Rabies in humans: symptoms, treatment and prevention

Rabies is an acute infectious disease caused by a virus that enters the human body when it bites a sick animal or sprays its saliva. Clinically characterized by severe damage to the nervous system. It is one of the most dangerous infectious diseases. Without specific treatment - the introduction of a vaccine against rabies - the disease ends in a fatal outcome. The earlier a person seeks medical help after a bite, the less chance of getting sick. Let's get acquainted with the causes, signs of rabies in people, talk about the principles of its diagnosis and treatment, as well as how to avoid this dangerous ailment.

Historical facts

Rabies existed on the planet Earth even before our era, and to this day mankind has not devised a way to destroy the circulation of the pathogen in nature. The name of the disease came from the word "demon". This is how the clinical symptoms of the disease were treated in ancient times, believing that a demon enters into a person. There are some countries where rabies is not registered: Great Britain, Norway, Sweden, Japan, Finland, Spain, Portugal, New Zealand, Cyprus (mostly island countries). Until July 6, 1886 all cases ended with a 100% fatal outcome. It was on this day that the first specific rabies vaccine was used (Rabies - rabies in Latin), created by the French scientist Louis Pasteur. Since then, the fight against the disease ended in victory (recovery).

Causes

Rabies is a viral infection caused by Neuroiyctes rabid from the Rabdovirus family. The causative agent is destroyed by boiling for two minutes, inactivated by alkaline solutions, chloramine, 3-5% carbolic acid. For the virus, direct sunlight is damaging, drying. But the freezing, exposure to antibiotics and phenols does not affect the virus.

In nature, the virus circulates among warm-blooded animals and birds. The source of the infection is any (!) Rabid animal. Most often a person becomes infected from dogs, cats, wolves, foxes, bats, crows, cattle. Usually such animals and birds behave inadequately, attack people and other animals, biting them and infecting in this way. It is believed that a rabid person, if bitten by another, can also be a source of infection. The virus is transmitted with saliva: with a bite and even just a drop of saliva on the skin and mucous (due to the possible presence in these areas of microdamages that are not visible to the eye).

The incubation period (the time from the moment the pathogen enters the body before the onset of the first symptoms) lasts on average from 10 days to 3-4 months. Single cases of the disease with an incubation period of about a year are recorded. The timing of the onset of the first symptoms depends on many factors: the places of the bite (the most dangerous ones are in the head, the genitals, the hands), the amount of the virus that has entered the body, the state of the immune system. Even the kind of animal in this case plays a role. Be aware that any animal bite is considered a potential risk of rabies, and you should immediately seek medical help.

How does rabies develop?

The virus gets through the damage to the skin and mucous membranes in the end of the nerves. Penetrates into nerves and moves towards the brain, multiplying in parallel. The speed of movement of virus particles is 3 mm / h, which is why bites in the head, face and hands are very dangerous (very close to the central nervous system). Penetrating into the brain, the virus destroys the cells of the cortex of the cerebral hemispheres, the cerebellum, the subcortical formations, the nuclei of the cranial nerves, the medulla oblongata. Simultaneously, the virus rushes back through the nerve trunks, now in a downward direction. Thus, the whole nervous system of a person is affected.

As a result of the accumulation of the virus, specific conglomerates are formed in the cells of the brain: Babesh-Negri body. They are found in the brain after the autopsy of those who died from rabies.

Symptoms

In total, three stages of rabies are distinguished, differing from each other with different symptoms:

• the initial stage (the period of precursors, the prodromal period) - lasts 1-3 days;
• stage of excitation (heat, hydrophobia) - lasts 1-4 days;
• period of paralysis (stage of "sinister calm") - lasts from 1 to 8 days according to different data (very rarely 10-12 days).

initial stage

The patient has painful and unpleasant sensations in the area of ​​the bite, even if by this time the wound has completely healed. If, as such, there was no bite, then such sensations appear in the place where the saliva of the diseased animal falls. A person feels a burning sensation, pulling and aching pain towards the center (along the nerve trunks up to the brain). The site of the bite itches, has increased sensitivity, can even swell and blush.

Body temperature rises to low-grade figures: 37-3, ° C. The state of health worsens, headaches, disturbed sleep and appetite, general weakness can disturb. Along with these symptoms there are disorders of mental activity: there is an unreasonable anxiety, fears, anguish, indifference to everything that is happening. Man is locked in himself. Sometimes there can be periods of irritation. If the bite was in the face area, the patient may be disturbed by visual and olfactory hallucinations: everywhere smells are felt, things or phenomena that do not actually appear. Characterized by nightmarish dreams.

