👉 Infection, specifically infectious disease, occurs when a pathogen—such as bacteria, viruses, fungi, or parasites—enters a host and begins to multiply or cause harm. This process involves several steps: the pathogen must first adhere to specific cells or tissues, often by binding to receptors on the host cell surface; it then invades these cells or tissues, sometimes using mechanisms that allow it to bypass normal defenses; and finally, the pathogen replicates, either within the host cell or in the surrounding environment, leading to symptoms and potential damage to the host's tissues and organs. The body's immune system responds to the infection by mounting an attack, but if the pathogen is highly virulent or the host's defenses are weakened, the infection can lead to disease. Understanding the mechanisms of infection is crucial for developing treatments and preventive measures.
