Lecture on smallpox (Variola)

2021-03-23 12:00 AM

The virus is resistant to a solution of Ether Phenol Glycerine alcohol and ice. Temperatures above 550C and solutions of Methylene Blue, potassium permanganate, and ultraviolet light inactivate the smallpox virus quickly.

Define

Smallpox is an acute infectious disease, caused by the smallpox virus (Variola virus), spread mainly through the respiratory tract. Clinically, the disease has a syndrome of serious infection - severe systemic intoxication, which ranges from maculopapular to dehydration and purulent discharge, leaving permanent scars.

Smallpox easily causes a large epidemic with a high mortality rate, so it is classified as a "Very serious disease".

Lecture on smallpox (Variola)

Research history

Smallpox is known for many years BC, Central African countries are considered to be the first to detect the disease. The disease is clearly described in the literature in the 7th century. But until the eighth and seventeenth centuries, there were studies on the etiology, epidemiology, and immunology of the disease. In 1906 Paschen discovered a virus that caused smallpox. Guarnieri in 1891 also suggested that the cause of the disease were the "particles" in the protoplasm of the epithelial cell.

The smallpox vaccine was formulated and used by Jenner in 1798.

Lecture on smallpox (Variola)

Epidemiology

Pathogens

Smallpox virus (Variola Virus) belonging to the Poxviridac meeting has a size of up to 300 micrometers. In dry weather, the virus can survive for a long time at temperatures from 4 to 200C and can live from 3 to 17 months. In the dry weather environment, lack of sunlight, the lack of oxygen does not disappear for many years, in the pea scales for one year.

The virus is resistant to a solution of Ether Phenol Glycerin alcohol and ice. Temperatures above 550C and solutions of Methylene Blue, potassium permanganate, and ultraviolet light inactivate the smallpox virus quickly.

Inoculum

The person is the only source of the disease, the patient is the one from the end of the incubation period until the pimple is flaky. The most infectious time is when the pus turns pus and scabs without a person carrying the smallpox virus

Infection

Spread mainly through the respiratory tract, the virus contained in nasopharynx fluid is released into the surrounding environment when the patient sneezes and sneezes in contact with healthy people. This is a direct route of transmission

Indirect transmission through air objects contaminated with pus, bean flakes, and inhaled secretions of healthy people can also be caused by skin scratches that the healer is infected.

Sense of the body

People of all races of all ages can get the disease. Children most susceptible to disease, children under 1 year old are less likely to get sick due to the immunity passed from the mother, from the second month, the immunity decreases.

After the disease has a stable immunity. There is a cross-immunity between smallpox and vaccination (cow smallpox).

Smallpox epidemics usually occur in winter, cold and dry climates.

According to the World Health Organization (WHO): The last case of smallpox was recorded in 1977 in Somalia. In 1980, WHO declared smallpox has been eliminated worldwide thanks to a vaccination program. However, because of the dangerous nature of the disease, understanding all about the disease needs attention.

Mechanism of pathogenesis and pathology 

Mechanism of pathogenesis

Smallpox virus from the entrance is the respiratory tract mucosa (rarely through scratched skin) along the lymphatic pathway into the bloodstream in the endothelial inter-retinal cells of the bone marrow, spleen, and liver to develop and reproduce. real. The second time the virus enters the bloodstream, it is localized in the skin, mucous membranes, adrenals, brain, and other organs, causing severe infectious intoxication according to which symptoms of the disease rash.

Injury from pathological surgery

The characteristic lesion of the skin is the water degeneration of the layer (Staatun Malpighii) which forms a fluid-filled bulge with many compartments due to the undamaged connective organization. The bulges with the central concave dilate gradually with the process of invading necrotic leukocytes deep to the epidermis to form opaque fluid-filled bulges, after scabbing, leaving permanent scars.

Injuries in the internal organs are different and are not disease-specific

Clinical

Clinical forms of smallpox

Light form.

Atypical form.

Typical conventional form.

Flat Typs.

Smallpox can be hemorrhagic.

Typical smallpox 

Incubation period

Average 12-13 days, the shortest 5 days and longer 15 days.

Onset period

Sudden onset with high fever and spontaneous chills, rapid pulse temperature 40 - 410C. After a few hours, the patient was very tired, a headache could not withstand dizziness, tinnitus, abdominal pain along the lumbar spine and joint muscles, causing the patient to be bedridden with urinary retention.

Patients with persistent vomiting of epigastric pain, congestion in the skin of the face and conjunctiva, have tears of fear of light, and eyes are sparkling with fear. Patient cough, painful throat, difficulty breathing.

Appeared "rash" like measles in the groin, underarms under the breast. After 1-2 days, the "money" goes all out. "Pre-rash" is found in 24-40% of patients.

Full-blown period

This is when the pimples start to grow so it is also called the eruption period.

