What increases the likelihood of infection when introduced to a host?

The likelihood of infection is indeed closely tied to inoculum size. This term refers to the quantity of pathogens that enter a host. A larger inoculum increases the chance that enough pathogens will successfully establish an infection before the host's immune system can mount an effective response.

When a substantial number of pathogens are introduced, the probability increases that some will successfully attach to host cells, evade immune detection, and begin the process of multiplication. In essence, a higher inoculum means a greater challenge for the host's defenses.

While other factors, such as host resistance, pathogen virulence, and environmental factors, play significant roles in the dynamics of infection, the specific aspect of inoculum size directly addresses the initial number of pathogens involved in an infection event, making it a crucial factor in determining infection likelihood.