What does the rabies virus affect? Sanitary microbiology

The importance of viruses in medicine can be compared to a mass destructive factor. When they enter the human body, they reduce its protective capabilities, destroy blood cells, and penetrate the nervous system, which is fraught with dangerous consequences. But there are special types of viruses that leave no chance of survival. Rabies is one of these.

What is rabies and how dangerous is it to humans? How does infection occur in people and are there outbreaks of infection in our time? How does the disease manifest itself and how does it end? Is there a cure for this disease and what prevention is needed? Let's find out everything about this dangerous infection.

Description

It is unknown where the rabies virus came from. Since ancient times, it has been called hydrophobia, because one of the common signs of advanced infection is the fear of water.

The first scientific works appeared in 332 BC. e. Aristotle also suggested that a person becomes infected with rabies from sick wild animals. The name itself comes from the word demon, since long before the viral nature of the infection was discovered, a sick person was considered possessed by evil spirits. Aulus Cornelius Celsus (an ancient Roman philosopher and physician) called the infection hydrophobia and proved that wild wolves, dogs and foxes are carriers of the disease.

The foundations for the prevention and treatment of the rabies virus in humans were laid by the French microbiologist Louis Pasteur in the 19th century, who, as a result of many years of research, developed an anti-rabies serum that saved more than one thousand lives.

At the very beginning of the last century, scientists were able to establish the viral nature of the disease. And exactly 100 years later, they found out that rabies can be cured even at the stage of the first signs of the disease, which was not the case before. Therefore, this, as everyone previously believed, was a fatal disease, today it is considered curable, but under certain circumstances.

What is rabies

Rabies is a neurotropic (affecting the nervous system) acute viral infection, which can be infected by animals and humans. After the virus enters the body, the symptoms quickly increase in intensity, and the infection ends in death in most cases. This is due to the characteristics of the microorganism.

How dangerous is the rabies virus?

  1. It is resistant to low temperatures and does not react to phenol, Lysol solution, sublimate and chloramine.
  2. It cannot be killed with a strong antibacterial drug; even viral agents are powerless.
  3. At the same time, the rabies virus is unstable in the external environment - it dies when boiled after 2 minutes, and under the influence of temperatures above 50 ºC - in just 15. Ultraviolet light also quickly inactivates it.
  4. The virus moves to the nerve cells of the brain, causing inflammation.
  5. The microorganism exists on almost all continents and, according to WHO estimates, more than 50 thousand people die from it every year.

The rabies virus can be found not only in African and Asian countries, but also in the post-Soviet space, as it is spread by wild animals.

Causes of human infection

How is rabies transmitted to humans? This is a typical zoonotic infection, that is, people become infected from a sick animal. The natural reservoir of the virus is carnivores.

  1. The carriers of infection are foxes and wolves in our forests. Moreover, the main role in the spread of the rabies virus belongs to foxes.
  2. In the countries of America, raccoon dogs, skunks, and jackals play a large role in infecting people.
  3. In India, bats are involved in the spread of infection.
  4. Pets such as cats and dogs can also infect humans.

What are the ways of transmission of the rabies virus? - through wound surfaces or mucous membranes, where the virus found in the animal’s saliva enters.

How does infection occur? The virus is active in the last days of the incubation period and during the development of manifestations of the disease, it is then that it is already present in the saliva of a sick animal. When the rabies pathogen gets on the mucous membranes or on a wound, it enters the human body and begins to multiply.

How can you get rabies from a dog if there was no bite? Contact with the saliva of an infected pet is sufficient. It is almost impossible to suspect the disease during the incubation period, but the virus is already present and actively multiplying inside. This is another dangerous moment in the spread of infection. What are the signs of rabies in a person from a dog bite? - they are no different from those when infected by other animals. The only thing that matters is the size of the animal. The larger the dog, the more harm it can cause and the faster the infection will develop.

There is an assumption about where the virus comes from - scientists have come to the conclusion that there is a reservoir in nature - these are rodents with rabies that did not die immediately after infection.

Nowadays, foci of infection can be found absolutely everywhere, in any country in the world. But outbreaks of the disease were not recorded in those regions where anti-rabies serum is actively used (Japan or on the islands of Malta, Cyprus).

Susceptibility to infection is universal, but children are more likely to get sick in the summer-autumn period due to visiting the forest. Can you get rabies from a person? Throughout the history of studying the disease, doctors have been afraid that a sick person is dangerous to others. But this is almost impossible, because he is closely monitored, including his rigid fixation on the bed or complete isolation from others.

Is rabies transmitted through a scratch? - yes, this is a possible way of contracting an infection, provided that a large amount of saliva gets into the wound. The virus is concentrated in the muscle mass, then reaches the nerve endings. Gradually, the microorganism captures an increasing number of nerve cells and affects all their tissue. When the rabies virus multiplies in cells, special inclusions are formed - Babes-Negri bodies. They serve as an important diagnostic sign of the disease.

The infection reaches the central nervous system and affects important structures of the brain, after which convulsions and muscle paralysis appear. But not only the nervous system suffers; the virus gradually penetrates the adrenal glands, kidneys, lungs, skeletal muscles, heart, salivary glands, skin and liver.

