Which of the following apply to gastroenteritis:

A) refers to infection and inflammation of the gastrointestinal tract
B) standard presentation includes vomiting, diarrhea, abdominal cramping
C) severe presentation includes dehydration, hypoxia/hypotension, and possible death
D) gastroenteritis can be caused by viruses, bacteria, protozoa, and helminths
E) all of the above apply