Ways of exogenous infection. exogenous retroviruses. endogenous retroviruses. properties of retroviruses. What is a bacterium

An exogenous infection is an infection, the causative agents of which are microorganisms that come from the environment with food, water, air. Ways of transmission are different: transmissive, contact and others. Knowing these features helps to avoid infection.

Every day around a person in the external environment there are many microorganisms, both beneficial and not very healthy. Dangerous bacteria live in water, air, food and are transmitted exogenously or endogenously. An exogenous infection is an infection that enters the body from the external environment.

The science that studies the transmission of infection is called epidemiology.

Any microbes, regardless of the route of transmission, can enter the bloodstream and cause serious illness.

To start the infectious process, you will need a certain amount of an infectious agent and an entrance gate, which are human living tissues. Exogenous modes of infection transmission include various routes.

Airborne

The most common way of transmission of infection from the external environment is air. In this way, through the smallest secretions, bacteria and viruses penetrate inside. Such transmission is typical for tuberculosis, influenza, whooping cough and other diseases. Infection occurs during inhalation of infected air, sneezing, talking.

contact way

When microorganisms attack the mucous membranes and skin of the patient, they can be transmitted to another person by contact, through household items, shaking hands, in contact with a wound, during an operation. Sick people, carriers of the infection, animals, insects and objects surrounding a person carry the infection.

There is direct contact from the source of infection to a person and indirect contact, when infectious agents are transmitted through intermediate household items. During medical manipulations, pathogenic microorganisms enter the patient through surgical instruments, injections. And such sexual infections as gonorrhea, syphilis are indulged in a contact way, as well as mononucleosis, fungal diseases, for example, mycosis of the feet.

Insect bites

Pathogenic microorganisms are able to get from an insect to a person during a bite. For example, malaria, which is carried by mosquitoes, encephalitis due to a tick bite, plague, typhoid and many other diseases. This way of transmission is called transmissible.

Fecal-oral transmission

Very often, microbes get through dirty unwashed products, which are also exogenous routes of transmission. Through the fecal-oral route, microbes enter the gastrointestinal tract and cause many intestinal disorders and poisoning.

Prevention of exogenous infection

The main manifestation of the infectious process is intoxication of the body, which is often expressed by weakness, dizziness, nausea or vomiting, depending on the pathogen and the route of transmission of the infection. If the upper respiratory tract becomes infected with respiratory diseases, a runny nose or cough appears. To avoid infection, you should follow certain rules.

How to protect yourself in public places

Unfortunately, careful personal hygiene may not be enough for quality prevention, because microbes live almost everywhere around a person.

For example, with influenza, the infection lives in crowded places, where the risk of infection increases significantly. In such cases, if possible, it is best not to contact people who have a runny nose or cough.

Masks are used to protect against the transmission of pathogens through the air. During the influenza epidemic, the mask becomes the best way to protect against infection in crowded places. There are products made of fabric, gauze, as well as liquid masks with an absorbent substance that is surrounded by a film or cloth. The gauze mask should consist of 4 layers, and it will have to be changed every two hours.

When you get home, you should always wash your hands with soap and water, because they contain germs, dust and other particles. Do not touch the face and mucous membranes with dirty hands. You need to wash not only your hands, but also your face, especially after visiting a hospital or clinic. Washing the nasal cavity is one of the few methods of protection against colds and viral diseases. For this, various aerosols with sea water, weak antiseptic solutions are suitable.

How to avoid contact infection

When visiting saunas, baths, public toilets, one should be attentive to personal hygiene. Such places should be regularly treated with disinfectants. Open areas of the body should not come into contact with household items in public places. Mucous membranes are also important to protect from contact with the external environment. Sexual contact should be protected, especially in cases where the partner is unstable.

To avoid penetration of infection into the wound, a sterile dressing is applied to the damaged area of ​​the skin. An exogenous infection can cause serious complications, so the wound surface will require treatment with antiseptic solutions.

Insect bite protection

Prevention of transmissible human infection through bites consists in the use of repellents for spraying on exposed areas of the body and clothing. In the warm season, protective nets are used on the windows.

For many infections that are characterized by an exogenous route of transmission, there are vaccines used to prevent diseases such as diphtheria, rubella and many others.

Vaccination is also used to prevent influenza epidemics.

It is important to always follow the rules of personal hygiene, wash your hands, do not eat dirty fruits and vegetables, boil water from a tap or from unknown sources, milk. It is also important to properly heat treat food, use disinfectants for rooms and household items. The house needs to be cleaned frequently. Bacteria surround a person daily and are present in soil, water, air and food. An infection can harm your health at any time, but knowing the prevention methods that protect against dangerous microbes from entering the body can significantly reduce the risk of infection.

Various infections for pregnant women are of great danger, since they can infect the fetus in utero.

Water should not be taken directly from lakes or rivers when there is a high risk of contamination. If necessary, boil the water for one minute to remove cryptosporidium and other microorganisms from the water. Using a submicron water filter for personal use may reduce the risk of infection. Be aware that swimming can accidentally ingest water and increase the chance of acquiring Cryptosporidium, even in public pools. Avoid situations where you can breathe in environmental spores, especially damp and dark areas. Hot tubs with hot water, saunas and other shared bathrooms are generally not recommended. Bacteria and other microorganisms thrive in warm water. However, if the immunosuppressed person is confident that the bath is disinfected regularly as recommended, there are no contraindications that prevent its use. Caving should not be practiced due to the contamination risks associated with guano exposure. Travel abroad: For people at very high risk of infection, this risk increases when traveling to developing countries.

• source of infection, such as a sick person;
• pathogen transmission mechanism - horizontal, vertical, artificial or artificial;
• susceptible organism.

