Which of the following is NOT a route of exposure for pathogens?

Manipulation is not considered a standard route of exposure for pathogens. Typically, pathogens can enter the body through specific, defined routes: inhalation refers to breathing in infectious agents, ingestion involves consuming them through food or drink, and injection involves introducing them directly into the bloodstream, often through needles.

Manipulation, while it can involve physical contact with contaminated surfaces, does not represent a direct or recognized pathway through which pathogens are primarily transmitted. Instead, it is more of an activity that might lead to a route of exposure, as it may facilitate contact with pathogens present on surfaces or objects. Thus, it lacks the specificity and established understanding of the other exposure routes, which are well-documented methods of how infections can enter the body.