The human papilloma virus (HPV) is the most common viral infection of the genital tract.
HPV is a group of viruses, which is extremely widespread all over the world. There are over 190 types of this virus, of which at least 13 will lead to the development of cancer (are known as the high-risk types). The human papilloma virus is transmitted primarily by sexual contact, and most of the people you infect them shortly after they begin to lead a sexual life. Two types of HPV (16 and 18) cause 70% of all cases of cancer of neck of uterus (cervical cancer) and precancerous conditions of the cervix.
The chance of getting
The human papilloma virus is transmitted primarily by sexual contact, and most of the people you infect them shortly after they begin to lead a sexual life. But for the transmission of the virus is not compulsory, penetrating sex. Naked genital contact is well established through the transmission of papillomavirus infections. Risk groups of HPV infection are children and adolescents 15-18 years.
Cancer of the neck of the uterus develops later acquired sexual infection some types of HPV. The risk factors for the development of cervical cancer: the first sexual intercourse at an early age; many sexual partners; suppression of the immune system (for example, people infected with HIV are at increased risk of HPV infection and become infected with a wider spectrum of HPV types).
The symptoms and the forecast incidence of the disease
Most HPV infections do not lead to the appearance of symptoms or disease and are they (about 90% pass in a matter of 2 years). However, the stable infection some types of HPV (often type 16 and 18) can lead to the development of premalignant pathological conditions. Without treatment these conditions can develop cancer of the neck of the uterus. Today, cervical cancer is the most common disease, which correlated with the human papilloma virus. Cervical cancer is the fourth among the most common types of cancer in women, and the seventh in general: an estimated 528 000 new cases worldwide in 2012.
The symptoms of cervical cancer usually appear only in an advanced stage of the cancer and may include the following:
- Irregular, intermenstrual (in the period between monthly or pathological vaginal bleeding after sexual intercourse;
- Sore back, legs or in the area of the basin;
- Fatigue, weight loss, loss of appetite;
- Unpleasant sensations in the vagina or your selection with an unpleasant odor;
- A swollen leg.
In the later stages may appear more serious symptoms.
Human Papillomavirus infection also ties 20-90% of cases of squamous cell carcinoma of the anus, and pharynx, vulva, vagina and penis. According to estimates, up to 90% of all cases of anal cancer are due to HPV-16 and HPV-18, and 40% of the cases of cancer of the vulva, which occurs especially in elderly women, are associated with the HPV virus-16.
HPV infection, because the types of low-risk, cause anogenital warts of men and women (the condylomata acuminata or venereal warts). The average time between the initial infection types HPV-6 or 11 and the development of venereal warts is 11-12 months for men and 5-6 months the young women 16. Anogenital genital warts are difficult to treat.
HPV-6 and HPV-11 can cause a rare condition known as recurrent respiratory papillomatosis (RRP), where warts form on the larynx or other parts of the respiratory tract. RRP is observed mostly in children under the age of 5 years (juvenile RRP) or in the subjects at the third the top ten of life (adult RRP). In rare cases, women with HPV genital infection can transmit the virus to child during birth. Rhinitis not RRP can lead to a serious problem due to obstruction of the respiratory tract.
Complications after the disease
Established that cervical cancer in 100% of cases driven by oncogenic types of human papillomavirus (HPV). In women with a normal immune system, the cancer of the neck of the uterus is developed for 15-20 years. In women with a weakened immune system, for example, with HIV infection in the absence of treatment, its development may need to be only 5-10 years. Despite the limited data on anogenital cancers, other than cancer of the neck of the uterus, a growing number of evidence indicates a cause of the human papilloma virus with cancer of the anus, vulva, vagina and penis. And although these types of cancer are less common than cervical cancer, their association with HPV make them potentially capable of prevention through the use of these same strategies of primary prevention, such as cancer of the neck of the uterus.
Types of HPV do not cause cancer (especially types 6 and 11) can cause genital warts and respiratory papillomatosis (a disease in which the tumors grow in the airway, the nose and mouth into the lungs). And even if these were very rarely lead to death, which can often lead to illness. Genital warts are widely disseminated and are very contagious.
