Nosema is a common parasite of honey bees, and does not cause any obvious signs of disease. But should the prevalence of infection in the hive get out of hand, then the disease “nosemosis” may become apparent at the colony level, resulting in poor performance, or even depopulation.

Since the invasion of N. ceranae worldwide, we've learned a lot more about this parasite and its effects upon individual bees, but are still not completely clear as to its effects upon the colony as a whole.

Effects of Nosema upon an individual bee