Penetration of the rabies virus into the salivary glands and its reproduction causes further spread of the disease. The infection spreads faster if a person is bitten by an animal in the upper half of the body. A bite to the head and neck will lead to rapid spread of infection and a large number of complications.

Periods of disease development

There are several stages in the development of rabies:

  • incubation or period without manifestations of the disease;
  • the initial or prodromal period of rabies, when there are no visible typical signs of infection, but the person’s well-being significantly deteriorates;
  • stage of heightened or excited;
  • terminal stage or paralytic.

The most dangerous time is the onset of the disease. The incubation period for rabies in humans ranges from 10 to 90 days. There are cases where the disease developed a year after the animal’s bite. What is the reason for such a big difference?

  1. As already noted, the location of the bite plays an important role in this. If an animal infected with the rabies virus bites a person in the upper half of the body, the time frame for the development of the disease is reduced. In case of trauma to the foot or lower leg, infection develops more slowly.
  2. Depends on the age of the affected person. In children, the incubation period is much shorter than in adults.
  3. The type of infected animal also matters. The bite of small carriers of infection is less dangerous, a large animal will cause more damage and the disease will develop faster.
  4. Another important aspect is the size and depth of the wound, bite or scratch.
  5. The greater the amount of rabies pathogen that gets into the wound, the greater the chances of rapid development of the disease.
  6. The reactogenicity of the human body also plays a role, or, in other words, how susceptible its nervous system is to a given pathogen.

Symptoms of rabies in humans

What are the first signs of rabies in humans?

But even at this time it is almost impossible to suspect the onset of the disease, because such symptoms accompany many infectious diseases, not only rabies.

Symptoms during periods of height or excitement

After a short prodrome, another period follows - the height. It does not last long, from one to four days.

Additionally, the symptoms of the disease are accompanied by severe attacks of aggression:

  • a person scratches, and sometimes even tries to bite himself and others, spits;
  • the victim rushes around the room, trying to hurt himself or others;
  • people infected with the rabies virus develop abnormal strength, they try to break the surrounding furniture and hit the walls;
  • attacks of mental disturbance appear - auditory and visual hallucinations, delusions occur.

Outside of attacks, the person is conscious and feels well, he is in a state of relative peace. During this period, the rabies patient vividly describes his experiences and suffering during the attack.

Symptoms of rabies during paralysis

How does the period of paralysis manifest during the development of rabies?

  1. Due to muscle paralysis, a person experiences constant salivation, but he cannot swallow and therefore constantly spits.
  2. Movement in the arms is weakened due to paralysis of the shoulder muscles and limbs.
  3. The jaw of such patients often hangs due to weakness of the facial muscles.
  4. In addition to paralysis, in patients with rabies in the last stage of the disease the body temperature rises.
  5. Disturbances in the functioning of the cardiovascular and respiratory systems are increasing, so another attack for a person can end in failure.
  6. Further, the symptoms of rabies in people fade away - a general calm of the person sets in, fear and anxiety disorders disappear, and attacks are also not observed.
  7. The violence of rabies is replaced by apathy and lethargy.

The total duration of all periods of the disease is no more than 10 days, excluding the incubation period.

Atypical course of rabies and prognosis

In addition to the familiar classic course of rabies, there are several other variants that are uncharacteristic of this infection.

  1. The disease occurs without fear of light or water, and begins immediately with a period of paralysis.
  2. Perhaps the course of the disease is with mild symptoms, without any special manifestations.

Doctors even suggest that one of the important factors in the spread of the disease is the hidden or atypical course of the infection.

The prognosis of rabies is always difficult to predict. Here, perhaps, there are two main options - recovery or death from rabies. The later therapy is started, the more difficult it is to cure the patient. The last period of the disease is always unfavorable in terms of recovery; at this time a person no longer has a chance.

Step-by-step diagnosis of rabies

Diagnosis of the disease begins with a detailed history of the affected person.

At the initial stage of disease development, the fundamental principle of diagnosing rabies in humans is the analysis of symptoms. For example, conclusions can be drawn based on seizures after a patient comes into contact with water.

Treatment

Rabies therapy begins with an important stage - complete isolation of the person in a separate room, in which there are no irritants, so as not to provoke attacks.

Then, treatment of rabies in humans is carried out taking into account the symptoms.

  1. First of all, they try to correct the functioning of the nervous system, because the main problems are due to inflammation of the centers of the brain. For this purpose, sleeping pills, drugs to reduce pain, and anticonvulsants are prescribed.
  2. Considering that patients with rabies are weakened, they are prescribed parenteral nutrition, that is, glucose, vitamins to maintain the functioning of the nervous system, plasma-substituting substances and simply saline solutions are administered using solutions.
  3. Is rabies in humans treated with antiviral drugs or other treatments? In the later stages, the disease is incurable and ends in death. Even the most modern antiviral drugs are ineffective and therefore are not used against rabies.
  4. In 2005, a girl was cured in the United States who, during the height of her illness, was put into an artificial coma, and after a week of brain shutdown, she woke up healthy. Therefore, active development of modern methods for treating patients with rabies is currently underway.
  5. In addition, they are trying to treat the disease with immunoglobulin for rabies in combination with mechanical ventilation and other methods.

