Which term describes an illness resulting specifically from a pathogenic organism?

The term that describes an illness resulting specifically from a pathogenic organism is "infectious disease." Infectious diseases are caused by parasites, bacteria, viruses, or fungi that invade the body and multiply, leading to various symptoms and health issues. Examples include diseases like influenza, tuberculosis, and COVID-19. The defining characteristic of these diseases is their origin in living pathogens that can reproduce within the host's body.

Understanding this, the term "pathophysiology" pertains to the study of the functional changes that occur in the body as a result of a disease, but it does not refer to the disease itself. "Communicable disease" refers to diseases that can be transmitted from one individual to another, which overlaps with infectious diseases but does not encompass all aspects, such as those that might not be easily transmissible even if they are caused by pathogens. Finally, "etiological disease" generally relates to the cause or origin of a disease rather than specifically indicating that a disease arises from a pathogenic organism. Therefore, "infectious disease" is the most precise and relevant term for an illness that arises specifically due to a pathogen.