👉 Infection is determined by a complex interplay of factors involving both the host and the pathogen. The process begins when a pathogen, such as a bacterium, virus, fungus, or parasite, enters the body through various routes like ingestion, inhalation, or direct contact. For infection to occur, the pathogen must then survive and multiply within the host's environment, often requiring specific conditions such as temperature, pH, and nutrient availability. The host's immune system plays a crucial role; if it fails to recognize and combat the pathogen effectively, the infection can take hold. Genetic factors in both the host and pathogen also influence susceptibility and resistance. For instance, certain genetic variations can make individuals more prone to infections or affect how well their immune system responds. Additionally, environmental factors like hygiene, nutrition, and exposure to pathogens can impact the likelihood of infection. Once the pathogen establishes itself, it can cause disease by disrupting normal cellular functions, triggering inflammatory responses, or directly damaging tissues. The severity and outcome of the infection depend on these multiple determinants, including the pathogen's virulence, the host's immune status, and the specific tissues affected.
