Childhood disease is a term used to describe illnesses that are commonly contracted by children. MUMPS, a five letter word, is an infectious disease caused by a virus that primarily affects the salivary glands. MEASLES, a seven letter word, is a highly contagious viral illness that can cause serious health complications, including pneumonia and encephalitis. Rickets, also a seven letter word, is a condition caused by a lack of vitamin D, calcium, or phosphate, which leads to softening and weakening of the bones.