This is the 4906th most frequent Japanese word.
病原
"病原" means "pathogen" or "cause of a disease."
Here, '病原' is used in its noun form to refer to the concept of a pathogen, directly providing its definition.
病原は感染症の原因となる微生物です。
Pathogens are microorganisms that cause infectious diseases.
In this sentence, '病原' is part of the compound '病原性', meaning 'pathogenicity', describing the characteristics of the bacteria.
病原性を持つ菌が食品から発見されました。
Bacteria with pathogenic properties were discovered in food.
The word '病原' is used as the object in the sentence, focusing on the action of identifying specific pathogens.