The viral infection itself is troublesome and complicates life. Scientists, summing up their many years of observation, report that this is not the end of bad news for patients. What additional threats are the microbes that infect us: human papillomavirus (HPV), Epstein-Barr virus (EBV) and hepatitis viruses (HBV and HCV).
Scientists' reports that some fairly commoncancersmay be caused byviruseshave revolutionized medicine. This is because it creates the possibility of effective protection against infection and thus against the development of neoplastic disease in the future - for example by minimizing the risk of infection with them or by universal vaccination. Carriers of theEBV ,HPV , hepatitis B and C viruses know that infections caused by these organisms are serious and that treatment is long-term and not always effective. In addition, it has been proven that the long-term presence of viruses in the body can lead to the development of various types of cancer. Fortunately, the path from infection to cancer is long and complicated. In studies conducted on cells cultured in vivo, it turned out that neoplastic transformation takes place only after massive infection - one cell must "attack" about a million virus particles.
Oncogenic viruses
In the past, scientists assumed thatoncogenic virusesform a completely separate group of microorganisms thanks to certain, characteristic only for them, features:
- skills to initiate the neoplastic process;
- specificity of action only on specific species and even lines of animals;
- activity conditioned by the age of the host.
A thorough analysis of these and other properties of known oncogenic viruses has shown that these microorganisms sometimes belong to distant units of the taxonomy. They differ in size, structure, and the type of nucleic acid you have. Presumably, many viruses that cause infectious diseases in humans and animals may, under certain conditions, exhibit oncogenic properties.
HPV or human papillomavirus
HPV is recognized as the primary contributor to the development of cervical cancer. In Poland, in the registry of the most common malignant neoplasms in women,this cancer is in the infamous second place, and the mortality rate for this disease remains at one of the highest levels in Europe. HPV is also responsible for the development of vaginal, vulva, and rectal cancers. It is estimated that almost 700 million people (data for 2007) who are sexually active (this way the virus is transmitted) are carriers or suffer from HPV, although most often infection with this virus is asymptomatic.
» To date, more than 100 types of HPV have been distinguished (marked with numbers according to the order of their identification), which according to the adopted taxonomy are included in the Papillomaviridae family. HPV infections are widespread, and oncogenic types of papillomaviruses are classified as sexually transmitted infections. Scientists distinguished three groups at risk of developing cancer: high-risk (HPV 16 and 18), medium-risk (HPV 31, 33, 35, 39, 45, 52, 56, 58, 59 and 68) and low-risk (HPV 6). , 11, 42, 43, and 44)
Due to a natural immune response, half of HPV infections resolve spontaneously within two years of infection. If this does not happen, cauliflower-like or pointed warts (so-called genital warts) appear at the sites of the virus entry into the body, which do not infiltrate adjacent tissues, which - if infected with a mild type of virus - are not dangerous apart from aesthetic reasons. However, doctors suggest removing each of the visible skin lesions resulting from contact with the virus.
» Although the hypothesis about the association of HPV infection with the development of cervical cancer was formulated and confirmed as early as 1975, it was not until 2002 that the first results proving the effectiveness of the vaccine against HPV type 16. Three years later, the 100% effectiveness of vaccination against HPV 6, 11, 16, 18 was confirmed, and in 2007 the first vaccine in Poland was introduced to pharmacies. It is assumed that if HPV vaccines were used on a global scale, the incidence of invasive cervical cancer would drop by over 90%, and the number of deaths as a result of this cancer by about 95%. Additionally, these vaccines can significantly reduce the incidence of genital warts. Today, doctors recommend vaccination against HPV (three doses) of young women who have not yet started intercourse.
EBV - Epstein-Barr virus (EBV)
EBV is one of the most common viruses in the human population. It attacks epithelial cells in the mouth, pharynx and B lymphocytes. Primary infection is often asymptomatic or causes infectious mononucleosis.(so-called "kissing disease"). Having mononucleosis gives permanent immunity to this disease.
