Pathogen must adhere to protein or carb in host cell cytoplasm in order to prevent being removed by cilia or other non specific immune defenses
Must replicate w/in/on host cell in order to have a critical mass of pathogen in order to cause infection
Moving directly from one cell to an adjacent cell, in blood, lymph, along nerves, across placenta.
Damage host tissue by directly killing cells or inducing apoptosis.Or indirectly stimulating immune responses to damage host tissue.
Shed from host cell to infect other cells