👉 Infection refers to the process by which a pathogen, such as a virus, bacterium, or parasite, enters and takes control of a host's cells, leading to illness or disease. This can occur through various routes, including respiratory droplets, contaminated food or water, vectors like mosquitoes, or direct contact with infected individuals or surfaces. Once inside the host, pathogens replicate, often causing damage to tissues and organs, which triggers the body's immune response. However, in some cases, the pathogen may evade or suppress this response, leading to chronic infection. For example, HIV infects and destroys CD4+ T cells, weakening the immune system, while tuberculosis bacteria can hide within host cells, making them difficult to eliminate. Understanding infection is crucial for developing prevention strategies, such as vaccines, antibiotics, and hygiene practices, to reduce the spread and impact of infectious diseases.
