Rabies in humans: signs, treatment and prevention
Rabies is an acute infectious disease characterized by severe damage to the central nervous system and in the absence of timely vaccination leading to death.This disease has long been known to mankind.Back in the 1st century ADCornelius Celsus described the case of rabies in humans.And now rabies is found everywhere.Physicians managed to make a significant breakthrough: at the end of the XIX century Louis Pasteur invented an antirabic vaccine that saved the lives of many people.But in the 21st century, a rabies cure has not yet been developed and people continue to die from this ailment.
According to the Global Alliance for the Control of Rabies( GARC), approximately 160 people die each day from rabies!Most of the victims are residents of developing countries, where there are no vaccines and government programs to eliminate rabies among animals.Table of Contents: Causes of Rabies Signs
The causative agent of the disease is the virus of the family Rabdoviridae, the genus Lyssavirus.This is a zoonotic infection.A person becomes ill with a bite or ablution of damaged skin, mucous membranes of an infected animal.From the place of introduction, the virus spreads through nerve fibers and reaches the brain, where it is fixed in the medulla oblongata, the hypocampus.Here the microorganism begins to multiply, causing the development of characteristic changes: the appearance of edema of tissues, hemorrhages, degenerative and necrotic foci.Then the virus with the blood flow spreads throughout the body and enters the salivary glands, heart, lungs, kidneys, adrenals.
It is noteworthy that a sick animal becomes infectious already in the last ten days of the incubation period, that is, before the appearance of the first clinical signs of the disease.So, an adequate and healthy at first sight animal can be a potential source of rabies.Sources of infection are sick foxes, dogs, cats, wolves, raccoon dogs, jackals, bats.The greatest incidence of rabies is observed in the summer-autumn period.
Many people are interested in whether it is possible to catch rabies from a sick person if it attacks and bites a healthy person?Theoretically, this is possible.In fact, no such case has been recorded in history.
Symptoms of rabies
The incubation period can be as long as twelve days or can last up to one year.But on average this period with rabies is one to three months.The duration of the incubation period, in the first place, is influenced by what part of the body the sick animal has bitten.Thus, the shortest duration of the incubation period is recorded with bites in the head, neck, upper extremities, and the longest - with a bite localized in the lower extremities.A short incubation period is observed in children.No less influence is exerted by the state of the body's immune system, the depth of the wound, and the number of pathogens that have fallen into the wound.
There are three stages of the disease:
- Initial( depression);
The first signs of the disease are the appearance of twitching, itching, burning, drawing pains in the bite area, even if the wound has already fully healed.Sometimes the wound can become inflamed again, in this area the skin swells and turns red.
The victim notes a general malaise, there may be a headache.The temperature rises to 37-37.5 degrees and is held at this level.
At this time there are already signs of damage to the nervous system: a person becomes depressed, depressed, anxiety, fear, and less often - irritability.Such a person closes in himself, refuses to communicate, eat, does not sleep well.The duration of the initial stage is only one to three days.At the end of this period apathy is replaced by excitability, there is an increase in heart rate and respiration, the appearance of constricting pain in the chest.
The patient becomes more restless.In this stage, the most characteristic sign of the disease - hydrophobia - already appears.When you try to swallow water in a person there are painful spasms of swallowing and auxiliary respiratory muscles.Therefore, even with the sound of running water from the tap, a person becomes restless, breathes noisily, taking short breaths.
The central nervous system gradually becomes susceptible to any stimuli.Muscle cramps can be triggered by the breath of air( aerophobia), loud sound( acoustophobia) or bright light( photophobia).
The sharply widened pupils attract attention, the patient's gaze is directed to one point.The pulse is much faster, there is an increase in saliva and sweating.The patient is not able to ingest so much saliva, and therefore constantly spits or saliva drips down the chin.
At the height of the attack there is a psychomotor agitation, the patient becomes aggressive, tears his clothes, rushes through the ward, attacks people.At the same time, consciousness fades and the patient suffers from intimidating hallucinations.In inter-criminal periods, consciousness can become clear and then the patient is able even to respond adequately and answer the questions posed.The duration of this period is two to three days.
At this stage, seizures and hydrophobia cease.Others often perceive such changes as an improvement in the condition of the patient, but in reality this indicates an imminent death.
Body temperature during this period rises to critical figures: 40-42 degrees.There is a rapid heart rate, a drop in blood pressure.Death usually comes within 12-20 hours of paralysis of the respiratory center or heart.
