👉 Expansion of "infection" refers to the process by which a pathogen, such as a virus, bacterium, fungus, or parasite, enters and begins to multiply within a host organism. This entry can occur through various routes, including ingestion, inhalation, skin contact, or injection. Once inside, the pathogen interacts with the host's cells, often evading or suppressing the immune system's defenses. The infection then spreads, either directly to nearby cells or systemically throughout the body via the bloodstream or lymphatic system. As the pathogen replicates, it can cause damage to host tissues and organs, leading to symptoms that vary depending on the type of infection. For example, bacterial infections might cause inflammation and pus formation, while viral infections can lead to cell damage and immune responses like fever and fatigue. The body's response to the infection, including the activation of immune cells and the production of antibodies, is crucial in controlling and eventually eliminating the pathogen, though some infections may persist or become chronic.