There is a high global mortality of cervical cancer (52%), the cause of which is the human papilloma virus. In 2012, approximately 270 000 women died of cervical cancer registered, and more than 85% of these deaths occurred in countries of low and middle income.
Screening for cervical cancer is to test it pre-cancerous conditions and cancer among women who have no symptoms and feel perfectly healthy. If screening identifies the pathological conditions, it is easy to treat and prevent the development of cancer. The selection may also reveal the cancer at an early stage, with a high probability of healing.
Taking into account the fact that precancerous conditions evolve over the course of the years, every woman in the age of 30-49 years, we recommend screening at least once in your life, the better it is. Screening is effective in reducing the mortality from cancer of the neck of the uterus only in case of participation of a significant number of women.
Currently there are 3 different types of selection:
- A normal test of Papanicolaou (Pap) cytology and liquid (LBC);
- Visual inspection with the use of acetic acid;
- Test for the types of high-risk HPV.
In developed countries, there are programs that offer women the possibility of overcoming the selection, which allows to detect the majority of premalignant lesions in stages, when they can be easily treated. The early treatment of the human papilloma virus, you can avoid up to 80% of the cases the development of cervical cancer in these countries.
In developing countries with limited access to an effective selection means that the disease often reveals itself only in the later stages, when you develop the symptoms. In addition, the treatment of the disease in these later stages is ineffective, which leads to high levels of mortality from cervical cancer registered in these countries.
The effectiveness of the vaccine
The results of the clinical tests show that there are currently two vaccines are safe and very effective in preventing infection by HPV 16 and 18. Both of the most effective vaccines, if vaccination is carried out before the exposure of the human papilloma virus. Therefore, it is preferable to vaccination before the first sexual intercourse. The vaccines do not treat HPV infection or associated with the HPV disease (such as cancer).
In some countries, introduced the vaccination of boys against the human papilloma virus, because it can prevent genital cancer in men and in women, and one of the available vaccines can also prevent the development of genital warts in men and women. In addition, the vaccination of boys to prevent the circulation of HPV in the population of adolescents and young adults. The WHO recommends vaccination of girls aged between 9-13 years old, as this is the most effective, from the point of view of the costs, a public health measure against cervical cancer.
The HPV vaccination does not replace screening for cancer of the neck of the uterus. In countries where the HPV vaccine put in place, it may also be necessary to develop screening programs. By the end of 2013, the vaccine against the human papilloma virus has been introduced in 55 countries, the world health organization.
Modern mathematical models show that when the cover girls of 12-13 years of age a full course of primary vaccination (3 doses) vaccine against hpv infection, it is possible to predict the reduction in the risk of developing cancer of the neck of the uterus to 63%, cervical intraepithelial neoplasia of third degree of severity (pre-cancerous) – 51%, cytological violations in the groups of age up to 30 years – 27%.
There are currently two vaccines that protect against 16 and 18 types of human papilloma virus, which causes at least 70% of the tumors in the neck of the uterus. These vaccines can also provide some cross-protection against other, less common types of HPV that cause cervical cancer. One of these vaccines also protects against HPV types 6 and 11, which cause anogenital acuminata.
The development and registration of vaccines against human papillomavirus infection have evaluated the possibility of primary prevention of cervical cancer.
The last epidemic
Cervical cancer is the second most common type of cancer among women — according to estimates, every year is recorded 530 000 new cases of the disease, approximately 270 000 patients die.
The incidence maintains an upward trend.
The probability of disease of cervical cancer to every woman in the media in the course of life of 0.53%.
Historical notes and curiosities
In the mid-seventies of the xx century the scientist Harold zur Hausen discovered that the women who are suffering from cancer of the neck of the uterus, always infected by the human papilloma virus. In 1983, he discovered the hpv DNA in the biopsies of cancer of the neck of the uterus, and this event can be considered as the opening of the virus oncogenes of HPV-16. In 2008, the committee for the Nobel prize awarded the Nobel prize for physiology or medicine Harald zur Hausen for the discovery of what the virus papilloma virus can cause cervical cancer.