Phase 1
Harmful microbes need to bind to host epithelial surfaces to cause an infection.
Phase 2
Microbes use adhesin molecules to bind to receptors on host cells.
Phase 3
Binding of microbes to epithelial cells triggers an inflammatory response in the host and causes discomforts.
Phase 4
An infection occurs when harmful microbes multiply at host surfaces or invade tissues. In these situations, discomforts may worsen.