Today, few people are not familiar with the words " herpes virus", "herpes infection" or "viral fever." And no wonder. Indeed, according to medical statistics, up to 90% of the world's inhabitants are infected with one or another serotype of herpes virus. Herpetic infections in children and adults are acute infectious diseases caused by a whole group of pathogens that manifest themselves in a different clinical picture and have very different consequences for our body.
So different, but all bad
Herpes viruses (from the Greek word herpes - creeping) are very widespread in nature. Today, microbiologists have classified about 100 viruses of this group, parasitizing in organisms of various taxonomic groups (from bacteria, fish to mammals).
In humans, 8 types of antigens have been identified, which cause herpes infections that are different in etiology and manifestations. But all representatives of these pathogens are characterized by high contagiousness (infectiousness), the presence of a latent (latent period) form, leading to lifelong virus carriage, and a rather good ability to maintain virulence in the environment. At normal rates, they are viable for a day, on motets and various metal handles - up to 2 hours, on plastic and wood - about 3 hours. They tolerate even high frosts well, and inactivate for half an hour at temperatures above 50 ° C.
Human Herpes Viruses 1-5
These pathogens belong to the Herpesviridae family, which includes three subfamilies - alpha, beta and gamma herpes viruses. Today, 8 clinically significant human viruses are isolated, 5 of which are made in the analysis of TORCH infections (TO - toxoplasma, R - rubella (rubella), C - cytomegalovirus, N - herpes). The most common viruses are herpes simplex viruses 1 and 2. It is about them that we are talking about when they talk about the presence in almost 90% of the population of antibodies to these types of herpes viruses. They make us virus carriers in childhood, and it’s very difficult not to get infected:
- Herpes simplex virus type 1 (HSV-1) is a labial form. The causative agent of Herpes Labialis. The face, lips, mucous membranes of the mouth and nose, rarely the cheeks are affected. The most common symptoms of a herpes infection of this type are the so-called fever on the edge of the lips. Although the infection spreads throughout the body, it manifests itself in the appearance of vesicles in the nasolabial triangle. Relapses appear with a frequency of about 3 times a year.
- HSV-2. This is genital herpes. According to statistics, 50% of the occurrence of infection in this localization is caused by herpes simplex viruses of type 1. Routes of infection - most often oral and genital. At the same time, relapses of herpetic infection in the first type occur much less frequently than in genital (every two to three months, or even more often). The duration of the active phase is longer, and the lesion area is longer. This is a serious disease that increases its prevalence in the population (up to 24% of those infected).
- HSV-3. The causative agent of Herpes Zoster, causes shingles or viral chickenpox. The peculiarity of this infection is the defeat of people aged 35-45 years and older. This is a polytropic virus, the affected areas are mucous membranes, feet and palms, scalp, trunk. In this case, the zones of the appearance of bubbles with liquid are huge in area.
- HSV-4. The causative agent of the Epstein-Barra virus causes infectious mononucleosis, an acute viral infection in which the lymph nodes, the back of the oropharynx, liver and spleen are affected in the most severe cases. Other names for this disease are monocytic tonsillitis, benign lymphoblastosis.
- Cytomegalovirus (Human betaherpesvirus 5) is the fifth type. One of the viruses that occurs at low immune status and is very dangerous in case of intrauterine infection. In addition, this type of herpes virus affects the internal organs (heart, lungs, kidneys).
Diagnosis: herpes infection type 6-8
These are types of herpes viruses that do not yet have enough clinical evidence and are not so common in the human population.
- HSV-6 comes in two flavors: 6A - viral proliferative diseases associated with unnatural cell proliferation (various tumors, lymphomas, lymphosarcomas), 6B - causes sudden exanthema, multiple granular rash. There is evidence of involvement of this type in the development of acute hepatitis and even death.
- HSV-7 causes chronic fatigue syndrome and is accompanied by paroxysmal tremors.
- HSV-8 is a specific virus that causes severe Kaposi’s sarcoma in AIDS patients.
According to the World Health Organization, mortality due to herpetic infections is in second place (15.8%), giving priority to hepatitis viruses (36%). And by the age of 18, about 90% of urban residents become carriers of one or even several serotypes of herpes viruses.
The structure of the virion
Structurally mature particles (virions) of herpes are quite large - up to 200 nanometers in diameter. The hereditary material in them is represented by a double-stranded DNA molecule. In addition to the protein membrane, the virion has an external supercapsid - the outer membrane, which includes lipids and glycoproteins. The core (nucleocapsid) consists of 162 capsomeres and has the form of a multifaceted cube. The surface is covered with protein spikes, which ensure the attachment of the virion to the membranes of the host cell and facilitate the penetration of viral DNA inside.
After this, the virion loses its envelope, its nucleic acids integrate into the host, and the replication process starts. The formation of young virions and their membranes is due to the resources of the host cell. As they accumulate, they break the cell membrane and enter the intercellular space in search of new victims. In the dormant stage, the virus persists in the nerve ganglia and does not manifest itself in any way.
Classification of herpetic infection
Due to the variety of pathogens, there is no universal classification of these infections. But depending on the fundamental criteria, the following types of herpes infections are distinguished:
- The criterion of clinical manifestations: typical forms of infection (with rashes) and atypical forms (without rashes or with minor).
- Depending on the severity of the course: mild, moderate and severe herpetic infections.
- By the localization of the inflammatory process: genital or epithelial, herpetic lesions of the nervous system, eyes, oral cavity and so on.
- In accordance with the form of the course of the disease: acute primary and chronic recurrent infections.
It is in connection with such a complex classification of this type of infection that a wide range of specialists is involved in its treatment and diagnosis - from venereologists to neuropathologists, and even oncologists.
