are spread to other colony members through fecal matter. The disease impairs the digestion of pollen, thereby shortening the life of the bee. A greater proportion of worker bees become infected than drones or queens, probably due to the comb-cleaning activities of young bees in which drones and queens do not participate. Nosema-infected bees do not attend or feed the queen to the same extent as healthy bees, which helps the queen to escape infection. When the queen becomes infected, her ovaries degenerate and her egg-laying capacity is reduced due to atrophy of the oocytes. Queens that become infected by the parasite during the brood-rearing season are superseded by the bees. The seasonal trend of typical infections exhibits low levels during summer, a small peak in autumn, and a slow rise of infection during winter. It is more common during times of confinement - winter and spring. In the spring, the level of infection increases rapidly as brood-rearing starts and while flight possibilities are still limited. Colonies in northern climates are more seriously affected than colonies in the south because of the increased amount of time bees are confined in the hive. Nosema, if left untreated, can cause queen supersedure, winter kills, reduced honey yields, and dwindling populations. Diagnosis Diagnosis is dependent on microscopic examination of the ventricular (midgut) content and/or fecal matter or on PCR analysis of infected tissue. No specific outward sign of disease may be present, although in dissections, the ventriculus often appears whitish and swollen in late stages of infection. The disease is easily detected in samples of whole bees macerated in water. The fluid is examined under a light microscope at 250–500 x magnification where the characteristic Nosema spores can be observed. Though the spores of N. apis and N. ceranae have slight morphological and ultrastructural differences, they cannot be reliably differentiated via light microscopy. PCR analysis or electron microscopy of spores are the only reliable ways to differentiate between the two types of Nosema infection, given genetic variation and variation in the number of sporular polar filament coils between the two species. Treatment Treatment with the antibiotic Fumidil B (prepared from Aspergillus fumigatus, the causative agent of stonebrood), inhibits the spores reproducing in the ventriculus, but does not kill the spores. A disinfection of the honeycombs and utensils is recommended for an extensive disease outbreak. The spores are sensitive to chemicals such as acetic