What are disease-causing microorganisms commonly referred to as?

Disease-causing microorganisms are commonly referred to as pathogens. This term specifically denotes any biological agent that causes illness or disease, such as bacteria, viruses, fungi, or parasites. Pathogens can be found in various environments, including water supplies, and are a significant concern in public health and environmental science.

While contaminants broadly refer to any substance that makes something impure or unclean, not all contaminants are pathogenic or harmful. Toxins refer specifically to poisonous substances produced by living organisms, which may or may not be microbial. Carcinogens are substances or agents that can cause cancer, and they are an important category in toxicology, but they do not encompass all disease-causing microorganisms. Thus, pathogens is the most precise and appropriate term for microorganisms that lead to diseases.