This video is about a deadout colony that quickly came from a strong overwintered colony to a very weak colony in a matter of a few weeks. The symptoms make it look like Nosema.
Nosema is a late winter disease that can cause the demise of a colony. Nosema is a stress related disease and causes bee diarrhea in a colony. The stress is caused by winter related issues. Mites can sometimes be a contributing factor. Beekeepers used to treat for Nosema using Fumigillan, an antibiotic, mixed in syrup. It is no longer available for sale.
Life without Fumigillan