Commercial honeybees are tough. They get trucked cross-country to pollinate vast crops, often while fed unnatural diets such as sugar water and soy flour. Their hives are treated with chemicals to deter parasites, and they're exposed to pesticides and fungicides in the fields where they work and feed.
"I can feed you a diet of Hershey bars, keep you up all night, truck you around, and spray Raid in your face, and I guarantee you'll get sick," says Jerry Hayes, Florida's assistant chief of apiary inspection. "That's kind of what's happening to bees."
from Scientific American "Is Life Too Hard for Honeybees?"
they also have an article on the new bee medicine