Poliomyelitis is an acute viral disease affecting the central nervous system, primarily the spinal cord, and sometimes causing paralysis. The main method of spreading is considered direct or indirect contact with the patient( through the hands, handkerchiefs, clothing, etc.).Also spreads through products, water, with air.
What is it? Poliovirus( poliovirus hominis) of the family Picornaviridae of the genus Enterovirus is the causative agent of poliomyelitis. There are three serotypes of the virus( predominant type I): I - Brunhilda( isolated from a sick monkey with the same name), II-Lansing( isolated in Lansing) and III-Leone( isolated from the sick boy McLeon).
In some cases, the disease occurs in an erased or asymptomatic form. A person can be a carrier of a virus, allocating it to the external environment together with feces and secretions from the nose, and at the same time feel absolutely healthy. Meanwhile, susceptibility to poliomyelitis is quite high, which is fraught with a rapid spread of the disease among the children.
How is poliomyelitis transmitted, and what is it?
Poliomyelitis( from other Greek - πολιός - gray and μυελός - spinal cord) - children's cerebrospinal paralysis, acute, highly contagious infectious disease caused by the defeat of the gray matter of the spinal cord by poliovirus and characterized primarily by the pathology of the nervous system.
Basically occurs in an asymptomatic or erased form. Sometimes it happens that the poliovirus penetrates the CNS, multiplies in motoneurons, which leads to their death, irreversible paresis or paralysis of the innervated muscles.
Infection occurs in several ways:
- Airborne droplet - is realized by inhalation of air with viruses weighed in it.
- Alimentary route of transmission - infection occurs when eating contaminated food.
- Contact-household way - is possible when using one dish for food intake by different people.
- Waterway - the virus enters the body with water.
Especially dangerous in the infectious plan are people who carry the disease asymptomatically( in an apparatus form) or with nonspecific manifestations( small fever, general weakness, increased fatigue, headache, nausea, vomiting) without signs of CNS damage. Such people can infect a large number of people in contact with them, becausediagnosis of the diseased is very difficult, and, consequently, these individuals are practically not exposed.
Poliovirus vaccine
Specific prevention is polio vaccination. There are 2 types of vaccines against poliomyelitis:
- live vaccine Sebina ( OPV - contains live attenuated viruses)
- inactivated ( IPV - contains polioviruses of all three serotypes killed by formalin).
Currently, the only manufacturer of polio vaccine in Russia FSUE "Enterprise for the production of bacterial and viral preparations of the Institute of Poliomyelitis and Viral Encephalitis. M.P.Chumakova "produces only live vaccines against poliomyelitis.
Other preparations for vaccination are traditionally purchased abroad. However, in February 2015 the company presented the first samples of inactivated vaccine of its own design. The beginning of its use is planned for 2017.
Symptoms of poliomyelitis
According to WHO, poliomyelitis affects mainly children under 5 years of age. The incubation period lasts from 5 to 35 days, the symptoms depend on the form of poliomyelitis. According to statistics, most often the disease proceeds without disrupting the motor functions - one paralytic case involves ten nonparalytic cases. The initial form of the disease is the form of the drug( non-paralytic poliomyelitis).It is characterized by the following symptoms:
- General ailment;
- Temperature rise up to 40 ° C;
- Decreased appetite;
- Nausea;
- Vomiting;
- Muscle aches;
- Sore throat;
- Headaches.
The above symptoms gradually disappear within one to two weeks, but in some cases, a longer period may also occur. As a result of headache and fever, there are symptoms that indicate the defeat of the nervous system.
In this case, the patient becomes more irritable and restless, emotional lability is observed( mood instability, constant change of mood).Also there is a rigidity of muscles( that is, their numbness) in the region of the back and neck, the signs of Kernig-Brudzin indicative of active development of meningitis appear. In the future, the listed symptoms of the drug form may grow into a paralytic form.
Abortive form of poliomyelitis
In abortive form of poliomyelitis, sick children complain of an increase in body temperature to 38 ° C.Against the background of the temperature observed:
- malaise;
- weakness;
- lethargy;
- mild headache;
- cough;
- is a common cold;
- abdominal pain;
- vomiting.
In addition, redness of the throat, enterocolitis, gastroenteritis or catarrhal angina is observed as concomitant diagnoses. The duration of the manifestation of these symptoms is about 3-7 days. Poliomyelitis in this form is characterized by pronounced intestinal toxemia, as a whole there is a significant similarity in manifestations with dysentery, the course of the disease can also be cholera-like.
Meningial form of poliomyelitis
This form is characterized by its own severity, with similar symptoms with the previous form:
- temperature;
- general weakness;
- malaise;
- abdominal pain;
- headaches of varying degrees of intensity;Runny nose and cough;
- decreased appetite;
- vomiting.
On examination, the throat is red, there may be plaque on the palatine arch and tonsils. This condition lasts 2 days. Then the body temperature is normalized, the catarrhal phenomena decrease, the child looks healthy for 2-3 days. After this, the second period of body temperature increase begins. Complaints are becoming more pronounced:
- a sharp deterioration in condition;
- severe headache;
- vomiting;
- pain in the back and legs, usually the legs.
In an objective examination, the symptoms that characterize meningea are diagnosed( positive symptom of Kernig and Brudzinsky, rigidity in the back and occipital muscles).Improvement of the condition is achieved by the second week.
Paralytic poliomyelitis
Develops quite infrequently, but, as a rule, leads to disruption of many functions of the body and, accordingly, to disability:
- Bulbar. Particularly heavy is the development of bulbar paralysis. The whole group of caudal nerves is affected. Selective defeat of one, two nerves for poliomyelitis is atypical. If the reticular formation, the respiratory and vascular centers are damaged, consciousness, respiratory disorders of the central genesis, can be disturbed.