» After a primary EBV infection, the viruses stay in the body for life. The causal relationship of EBV infection with nasopharyngeal cancer and Burkitt's lymphoma is beyond doubt. In addition, the results of recent studies suggest that EBV is also involved in the development of cancer of the stomach, tonsil and tongue. It is also associated with several other diseases of a cancerous nature - Hodgkin's disease and oral leukoplakia in AIDS patients.
» Because EBV is spreading, among others by droplets, it is difficult to consciously protect against infection. To minimize the risk of contracting EBV-related diseases, you should follow basic hygiene rules and remember to wash your hands thoroughly.
Hepatitis B and C viruses (HBV, HCV)
HBV and HCV are recognized as etiological factors in the development of liver cancer, mainly on the basis of chronic inflammatory processes in this organ. HBV infections are spread through sexual contact, the repeated use of contaminated needles, surgical and dental instruments, mother-to-newborn transmission during labor, and through blood transfusions and contaminated blood products. HBV infection can take three different forms:
- acute inflammation, followed by complete recovery and complete immunity to reinfection (more than 90% of hepatitis B cases);
- hepatitis, which develops very quickly but lasts for a short time; in about 90 percent in cases, this condition leads to death due to cirrhosis of the liver (it affects less than 1% of HBV infections);
- chronic infection leading to the development of a carrier state (concerns about 10% of all HBV infections).
Epidemiological data clearly indicate a significant role of HBV in the process of cancer development. Such cases occur in people who have become chronically infected with the virus. It is estimated that about 10-25 percent. these will develop a cancerous condition called hepatocellular carcinoma. HBV is believed to cause the accumulation of a series of mutations in host genes that regulate cell growth, making liver cells more susceptible to neoplastic transformation through exposure to external carcinogens such as a fungal toxin (aflatoxin).
Virus hepatitis C (HCV) was only identified in 1989. The detection rate of the infection is very low, in addition, the averageit is long from the entry of the virus into the body to the moment of causing serious he alth effects, it can take up to 30 years. For this reason, a significant percentage of those infected are unaware of their serious condition.
» HCV is transmitted through blood and blood products, so you can become infected during blood transfusions, during childbirth, surgery, at the beautician, hairdresser; Nakomans who share syringes are also at risk. HCV infections are not classified as diseases spreading sexually, but the probability of infection during sexual contact, although very low (approx. 1-3%), does exist. This mainly applies to homosexual couples and damage to the epidermis and mucous membranes during anal intercourse - the presence of HCV in semen has not been confirmed.
» The initial stage of HCV infection is called acute infection. The consequence of some of these cases is the development of hyperacute hepatitis and hepatic coma. In other cases, the acute phase may be followed by the phase of chronic infection, during which there is severe and extensive damage to the liver parenchyma, which in turn may lead to cirrhosis of this organ and then to the development of neoplasms. Tumor transformation of hepatocytes probably occurs in response to hormonal disturbances, spatial changes in the liver cell layout, and the production of certain substances called growth factors and the abnormal spread of oncogenes ('tumor genes'). Uninterrupted and prolonged exposure to these factors may induce tumor formation in the liver.
» A vaccine against HCV has not yet been invented, so antiviral drugs remain the only effective form of preventing the spread of the HCV epidemic. For your own safety, when visiting your dentist or surgeon, pay attention to whether the equipment they are using is disposable or whether it has been sterilized and the person performing the procedure has disinfected the hands and put on disposable gloves. Blood tests for HCV are recommended in pregnant women to minimize the risk of transmission of the virus from an infected mother to her baby during labor.
» The same safety rules apply to HBV, and a vaccine against HBV is available. The mechanism of its action is based on the induction of an immune response with the production of antibodies which, after possible contact with the virus, would surround it, preventing it from binding to the host cells and penetrating them. Everyone at risk should be vaccinated - sexually active and patients preparing for treatments inhospitals.
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