The pulse and breathing gradually increase, anxiety grows.

Stage of excitement

Characterized by increased sensitivity to all environmental influences: light, sounds, smells, touches. Especially typical is the fear of water: hydrophobia. When you try to take a sip of water, there is a convulsive painful contraction of the muscles of the pharynx and the respiratory muscles, right down to vomiting. Then spasms arise even from the sound of pouring water or its kind. Excitability of the nervous system reaches such a limit that any external stimuli provoke convulsions. Patients begin to be afraid of light, noise, air blowing, as all this provokes painful contractions of muscles, painful for the patient.

Increases the tone of the sympathetic nervous system. Pupils sharply expand, eyes seem to protrude forward (exophthalmos), eyes fixed in one point. The arterial pressure rises, the heart rate increases, the pulse dramatically increases. Breathing becomes frequent. There is profuse sweating, pronounced salivation (while saliva contains a rabies virus, which means it is contagious).

Periodically, there are attacks of severe psychomotor agitation, during which consciousness is disturbed, and the person does not control himself. The patients become aggressive, attack the surrounding people, tear their clothes to shreds, beat their heads against the walls and the floor, shout in a different voice, spit, and bite. During an attack they are not left with hallucinations of a menacing nature. Heart and respiratory disorders grow, breathing and palpitation can stop, then death occurs.

Consciousness comes back between attacks to the patient, behavior becomes adequate. In the end, one of the bouts of excitement ends with the formation of paralysis, and the last stage of rabies comes.

Stage of paralysis

The immobility of the limbs, the tongue, the eye muscles, the muscles of the pharynx and the larynx develops. The patient seems to calm down. Cramps stop, fear of water disappears. The patient no longer reacts violently to light and sounds.

The body temperature rises sharply to 40-42 ° C. Arterial blood pressure drops, and the heart rate increases. Against the background of the defeat of the respiratory and cardiovascular centers, death occurs.

Occasionally, rabies occurs atypically: there are no symptoms of hydrophobia and motor excitement, immediately paralyzes form. In such cases, rabies is not recognized, only at the autopsy Babes-Negri body is found, which confirms the diagnosis.

Principles of diagnostics

The diagnosis is established based on the history of the disease (bite of the sick animal) and clinical manifestations.

Diagnosis is based on anamnesis data: an animal bite or osluzhnenie skin. Then the specific signs of rabies play a role: hydrophobia, increased sensitivity to irritants (sounds, light, draft), copious salivation, attacks of psychomotor agitation with convulsions (even in response to the slightest movement air).

From laboratory methods, one can note the detection of rabies virus antigens in the prints from the surface of the cornea. In the analysis of blood, leukocytosis is noted due to an increase in the lymphocyte count. After the death of the patient at the autopsy, the Babesh-Negri body is found in the substance of the brain.

Principles of treatment

There are no statistically reliable methods of treating rabies. If the patient already had initial signs, then the disease is incurable. To help the patient is possible only in the incubation period, and the earlier, the better. For this, a rabies vaccine is administered, but this measure is considered preventive.

When the patient has already developed signs of rabies, usually carry out the so-called symptomatic treatment to alleviate his condition. For this person put in a separate room, isolate him from light, noise, draft (so as not to provoke convulsions). Drugs are used narcotic substances, anticonvulsants, muscle relaxants. In the presence of severe respiratory disorders, the patient is connected to the device of artificial ventilation. These manipulations prolong the life of the patient for several hours or even days, but the outcome is still unfavorable: a person dies. The introduction of rabies immunoglobulin and vaccine, when the symptoms of rabies have already appeared, is not effective!

Since 2005 around the world, several cases of recovery from rabies have been reported without the use of an anti-rabies vaccine. In 2005 in the US, a 15-year-old girl survived as a result of her introduction into an artificial coma from the moment signs of rabies appeared. While she was in a coma, she used drugs that stimulate the immune system. Such treatment was based on the assumption that the human body simply does not have time to develop antibodies against the rabies virus, and if you "turn off" the nervous system for a while, then there is hope for healing. A miracle happened - and the girl recovered. A similar method of treatment was called the "Milwaukee protocol." Later, this protocol was tried to apply to other cases of rabies: out of 24 attempts, only one success was completed, the remaining 23 people were killed.

