Great educational, thought provoking thread! I'm not a school nurse but school isn't the only setting where animals are potentially a benefit to patient care (well, and the healthcare staff too!) but other factors unfortunately have to be considered also.
Here's a link that contains info that might be helpful to some, who like me, were confused about some of the differences in laws etc.
Differences between Service, Emotional Support, and Therapy Animals - SERVICE DOG AND EMOTIONAL SUPPORT ANIMAL LETTERS & REGISTRATION