noun which may take the genitive case particle 'no', noun
infectious; contagious
Medical term used to describe diseases that can be transmitted from person to person or from animal to person. Often used attributively with の.
この病気は伝染性が高い。
This disease is highly contagious.
伝染性のウイルスに注意
Please be careful of infectious viruses.
Compound of 伝染 (transmission, contagion) and 性 (nature, property). The exact historical derivation is uncertain, but the term follows standard Sino-Japanese word formation patterns.