Prevention

Due to the lack of effective treatments for rabies, prevention remains the most reliable method today.

Nonspecific prevention of rabies begins with the extermination of infection vectors and detection, as well as elimination of the source. In recent times, they carried out so-called sweeps of wild animals and exterminated them. Since in nature the fox and wolf rank first in the spread of rabies, they were destroyed. Nowadays such methods are not used, only in case of changed behavior can special services deal with it.

Since animals can spread the rabies virus in urban environments, much attention is paid to preventive measures for domestic dogs and cats. For this purpose, they are given specific rabies prevention - they are regularly vaccinated.

Non-specific methods of protection against rabies include burning the corpses of dead animals or people so that the virus does not continue to circulate in nature. In addition, doctors strongly recommend that if you are bitten by an unfamiliar animal, immediately wash the wound with large amounts of liquid and go to the nearest medical center for emergency assistance.

Specific prevention of rabies

Emergency prevention of rabies consists of administering rabies vaccine to the affected person. To begin with, the wound is actively washed and treated with antiseptic drugs. If a person is suspected of being infected with the rabies virus, excision of the edges of the wound and suturing it, as is done under normal conditions, is contraindicated. It is important to follow these rules, because when surgical treatment of a wound is performed, the incubation period of rabies is significantly reduced.

Where are rabies injections given? - anti-infection drugs are administered intramuscularly. Each vaccine has its own characteristics in purpose and administration. The dose of the drug may also vary depending on the conditions. For example, it depends on the location of the bite or on the duration of the injury and contact with animals. The rabies vaccine is given in the deltoid muscle or in the anterolateral thigh. There are vaccines that are injected into the subcutaneous tissue of the abdomen.

How many injections does a person get for rabies? - it all depends on the conditions. It matters who is prescribed the drug - the victim or a person who, due to the nature of his work, may encounter infected animals. The creators recommend administering different types of vaccines according to their own developed schedule. After the bite of an animal with rabies, the method of administering the drug six times can be used.

When vaccinating, it is important to meet several conditions:

  • for some time after it and the entire period when a person is vaccinated, you cannot introduce unusual foods into the diet, as allergies often develop;
  • if it was possible to observe the dog and it did not die from rabies within 10 days, the vaccination schedule is reduced and the latter are no longer given;
  • alcohol and rabies injections are incompatible, the consequences can be unpredictable, and the vaccine simply will not work.

During the entire period of administration of the rabies vaccine, a person must be under the supervision of doctors. Emergency rabies immunoprophylaxis is most often carried out in an emergency room, which is equipped with everything necessary for this.

What side effects can a person have after receiving rabies injections? In the past, vaccines made from animal nerve tissue were widely used. Therefore, several years ago, after the use of rabies vaccination, brain diseases such as encephalitis and encephalomyelitis developed. Now the composition and methods of manufacturing the drugs have changed slightly. Modern vaccines are much easier to tolerate; after their use, only sometimes an allergic reaction occurs or individual intolerance appears.

Effective anti-rabies drugs have not yet been invented that could save a person’s life during the development of the disease. Its most common complication is death. For this reason, rabies is one of the most dangerous infections. Therefore, after an animal bite, there is no need for heroism - it is important to promptly seek help at the emergency room.

Fixed rabies virus

"...Fixed rabies virus is an attenuated strain of rabies virus obtained by long-term passaging through the brain of a rabbit. Production strains of fixed rabies virus are stored in the L.A. Tarasevich GISC and are issued once a year to institutions that have the right to work with microorganisms of III - IV pathogenicity groups..."

Source:

"SAFETY OF WORKING WITH PRODUCTION STRAINS OF FIXED RABIES VIRUS. METHODOLOGICAL INSTRUCTIONS. MU 3.3.1.1099-02"

(approved by the Chief State Sanitary Doctor on January 15, 2002)


Official terminology. Akademik.ru. 2012.

See what “Fixed rabies virus” is in other dictionaries:

    fixed rabies virus- vaccine strain of V. rabies, characterized by a strictly defined incubation period for the disease in rabbits during intracerebral infection ... Large medical dictionary

    PASTEUR VACCINATIONS- PASTEUR VACCINATIONS, or anti-rabies vaccinations, are preventative. anti-rabies measure (see). A fixed poison (virus fixe) is used as an antigen (see Rabies), which has been used to this day. time continues almost everywhere... Great Medical Encyclopedia

    Immunization- I Immunization (lat. immunis free, free from anything; synonym: immunoprophylaxis, protective vaccinations, preventive vaccinations) specific prevention of infectious diseases of people and animals. Immunoprophylaxis of a number of... ... Medical encyclopedia

    RABIES- honey Rabies is a viral infectious zoonotic disease with a contact mechanism of transmission of the pathogen, occurring with the development of severe progressive damage to the central nervous system with a fatal outcome. Classified as a particularly dangerous infection. Etiology...... Directory of diseases

    passage- a, m. passage m., German. Passasche. outdated 1. originally military. Path, passage, crossing. PPE 385. And all the passages and transportations and crossings are all their cost. 1711. AK 4 29. We have received your letter, to which we have no other answer, only... ... Historical Dictionary of Gallicisms of the Russian Language

"...Fixed rabies virus is an attenuated strain of rabies virus obtained by long-term passaging through the brain of a rabbit. Production strains of fixed rabies virus are stored in the L.A. Tarasevich GISC and are issued once a year to institutions that have the right to work with microorganisms of III - IV pathogenicity groups..."

