Pathogenous

Pathogenous refers to any agent capable of causing disease. This term is often used interchangeably with "pathogen," which typically designates a biological agent such as a bacterium, virus, fungus, or protozoan. However, pathogenous can also encompass non-biological factors like toxins or even genetic predispositions that lead to illness. The key characteristic of a pathogenous entity is its ability to disrupt the normal physiological functioning of a host organism, resulting in a disease state.

The study of pathogenous agents and their mechanisms of disease causation is known as pathogeneis. This field investigates how these agents enter a host, colonize tissues, evade or overwhelm the host's defenses, and inflict damage. Understanding pathogeneis is crucial for developing effective diagnostic tools, treatments, and preventative measures against infectious and non-infectious diseases. Different pathogenous agents employ diverse strategies; for instance, viruses hijack host cell machinery for replication, while bacteria may produce toxins that harm host cells or trigger inflammatory responses. Fungi and protozoa can invade tissues directly or compete with host cells for nutrients.