Varicella is an acute infectious disease of viral etiology characterized by the appearance of the characteristic rash bubble in the background of General intoxication syndrome. The causative agent of chicken pox – herpes virus 3 transmitted from the patient by airborne droplets.
Varicella is among the most common childhood infections. It manifests itself in a rich bubble itchy rashes that appear on the height of fever and obstipation manifestations. A typical clinic to diagnose the disease without conducting any additional studies. Treatment of chickenpox is mainly symptomatic. To prevent secondary infection is recommended antiseptic treatment of the lesions.
Varicella is an acute infectious disease of viral etiology characterized by the appearance of the characteristic rash bubble in the background of General intoxication syndrome.
Characterization of the pathogen
Chickenpox causes the Varicella Zoster virus of the family of herpes viruses, the human herpes virus type 3. This DNA-containing virus that little resistant in the environment, capable of replication only in humans. Virus inactivation occurs rather quickly when exposed to sunlight, UV radiation, by heating, drying. Reservoir and source of varicella are sick people in the last 10 days of the incubation period and the fifth to seventh day of the period of the rash.
Chickenpox is transmitted by aerosol mechanism by airborne droplets. Due to the weak resistance of the virus to contact-household transmission is difficult to implement. The spread of the virus with fine aerosol emitted by patients during coughing, sneezing, talking, possibly at a sufficiently large distance within the room, likely drift with the current of air to adjacent rooms. There is a likelihood of transmission is transplacental.
People have a high susceptibility to infection, after the transfer of varicella remains intense lifelong immunity. Children first months of life protected from infection received from the mother’s antibodies. Chickenpox is most common in children of preschool and younger school age enrolled in organized children’s groups. Of the order of 70-90% of the population perevalivaet chickenpox before the age of 15 years. The incidence in the cities more than 2 times higher than in rural areas. The peak incidence of chicken pox have for the autumn-winter period.
Pathogenesis of varicella
Entrance infection atriums is the mucous membrane of the respiratory tract. The virus is introduced and accumulates in the epithelial cells, spreading subsequently to the regional lymph nodes and then into the General circulation. Circulation of the virus through the blood causes the phenomenon of intoxication. The chickenpox virus has an affinity for epithelium epithelial tissues. Replication of the virus in epithelial cell contributes to its destruction, in the place of the dead cells remain cavity filled with exudate (inflammatory liquid) is formed vesicle. After opening the vesicles are brown. After separation of the crust is found underneath the newly formed epidermis. The rash of chickenpox can form on the skin and mucous membranes, where vesicles rapidly progressing erosion.
Chickenpox in people with weakened immune system severe, contributes to the development of complications, secondary infections, exacerbation of chronic diseases. In pregnancy, the likelihood of transmission of chickenpox from mother to fetus is during the first 14 weeks of 0.4% and increases up to 1% up to 20 weeks, after which the risk of infection of the fetus is virtually nonexistent. As effective preventive measures for pregnant women suffering from chickenpox, prescribe specific immunoglobulins that help to reduce the likelihood of transmission to the child to a minimum. More dangerous chicken pox, which developed a week before the birth and after the birth month.
Persistent lifelong immunity protects the body from re-infection, however, significant reduction in the immune properties of the body adults who had chickenpox as a child can catch her again. The phenomenon of latent carrier of the chickenpox virus, accumulating in the cells of the ganglia and can be activated, causing shingles. Mechanisms of viral activation in this carriage not yet clear.
Symptoms of chickenpox
The incubation period of varicella ranges from 1-3 weeks. In children, prodromal phenomena are weakly expressed or not observed, in General, for light with a slight deterioration of General condition. Adults are prone to more severe chickenpox with severe symptoms of intoxication (fever, headache, body aches), fever, sometimes marked nausea, vomiting. Rashes in children can occur suddenly in the absence of any General symptoms. In adults, the period of rash often begins later, fever with the appearance of the elements of the rash may temporarily persist.
Rash varicella is in the nature of bullous dermatitis. Rashes represent the individual elements that occur on all areas of the body and pread without any patterns. Elements of the rash initially represent red spots, progressing to papules and then to smooth small single-chamber vesicles with clear fluid, spodumene in the piercing. Revealed vesicles form a crust. Chickenpox is characterized by the simultaneous existence of elements at different stages of development and the emergence of new (podsypanina).
