What term describes the agents that cause diseases, such as bacteria and viruses?

The term that describes agents that cause diseases, such as bacteria and viruses, is pathogens. Pathogens are microorganisms that can lead to infections and diseases in hosts, including humans. They encompass a wide range of organisms, including bacteria, viruses, fungi, and parasites, which can invade the body and cause various health issues. Understanding pathogens is crucial in fields like medicine and public health because it helps in developing strategies for prevention, treatment, and control of diseases.

In contrast, antigens refer to substances that can provoke an immune response, not necessarily causing disease directly. Toxins are poisonous substances produced by living organisms, including some bacteria, but they do not encompass all disease-causing agents. Allergens are substances that can cause allergic reactions, which is a different type of response than what is initiated by pathogens.