Source:

"SAFETY OF WORKING WITH PRODUCTION STRAINS OF FIXED RABIES VIRUS. METHODOLOGICAL INSTRUCTIONS. MU 3.3.1.1099-02"

(approved by the Chief State Sanitary Doctor on January 15, 2002)

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MU 3.3.1.1099-02

METHODOLOGICAL INSTRUCTIONS

3.3.1. VACCINE PREVENTION

Safety of working with production strains of fixed rabies virus


Date of introduction 2002-04-01

1. DEVELOPED by the Russian Research Institute "Microbe" of the Ministry of Health of the Russian Federation (MD I.A. Dyatlov, PhD A.K. Nikiforov, PhD S.A. Eremin); State Research Institute for Standardization and Control of Medical Biological Preparations named after. L.A. Tarasevich of the Ministry of Health of the Russian Federation (Dr. A.A. Movsesyants, Ph.D. I.A. Ozeretskovsky, Researcher G.B. Ageenko).

3. APPROVED by the Chief State Sanitary Doctor of the Russian Federation - First Deputy Minister of Health of the Russian Federation G.G. Onishchenko on January 15, 2002. Entered into force on April 1, 2002.

4. INTRODUCED FOR THE FIRST TIME.

1 area of ​​use

1 area of ​​use

1.1. These guidelines have been developed in accordance with the Federal Law "On the Sanitary and Epidemiological Welfare of the Population" dated March 30, 1999 N 52-FZ, the "Regulations on State Sanitary and Epidemiological Standards" and the sanitary rules "Safety of working with microorganisms of III-IV pathogenicity groups and helminths SP 1.2.731-99".

1.2. The requirements of these guidelines are mandatory for health authorities and institutions of the constituent entities of the Russian Federation.

2. Normative references

These guidelines use references to the following regulatory documents:

2.1. Federal Law "On the Sanitary and Epidemiological Welfare of the Population" N 52-FZ of March 30, 1999

2.2. Sanitary rules "Safety of working with microorganisms of III-IV pathogenicity groups and helminths. SP 1.2.731-99".

2.3. Sanitary rules "Procedure for recording, storage, transfer and transportation of microorganisms of I-IV pathogenicity groups. SP 1.2.036-95".

2.5. Sanitary rules for the design, equipment and maintenance of experimental biological clinics (vivariums), approved. Ministry of Health of the USSR dated April 6, 1973 N 1045-73.

2.6. Building codes and regulations "Public buildings and structures". SNiP 2.08.02-89 and “Manual for the design of healthcare institutions” in 5 volumes. - T.1, 3, 5. Gosgrazhdanstroy. - M., 1989.

2.7. OST-42-21-2-85 "Sterilization and disinfection of medical devices. Methods, means. Regimes."

2.8. Order "On approval of temporary lists of harmful, hazardous substances and production factors, as well as work during which preliminary and periodic medical examinations are carried out", approved. Ministry of Health and Medical Industry and State Committee for Sanitary and Epidemiological Surveillance of Russia dated 05.10.95 N 280/88.

2.9. "Instructions for the operation and monitoring of the effectiveness of ventilation devices at healthcare facilities", approved. Ministry of Health of the USSR dated March 20, 1975

2.11. "Guidelines for the use of bactericidal lamps for disinfecting indoor air and surfaces", approved. Ministry of Health and Medical Industry of Russia dated 02.28.95 N 11-16/03-06.

2.12. "Guidelines for monitoring the operation of steam and air sterilizers", approved. Ministry of Health of the USSR dated February 28, 1991 N 15/6-5.

2.13. "Safety rules, industrial sanitation and sanitary and anti-epidemic regime for enterprises producing bacterial and viral preparations", approved. Ministry of Health of the USSR dated August 30, 1979

2.14. Methods of laboratory research on rabies. WHO. - Geneva, 1975.

3. Terms, definitions and abbreviations

An accident is an emergency situation in which there is a real or potential possibility of releasing a pathogenic agent into the air of a production area, the environment, or contamination of personnel.

Biological safety is a system of medical-biological, organizational, engineering and technical measures and means aimed at protecting working personnel, the population and the environment from the effects of pathogenic biological agents.

A biological safety cabinet is a structure used for physical isolation (containment and controlled removal from the work area) of microorganisms in order to prevent the possibility of infection of personnel and contamination of the air of the work area and the environment.

A boxed room (boxing) is an isolated room with a vestibule (pre-boxing area).

Laboratory is a structural unit that carries out experimental and/or/ production work with pathogenic biological agents.

“Infectious” zone is a room or group of laboratory rooms where manipulations with production strains of the fixed rabies virus are carried out.

“Clean” zone is a room or group of laboratory rooms where manipulations with production strains of the fixed rabies virus are not carried out.

Production work - work on the production of medical immunobiological preparations using production strains of the fixed rabies virus.