• bacillus carriers are patients or medical workers, less often animals;
• patients with purulent-inflammatory diseases;
• iatrogenic infections, when infection occurs from medical staff within the walls of the hospital.

Ways of infection with exogenous infection

Horizontal

• Airborne. The most common way of infection. From the air, macroscopic "creatures" get inside a healthy person. It is enough to be near the source of infection - a sick person or inhale contaminated air. In this way, measles and a number of other diseases are spread.
• Air and dust. This type is typical for pathogenic agents that retain their pathogenic properties for several days. When sneezing and coughing, they enter the air, then settle on dust particles and enter the body. These are pathogenic microorganisms of diseases such as diphtheria, scarlet fever, tuberculosis.
• Fecal-oral. The causative agents of diseases of "dirty hands" - intestinal infection, helminthiasis and salmonellosis. There are two methods here. The first is the alimentary method of infection, when pathogens settle on food, getting on them from the soil, animal waste. The second is the aquatic mode of distribution. Drinking raw water, you can get cholera or typhoid fever.
• Contact household. Allocate direct and indirect routes of infection. With direct transmission, a person becomes infected by direct contact with the patient through saliva, kiss, sex. These are gonorrhea, syphilis, as well as erysipelas, herpes, scabies. With the indirect method, pathogens settle on various household items, that is, the carrier of the virus, for example, wiped himself with a towel or took a glass and left some of his "disease-causing friends" on them. A healthy person used the same items and after some time fell ill with dysentery or typhoid.
• Transmissive. Infection occurs as a result of human interaction with disease carriers. In the non-specific way, the carriers are insects - flies and cockroaches, which carry pathogenic microorganisms on their paws that get on food or drinks. Flies can introduce typhoid fever bacillus, hepatitis A virus, or intestinal pathogens into food. Insects that carry only one type of disease are “responsible” for a specific route of infection. Mosquitoes carry malaria, ticks carry encephalitis, fleas carry plague, and lice carry typhus.

vertical

• hepatitis B;
• measles;
• chickenpox;
• bacteria - staphylococci and streptococci.

Those who choose to travel should avoid food and drink that may be contaminated, in particular raw fruits and vegetables, raw or undercooked meats and seafood, tap water, ice made with tap water, milk and water. unpasteurized dairy products and products offered by street vendors. Among the foods and drinks that are generally safe from the point of view of infections are very hot foods, fruits that the traveler himself removes the skin or peel, bottled drinks, coffee and hot tea, beer, wine and water when boiled for one minute. . Although treating water with iodine or chlorine is not as effective as boiling water, this method can be used when it is not possible to boil water. Generally, preventive antimicrobials are not recommended for travelers, but your doctor may advise you to take certain medications with you. The effectiveness of these agents depends on local antimicrobial properties that are rarely known. Consult your doctor's decisions based on your level of risk of infection, as well as the region and duration of your trip. If you're feeling good, you can dust, scrub, clean windows, mop floors, and clean bathrooms in the usual way. However, avoid cleaning or removing dust from places where a lot of precipitation can be filmed. Use common sense and avoid cleaning areas that haven't been touched in years. In general, construction or renovation sites should be avoided due to the possibility of fungi or mold scattered in the dust. If this cannot be avoided, an immunocompromised person can reduce the risk of infection by using a special respirator that filters particles tightly attached to the face. Wear gloves for washing heavily soiled areas and toilets. . There are a few cases where a mask is appropriate, such as if an immunosuppressed person has to enter an area under construction or renovation, or be exposed to copious emissions of dust or debris.

Infection of a child can also occur during childbirth and during lactation, therefore, HIV-infected and syphilis-infected women are strictly prohibited from breastfeeding their children from the first days of their life.

artificial or artificial

• hepatitis B, C, D;
• toxoplasmosis;
• malaria;
• syphilis;
• listeriosis.

There are two types of such a source of infection - hemocontact and inhalation.

In addition, if it is necessary to have close contact with other people suffering from a respiratory infection, the mask reduces the risk of infection. Drugs that your doctor or health care provider may prescribe or recommend to you.

• Filgrastim Pegfilgrastim Sargrast.
• Sulfamethoxazole - trimethoprim Acyclovir ® Fluconazole ® Intraconazole ®.

When to call your doctor or health care provider for a possible infection. Call immediately if you have.

• Chills or tremor.
• Sudden onset of new pain without explanation.

Blood contact includes such methods of infection:

• Transfusion. Infection occurs during the transfusion of blood or its components. This can happen due to poor-quality examination of the donor, reuse of disposable instruments, absence or incorrect sterilization of reusable surgical instruments, violation of the rules for storing biological material - blood and its components.
• Transplant. Infection during transplantation of donor organs.
• Parenteral. Microorganisms enter the body when the integrity of the skin or mucous membranes is damaged during surgery, injections or diagnostic measures. Infection can occur if non-sterile surgical instruments are used, re-use of disposable instruments, when an infected specialist works without gloves or a mask.

Blood in the urine. You need to urinate more often than usual.

• Sore throat.
• Sores in the mouth.
• White coating on the mouth, especially on the tongue.
• Signs of a bladder infection.
• Burning when urinating.

The main symptom of infection is intoxication of the body, which manifests itself in the form of:

• weaknesses;
• dizziness;
• nausea;
• vomiting;
• rashes;
• elevated body temperature;
• flow from the nose.

Symptoms vary depending on the type of pathogen, but if you can try to protect yourself from some infections transmitted by airborne, fecal-oral or contact routes, then with an artificial route of infection, nothing depends on a person.

Do you want to be tested for gonorrhea? Find a Health Center →

But if you see signs of gonorrhea, get it tested immediately. Here we will explain what to look for.

