Nosema apis is a microscopic fungus that infects honeybees, particularly affecting their digestive systems. It is a type of microsporidian parasite that can lead to a condition known as nosemosis, which can weaken bee colonies and reduce their lifespan. Infected bees may show symptoms like dysentery, reduced foraging ability, and overall poor health. The transmission of Nosema apis occurs through spores found in contaminated food or water sources. This parasite thrives in crowded conditions, making it a significant concern for beekeepers. Effective management practices, such as maintaining hive cleanliness and monitoring bee health, can help mitigate its impact on bee populations.