Rabies in humans symptoms
Mar 23, 2018
Rabies is an acute zoonotic, viral infection of the brain that first attacks animals. Raccoons, skunks, bats, foxes and other mammals can be rabid;home dogs and cats can also be infected. Rabies can be transmitted to people through the saliva of an infected animal, usually with a bite, although the virus can also get into the blood when licking the damaged skin. After the bite, the virus multiplies in the muscle tissue, then affects the endings of the peripheral nerves, multiplies in the neurons and through the spinal ganglia reaches the central nervous system, causing clinical manifestations. Basically, the virus accumulates in the brain and salivary glands.
Rabies is fatal if not immediately taken to prevent the development of the disease. Therefore, if you are bitten by an animal, immediately consult a doctor. Do not wait to see if you get angry;as soon as symptoms appear, the disease becomes irreversible, despite treatment, and death occurs in a few days. Symptoms most often appear in four to eight weeks, but there are cases when they appear in the period from 10 days to six months after the bite. Treatment consists of several injections of the vaccine and is effective only if it is prescribed on time.
• The cause of rabies is a virus that belongs to the family Rhabdoviridae, the genus Lyssavirus.
• Symptoms at the initial stage: fever, muscle pain, headache, poor overall health, loss of appetite, difficulty swallowing, tingling and twitching of the muscle at the site of the bite.
• Severe muscle spasms caused by swallowing fluid( hence the name rabies).
• Excitement and aggressiveness. Periods of anger are followed by periods of tranquility, but as the disease progresses, quiet periods become more and more short and less frequent.
• Salivation due to excessive salivation and difficulty in swallowing.
• Convulsions, paralysis and coma.
• Case history and physical examination.
• Nerve tissue biopsy.
• Every effort must be made to catch a bitten animal so that its brain can be tested for the presence of a virus. A healthy looking animal is monitored for 10 days to reveal any anomalies in its behavior.
It is important to recognize rabies in an animal that bites a person in a timely manner. Laboratory diagnosis of rabies in animals that have bitten a person, and the dead people is based on the detection in their brain of a specific antigen( by fluorescent antibody method) and the detection of the virus( by bioassay).In the conditions of the virological laboratory of sanitary-epidemiological institutions, it is possible to conduct studies using the fluorescent antibody method. The detection of a virus by a bioassay requires special conditions, and it is carried out only in special laboratories.
The material for the study is the brain. In addition to the brain, it is possible to examine the tissue of the submandibular salivary glands. However, in this tissue the rabies virus is contained in less quantity than in the brain. When taking material for examination, the corpses of animals and people are opened with the necessary precautions, in rubber gloves and masks on the entire face of cellophane or organic glass. The brain is sterically removed from the cranium and small( 0.5-1.0 g) pieces are taken from different parts: the cortex of the cerebral hemispheres, the cerebellum, the medulla oblongata and the ammon horn.
For a biological sample, the pieces of the brain are placed in a sterile, tightly closed jar with undiluted neutral sterile glycerin or diluted 1: 2 with isotonic sodium chloride solution.
For the microscopic examination, pieces 3-4 mm thick are cut out in the transverse direction from the same parts of the brain as for the biological sample. After taking a piece of the brain in a separate bowl, take pieces of submandibular salivary glands. Unfixed pieces of the brain and submandibular glands are stored and sent in compliance with the rules for handling material from patients with especially dangerous infections.
Highly sensitive and specific is the method of fluorescent antibodies, the results of which completely coincide with the results of the biological sample. Moreover, using the fluorescent antibodies method, the answer can be obtained very quickly( within a few hours after the beginning of the study).Specific antigen in rabies can be detected in smears -prints and histological sections from the brain and submandibular salivary glands. For the diagnosis of rabies use direct and indirect variants of the method of fluorescent antibodies. The antigen of the rabies virus is detected in preparations in the form of bright green granules of various shapes and sizes - from barely noticeable to 15-20 mm in diameter - on a dull yellowish background of normal brain tissue. The specificity of the detected fluorescence is checked by the introduction of a control.
To make a bioassay, the sterile pieces of pieces from different brain activities are ground in a mortar, then, by adding saline solution, a 10% suspension is prepared. If there is no confidence in the sterility of the material, antibiotics( 500 units of penicillin per gram of tissue) are added to it. After a 30-minute contact at room temperature, the test material is injected into the brain in 5 to 6 white mice weighing 4-5 g. They quickly show signs of severe disease. Starting from the 4th day after infection, one infected animal is killed. In their brains, when studying smears-prints using the fluorescent antibody method, a specific antigen is detected.
Clinical manifestations, results of pathoanatomical dissection, fluorescent antibody method and biological test are sufficient to confirm or exclude a diagnosis of rabies.
• Get medical attention immediately if you are bitten by an animal.
• Rinse the wound thoroughly with soap and water and then use an antiseptic.
• Vaccination two days after a bite usually stops the development of the disease. Two types of immunization are needed: passive immunization provides antibodies for immediate protection against rabies virus;The active vaccine causes the production of antibodies for long-term protection against the virus. A passive vaccine is injected around the wound and into the muscle. The active vaccine is administered in several steps. People who have already received an active vaccine should receive only passive treatment.
• Antibiotics and re-immunization against tetanus may be required to prevent associated bacterial diseases.
• If symptoms occur, hospitalization is necessary;However, the prospect of developing the disease in this case is unfavorable.
• Vaccinate pets against rabies. Rabies in wild animals remains a problem.
• People at high risk of disease( veterinarians and other people working with animals, hunters, cave explorers and people planning to live in developing countries where rabies is common) should be vaccinated annually.
Preparations for the diagnosis, prevention and treatment of rabies:
1) anti-rabies luminescent serum;2) anti rabies gamma globulin, prepared from blood serum of horses immunized with a fixed rabies virus;used intramuscularly at the rate of 0.25-0.5 ml per 1 kg of body weight according to special schemes, depending on the severity of the bite;
3) an anti-rabies inactivated culture vaccine is obtained by accumulating a rabies virus in a primary culture of Syrian hamster cells or transplantable diploid cells of the human lungs;Inoculations are combined with the administration of anti-rabies gamma globulin.
• In areas where rabies is common, street animals are often killed to prevent the spread of the disease.
• In countries where there is no rabies, for example in England, Japan and Australia, imported animals undergo quarantine.
• Attention! Call a doctor immediately if you are bitten by an animal;do not wait for the appearance of symptoms of rabies.