Fixed rabies virus* is an attenuated strain of rabies virus obtained by long-term passage through the brain of a rabbit. Production strains of the fixed rabies virus are stored in the GISC named after. L.A. Tarasevich and are issued once a year to institutions that have the right to work with microorganisms of III-IV pathogenicity groups.
_______________
* For example, the “Moscow” and “CVS” strains of the fixed rabies virus.


PPE - personal protective equipment.

4. Requirements for organizing work with production strains of fixed rabies virus

4.1. General requirements

Work with industrial strains of the fixed rabies virus can be carried out in laboratories that have a permit issued in the prescribed manner by the Chief State Sanitary Doctor of a constituent entity of the Russian Federation for a period of 5 years. It becomes invalid upon relocation or redevelopment of the laboratory, and can also be canceled if biological safety requirements are violated.

4.2. Requirements for production strains of fixed rabies virus

The WHO Expert Committee (1972) recommended the following requirements for production strains of fixed rabies virus:

- careful recording of passage history;

- carrying out no more than 10 passages in production since the last control of its biological properties;

- minimal pathogenic activity for laboratory animals when administered extraneurally;

- antigen specificity and immunogenic activity;

- study of the properties of the production strain of the fixed rabies virus after every 10 passages.

The fixed rabies virus must have the following main characteristics:

- short incubation period (4-5 days);

- greater pathogenicity for rabbits during intracerebral infection;

- significant weakening of the ability to form Negri bodies;

- cause a paralytic form of rabies without signs of excitement;

- accumulation in the central nervous system of mice up to 6.0-7.0 IgLD/0.03 ml;

- high affinity for the central nervous system and low affinity for internal organs.

4.3. Requirements for laboratory premises and equipment

4.3.1. Laboratories working with production strains of fixed rabies virus should be located in a separate building or an isolated part of the building with a separate entrance.

4.3.2. The laboratory must be provided with water supply, sewerage, electricity, heating and ventilation. All laboratory premises must have natural and artificial lighting depending on the type of work in accordance with the requirements of current regulatory documents.

4.3.3. Laboratory premises should be divided into “infectious” and “clean” zones. Planning decisions and placement of equipment must ensure the flow of promotion of production strains of the fixed rabies virus and compliance with the requirements of these instructions.

4.3.4. The laboratory must have a set of workrooms and other premises, including a shower room, in accordance with the production capacity and range of technological operations performed.

4.3.5. The interior decoration of the premises must be done in accordance with the functional purpose. The surface of the floor, walls, and ceiling in the laboratory premises of the “infectious” zone should be smooth, without cracks, easy to process, resistant to detergents and disinfectants, and the floors should not be slippery.

4.3.6. Windows and doors of premises in the “infectious” area of ​​the laboratory must be sealed.

4.3.7. Existing exhaust ventilation from the “infectious” zone of the laboratory must be isolated from other ventilation systems and equipped with fine air filters. When using Class II biological safety cabinets equipped with an exhaust ventilation system with “Like” fine filters, the exhaust ventilation system can be used without installing filters.

4.3.8. It is allowed to install air conditioners in work rooms and boxes. When working with production strains of fixed rabies virus, air conditioners must be turned off.

4.3.9. Laboratory furniture in the “contaminated” area must have a coating that is resistant to detergents and disinfectants. The surface of the tables should not have seams or cracks.

4.3.10. The width of passages to workstations or between two rows of protruding equipment must be at least 1.5 m (including protruding structures).

4.3.11. Premises where work is carried out with production strains of the fixed rabies virus must be equipped with bactericidal lamps in accordance with the “Guidelines for the use of bactericidal lamps for disinfecting air and surfaces in premises.” The lamps are turned on after wet cleaning. Entry into the room is permitted only after ventilation for at least 30 minutes (when using ozone-free bactericidal lamps, ventilation is not required). It is necessary to keep a record of the operating time of each lamp with a note in the log.

4.3.12. When windows are oriented to the south, it is necessary to protect work tables from direct sunlight by using light-protective films and blinds made of material resistant to disinfectants.

4.3.13. Laboratory premises must be impenetrable to rodents and insects.

4.3.14. The laboratory must be provided with fire extinguishing equipment.

4.4. Requirements for carrying out work in the laboratory

4.4.1. Work with production strains of the fixed rabies virus is carried out by specialists with higher and secondary specialized education who have undergone special training.

4.4.2. Personnel are allowed to work with production strains of the fixed rabies virus after being instructed in compliance with biological safety requirements. Subsequent briefings are carried out at least once a year, with entries in the appropriate journals.

4.4.3. Instruments, equipment and measuring instruments used in the laboratory must be certified, technically sound, subject to metrological control within the established time frame, and have a technical passport. For each device (installation), rules (instructions) for its operation must be developed, taking into account biological safety requirements.

4.4.4. The laboratory must use approved disinfectants (3% chloramine). The shelf life of the prepared solution should not exceed 15 days.

4.4.5. In the premises of the “infectious” zone of the laboratory, the following is carried out:

- work with animals (infection, dissection);

- keeping infected animals;

- disintegration, homogenization of brain tissue and other operations with the probable formation of an aerosol;

- infection of cell culture;

- preparation of suspensions and suspensions;

- work with lyophilized production strains of fixed rabies virus.