Acne grows:

Day 4 of the illness decreases, the patient feels comfortable and appears as pale pink macula from the top. First, on the forehead, scalp temples, face then down to the neck, hands, chest, back, and finally on the legs. After 48 hours, you grow the whole body, the more you grow, the less you grow. The board has the characteristics of:

At first, after a day the nodule is raised, so dark red called papule, the papules grow bigger and grow with pea deep into the skin. On the 6th day of the disease, the papules become vesicles contained in the surrounding water with red edges, the burns have many compartments, so when the needle is inserted, they do not collapse. The bulges are somewhat stiff, some with a central concave.

On the oral mucosa, eyes, nose, and intestines also appear as skin rashes, punctured blisters leave ulcers with red edges, causing coughing pain and loss of coughing up purulent sputum.

Purulent pimples:

From day 7 to 8 of the disease: The bulge becomes pus-filled, with swelling around it, darker red, and the centre of the pimple is concave (posterior concave).

Swollen subcutaneous tissue makes two faces puffy. The process of pustular pimples is also from top to bottom.

The whole patient got worse during the day with a moderate fever, high fever at night of 40 0 C, severe headache, lethargy, rapid pulse, low blood pressure, bad breath, difficulty breathing, liver, spleen.

Scaly acne:

From days 12-13 the pustular disease dries out and crusted yellow-brown. The patient feels comfortable, the body temperature decreases but the itching is more. The process of crusting pox is also in the top-down order

Recovery period

After growing for 20 days, the pea scabs gradually peel off, leaving a brown concave scar, after a few months of turning shiny white, the deepest in the face of the nose and forehead ... the scars last a lifetime.

Symptom clinical form

Light form

Common in patients who have received the smallpox vaccine. The rash grows sparse, not enough stages of the nodule. The patient has a cough, sore throat

Atypical form

Clinically only fever, no rash, which can only be diagnosed during an outbreak through specific testing.

Typical conventional form

Accounting for 70% of patients in an outbreak, this can be divided into three types:

Semi-converging form: Pus thickened, concentrated in clumps on the face, scattered in other places, death 37%. Scattered rash grows sporadically, alternating between healthy skin areas. 9% mortality

Flat smallpox:

Convergence or semi-converging purulent eruption but flat and not centrally concave, common in children, high mortality

Hemorrhagic smallpox:

This form is often severe in pregnant women, and clinical bleeding on the skin, mucous membranes is accompanied by severe systemic toxicity.

Early hemorrhagic smallpox (malignant smallpox - Variola Fulinans): Severe systemic condition as early as 2-4 days of the disease, when the rash has not yet grown, swelling of the face and feet, bleeding under the skin, bleeding viscera. The patient died from the very first days of illness.

Late hemorrhagic smallpox (secondary hemorrhagic smallpox): Hemorrhage after pustular pustules, the pimples may contain bleeding around them.

Complications

Common bacterial or viral superinfection. Common bacterial superinfection is bronchitis, abdominal abscess, larynx, fever, cough, chest pain, difficulty breathing easily die. There may be otitis media, mastoiditis, septicemia.

Superinfection caused by a virus: Meningitis-encephalitis, patients can be quadriplegic, hemiplegia.

Definite diagnosis

Clinical

Sudden onset of high fever with rash.

The rash grows in order from the face with the body, limbs progressing in stages, maculopapular nodules, pus bulging, scaly. Same age in the same area.

Scaly rash that leaves permanent scars.

Signs of heavy body.

Test

Virus isolation: On tissue medium and in developing embryos, specimens are taken from a purulent rash on the skin and mucous membranes, nasal fluid, eyes, and blood urine. Results are usually delayed after 10-15 days for results

Serum reaction for antibodies.

Screening for smallpox virus on an electron microscope, with immunofluorescence

Epidemiology

The disease spreads through the respiratory tract, so it is easy to become a large epidemic, encountered in people who have not been vaccinated against smallpox

Differential diagnosis

Differential diagnosis with chickenpox: The onset is not faint, mild fever grows out of order, in several waves, on a skin rash of different ages, the rash leaves no scars.

Treatment

The principles of treatment

Must comply with the "extremely dangerous" disease regime.

There is no specific treatment.

Only treat symptoms such as detoxification, pain relief, heart attack, fostering body to improve resistance, treating acne to prevent superinfection and complications.

Specific treatment

Specific gammaglobulin: 3-6 ml intramuscularly. Repeat injection twice.

Treatment against superinfection: Antibiotics must be used, preferably according to the antibiotic chart, and a combination of antibiotics.

Immobilize the patient, eat warm liquid with enough nutrition, enough vitamins.

Detoxification: Salty, sweet serum infusion to compensate for water and electrolytes.

Anti-cardiomyopathy: By ouabain 1/4 mg, 1-2 times/day or caffeine, coramin.

Reducing anti-pain fever: Paracetamol, Analgin.

Anti-convulsive delirium: By aminagin 0.025g, pipolphen 0.05g, spactein 0.05g each drug 1 tube, mixed intramuscularly 2 times / day.

Skincare of oral mucosa with 1-2% Natribicarbonate solution. Keep from scratching and breaking pimples, dab 2-5% purple medicine solution on broken peas. Take a warm bath, change your bedding often.

Prevention

The best measure is smallpox vaccination.