- Pontine. This type of poliomyelitis is characterized by the development of paresis and paralysis of the facial nerve, in which a partial or complete loss of facial motions occurs.
- Encephalitic. The substance of the brain and subcortical nuclei is affected( very rarely).Developed central paresis, convulsive syndrome, aphasia, hyperkinesia.
- Spinal. The weakness and pain in the muscles are gradually replaced by paralysis, both general and partial. The defeat of the muscles with this form of poliomyelitis can be symmetrical, but paralysis of individual muscle groups occurs throughout the body.
Four periods are distinguished during the course of the disease:
- preparative;
- is paralytic;
- is reconstructive;
- residual.
The preparatory stage
Differs quite a sharp onset of the beginning, high body temperature, general malaise, headache, digestive disorders, rhinitis, pharyngitis. This clinical picture persists for 3 days, then the condition is normalized for 2-4 days. After a sharp deterioration occurs with the same symptoms, but more pronounced intensity. The signs are as follows:
- pain in the legs, arms, back;
- reduced reflexes;
- hypersensitivity;
- reduction in muscle strength;
- convulsions;
- confusion;
- excessive sweating;
- spots on the skin;
- goosebumps.
Paralytic stage of
This is the stage when suddenly a patient breaks paralysis( for a couple of hours).This stage lasts from 2-3 to 10-14 days. Patients for this period often die from severe respiratory and circulatory disorders. It has such symptoms:
- flaccid paralysis;
- disorders of the defecation act;
- decreased muscle tone;
- restriction or total absence of active movements in limbs, body;
- defeat predominantly the muscles of the arms and legs, but the muscles of the neck, trunk can also suffer;
- spontaneous muscular pain syndrome;
- damage to the medulla oblongata;
- disorders of urination;
- lesion and paralysis of the diaphragm and respiratory muscles.
In the recovery period of poliomyelitis, which lasts up to 1 year, gradual activation of tendon reflexes occurs, movements in separate muscle groups are restored. Mosaic lesions and unevenness of the restoration cause the development of atrophy and muscle contractures, lagging of the affected limb in growth, the formation of osteoporosis and atrophy of bone tissue.
The residual period, or the period of residual events, is characterized by the presence of persistent paresis and paralysis, accompanied by muscular atrophy and trophic disorders, the development of contractures and deformation in the affected limbs and parts of the body.
Post-poliomyelitis syndrome
After suffering polio, in some patients for a long time( an average of 35 years) there are limited opportunities and a number of manifestations, the most common of which are:
- progressive muscle weakness and pain;
- general weakness and fatigue after minimal stress;
- muscle atrophy;
- breathing and swallowing;
- breathing disorders in sleep, especially nocturnal sleep apnea;
- poor tolerance of low temperatures;
- cognitive impairment - such as reduced concentration and difficulty with remembering;
- depression or mood swings.
Diagnosis
In the case of polio, the diagnosis is based on laboratory tests. In the first week of the disease, the polio virus can be isolated from the secretion of the nasopharynx, and from the second - from the feces. Unlike other enteroviruses, the causative agent of poliomyelitis is very rarely isolated from the cerebrospinal fluid.
If it is impossible to isolate and study the virus, a serological analysis is performed, based on the isolation of specific antibodies. This method is quite sensitive, but it does not distinguish between post-vaccination and natural infection.
Treatment
Measures against poliomyelitis require mandatory hospitalization. Assign bed rest, taking painkillers and sedatives, as well as thermal procedures.
In case of paralysis, complex restorative treatment is carried out, followed by maintenance treatment in the sanatorium-resort zones. Such complications of poliomyelitis as a respiratory failure require urgent measures to restore respiration and resuscitate the patient. The focus of the disease is to be disinfected.
Prognosis for life
Mild forms of poliomyelitis( taking place without CNS and meningeal lesions) are traceless. Severe paralytic forms can lead to persistent disability and death.
Thanks to the long-term targeted vaccination of poliomyelitis in the structure of the disease, mild inpatient and abortive forms of infection predominate;paralytic forms occur only in unvaccinated individuals.
Prevention
Nonspecific is aimed at general strengthening of the body, increasing its resistance to various infectious agents( hardening, proper nutrition, timely sanitation of chronic foci of infection, regular exercise, optimizing the sleep-wake cycle, etc.), fighting insects that are carrierspathogenic microorganisms( various types of pest control), observance of personal hygiene rules( first of all it is washing hands after the street and after visiting the toilet), careful processingvegetables, fruits and other products before consuming them for food.
Vaccination is used to prevent the development of poliomyelitis, which is carried out with the help of live attenuated viruses - they can not cause the development of the disease, but cause a specific immune response of the organism with the formation of long-term stable immunity. To this end, in most countries of the world, poliomyelitis vaccination is included in the mandatory vaccination calendar. Modern vaccines are polyvalent - contain all 3 serological groups of the polio virus.
Poliomyelitis today is a very rare infection due to vaccination. Despite this, some cases of the disease are still registered on the planet. Therefore, knowledge of the basic symptoms and methods of prevention is simply necessary. Forewarned is forearmed!
Global number of cases of
Since 1988, the number of cases of polio has decreased by more than 99%.It is estimated that, from 350,000 cases in more than 125 endemic countries, up to 359 cases registered in 2014.Today, only individual territories of the two countries of the world remain endemic for this disease with a minimal area in the history.
Of wild poliovirus strains( type 1, type 2 and type 3), wild poliovirus type 2 was eliminated in 1999, and the number of cases of wild poliovirus type 3 decreased to the lowest level in history - from November 2012 in Nigeriano new cases were reported.