👉 Infection occurs when a pathogen, such as a virus or bacterium, enters a host and begins to multiply, often causing disease. This process starts when the pathogen breaches the body's defenses, typically through breaks in the skin or via the respiratory, digestive, or urinary tracts. Once inside, the pathogen can invade host cells or tissues, replicate, and spread to other parts of the body. The immune system then responds by mounting an attack, but if the infection is severe or the host's defenses are compromised, it can lead to illness. Understanding infection is crucial for developing treatments and preventive measures like vaccines and antibiotics.