Gonorrhea doesn't always have symptoms

Prevention

• during epidemics of viral infections, large crowds of people are avoided;
• wear a multilayer gauze bandage that needs to be changed frequently - every 2 hours;
• temporarily refuse, if possible, to communicate with people who have signs of the disease;
• indoors, the air is disinfected using ultraviolet lamps or other disinfection devices (even daily ventilation reduces the number of germs in the air);
• when they come from the street, they wash their hands with soap, be sure to rinse their face, and after going to the clinic or hospital they wash their nose.

• do not use other people's personal hygiene products;
• wet cleaning is carried out in the room;
• if there is a patient at home, then in common areas for washing floors, toilets, bathrooms and kitchens, an antiseptic is used;
• they try to isolate a sick person for the duration of the illness.

Gonorrhea can cause more serious health problems and even cause infertility if left untreated. However, it is usually easily treated with medication. Most people with a vagina who get gonorrhea have no symptoms. If they show symptoms of gonorrhea, they appear about a week after contracting this infection.

Abnormal vaginal discharge, which may be yellowish or bloody. Bleeding between periods. People with a penis are more likely to have symptoms if they get gonorrhea. Symptoms usually appear a week after infection.

• wash their hands - before and after eating, when cooking, after going to the toilet and outside;

  Petted a pet or played with it? Don't forget to wash your hands with soap!

• vegetables and fruits are washed thoroughly under running water; for best effect, use a soft sponge or brush;
• dishes are brought to full readiness, avoiding eating uncooked meat, steaks with blood;
• water and milk are boiled, since at high temperatures the bulk of the pathogenic microflora dies.

Keep an eye on your pets - use flea collars and wash your pets regularly with flea shampoos.

Yellow, white, or green discharge from the penis Pain or burning when urinating Pain or swelling in the testicles Gonorrhea can also infect the anus if you have anal sex, or you can spread the infection to your anus from another part of your body. Anal gonorrhea usually does not show symptoms. However, signs of gonorrhea in the anus may include.

Itching in or around the anus Discharging from the anus Pain in bowel movements. . Throat infections caused by gonorrhea also usually do not cause symptoms. If symptoms appear, it's usually just a sore throat. If you or your sexual partners have any of these symptoms, contact your nurse, or doctor.

What factors, other than the ability of the immune system to resist the attack of viruses, further increase the likelihood of infection is not known exactly. For example, if out of four children playing together in the same conditions, one has a streptococcal infection, then not all three, but only two, may become infected. The third has a chance to become a carrier of an infection that will or will not manifest itself in his body in the future. The probability of infection, in a word, is determined by antibacterial resistance and type-specific immunity.

Biological warfare is the use of microbiological agents for hostile purposes. It is not clear if other countries or dissident groups have the resources for biological warfare. For various reasons, experts consider the use of biological agents unlikely in formal warfare. However, biological agents are considered by some to be ideal weapons for terrorists. These agents may be provided clandestinely and may have delayed effects, allowing the user to remain undetected.

Potential biological agents include carbuncle, botulinum toxin, brucellosis, hemorrhagic fever virus, plague, smallpox, and tularemia. Each is potentially fatal and, with the exception of carbuncle, botulinum toxin, and tularemia, can be passed from one person to another. Direct human-to-human transmission of brucellosis is extremely rare.

An infection of the same type in the organisms of different people can manifest itself in different ways. One child will have rhinitis, another will have tonsillitis, and the third will have otitis media. The fight against streptococcal infection is complicated by the fact that many strains practically do not respond to the treatment of their habitat with hot water. That is why washing toys and dishes in warm water, even with the use of chemicals, does not give a positive result in the destruction of bacteria. At a temperature of 70 degrees, microbes also continue to live, but 90% of them die after one hour. Exposure to negative temperatures will also not give an effect: if the blood is frozen, streptococci can live in it for several months. Exposure to strong disinfectants can be effective.

Anthrax spores are relatively easy to prepare and, unlike most other agents, can be airborne, creating the possibility of spread by aircraft. Theoretically, 1 kg of anthrax could kill up to 1,000 people, although technical difficulties in preparing the spores as a fine enough powder may actually limit the number of deaths to a fraction of that number.

Most people have been infected with anthrax without developing the disease, possibly due to the widespread use of the antibiotic ciprofloxacin. However, there was extreme public concern about these incidents. The number of false threats of anthrax was very high. More false alarms, both rumors and reports of anxious citizens who confused harmless materials with anthrax, have been reported since the carbuncle attack.

Infection of healthy people can only occur through contact with a sick person. These bacteria are not transmitted by any other living organisms. Both a simple carrier of viruses and an already sick person can infect. Bacteria easily spread in the air when communicating with the patient, get and retain their activity on toys, dishes, and other objects. Even in a dried state, the bacteria continue to be in the air or on surfaces, and when it enters the body, they begin to damage.

The bacterium was introduced by a religious cult that was trying to influence the results of local elections. No one died and the elections were not affected. Chicken soup, toasted slices, fruit, liquids only: we all have our own way of coping with a cold, flu or stomach upset. But scientists now understand that there is actually a link between the food we eat when we are sick and recovery time, and that, depending on the infection, it is best to eat or not eat at all.

A study that has just been done on mice has shown that eating more food when fighting a viral infection like the common cold and flu can help speed up recovery, but on the other hand, if we fight a bacterial infection like a food poisoning, food intake can seriously worsen the situation.

The most susceptible to streptococci are small children who are not yet accustomed to the rules of personal hygiene and constant hand washing. However, it cannot be said that bacteria will not settle in the human body of an adult. The chances of catching an infection decrease only after the age of forty. Exacerbation and growth of morbidity occur in the autumn-winter time.

When animals are infected, they stop eating, which switches their metabolism to starvation. The question is, is there any benefit from this and is it also important for people? - lead researcher Ruslan Maizhov. Before moving on to the survey results, let's first take a look at how our body reacts to various infections. We basically know two types of infections: bacterial and viral.

