 years, as well as for boys aged 9 to 15-17 years. If desired, men who care about their health, can also apply for vaccination at a young age (vaccine "Gardasil"). The effectiveness of both vaccines is about 99%.

It must be said that if the infection is already present in the body, vaccination will not be of use, since it does not affect the course of the disease. Treatment of a viral infection should be done already with other drugs, for this purpose. And vaccination is an effective preventive measure.

But this measure has its drawbacks. Teenagers who have been vaccinated begin to feel invulnerable, ignore the elementary measures of contraception (we are talking about condoms), do not really think about the health of their sexual partner, "collect" their sexual partners, etc., considering that they do not face anything. Over time, this behavior may become a habit, but the vaccine is limited in duration, and doctors usually give a 99% guarantee for 3 years. Further, such indiscriminate sexual behavior can lead to infection with papillomavirus.

[30], [31], [32], [33], [34]

Forecast

The prognosis of diseases caused by papillomavirus infection depends on many factors, the main ones being hereditary predisposition and hormonal background. This is especially true for women who have lost the synthesis of the female hormone estrogen and its metabolism. The earlier the infection is detected, the easier it is to prevent the unpleasant and dangerous consequences of its reproduction.

But even if the patient already has external symptoms of the disease, this is not a reason to panic. First, in the absence of HIV infection, the disease recedes even from the use of immunomodulators, especially if pre-conditioned with the formed condylomas and anogenital warts. The worst is the prognosis in people with immunodeficiency, because their body is simply not able to fight infection, so any infectious diseases in such patients proceed with complications.

Secondly, the appearance of genital warts or the development of dysplastic processes in the uterus does not yet speak about oncology. Usually it takes at least 5 years before the benign neoplasm becomes malignant. During this time, you can successfully pass more than one course of treatment, which can prevent such dangerous consequences.

It's another matter if a woman after infection with papillomavirus infection does not show to the doctor during these 5-10 years, and the disease will progress. But even here there is one point, the danger of cervical cancer is often too exaggerated. If the disease is detected in the first stage, the survival rate in this case is 90-92%, which is significantly higher than in many other cancers. However, at the third stage the probability of successful treatment is already reduced threefold.

It must be said that women (not to mention men) have time to prevent possible complications of HPV 18. The process does not develop rapidly, which means there is always a chance to stop it before the onset of sad consequences. And although removing the virus from the body is very problematic, there is always the opportunity to minimize its negative impact.

[35], [36], [37], [38], [39],

A bit of history

Until the end of the nineteenth century, mankind was at a loss. People were sick and dying, but the doctors could not understand what caused more and more new diseases, which did not respond to treatment with drugs at that time. Some people died of flu, strange strange new growths appeared on the body of others. And doctors could not give an answer, what caused these pathologies, because laboratory studies of that time could not identify the pathogen.

And such an elusive pathogen were the viruses. This word was called microscopic particles, the size of which was a hundred times smaller than the size of the bacterial cell. Russian scientist Dmitry Iosifovich Ivanovsky discovered them in 1892, although the name of the new form of life was given a little later.

Since then, the development in science, which in the twentieth century has been called virology, began to appear actively. It was during this century that many viruses were discovered that turned out to be the causative agents of yellow fever, smallpox, poliomyelitis, ARVI and influenza, HIV infection, cancer, etc.

It must be said that humanity learned about the papillomavirus infection not in the nineteenth century. Mention of condylomas and warts can be found in the writings of doctors of ancient Greece (the first century BC). It was also noted there that the disease has a sexual way of transmission of infection. But the agent itself did not detect condylomas for another two dozen centuries.

The fact that the cause of the appearance of warty neoplasms on the skin and mucous membranes is the virus, it became known only in the middle of the 20th century, when these microscopic particles could be isolated from warts, and later also by papillomas, formed on the mucous of the genital organs. But for the first time the virus of papilloma was isolated in 1933 due to the American virologist Richard Schoup.

The further development of virology as a science has shown that there are not one, but several types of HPV. They are called HRC 6, HPV 18, HPV 35, HPV 69, etc. Some types, hitting the human body, take root, but do not show themselves. They are almost all of us, but we do not suspect about the virus carrying. Other types can be called not just parasites, but human enemies, because they can cause dangerous diseases.

[40], [41], [42], [43]