Formally known as Varicella, chickenpox is a virus, which means that there’s no good treatment (see Differences Among Germs). It’s quite uncommon now, ever since a childhood vaccine was invented in 1995. Most people with chickenpox got better, though rare persons got complications and died. The virus is more dangerous to adults than to children.
Chickenpox begins with a fever and then an itchy rash. Small blisters on a red base (“teardrops on a red sea”) begin on the head and face, soon covering the body. The illness lasts a week, and is very contagious (to the unvaccinated) until the blusters crust over. Adults are at risk of pneumonia. A complication much later in life is Shingles (see Herpes Zoster).