Nosema Disease of Bees

an infectious disease of bees caused by unicellular parasites of the genus Nosema. The Mal-pighian tubes and the epithelial cells of the midgut are primarily affected. Infected bees are the source of the causative agent. Nosema spores are transmitted through such apian products as honey, beebread, and honeycomb. Among the factors that predispose bees to nosema disease are a prolonged wintering period, poor winter feed, high moisture content in the winter hive, and an extended period of unfavorable weather for flying. Many of the bees in an infested colony die during the winter and during the first month after the hives are taken outdoors. The abdomen of the dead insects is enlarged and soft. Diarrhea and sluggishness are the visible symptoms of nosema disease; the diagnosis is confirmed by microscopic examination of the intestinal contents. Treatment makes use of a syrup that contains the antibiotic fumagillin. Nosema disease is prevented by proper maintenance of the winter hive. Should the infestation arise, formaldehyde fumes are used as a disinfectant.