Bacterial infections, which include bronchitis and pneumonia, are caused by single-celled organisms that can develop and multiply in our bodies. Fortunately, most bacterial infections are treatable with antibiotics to limit their colonies. Viral infections, such as the flu or a cold, on the other hand, are not self-replicating like bacteria. Instead, they take our cells and make them make more copies of the virus and therefore spread throughout the body. Viral infections usually do not respond to antibiotic treatment, but some antiviral agents can prevent their spread in intact cells. When we are infected with harmful bacteria or viruses, our immune system is instantly activated, the first defensive response is increased inflammation in different areas of the body.

For introduction and vital activity in the human body, streptococci choose the surface of the tonsils, as well as lymphoid tissue on the respiratory organs. There are cases, but much less often, when an infection in the human body appears through the skin, on which there are wounds and cracks, burns or diaper rash. In the place where streptococci are introduced, a primary focus is formed, from where the inflammatory process originates. From it, in the future, microbes also enter other tissues of the internal organs, causing severe general intoxication. Microbes are active, multiply, release toxic products and components resulting from protein breakdown. Often a streptococcal infection turns into necrosis - purulent tissue damage with their subsequent death.

Streptococcal infection tends to spread at an astonishingly fast rate in tissues and organs. At the initial stages of their impact, phlegmon and periadenitis develop. With further entry of microbes into the Eustachian tubes, inflammation is localized in the middle ear, which causes otitis media, sinusitis, ethmoiditis, mastoiditis. The advanced stage of the disease may result in the formation of purulent metastases and septicopyemia. Timely initiated and competently prescribed treatment is a guarantee that the spread of infection can be stopped and the onset of irreversible pathological changes can be prevented.

It is impossible to recognize a streptococcal infection on your own. For this, clinical examinations and analyzes are necessary so that doctors can isolate streptococci in the group of bacteria present in the body. The earlier the patient goes to the doctor, the higher the likelihood that the diagnosis will be carried out correctly.

Various infections can live in the human body. Pathogenic organisms take root, multiply and worsen the well-being of a person. Infections can be transmitted by airborne droplets, with open wounds and in other ways.

The concept of endogenous infection

With a weakened immune system, a person is at risk of various diseases. An endogenous infection is an infection that lives in the person himself and begins to develop with a decrease in the body's resistance.

There are untreated teeth, tonsils or skin diseases. Endogenous infection is transmitted in the following ways:

• by blood flow;
• along with the flow of lymph;
• contact.

Sometimes the endogenous route of infection is non-standard: for example, when sneezing, bacteria enter an open wound. Infection occurs with those bacteria that lived in a person - in his other organs and tissues. This form is called autoinfection.

An endogenous infection is not only one that manifests itself as a result of a decrease in immunity. It can occur as a concomitant disease with various disorders of the gastrointestinal tract. A stomach ulcer, having become perforated, infects other organs of the abdominal cavity with bacteria, which causes foci of inflammation.

Irritable bowel syndrome can be caused by a bacterial disease and lead to serious consequences.

A feature of endogenous infection is the absence of an incubation period.

Autoinfection

Autoinfection is part of endogenous infection. The patient becomes infected himself, bringing bacteria from one part of the body to another. Autoinfection is divided into 2 types:

The endogenous route of infection is different. If the infection spreads through the blood, then it is called bacteremia or viremia, depending on who is the causative agent of the disease. At the same time, microorganisms do not multiply in the blood, but choose those human organs and tissues where they can stop and increase their number. If it multiplies in the blood, then a severe disease begins, the name of which is blood sepsis.

Exogenous infection

Exogenous infection occurs as a result of the penetration of microorganisms into the body from the outside. Each pathogen enters the body in its own way: through the mouth, genitourinary system, mucous membranes, etc.

The mechanisms of transmission of exogenous infection can be as follows:

The pathogen settles in the tissues or circulates through the body, multiplies and releases toxic substances. At the same time, the human defenses increase and the virus or bacteria is suppressed. If a person is a carrier of the pathogen, then there may not be any clinical manifestations. In some diseases, symptoms may appear after a while. Exogenous and endogenous infections should be treated under medical supervision.

Prevention during a planned operation

In surgery, special attention is paid to the prevention of the spread of pathogenic flora during operations. The operation can be performed only in a healthy state and the absence of inflammatory processes. To exclude possible foci of inflammation, testing is necessary.

Endogenous infection carries a serious risk of postoperative complications, therefore, in the preoperative period, patients undergo the following studies:

If, according to the results of the examination, an inflammatory process was revealed, then the operation is postponed until the cause is eliminated. During the ARVI epidemic, it is necessary to create conditions that reduce the risk of morbidity.

Prevention before emergency surgery

In an emergency, the question of the endogenous pathway of infection into the wound fades into the background. The patient's life must be saved. Examination in such a short period of time is impossible, but surgeons pay attention to the prevention of the spread of pathogenic microflora in the postoperative period. For these purposes, antibiotics and other drugs are used.

Treatment of endogenous infection

An endogenous infection is an infection for which prevention is the most effective way to fight. It is important to observe the rules of hygiene, the treatment of open wounds with an antiseptic. When performing operations, it is necessary to exclude the possibility of microorganisms entering the cavity. If you suspect the presence of inflammation in the body, you should consult a doctor in a timely manner.

For the treatment of infection, a course of drugs aimed at strengthening the immune system is prescribed. With strong immunity, the infection will not develop.

To prevent inflammation in the postoperative period, antibiotic therapy is carried out, strains are identified and the treatment of the underlying disease is carried out, and inflammation is affected.

An endogenous infection not cured in time is a risk of chronic diseases that can manifest themselves after a long period of time. An actively developing infection can develop serious complications in the body and lead to surgery, blood transfusion, or even death. What method to treat an endogenous infection should be decided by a qualified specialist.

