Cat food and treats are very strongly scented because cats don't have a lot of taste receptors; it's their sense of smell that cues them to eat. It's one of the reasons most dogs can't leave cat food alone -- it's VERY scented. It's possible that lot of medicine didn't seem appealing to Sammy because it fell down in the aroma department.

So sorry to hear about your colleagues. We got off very, very lucky.