👉 Infection refers to the process by which pathogens, such as bacteria, viruses, fungi, or parasites, enter and multiply within a host organism, leading to disease. This occurs when an invading microorganism breaches the body's natural barriers—like the skin or mucous membranes—and establishes itself in tissues or organs. The body's immune system then responds by initiating an inflammatory reaction and mounting an adaptive immune response to eliminate the pathogen. However, if the infection is severe, uncontrolled, or the host's defenses are compromised, it can result in illness or disease. Common examples include the flu (influenza virus), tuberculosis (Mycobacterium tuberculosis), and sexually transmitted infections like chlamydia. Understanding infection mechanisms is crucial for developing treatments and preventive measures, such as vaccines and antibiotics.
