👉 Infection, particularly infectious diseases, occurs when pathogens—such as bacteria, viruses, fungi, or parasites—enter and multiply within a host's body, disrupting normal cellular functions and causing illness. The process begins when these pathogens gain entry through various routes like respiratory droplets, contaminated food or water, or direct contact. Once inside, they can invade tissues, evade the immune system, or trigger an immune response that, in some cases, leads to inflammation and tissue damage. Effective communication between pathogens and host cells is crucial; pathogens often exploit host cell machinery to replicate and spread, while the host attempts to defend through immune responses. Understanding this interaction is key to developing treatments and preventive measures against infectious diseases.
