noun
A biological agent that causes disease; used in medical, biological, and public health contexts.
この病原体は感染力が非常に強い。
This pathogen is highly infectious.
研究者たちは新しい病原体を
The researchers identified a new pathogen.
ウイルス is a virus; 病原体 includes viruses but also other types of pathogens.
Compound of 病原 (byōgen, 'cause of disease') + 体 (tai, 'body, entity'). The term is a modern medical coinage.