The rash chickenpox causes intense itching, while combing possible infection of the vesicles with formation of pustules. Pustules healing can leave behind a scar (Ospina). Uninfected vesicles do not leave scars, after separation of the crusts reveals a new healthy epithelium. When suppuration spotted elements of the General condition usually worsens, intoxication is aggravated. The rash in adults is usually more abundant, in most cases from vesicles pustules are formed.
The rash is spreading in almost the whole body surface except the palms and soles, predominantly localizes in the area of the scalp, face, neck. The podsypanina (appearance of new elements) is possible for 3-8 days (in adults, as a rule, they are accompanied by a new feverish waves). Intoxication subsides simultaneously with the termination of podsypanin. The rash may appear on the mucous membranes of the mouth, genitals and sometimes on the conjunctiva. Spotted elements on mucous progressing to erosions and ulcers. In adults the rash may be accompanied by lymphadenopathy for children lymph nodes is not typical.
In addition to the typical course, there are removed form of varicella, occurring without signs of intoxication, and a rare transient rash, and severe, distinguished on bullous, hemorrhagic and gangrenous. Bullous form is characterized by rash in the form of large bubbles flabby, leaving after the opening of the long-healed ulcers. This form is characteristic of people with severe chronic diseases. The hemorrhagic form is accompanied by hemorrhagic diathesis, skin, and mucous membranes observed small hemorrhages can cause bleeding from the nose. Vesicles have a brownish tint due to hemorrhagic content. Individuals with significantly weakened organism chickenpox can occur in the gangrenous form: fast-growing vesicles with hemorrhagic content are revealed with the formation of necrotic black crusts surrounded by a rim of inflamed skin.
Complications of chickenpox
The vast majority of cases, chickenpox is a benign, complications are observed not more than 5% of patients. Dominating disease caused by secondary infection: abscesses, cellulitis, and in severe cases – sepsis. Dangerous, difficult therapy complication is viral (vetryanaya) pneumonia. In some cases, chickenpox can cause keratitis, encephalitis, myocarditis, nephritis, arthritis, hepatitis. Prone to complications and severe disease in adults, particularly with concomitant chronic diseases and weakened immune system. In children complications observed in exceptional cases.
Diagnosis of varicella
Diagnosis of chickenpox in clinical practice is based on characteristic clinical picture. General analysis of blood chickenpox non-specific, pathological changes can be accelerated erythrocyte sedimentation rate, either to signal inflammatory disease with intensity proportional to total intoxication symptoms.
Virological study involves the identification of virions with the vesicular fluid electromicroscopy, painted silver. Serological diagnosis is retrospective value, and is made with the help of the RAC, HAI in paired sera.
Treatment of chickenpox
Chicken pox are treated on an outpatient basis, with the exception of cases of severe with intense obscheintoksikatsionnogo manifestations. Causal treatment has not been developed, in the case of the formation of pustules resort to antibiotic therapy short course in average dosages. Individuals with immune deficiency can be prescribe antiviral drugs: acyclovir, vidarabine, interferon alpha (interferon new generation). Early interferon contributes to easier and short for infection, and reduces the risk of complications.
Therapy of chickenpox includes measures to skin care to prevent purulent complications: vesicles are lubricated with antiseptic solutions: 1% brilliant green solution, concentrate – potassium permanganate (“Zelenka”, “potassium permanganate”). Ulceration of the mucosa are treated with hydrogen peroxide at 3% dilution, or ethacridine lactate. Intense itching of the lesions facilitate lubricating the skin with glycerin or wiping with diluted vinegar, alcohol. As a pathogenetic means prescribed antihistamines. Pregnant women and patients with severe prescribe specific on anti-varicella immunoglobulin.
Forecast and prevention of varicella
The prognosis is favorable, the disease ends in recovery. Vesicles disappear without a trace, the pustules can leave scars smallpox. A significant deterioration of prognosis in persons with immune deficiency, severe systemic diseases.
Prevention of chickenpox is the prevention of introduction of infection in organized children’s collectives, for which the detection of cases made quarantine measures. Patients are isolated for 9 days after appearance of rash contact with the sick children divided for 21 days. If the day of contact with the patient accurately identified, the child is not allowed in the children’s team from 11 to 21 days after contact. Contact children who have had chickenpox, a weakened immune system as a preventive measure is prescribed on anti-varicella immunoglobulin.
Last time began to be applied vaccination against varicella. With this purpose, vaccines, Varilrix (Belgium) and Arawaks (Japan)