4.4.6. During work, workroom doors must be closed. Before work, the “outflow” ventilation is turned on. Leaving the work room during work is prohibited.

4.4.7. Infection of animals is carried out by at least two employees.

4.4.8. When pipetting, you must use rubber bulbs or automatic devices.

4.4.9. Before use, glassware, pipettes, equipment, syringes, etc. must be checked for integrity and serviceability.

4.4.10. Ampules with lyophilized production strains of the fixed rabies virus are opened sterilely over a tray or tray with a gauze napkin soaked in a disinfectant solution. The upper end of the ampoule is heated over a burner flame, the paraffin is removed, then with a piece of sterile cotton wool soaked in sterile water, the extended end of the ampoule is carefully touched to form a crack. The same damp cotton wool is drawn around the spout of the ampoule. After a circular (or not completely circular) crack has formed, the end of the ampoule is covered with gauze or cotton wool and broken off with tweezers.

4.4.11. After opening the ampoule, add 1.0 ml of sterile distilled water and shake gently. The resulting suspension containing the fixed rabies virus is used to infect laboratory animals.

4.4.12. For intracerebral infection of a rabbit, it is securely fixed on a special machine or given light anesthesia (2-2.5 ml of Rometar solution intramuscularly 20-30 minutes before infection). Then the hair in the area of ​​intended injection is carefully cut, treated with a 70% ethanol solution and a 5% iodine solution, and using a sterile 2 ml syringe and a needle size N 20 (10x0.90) inject 0.25 ml of a suspension of the fixed virus rabies strain. The puncture is made approximately in the middle of the line connecting the outer corner of the eye and the ear. When large rabbits are infected, you can use a stainless steel awl or trocar. Obvious signs of paralysis appear in rabbits on the 4th day after inoculation; in rare cases they develop before 7 days. The brain is removed from the animal only after the development of a complete picture of paralysis characteristic of a fixed rabies virus. The first symptoms of experimental rabies include: increased body temperature, fearfulness and dilated pupils. Then meningeal phenomena appear, paresis, usually starting from the hind limbs, rapidly progressing paralysis, involving all limbs, cervical and occipital muscles.

4.4.13. Sick rabbits with a picture of complete paralysis, but with breathing still remaining, are killed by total bleeding. The brain is used to make rabies antigen. After decapitation, the skin is removed, the spine is separated along with the spinal cord, which is autoclaved (2.0 kG/cm (0.2 MPa). 132±2 °C) as infectious material.

4.4.14. To remove the brain, the animal is placed on a sectional tray with its belly down so that its head is on the edge of the table. Using tweezers, a scalpel and scissors, the head is separated from the body. Then the scalp is scalped, removing the ears and upper eyelids. The exposed surface of the skull is moistened with 70% alcohol and placed in a crystallizer. The crystallizer is transferred to a sterile box for antigen preparation. Before opening the skull, it is treated twice with 70% ethyl alcohol. Then the rabbit’s skull is secured in a special device (Appendix 1), which ensures reliable fixation of the animal’s head. Holding the sectioning knife in your left hand, use your right hand to open the skull with a hammer using four rectangular cuts. First, you should make an incision along the line connecting the middle of the eyes, then an incision in the parietal region, and then connect these two incisions with perpendicular cuts. Then, putting aside the dissecting knife and hammer, using tweezers and scissors, the dura mater is released and the anterior part of the brain is separated at the level of the olfactory lobe; cross the medulla oblongata behind the cerebellum, lift the brain, cross the optic chiasm and then transfer it to a sterile Petri dish for weighing.

4.4.15. To prepare the antigen, the brain, after weighing, is placed in a sterile mortar or homogenizer and crushed. Distilled water containing 0.5% phenol is added to the crushed brain to obtain a 10% brain suspension. The brain suspension is filtered through a triple layer of gauze. The sterility of the brain suspension is checked by inoculation on sugar broth, meat-extract agar and meat-extract broth with 0.1% agar and pieces of meat. The crops are kept at 37 °C for 5 days. It is allowed to use a sterile antigen preserved at a temperature of 4 °C for no more than 14 days for immunization of producing horses.

4.4.16. To prepare stock cultures of fixed rabies virus, the rabbit brain is placed in a sterile mortar or homogenizer and crushed. Distilled water is added to the crushed brain to obtain a 10% brain suspension. The sterility of the brain suspension is checked by inoculation on sugar broth, meat-extract agar and meat-extract broth with 0.1% agar and pieces of meat. The brain suspension is poured sterile into 4-5 ml aliquots and frozen at a temperature not exceeding minus 18 °C. The optimal temperature for storing fixed rabies virus strains is minus 70 °C. For infection, take one aliquot out of the freezer and place it in a refrigerator at 4 °C for 18-20 hours. After thawing, carefully select the middle phase of the brain suspension containing the maximum amount of virus using a Pasteur pipette.

