👉 Penetration refers to the initial step where a pathogen, such as a virus or bacterium, enters a host's body, often bypassing natural defenses like skin or mucous membranes. This entry can occur through various routes, including inhalation, ingestion, or direct contact. Once inside, the pathogen must navigate through bodily barriers and evade immune responses to establish itself. Infection follows, where the pathogen begins to replicate and cause damage or trigger an immune response. The interaction between the pathogen and host is critical; successful penetration and subsequent infection can lead to disease, while effective defense mechanisms can prevent or limit the spread of the pathogen.
