Short answers, pulled from the story.
Chickenpox, also known as varicella, is a highly contagious disease caused by varicella zoster virus, a member of the herpesvirus family. It produces a characteristic skin rash of small, itchy blisters that eventually scab over, usually starting on the chest, back, and face before spreading.
Chickenpox spreads through the air, typically via the coughs and sneezes of an infected person, and through contact with the blisters. The infection rate in close contacts reaches 90 percent, and a person is contagious from one to two days before the rash appears until all lesions have crusted over.
The rash and other symptoms such as fever, tiredness, and headaches usually last five to seven days, and the illness generally resolves on its own within a week or two. The rash itself may last for up to one month.
Chickenpox is usually more severe in adults than in children and is generally worse in adult men than in women or children. In England and Wales, 75 percent of deaths due to chickenpox occur in adults, and up to 10 percent of pregnant women with chickenpox develop pneumonia.
After a chickenpox infection, varicella zoster virus remains latent in the nerve tissue for about 50 years and can reactivate as shingles, also called herpes zoster. Shingles affects one in five adults who had chickenpox as children, and its connection to chickenpox was determined in 1888.
Michiaki Takahashi and his colleagues developed the live attenuated Oka strain vaccine in Japan in the early 1970s, and Merck and Co. licensed it in the United States in 1995. The varicella vaccine protects about 70 to 90 percent of people, with a greater benefit against severe disease.
Treatment mainly eases symptoms, using calamine lotion for itching, short fingernails to reduce scratching injury, and paracetamol for fever. Aspirin must not be used because it may cause Reye syndrome, and antiviral medication such as aciclovir is recommended for those at increased risk of complications.