4.4.18. Rules for dissecting mice. Mice in a state of severe terminal symptoms of rabies are killed with chloroform. The mouse corpse is fixed on a board with its back up. To do this, you need two pins - one to pin the base of the tail, the other to the tip of the muzzle. You can also use three pins to secure the front legs and tail. After treatment with alcohol, the scalp and neck are dissected using scissors and tweezers, exposing the skull. The skull is clamped in the eye sockets with surgical tweezers, and the roof of the skull is separated with curved scissors, exposing the brain. Using the same curved scissors, the brain is removed and transferred to a sterile Petri dish, which is weighed in advance. The Petri dish with brain tissue is weighed. The brain is then transferred to a sterile mortar, where a 10% brain suspension is prepared using a sterile pestle with the addition of distilled water. The suspension is poured into aliquots and stored at a temperature not lower than minus 18 °C. The optimal temperature for storing fixed rabies virus strains is minus 70 °C.

4.4.19. Upon completion of work, all objects with production strains of the fixed rabies virus must be removed to storage (refrigerators, thermostats, cabinets, etc.); It is mandatory to disinfect the working surfaces of tables with a 3% chloramine solution.

4.4.20. Used pipettes are completely (vertically) immersed in a disinfectant solution (3% chloramine), avoiding the formation of air bubbles in the channels. Duration of disinfection 60 minutes.

4.4.21. Used glassware and solid waste from the “contaminated” area of ​​the laboratory should be collected in closed containers and transferred to an autoclave or disinfected on site. Discharging undisinfected liquids into the sewer network is prohibited.

4.4.22. Transfer of production strains of fixed rabies virus and used utensils for disinfection should be carried out in closed containers to prevent infection of personnel during transportation. After completion of work, the room in the “contaminated” area of ​​the laboratory is locked and sealed. Sealing and removal of seals is carried out by laboratory employees who have permission from the head of the laboratory (unit).

4.4.23. Immunization of producing horses is carried out in accordance with the production regulations for “Liquid anti-rabies immunoglobulin from horse blood serum”.

4.4.24. Rules for antigen administration. The horse antigen is administered in a specially equipped room (operating room). Employees injecting the antigen are dressed in a type 3 anti-plague suit with rubber gloves. To administer the antigen, a device for mass vaccinations, PMP-1, is used, which is connected via a silicone hose to a needle and a bottle with antigen. The entire injection system is connected hermetically. The antigen injection site is pre-treated with a 70% alcohol solution. The needle is inserted subcutaneously and the antigen is slowly injected under slight pressure. After injection, the valve shuts off the antigen supply, and the skin at the site of needle insertion is clamped with hemostatic tweezers for 1 minute. The tweezers are removed, the injection site is treated with a swab moistened with a 70% alcohol solution, and a swab with collodion or furaplast with perchlorovinyl is applied. After use, the entire injection system is boiled for 30 minutes in a 2% soda solution. During the process of hyperimmunization, the general condition and temperature reaction of the producers are constantly monitored. If the temperature rises, the next injection of antigen is given after it drops to normal.

4.4.25. Storage of production strains of fixed rabies virus is carried out in the premises of the infectious zone. Storage, recording, transfer, transportation and destruction of production strains of fixed rabies virus are carried out in accordance with the requirements of SP 1.2.036-95.

4.4.26. Reception of visitors is permitted only in specially designated areas in the “clean” area of ​​the laboratory.

4.4.27. Removal of equipment, laboratory or household utensils, instruments, etc. from the laboratory is carried out only after they have been disinfected and with the permission of its director.

4.4.28. In the “contagious” area of ​​the laboratory it is prohibited:

- leave dishes with production strains of the fixed rabies virus “Moscow” and “CVS” at the workplace after finishing work;

- pipette with your mouth, pour liquid infectious material over the edge of a vessel (test tube, flask, bottle);

- store outerwear, hats, shoes, umbrellas, shopping bags, cosmetics, etc., as well as food;

- smoke, drink water;

- leave the workplace unsupervised while performing any type of work with production strains of the fixed rabies virus;

- pour liquid waste (infected liquids, test material, etc.) into the sewer system without prior disinfection.

4.4.29. It is allowed to carry out experimental and production work with production strains of the fixed rabies virus in the same premises. Experimental and production work must be separated in time. Experimental material should be stored separately from production material in a specially designated refrigerator or thermostat.

4.4.30. All employees working with production strains of the fixed rabies virus must be under clinical observation. Periodic medical examinations are carried out in accordance with current orders (N 280/88 - Ministry of Health and Medical Industry and State Committee for Sanitary and Epidemiological Surveillance of Russia).

4.5. Requirements for the use of personal protective equipment (PPE)

4.5.1. Laboratory employees must be provided with medical gowns, pajamas (overalls), hats, replacement shoes and other personal protective equipment depending on the nature of the work performed and in accordance with current standards.

4.5.2. Work clothes and shoes must be individual, match the size of the workers and be stored separately from personal clothing.

4.5.3. When conducting research in boxed rooms, the medical gown is changed to an anti-plague or surgical gown, reaching the lower third of the leg. Additionally, rubber gloves, slippers and, if necessary, respirators (masks) are used. Operations requiring opening of the skull and spine must be carried out with rubber gloves, safety glasses and anti-plague gowns. It is also necessary to wear rubber or durable polyethylene aprons, which can be easily disinfected or destroyed.