In 2008 managed to save a 15-year-old boy from Brazil. For his treatment, the Milwaukee protocol, antiviral agents, sedatives and anesthetics were used. In 2011 survived 8-year-old child, in 2012. - 5 more people. In all cases, the treatment was carried out according to the protocol. Scientists have not yet agreed on what exactly helped these patients avoid death. It is assumed that the main role played an unusually strong immunity and, perhaps, a weakened form of the virus that caused the disease.

In the year 2009 in the US, a case of recovery from an antisocial woman with symptoms of rabies allegedly arose after a bite of a bat was recorded. This episode pushed scientists to the idea that a person can have abortive forms of rabies in analogy with animals. It is known that from 1% to 8% of animals that have been bitten by a known sick animal do not get rabies.

Prevention

Despite the described cases of recovery, to date, rabies is considered an incurable disease. It can be prevented only in one way: timely vaccination.

After biting the animal, it is necessary to wash the wound as soon as possible using household soap, treat with 70-degree alcohol or 5% iodine solution (if possible) and seek medical attention help.

In the medical institution, local treatment of the wound is performed, if necessary, seams are applied. Special prevention is then carried out by administering an anti-rabies vaccine and / or rabies immunoglobulin.

The rabies vaccine is a strain of rabies virus, derived from the laboratory. Its administration stimulates the production of antibodies. The vaccine can not cause rabies. The ampoule with the vaccine is opened, the contents are mixed with 1 ml of water for injection and injected intramuscularly into the shoulder region (children under 5 years old - in the thigh). Within 30 minutes after the injection, a medical observation is established for the patient, since an allergic reaction is possible. The course of vaccination is as follows: the first administration is on the day of treatment, then on the 3rd, 7th, 14th, 30th and 90th day. During the entire vaccination period, and also 6 months after it (ie, only 9 months), the patient is categorically contraindicated in alcohol intake. Avoid overheating, overcooling and overwork. The course of treatment with a vaccine is prescribed regardless of the time when a person was bitten. Even if seeking medical help occurs several months after the bite, a full course of vaccination is still conducted.

In some cases, along with the vaccine used and rabies immunoglobulin (with bites of the head, neck, face, hands, genitals, with multiple bites or very deep single bites, with mucosal osuscules, any damage caused by wild carnivorous animals, bats and rodents). Antibacterial immunoglobulin is applied at the rate of 40 IU / kg (horse) or 20 IU / kg (human). It is necessary to try to introduce the entire dose into the tissues around the place of the bite. If this is not possible, the remainder of the drug is injected intramuscularly into the shoulder or thigh. Immunoglobulin in the latter case should be administered to sites other than the introduction of the vaccine. If more than 3 days have passed since the contact with the animal, then rabies immunoglobulin is not used.

When the vaccine is used:

• with single surface bites, scratches, abrasions caused by wild and domestic animals;
• with multiple bites or a single deep bite inflicted by wild and domestic animals;
• when the intact skin or mucous membrane is infected with wild and domestic animals.

In this case, if it is possible to observe the animal that caused the damage, and within 10 days it remains healthy, only the first three injections of the rabies vaccine are made. If it is impossible to observe the animal for any reason, the vaccination course is carried out completely.

Such a scheme of rabies prevention almost 100% saves a person from a disease.

The use of the vaccine can have side effects. Locally there may be a small swelling, redness and itching. The nearest lymph nodes may increase. Of the general symptoms should be noted headache, general weakness, a slight increase in body temperature. To eliminate these symptoms, antipyretic and antiallergic agents are used.

People who are more often confronted with the rabies virus by their activities are shown mandatory preventive vaccination against rabies. This category includes veterinarians, hunters, foresters, slaughterhouse workers, persons performing work to catch neglected animals. This vaccine is given to 1 ml in the first month 3 times (1, 7, 30 days), then once a year, and then once every three years.

The general methods of preventing rabies include vaccination of domestic animals against rabies, catching stray dogs and cats, regulation of the density of wild animals (in foxes). To hunt for wild animals should not be allowed unvaccinated dogs.

Rabies is a deadly disease caused by the bite of a sick animal. To date, there is only one sure way to avoid the disease: in case of a bite, immediately seek medical help and get vaccinated with an anti-rabies vaccine.