Endogenous retroviruses

The idea that carrier genes could originate in viruses seems almost philosophical because of its strangeness. We are accustomed to consider our genome the basis of our personality. We know who our biological parents are because they gave us their DNA. Our DNA contains more than just skin color or diabetes susceptibility. It contains all of our nature. That's why the idea of ​​cloning is so contrary to our nature - no one should use "second hand" genes. But if most of the genes entered the body through the mediation of viruses, can it be considered so unique? Or is each of us just a hodgepodge of genes put together through evolution? It's like imagining that the world is filled with hybrid monsters, and the clean lines have long been blurred.

For many decades, microbiologists have become accustomed to noticing "traces" of viruses in many of the microbes they study. As long as microbes were the only living organisms whose genes were obviously borrowed from viruses, we could turn a blind eye to this fact, considering it just a lucky coincidence, characteristic only of "lower" life forms. However, now we can no longer comfort ourselves in this way. If we peer into our own genome, we will find traces of viruses. Thousands of viruses.

We need to say thank you to the horned rabbit, as it was he who opened our eyes. The myth of the horned rabbit was one of the clues that led virologists to realize that certain viruses can cause cancer. In the 1960s, one of the most closely studied cancer-causing viruses was the avian leukemia virus ( avian leukosis virus). At that time, the virus was spreading rapidly through chicken farms and threatened the entire poultry industry. Scientists have found that this virus belongs to a group of so-called retroviruses. Retroviruses insert their genetic material into the DNA of the host cell. When a cell divides, it copies the DNA of the virus along with its own. Under certain conditions, the cell is forced to produce viruses with all their genes and protein coat so that they can get out and infect other cells. Retroviruses sometimes turn cells into cancer cells if their genetic material enters the wrong place in the host cell's genome. Retroviruses have special "knife switches" that cause the cell to produce proteins according to the genes located in the neighborhood. Sometimes these "breakers" turn on the carrier's genes, which should be suppressed and cause cancer as a result.

The avian leukemia virus turned out to be a very strange retrovirus. At that time, scientists tested for the presence of the virus by examining the blood of a chicken for the proteins of the virus. Sometimes they found avian leukemia virus proteins in perfectly healthy birds that had never developed cancer. Stranger still, birds carrying the viral proteins could produce healthy chickens that also carried the proteins.

Robin Weiss, a virologist at the time at the University of Washington, wondered if it could be that the virus had become an integral yet harmless part of the chicken's DNA. He and his colleagues exposed the cells of healthy chickens to mutating chemicals and radiation to see if they could release the viruses from their hiding place. As they expected, the mutated cells began to reproduce avian leukemia viruses. In other words, these healthy chickens didn't just carry viruses in some of their cells; the genetic instructions for the production of viruses were implanted in all their cells, and then passed on by them to their descendants.

These latent viruses were not limited to one single breed of chicken. Weiss and other scientists have found avian leukemia virus (AVL) in many breeds, raising the chance that the virus is an ancient component of avian DNA. To find out how long ago an IDP infected the ancestors of modern chickens, Weiss traveled to the Malaysian jungle with his colleagues. There they caught a Banking Jungle Chicken red jungle fowl), the closest wild relative of the domestic. The Banking Jungle Chicken carried the same IDP that Weiss had discovered. On subsequent expeditions, he found that other species of jungle fowl did not have the virus.

From this study, a hypothesis was born of how the IDP merged with the chickens. Thousands of years ago, the virus infected the ancestors of modern domestic chickens, causing tumors. But something else happened to at least one of the birds. Instead of giving the bird cancer, the virus was suppressed by the bird's immune system. Without harming her, the virus spread through her body until it reached her genitals. When an infected bird mated, its eggs also carried viral DNA.

As the infected embryo grew, all of its cells also acquired the DNA of the virus during division. When the chick hatched, it was already infected. And since the IDP was now part of his genome, he passed it on to his descendants as well. The virus has remained a silent passenger from generation to generation for thousands of years. But under certain conditions, the virus could resume its activity, re-form tumors and begin to spread among birds. Scientists realized that this new virus is the only one in its class. They called it an endogenous retrovirus; endogenous means produced internally. Soon they were able to detect endogenous retroviruses in the genomes of mammals as well. In fact, viruses inhabit the genome of almost all groups of vertebrates - from fish and reptiles to mammals.

Some of the retroviruses discovered cause cancer, but not all. Some seem to be tightly controlled by their hosts. Certain endogenous retroviruses carried by mice cannot infect mouse cells, but successfully spread among rats.

Other endogenous retroviruses turned out to be defective, having undergone a mutation that deprived them of the ability to go into their usual form. They were still able to copy their genetic material, which was re-incorporated into the host's genome. Scientists have also found viruses so mutated that they can't do anything at all. All that is left for them is to serve as ballast in the genome of their carrier.

Finding endogenous retroviruses in other biological species, scientists could not help but look for them in our DNA. After all, we suffer from many diseases caused by retroviruses. Virologists have made unsuccessful attempts to isolate retroviruses from human cells. However, during the scanning of the human genome, they managed to find irrefutable evidence of their presence in some segments. Many of the segments carrying retrovirus genes resembled similar segments in monkeys, suggesting that retroviruses infected our ancestors thirty million years ago, and possibly earlier. But some segments of human DNA that bear a reminder of retroviruses have no analogues in other species. It is possible that they were formed about a million years ago by introducing the DNA of retroviruses into the genome of our ancestors.

To test this, Thierry Heidman ( Thierry Heidmann), researcher at the Gustav Rusi Institute ( Gustave Roussy Institute) in Villejuive, France, attempted to revive a human endogenous retrovirus. By examining the genomes of different people, he found slightly different versions of the retroviral DNA segment. Presumably, these differences appeared at the moment when the retrovirus was embedded in the genes of ancient people. In their descendants, a series of mutations struck various parts of the DNA of the virus.

