Before it causes disease, a pathogen must first cross:
A) the lining of the stomach.
B) the blood-brain barrier.
C) from the blood into a cell.
D) an epithelium barrier.

Question

Quizplus · Accepted Answer

Pathogens must first cross an epithelial barrier, which can be the skin or the lining of the gastrointestinal, respiratory, or urogenital tracts, to initiate infection. This is a critical step in the pathogenesis of many diseases.

Before It Causes Disease, a Pathogen Must First Cross