👉 Infection, in a biological context, refers to the process by which a pathogen—such as a virus, bacterium, fungus, or parasite—invades and takes control of a host's cells or tissues, leading to disease. This occurs when the pathogen breaches the body's natural barriers, such as the skin or mucous membranes, and begins to replicate or cause harm. The immune system then responds by mounting an attack, but in some cases, the infection can evade or overwhelm these defenses, resulting in symptoms of illness. For example, a virus like influenza infects respiratory cells, hijacks their machinery to produce more viral particles, and spreads throughout the body, causing fever, cough, and other symptoms. Understanding infection is crucial for developing treatments and preventive measures, such as vaccines and antibiotics, to combat diseases and protect public health.