Heidman and his colleagues compared different variants of the virus-like gene sequence. They looked like four copies of Shakespeare's work, each transcribed by a not very diligent scribe. Each of them made their own spelling mistakes. Each copy could contain incorrectly spelled versions of the same word - for example, "honor", "rochem", "bake", "what". By comparing all four versions, the historian can reveal that the original word was "why."

With this method, Heidman was able to use mutated gene sequences found in the genome of modern humans to determine what the original version of retrovirus DNA looked like. Then he synthesized a DNA fragment according to the resulting genetic sequence. Having introduced it into a human cell, Heidman managed to get into the meter. Cells infected with this engineered virus produced new viruses capable of finding hosts. In other words, the original genetic sequence belonged to a living and functional virus. In 2006, Heidman named it the Phoenix, after the mythical bird that rose from the ashes.

Retroviruses pose a great danger to our health, being in a free state, but even being endogenous, they remain dangerous. Mutations can give them back the ability to split from your DNA and form viruses, causing new epidemics, and even causing cancer. Endogenous retroviruses, which can only reproduce themselves within our DNA, are also dangerous, as they can “turn on” genes that should be turned off at the most inopportune moment. The threat of retroviruses is so great that our ancestors evolved mechanisms designed solely to stop their spread.

Paul Bienatz ( Paul Bieniasz), a virologist at Rockefeller University, was able to discover two such mechanisms in 2007 by "resurrecting" an endogenous retrovirus in the same way that Heidman had done with Phoenix a year earlier. Bienaz christened his virus HERV-K[con]. After infecting human cells with it, he found that the cells fought it off with two proteins called AROBESZ. Bienaz's experiments have led to believe that these proteins are aimed at sabotaging the process of reproduction of a retrovirus that is trying to re-introduce itself into human DNA. Proteins undermine the process of copying genes, causing many mutations in new viruses. New mutations are like a hail of bullets. Some of them will whistle past without causing harm, but if even one of them touches a vital section of DNA, then it can cause irreparable damage and make the virus unable to reproduce further.

Proteins such as AROBESZ are effective against retroviruses but cannot eradicate them completely. Over millions of years, a mass of genetic material has accumulated in our genome, inherited from now dead viruses. Each of us has almost 100 thousand DNA fragments of endogenous retroviruses, which is about 8% of the total number of genes. To imagine their number, you need to remember that all 20 thousand genes that form the proteins that make up our entire body make up only 1.2%. Scientists have also found millions of small pieces of "jumping DNA" in the human genome. It is likely that many of these fragments also belong to the DNA of retroviruses, torn to the smallest pieces by many mutations and capable of only copying themselves.

The development of medicine and microbiology made it possible to learn a lot of interesting and useful information about the organisms that exist in our body. Some are beneficial, others cause various diseases. The Klebsiella bacterium is one of the microorganisms that carry out their activities as part of the normal intestinal microflora.

What is a bacterium?

Klebsiella in the body looks like a rod-shaped microorganism. It belongs to the family called Enterobacter. Modern research has identified 4 species, among which the most common:

• wand Friedlander;
• pathogen in the large intestine.

This microorganism belongs to the group of opportunistic pathogens. The location is the intestines, mucous membranes, skin and respiratory tract.

It must be borne in mind that, in general, the stick does not cause harm, but in combination with some factors, it can trigger the development of many diseases.

In the case when the body is completely healthy, the pathogenic properties of Klebsiella do not manifest themselves, but in case of weakening, the bacteria begin to actively multiply, which is the first step towards the appearance of inflammation. An interesting point: in the body, the shape of the bacterium is rod-shaped, but after it enters the environment, its shape is rounded and covered with a protective capsule shell. It perfectly protects bacteria from the effects of various environmental factors unfavorable to them.

The main routes of entry into the body

The reason for the development of infection in some cases is associated with a weakening of the body's own protective factors, which leads to the activation of bacteria and the development of infections that are in a latent form. Entry routes:

• water;
• food;
• the soil.

The bacterium actively develops on the skin of children under the age of 1 year, and it also lives in the intestines of newborns in a higher concentration than in adults. This is due to the fact that the immune system of children in the first year of life is not sufficiently developed.

It is necessary to observe the rules of personal hygiene, wash vegetables and fruits, work in the garden or vegetable garden with special gloves. In addition, the source of the microorganism can be a person already infected with it, the carrier of the bacillus. Airborne transmission is also possible - a person with pneumonia transmits the disease during sneezing or coughing. The microorganism spices remains in the genital tract and does not cause problems if there are no concomitant diseases, it is often diagnosed in gynecology.

The bacterium actively develops in the body of older people who, due to age, have lost a strong immune system. The risk of infection is high in those who suffer from serious diseases, such as diabetes or oncology. The wand is not sexually transmitted. The incubation period varies and ranges from 1 hour to 7 days. Much depends on the strength of the body.

Diseases

Depending on the localization of the bacterium, it can cause various diseases, including:

• inflammation of the lungs;
• pneumonia;
• diseases of the urinary tract, including cystitis;
• meningitis;
• intestinal infections;
• conjunctivitis;
• dysbacteriosis;
• ozena;
• rhinoscleroma;
• sepsis.

Symptoms of pneumoniae entering the body can vary - it all depends on the disease that the microbe causes, for example, cough occurs with pneumonia, as well as fever, and indigestion - with dysbacteriosis.

The complex treatment of diseases caused by Klebsiella depends on the localization and severity of the ongoing process. Also, when prescribing treatment, it should be remembered that intestinal diseases are often caused by a mixed microflora, and not only by the action of this microorganism.

