Overview
Chicken pox is an acute infectious disease of viral etiology, characterized by the appearance of a characteristic blistering rash against the background of a general intoxication syndrome.
Characteristic:
Chickenpox is caused by the herpesvirus Varicella Zoster, which is also known as human herpesvirus type 3. This is a DNA-containing virus that can only replicate in the human body and is not particularly stable in the exterior environment. When exposed to sunshine, UV radiation, heating, or drying, the virus swiftly deactivates. Sick persons are the reservoir and source of chickenpox during the last 10 days of the incubation phase and the fifth to seventh day of the rash stage.
Chickenpox is spread by aerosol mechanism via airborne droplets. Contact-household transmission is difficult to conduct due to the virus's low resistance. The virus may be disseminated over a pretty long distance within the room by a tiny aerosol created by patients while coughing, sneezing, or talking, and it can be carried into neighbouring rooms by air movement. There is a chance of infection spreading transplacentally.
People are very susceptible to infection, and following exposure to chickenpox, strong lifetime immunity is maintained. Antibodies from the mother protect children in their initial months of life from infection. Chickenpox is particularly common in preschool and primary school-aged children who attend organised children's groups. Chickenpox affects around 70-90% of the population before the age of 15 years. The prevalence in cities is more than double that in rural regions. The autumn-winter season has the highest prevalence of chickenpox.
Pathogenesis:
The mucous membrane of the respiratory system serves as the infection's entry point. The virus infiltrates and concentrates in epithelial cells before spreading to regional lymph nodes and the general circulation. The virus's circulation in the bloodstream generates the phenomenon of universal intoxication. The varicella-zoster virus prefers the epithelium of integumentary tissues. The virus's multiplication in the epithelial cell adds to its death; in place of dead cells, cavities filled with exudate (inflammatory fluid) form a vesicle. Crusts persist after opening the vesicles. Following the splitting of the crust, a freshly developed epidermis is discovered beneath it.
Chicken pox is severe in persons with weaker immune systems, and it contributes to the development of complications, secondary infection, and chronic illness aggravation. During pregnancy, the risk of transmission of chickenpox from the mother to the foetus is 0.4% in the first 14 weeks and climbs to 1% until the 20th week, when the danger of infection of the foetus is virtually eliminated. Pregnant women with chickenpox are provided particular immunoglobulins as an effective prophylactic strategy, which assist lower the chance of transmission to the kid. More harmful is chickenpox, which appears a week before and a month after the delivery.
Persistent lifetime immunity consistently protects the body from re-infection; nevertheless, people who had chickenpox as a kid can become infected with it again due to a severe decline in the body's immunological characteristics. There is a process known as latent carriage of the varicella-zoster virus, which accumulates in nerve node cells and can be triggered, resulting in shingles. The mechanisms of viral activation in such carriage are yet unknown.