👉 Infection is a process where a pathogen, such as a bacterium, virus, fungus, or parasite, enters a host and begins to multiply, often causing disease. The process starts when the pathogen breaches the body's defenses, typically through breaks in the skin or mucous membranes. Once inside, the pathogen can adhere to and invade host cells, either by directly penetrating them or by exploiting cellular pathways. The pathogen then replicates, using the host's resources like nutrients and energy. This replication can lead to cell damage or death, triggering an immune response from the host. If the infection is successful, the pathogen can spread to other parts of the body, potentially causing systemic illness. The interaction between the pathogen and the host's immune system is crucial; a robust immune response can clear the infection, while a weakened or evasive pathogen may lead to chronic or persistent infections.