For the purpose of fast and high-quality treatment caused by the activity of the disease bacillus, a variety of bacteriophages are used, the main task of which is to restore the natural and healthy intestinal microflora. Antibiotics are rarely used in treatment, because they do not have the desired effect, and also further disrupt the health of the microflora in the intestine.

In the case of pneumonia treatment, antibiotic treatment is prescribed at the discretion of the doctor. Effective in the treatment of probiotics containing freeze-dried yeast fungi that can reduce the activity of the rod, stopping its development. Also, in the treatment of diseases caused by the Klebsiella stick, special attention is paid to the restoration of immunity, therefore a complex of vitamins is included in the course of rehabilitation therapy. Due to the fact that the microorganism masks its presence with other diseases, a doctor's consultation is necessary, self-treatment can aggravate health problems that have appeared, and timely professional treatment based on diagnostics and tests will not leave a trace of them.

• Symptoms and signs of Klebsiella infection;
• Features of the disease in pregnant women.

What to do if you have intestinal amoeba?

What you need to know about this disease in order to protect yourself and prevent infection of your loved ones?

Why is it so special that it is worth talking about it?

The international classification has identified the following forms of this disease:

1. Manifest amebiasis, in which clinical symptoms can be observed.
2. Asymptomatic amoebiasis.

Manifest amoebiasis has several manifestations:

1. Intestinal.
2. Extraintestinal. This includes the genitourinary, cerebral, pulmonary, hepatic.
3. Cutaneous.

The main type of manifest amebiasis is intestinal, and the rest are derivatives of it. This happens when the disease is severely neglected, pathogens multiply a lot. They penetrate the walls of the intestine, and the blood carries them throughout the body. Amoeba settle in different organs, contributing to the occurrence of amoebic abscesses.

Transmission routes

The disease is transmitted in the same way as any other intestinal infection. It happens through:

1. Infected water.
2. infected food.
3. Dirty hands.

In summer, you can become infected by swallowing amoeba cysts while swimming in an open body of water.

Development of the disease

The development of the disease occurs gradually, since not living amoebas, but cysts penetrate into a person. They will take some time to develop: there are no favorable conditions for cysts in the external environment, so many types of bacteria fall into a state of sleep, having previously been covered with a hard shell. Precisely because the cysts are in a dormant state, they can pass through the aggressive environment that is present in the stomach and small intestine.

As soon as the environment changes for the better for them, and the large intestine has the most acceptable climate for them, the cysts “wake up”. Then they are embedded in its walls. Lucky for those who have increased stomach acidity, lucky in this matter - amoebas do not survive in such an environment. Although you shouldn’t be especially happy - there are highly pathogenic amoebas, whose cysts are not even afraid of hydrochloric acid.

Intestinal amoeba can have the following life forms:

1. Large vegetative.
2. Small vegetative.
3. Cyst.

The size of large forms is about 30-60 microns, and cysts are from 8-9 to 23-24 microns.

Intestinal amoebiasis - what is it?

So, if intestinal amoebae are "habitual residents", when do they become dangerous and begin to cause harm? This happens when the host's body is weakened, which is facilitated by stress, SARS, acute respiratory infections and other similar effects on the immune system.

Distinctive features of amoebiasis

A distinctive symptom of the disease is stool and localization of pain. So, the stool will have the consistency and color of raspberry jam. As for the pain, it, unlike the defeat of the dysenteric amoeba, will not be localized in the left side of the abdomen. The stomach will hurt on the right side, because with a disease of this type, other parts of the large intestine are affected - higher ones.

Ulcers form on the intestinal mucosa. Then abscesses may appear in their place. In addition, other organs may also be affected. Lung and liver damage may occur.

signs

Various symptoms will help diagnose the intestinal type of amoebiasis:

1. Heat.
2. Blood in stools.
3. Weakness.
4. High fatigue.
5. Headache.

These symptoms are already a reason to call an ambulance. If amoebas are distributed throughout the body, they may additionally manifest themselves:

1. Jaundice.
2. Pain in the liver.

The liver can hurt and jaundice can appear, for example, with cholangitis, so to clarify the diagnosis, symptoms alone are not enough, you will need to do an ultrasound.

But it is not necessary to observe nausea among the symptoms, since it is not characteristic of this disease.

The symptoms also depend on the stage of the disease. So in an acute form, all the signs appear very pronounced and constantly disturb a person. The chronic course is less pronounced - the temperature is normal, the pain that occurs in the abdomen does not have an exact localization. Periodically, the patient is concerned about not pronounced flatulence.

To treat or not to treat?

Attention: “Of course, this is not fatal, but self-treatment of the disease can have disastrous consequences, in particular, contribute to its transition to a chronic form.”

In addition, it is very difficult for a non-specialist to determine the symptoms of amoebiasis, since they are similar to the symptoms of many other diseases.

If the disease is acute, and the necessary treatment is not provided, it is possible that amoebas, penetrating into the walls of the intestine, contribute to the appearance of ulcers. If they occur at the site of large vessels, bleeding may open. And this is a threat to the life of the patient. You will need immediate surgery. It will be necessary to turn to surgeons even when amoebiasis has passed into an extraintestinal form.

How to overcome the disease?

Treatment in medical institutions begins with diagnostics, for which samples of feces, urine, and blood are taken for analysis. Further, the treatment process is already in the hospital controlled by a doctor. Most often, a specialist prescribes an appointment:

1. Metronidazole, which must be taken for at least a week. If the patient is diagnosed with a severe case of the course of the disease, then treatment with metronidazole continues for 14-15 days. No less effective is Furamid.
2. Salt solutions. This is necessary to restore water balance.
3. Antispasmodics.
4. Enzyme preparations to stop the colitis syndrome. This is Panzinorm, Digestal.
5. Antibiotics. Necessary in the course of treatment to change the microbial biocenosis in the intestine.

