Chickenpox is a highly contagious viral illness caused by the varicella-zoster virus. It is characterized by a rash of itchy, fluid-filled blisters that appear on the skin. The virus is usually spread from person to person through respiratory droplets from coughing or sneezing, or by direct contact with the blisters.

Common symptoms of chickenpox include fever, fatigue, headache, and loss of appetite. The rash usually begins on the face and trunk and spreads to the rest of the body over several days. The disease is usually mild in healthy children and adults, but can be more serious in infants, pregnant women, and people with weakened immune systems.

A vaccine is available to prevent chickenpox and is recommended for all children and adults who have not had the disease.

Note: This is a general description. Please take professional health advice.