Nosema Ceranae

Early last year, a new parasitic disease, Nosema ceranae, was positively identified in Apis mellifera colonies in Spain. This was the first ever reported case of colonies infected by N. ceranae in Europe. It is now believed that the “Colony Collapse Syndrome” experienced over the years in Europe may be related to this disease.

The natural host for N. ceranae (until now) is Apis ceranae, the small honeybee of East Asia, and the two creatures, host and parasite, have lived in an uneasy equilibrium. We are all familiar, of course, with Nosema apis, which is a well known disease of the Western Honeybee. This rarely causes major losses in our colonies, although, if left untreated, it can cause queen-supersedure, winter deaths, reduced honey-yields and dwindling populations. Nosema ceranae is quite a different kettle of fish, however!

N. ceranae and N. apis have similar life cycles, but differ in spore morphology, with N. ceranae spores being slightly smaller. The most significant difference, however, is in its effect on our honeybees. Bees die within 8 days after exposure to N. ceranae. The foraging force seems to be affected the most. They leave the colony and are too weak to return, dying therefore in the field. This leaves behind a small cluster, and hence a weakened colony. N. ceranae does respond to Fumagillin (Fumidil B) which is some good news for the beekeeper. Even better news is that Nosema ceranae has not yet been identified in the U.K.

With thanks to University of Georgia USA Bee Letter January 2007. via BEES

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