Child is infected with chicken pox.

The most contagious time occurs when the person is manifesting the cold-like symptoms. This happens usually two to five days before the rash appears. As a result the time in which someone is most contagious occurs before the person even knows he has chicken pox. After the rash appears, the person is infectious for about five days or until all the lesions have begun crusting over.
Humans are the only animals that get chicken pox. So the only way to catch it is by being around a person who is infected. The virus is spread through secretions and by tiny droplets, so sharing saliva, sneezing, and coughing are good ways to pass the virus from one person to another.
Children with immune problems can have significant problems if infected with chicken pox. These include those children infected with HIV, the virus that causes AIDS, those with cancer, those on steroids for other illnesses, and newborn babies.
There is not a lot that can be done to completely eliminate the symptoms once a child is infected with chicken pox. Most treatment is then aimed at trying to alleviate the pain, itch, and fever associated with chicken pox.