How a pathogen enters the body
The main reservoir of the virus is an infected person. All types of causative agents of herpetic infection in children and adults enter the body in three ways:
- Perkutatny (contact household).
- Aerosol (airborne).
- Vertical (the fetus receives an infection from the mother).
Ways of infection are different, and often it is impossible to draw borders between them. Nevertheless, the most common contact-household route of infection is considered. The pathogen is transmitted through infected objects (dishes, toys, cosmetics, and so on). Infection is possible with kisses. In this case, often after it does not occur an acute phase, and the disease proceeds latently. Under certain circumstances, about which a little later, the virus breaks out and finds itself.
With genital herpes, infection occurs through sexual contact and oral sex. This type of herpes is part of the WHO special research program, which indicates its pathogenicity. In European countries, herpes is in second place among sexually transmitted diseases, second only to trichomoniasis.
With aerosol infection, the infection proceeds as an ARI. So children are more often infected, but in adults, herpetic infection can occur in this way. With primary infection, an acute form of the course of the disease occurs with severe symptoms of a respiratory disease, which disappears within a week.
Vertical route of infection and pregnancy
The fetus can get an infection from the mother in three ways:
- Most often, infection of the fetus occurs during the passage of the birth canal during childbirth. But only if the mother has severe symptoms of genital herpes. The risk of infection in this case is about 40%.
- An ascending infection through the cervical canal can enter the uterus and infect the fetus there. The probability of infection of the fetus is less than 5%.
- Transplacental transmission - infection of the fetus through the placenta at different stages of pregnancy. This is possible provided that the mother has various forms of herpes.
To begin with, it should be noted that the presence of antibodies in the mother’s blood against the viruses of primary herpes is not a contraindication to pregnancy and natural childbirth. Today, all pregnant women are tested for TORCH infections, and if antibodies are present, it’s very good. This means that the mother will pass them on to the fetus and partially protect him from the primary infection.
Relapsing herpes in a pregnant woman brings discomfort to the mother rather than a danger to the baby. Now, if no antibodies were found in the mother’s blood, this means that during the period of pregnancy, primary infection of the mother can occur, which is very dangerous for the baby.
Intrauterine infection of the fetus is the most severe infection in terms of consequences. Infection of the fetus in the first trimester of pregnancy leads to its death and miscarriage, in the second and third trimester of the fetus, disability and damage to the central nervous system are possible.
Stages of the development of the disease
As already mentioned, the development and symptoms of the disease are different in the case of primary and secondary infection with herpes simplex viruses. Most often, primary infection is successfully suppressed by the immune system and is asymptomatic. After that, the virus hides in the nerve cells and there passes into a dormant state. For many people, it will never manifest.
But in some cases, we are dealing with the true manifestation of a primary herpetic infection with all external symptoms. After treating the disease, the virus again slumbers in the nerve endings. Reactivation of the virus and the transition of the infection into a recurring form (periodic onset of symptoms) occurs when there are special conditions in the body.
In a healthy body, the immune system every second recognizes and destroys up to 3 thousand cells affected by various pathogens. A decrease in immunity status is the main reason for the recurrence of herpes, and stresses, overheating or overcooling, changes in time zones and climatic conditions (from minus 25 to plus 25 degrees during flights) lead to this. Relapses are promoted by the excessive use of alcohol, antibiotics and hormonal drugs that affect the immune system.
Separately, it should be noted such factors as immunopathological conditions - chronic diseases, oncology, the effects of radiation exposure, immunodeficiencies.
In this case, relapses and their symptoms can be weak and blurry and not cause the carrier particular discomfort.
TORCH screening and other research methods
Diagnosis of herpetic infections not so long ago became possible in the laboratory, as they are quite easy to differentiate according to clinical symptoms. In the absence of visible symptoms, laboratory tests are performed. Modern research methods for these infections have in their arsenal several methods, where the research material is scrapings of the skin and mucous membranes, biological fluids (saliva, urine, blood).
Virological methods use cell cultures and polymerase chain reactions. The method of paired sera and color samples is a fairly common serological analysis. Rapid TORCH screening methods were developed by WHO to analyze diseases dangerous to the fetus. But this analysis can be carried out not only for pregnant women.
Herpes simplex is not an easy treatment.
It has long been known that in adults, herpetic infection is detected in 90%. But only about 20% have clinical manifestations. Most of us become infected between the ages of 3 and 5 and remain carriers for life. It is impossible to get rid of the virus, but it is possible to alleviate its course or reduce the likelihood of manifestations. That is why the treatment of herpes infection comes down to the prevention of relapse and relief of the initial symptoms. Preventive methods include measures to strengthen the general immunity of the body and reduce factors that affect the status of the immune system.
With the first symptoms of infection, it is important to take emergency measures quickly. For rashes, topical application of antiviral drugs in the form of ointments is sufficient, for more serious manifestations and frequent relapses, special drugs are used to treat herpes infection (Acyclovir, Valaclavir, Pharmciclovir, Tromantadin). Treatment involves the use of special forms of interferon and the use of drugs that stimulate the production of the body's own interferons (for example, Cycloferon).
But the complexity of the treatment is that all effective drugs are quite expensive, and the treatment is long and is carried out according to a certain scheme, taking into account the specifics of the infection, the state of immunity and the associated diseases of the patient. That is why self-medication is not an option in this situation. Consultation with a competent specialist, quality examination is the key to successful “taming" of the virus and taking it under control. Parents need to know that frequent “colds” on the lips of their children can turn into a serious problem in the future, and not neglect turning to specialists for help.