On average, the disease lasts five to eight days.The classical version of the course of the disease is described above, but far from all cases of rabies proceeds in this way.So, sometimes the disease immediately manifests itself as excitation or paralysis, without an initial period.In some patients, there may be no attacks of psychomotor agitation and hydrophobia.
The diagnosis of rabies is based on epidemiological( bite of suspicious animals) and clinical data( attacks of psychomotor agitation with hydrophobia, drooling, hallucinations).Clinical diagnostic tests are of secondary importance.In the blood there is lymphocytic leukocytosis and a decrease( absence) of eosinophils.
In addition, the virus can be detected in saliva, cerebrospinal fluid.The selected material is plated on a cell culture or the mice are infected.
An accurate diagnosis of rabies is only possible after the patient's death.Pathologists perform a histological study of the brain in order to detect inclusions specific for the disease - Babes-Negri bulls.
Also very informative method is a histological study of the brain of a bitten animal.Of course, this is possible when the animal can be isolated.
As already mentioned, there are no effective methods of treating rabies.If a person already has symptoms of rabies, this will inevitably lead to death.The only way to prevent a fatal outcome is timely vaccination.The introduction of rabies immunoglobulin in the presence of symptoms of rabies is no longer effective.
In the treatment of the patient, all possible methods are used to alleviate the suffering of the patient.A person is placed in a room isolated from noise, a darkened room in order to avoid irritation of the nervous system with loud sounds, bright light.
In large doses, the patient is administered morphine, aminazine, dimedrol, chloral hydrate.With the development of signs of respiratory failure, the patient can be transferred to IVL.
Prevention, first of all, is to fight the source of the disease and prevent the infection of a person.For this purpose, pets are registered and vaccinated against rabies.If your pet is not vaccinated, but sometimes goes outside, there is always the possibility of infection with rabies.In addition, a person should always remember the possibility of infection and avoid, not contact with stray animals.Unfortunately, rabies is not only caused by biting by apparently sick wild animals, for example, a fox, but also by contact with street kittens and puppies.
What can I do if an animal bites a person after all?
- Wash the wound immediately with soap.Abundant washing of the wound can reduce the amount of the virus;
- Treat wound edges with 70% alcohol;
- Apply a bandage.No need to tie a tourniquet;
- Call the nearest emergency facility.
In the emergency room, the surgeon again rinses the wound with soapy water, treats the edges of the wound with alcohol-containing preparations, rinses the wound with an antiseptic and applies an antiseptic bandage to it.The edges of the wound with bites are not sutured.After carrying out these manipulations, they begin to conduct immunoprophylaxis.There are absolute and relative indications for vaccination.The risks of infection can be correctly predicted by the doctor, it is he who decides whether to vaccinate.
The times when the bitten person was made forty jabs in the stomach, have sunk into oblivion.Now the scheme for the introduction of an anti-rabies vaccine consists of six injections.The first vaccine is administered on the day of the bite( 0 day), then on the 3rd, 7th, 14th, 30th and finally 90th day.With bites of severe and moderate severity or with bites of any severity and delayed( after ten days) treatment of a person additionally injected once anti-rabies immunoglobulin.
Remember: only a timely vaccination capable of preventing the fatal outcome of rabies.If you bite an animal, you must contact the emergency department on the same day.
Upon the person's treatment in the emergency room, the surgeon is filled with an emergency notification of a bite to the animal, which is transmitted to the sanitary epidemiological service.Having received the notification, the epidemiologists begin to investigate the case.A bitten animal, even if it looks healthy at first glance, is isolated for ten days.If the specified period has passed, and the animal has no signs of disease, it can be argued that it is healthy.
If during this time the animal showed obvious signs of the disease, it is killed by veterinarians, the biomaterial is taken and sent to the research.
Symptoms of rabies in animals
How do you determine if the animal is sick?At the initial stage of the disease, the behavior of the animal changes, it becomes apathetic, avoids people, does not eat, and can on the contrary become very affectionate and contact.There is increased salivation.After a couple of days the animal becomes aggressive, gnaws inedible objects, tries to escape, attacks people and bites.
Because of the paralysis of the muscles of the larynx, the jaw is dropped in the animal, the tongue is taken out, the foamy saliva runs out of the mouth, the animal does not drink water.In dogs, barking becomes hoarse.Cats during this period often become shy, run into secluded places, where they die.At the last stage of the animal, convulsions of extremities, trunks are tortured.
But you should always remember that the animal becomes dangerous even ten days before the first symptoms of rabies, and not only when the disease is obvious.
Grigorova Valeria, medical reviewer