what is varicella

Varicella, also known as chickenpox, is a highly contagious disease caused by the varicella-zoster virus (VZV), a member of the herpesvirus family. It typically presents with a characteristic itchy skin rash that forms small blisters, which eventually scab over. The rash usually begins on the chest, back, and face, spreading to the rest of the body. Other symptoms often include fever, tiredness, headache, and loss of appetite. The disease generally lasts 5 to 7 days. Varicella spreads through airborne transmission, mainly by coughing, sneezing, or direct contact with the blisters. It has an incubation period of about 10 to 21 days after exposure. People are contagious from about 1 to 2 days before the rash appears until all the lesions have crusted over. Though most recover fully, complications can occur, such as pneumonia, inflammation of the brain, and bacterial skin infections. The illness tends to be more severe in adults than in children. After recovery, the virus remains dormant in nerve cells and can reactivate later in life as shingles. Vaccination against varicella has considerably reduced the incidence and severity of the disease.