If the disease is diagnosed in a chronic form in remission, then Quinamine, Ambilgar, Dihydroemitin, Emetin are also used for treatment.

But the treatment will be incomplete without observing certain food restrictions. Table No. 4 is recommended for such patients and the following are prohibited:

1. Baking, bread.
2. Any kind of sweets.
3. Soda.
4. Salty, spicy.
5. Fruit.
6. Vegetables.

Then the return to the usual food should be slow. This process should take at least two weeks.

It's worth reading

How is staphylococcus transmitted

• Staphylococcus - what is it?
• Causes of infection and routes of transmission
• At childbirth
• When breastfeeding
• Can you get infected through kissing?
• Is the infection from a dog or cat?
• What is dangerous infection with staphylococcus aureus
• Prevention of staph infection

The most common opportunistic bacterium is staphylococcus aureus. The microorganism is able to cause inflammation on the skin, affect the subcutaneous tissue, affect the internal organs. To avoid a dangerous infection, it is important to know how staph is transmitted and whether it is contagious.

Staphylococcus - what is it?

Staphylococcus aureus is a Gram-positive bacterium that is part of the healthy microflora of the human skin. A small amount of opportunistic pathogens is also present in the nose and throat, which is normal.

Under certain conditions (decreased immunity, concomitant diseases), the bacterium is capable of causing disruptions in the functioning of any organ or system. The most commonly affected are the skin, intestines and genitourinary system.

The severity of the lesion and the course of the staphylococcal infection depend on the type of pathogen:

1. Saprophytic staphylococcus. The bacterium affects the genitourinary system of women, causing cystitis and kidney pathology. Localization of bacteria of this type occurs in the genitals and on the epithelium of the urinary canal.
2. Staphylococcus aureus is the most common and harmful type of pathogenic microorganisms. The bacterium causes purulent inflammation of the skin layers in adults and children, and can affect the liver, heart, blood vessels and brain.
3. Epidermal staphylococcus. The bacterium is part of the normal microflora of the skin and all mucous membranes of a person. With strong immunity, cutaneous staphylococcus does not harm health. If the pathogen enters the bloodstream with weakened body defenses, the focus of inflammation can develop in the heart (in the inner shell).

Causes of infection and routes of transmission

Epidermal and saprophytic pathogens are constantly present on human skin.

The cause of its entry into the blood can be any violation of the integrity of the skin:

• scratches, abrasions, microcracks;
• wounds after surgery.

The risk of contracting Staphylococcus aureus is much higher. This is due to the fact that the bacterium constantly lives in the external environment and freely passes from person to person.

Main routes of transmission:

1. Medical instruments and equipment. You can become infected with a staphylococcal infection during intravenous nutrition, ventilation of the lungs, hemodialysis. Most often, patients have a weakened immune system, so the bacteria, once in the body, immediately affect the internal organs.
2. Food. Bacteria can be found on dairy products, cakes, eggs, meat. Once in the body, pathogenic microorganisms poison the intestines, causing severe intoxication.
3. Airborne (air-dust) way. Microorganisms are quickly transmitted between people through sneezing and coughing. Sometimes, in order to get sick, it is enough to be near the patient.
4. Household path. The causative agent of inflammatory processes withstands high and low temperatures, so its presence on household items of a sick person is quite possible. It is important to wash your hands after any contact with other people's things.
5. Nosocomial infections. The source of infection are patients with erased forms of staphylococcus aureus or staphylococcus carriers.
6. Sexual infection. During unprotected sex, staphylococcus aureus moves from the carrier to a healthy person through the mucous membranes of the urinary tract.

At childbirth

Children have a high probability of becoming infected in the hospital through any wounds or microtraumas during childbirth. As a result, a newborn may experience skin rashes of a purulent nature, damage to the lungs (pneumonia) and blood (pemphigus, sepsis).

When breastfeeding

If a woman is infected, infection with staphylococcus aureus in infants occurs through breast milk. Once in the intestine, the bacterium can cause dysbacteriosis of varying severity in a child.

It is also possible for a mother to become infected from a child while breastfeeding. If bacteria from the baby's saliva enters the cracks in the nipples, staphylococcus aureus provokes the development of severe inflammation in the chest, which develops into purulent mastitis.

Can you get infected through kissing?

Staphylococcal infection is transmitted through the mucous membranes. With saliva, pathogenic bacteria are able to pass from the carrier to a healthy person. Therefore, kissing is another way of transmitting staph.

Is the infection from a dog or cat?

Pets can be infected with staphylococcus aureus. In this case, the route of infection is an animal bite, in which saliva with bacteria enters the human body.

What is dangerous infection with staphylococcus aureus

Infection with staphylococcus threatens a person with the following consequences:

• pathology of the urinary system (cystitis, pyelonephritis);
• inflammation in the lungs (pneumonia);
• skin diseases (dermatitis, eczema, furunculosis);
• acute purulent processes of internal organs (abscess, peritonitis);
• inflammation in the brain (meningitis);
• gallbladder disease (cholecystitis).

Prevention of staph infection

To protect yourself from infection with staphylococcus aureus, you need to adhere to the basic preventive measures:

• personal hygiene (wash your hands often, use your own towels, do not take other people's things);
• timely and carefully treat any skin lesions with antiseptics and cover them with bandages (bandage, adhesive plaster);
• lead a healthy lifestyle to maintain the immune forces of the body;
• use condoms during sexual intercourse.

Among the opportunistic bacteria that a person encounters daily, the most dangerous is staphylococcus aureus. The microorganism is able to affect not only the skin and subcutaneous layers, but also penetrate the organs, causing purulent inflammation in the lungs, brain, genitourinary system, and intestines. Staphylococcal infection has many ways of transmission, which makes it especially dangerous for both children and adults.