Nosema disease is best described as which of the following?

• A. It is caused by a protozoan affecting drones
• B. It is caused by a virus affecting queen bees
• C. It is caused by a bacterium that infects larvae
• D. It is caused by a spore-forming fungus that primarily affects adult bees

Answer: (D)

Nosema disease is a microsporidian infection that forms spores and is fungus-like in nature. Because it consists of spore-forming intracellular parasites related to fungi, it’s best described as a spore-forming fungus-like organism that primarily affects adult bees. It is not caused by a virus or a bacterium, and it does not target larvae or solely drones. Infected adult bees show midgut damage, leading to dysentery and reduced lifespan, which is why the impact is seen most clearly in adult bees. Transmission happens when workers ingest spores from contaminated nectar, pollen, water, or equipment, and these spores propagate inside the gut, spreading within the colony.