👉 Infection occurs when a pathogen, such as bacteria, viruses, fungi, or parasites, enters a host and begins to multiply within its tissues or bodily fluids, disrupting normal physiological functions. This disruption arises from the pathogen's ability to invade host cells, evade the immune system, and cause damage through direct toxicity or by triggering excessive inflammatory responses. For instance, bacteria can release toxins that harm host cells, while viruses hijack cellular machinery to replicate, leading to cell death and tissue damage. The body's immune response, designed to combat these invaders, can also contribute to infection; an overactive immune reaction can cause collateral damage, exacerbating the condition. Understanding the mechanisms behind infection is crucial for developing effective treatments and preventive measures, such as antibiotics, antivirals, and vaccines, which target specific stages of the pathogen's life cycle or bolster the host's defenses.