4.5.4. Work clothes should be changed when soiled, but at least once a week.

4.5.5. Before washing, protective clothing must be decontaminated by soaking in a solution of 1% chloramine.

4.6. Requirements for material disinfection and room cleaning

4.6.1. Disinfection of various objects when working with production strains of the fixed rabies virus is carried out in accordance with the nature of the object to be disinfected.

Table

Object to be disinfected

Disinfection method

Disinfectant

Rabies(lat. Rabies, Lyssa, Hydrophobia) has long been known as a disease of wild and domestic animals. The rabies virus selectively infects cells of the central nervous system, so the disease is accompanied by agitation, convulsions, and then paralysis.

Morphology and biological properties. The rabies virus has the shape of a rod measuring 100-150 nm and is coated. It forms inclusions in the cytoplasm of affected cells, which were described in 1892 by Babes, and in 1903 by Negri. They are called Babes-Negri bodies. The shape of the inclusions is spherical, sizes 1-20 microns, according to Romanovsky they are colored red. Their detection in the cells of Ammon's horn has diagnostic value.

The virus is cultivated in the brain tissue of a mouse embryo, when infected in the yolk sac or brain of chicken embryos, and also in the body of a rabbit.

There are two types of rabies virus: a street virus that is isolated from sick people and animals, and a fixed virus obtained by Pasteur during long-term passages of a street virus through the brain of a rabbit (fix virus). The fix virus causes paralysis when infecting rabbits after a strictly fixed, shortened incubation period of 3-7 days. It is non-pathogenic for humans, dogs and other animals, is not excreted in the saliva of animals and humans, is rarely found in peripheral nerves and does not form Babes-Negri bodies. The fixed virus, which has lost its virulence for humans and animals, is used in the manufacture of rabies vaccines. In the mechanism of immunity that occurs after administration of rabies vaccines, the phenomenon of virus interference is of greatest importance. The essence of this phenomenon lies in the ability of one type of virus that has entered the host cell to delay the reproduction of another type of virus that entered the same cell later. The fixed virus, which has a high affinity for nervous tissue, multiplies quickly and prevents the development of the street virus.

Sustainability. The rabies virus is not stable in the external environment: it quickly dies when heated, under the influence of sunlight and disinfectants (formalin, phenol, sublimate). In 50% glycerol it can be stored at -20-40°C for several years.

Pathogenicity. All warm-blooded wild and domestic animals, and to a lesser extent birds, are susceptible to the street rabies virus. Paralytic forms of rabies occur in laboratory animals (rabbits, white mice, guinea pigs) through various routes of infection.

Pathogenesis and clinic. The rabies virus enters the human body through saliva through the bites of rabid animals or salivation of human skin by a sick animal. The virus reaches the central nervous system along the trunks of peripheral nerves and infects it. The incubation period for rabies most often lasts from 1 to 3 months and depends on the location of the bite. For bites of the face and neck, the period is shorter (from 10 days to a year). The disease begins with the appearance of pain at the site of the bite, feelings of fear, anxiety, and irritability. When trying to get drunk and even at the sight of water, convulsions of the swallowing muscles appear, which is why rabies is called hydrophobia, or hydrophobia. The patient is agitated, consciousness is impaired, and convulsive seizures are observed. Patients can bite and rush at medical personnel. After a few days, paralysis of the muscles of the limbs, face, and respiratory muscles occurs, and death occurs. The duration of the disease is 6-7 days.

Virological diagnostics. Methods for intravital indication of the rabies virus have not been developed. The diagnosis is made based on the typical clinical picture of the disease. After death, Babes-Negri bodies are found in the affected brain cells. A specific antigen can also be detected using fluorescent antibodies. The virus can be isolated by infecting laboratory animals: rabbits, white mice and guinea pigs, upon autopsy of which Babes-Negri inclusions are found in the cells of the affected brain.

Prevention and treatment. For the purpose of specific prevention, an anti-rabies vaccine, first proposed by Pasteur, is administered. Vaccines are prepared from a suspension of brain tissue of rabbits, sheep or sucklings of white rats infected with a fixed rabies virus. There are different types of vaccines, differing in the quantity and quality of preservatives. The Fermi vaccine contains 1% phenol, the Semple vaccine contains 0.25% of it, and the Phillips vaccine contains glycerol. In recent years, a live rabies vaccine has been proposed from a virus that is cultivated on bird embryos (Fleury vaccine). The effect of the vaccine is based on the phenomenon of virus interference. All people who have been bitten or salivated by sick or suspected rabid animals are vaccinated. There are no contraindications to the use of the vaccine, since this is the only way to save the infected. Usually, vaccinations are given multiple times over 12-30 days or more, depending on the severity of the bite, its location, and the time that has passed since the bite. The vaccine is administered subcutaneously into the abdomen.

Vaccinations should begin as soon as possible after the bite and be carried out according to existing instructions. The immunity that occurs after vaccination lasts up to 6 months. People who show signs of illness are not vaccinated. For severe bites in the head and neck area, gamma globulin or anti-rabies serum is administered simultaneously with the rabies vaccine. Suspicious animals are monitored for 7 days and, if no signs of disease are observed, they are considered healthy. There are no effective treatments for rabies.

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