What term describes an organism that causes disease?

The term that describes an organism that causes disease is "pathogen." Pathogens are agents, such as bacteria, viruses, fungi, or parasites, that can invade the body and disrupt normal bodily functions, leading to illness. They often evade the immune system and can multiply within the host, causing various health issues ranging from mild to severe diseases.

Understanding the role of pathogens is crucial in fields like medicine and public health, as it helps in developing strategies for prevention, treatment, and control of infectious diseases. For example, vaccines are designed to prepare the immune system to recognize and fight specific pathogens, thereby preventing diseases they cause.

In contrast, infection refers to the state of being infected by a pathogen, while antibodies are proteins produced by the immune system to identify and neutralize pathogens. A toxin is typically a poisonous substance produced by living cells or organisms and may cause disease but is not itself an organism. Thus, the distinction between these terms highlights the specific role of pathogens in disease causation.