What type of illness is caused by Bacillus cereus that features longer incubation and diarrhea as the primary symptom?

Bacillus cereus is known to cause two distinct types of illnesses: an emetic syndrome, which leads to vomiting and has a quick onset, typically associated with foodborne intoxication, and a diarrheal syndrome that has a longer incubation period and primarily results in diarrhea. The illness associated with longer incubation and diarrhea is classified as a foodborne infection.

In this case, when Bacillus cereus is ingested, cells of the bacterium can establish themselves in the intestines and produce enterotoxins that cause gastrointestinal symptoms. This process is characteristic of a foodborne infection, as it involves the growth of the bacteria in the host rather than an immediate reaction to pre-formed toxins that would characterize an intoxication.

Other options like foodborne intoxication typically refer to cases with immediate symptoms following consumption, which do not apply here. Bacterial allergy and viral infection are unrelated concepts as they involve different pathogens and mechanisms of action. Thus, foodborne infection is the appropriate classification for the scenario described involving Bacillus cereus with longer incubation and diarrhea as the primary symptom.