Contagious Disease
noun
A sickness that can transmit and then dye into you (aka get inside you and infect you, via transmission) is a contagious disease. Everyone cover their mouths when they cough and sneeze, and please wash your hands, okay?
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
世界で一番危険な伝染病は何ですか。
What is the most dangerous infectious disease in the world?