Monday, January 4, 2010

A New Nosema

Along with chemicals found in the honeycomb and honey bee viruses, Nosema disease appears to be a contributing factor in the large-scale die-off of honey bees that has been occurring since the spring of 2007. Extensive studies of the bees are being undertaken to look at any possible sources of this die-off which is being called Colony Collapse Disorder. Nosema apis is a fungal infection found anywhere in the world that our honeybees of European descent are managed. Nosema is a spore-forming microbe that causes dysentery in honey bees. Honey bees don’t defecate inside the hive, and dysentery occurs when infected colonies are confined to the hive unable to make cleansing flights during extended periods of cold weather. Bees with dysentery leave feces on the outside of the hive. Nosema disease occurs in adult bees and is readily spread as bees consume the spores while cleaning out infected hive cells or by sharing food. Nosema apis is generally only a problem in regions with extremely cold winters. In the southern United States and throughout the tropics, Nosema disease is rarely a problem

Researchers studying honey bee health found that Nosema apis has been largely replaced by a more virulent strain of the disease, Nosema ceranae. This replacement of diseases is itself an unusual occurrence. Nosema ceranae is a disease of the Asian honey bee, a different species from our European honey bee. While the original Nosema was known as a rarely deadly, winter-time condition, the new strain is an around-the-year disease that is suspected as being associated with Colony Collapse Disorder. Fortunately, for the beekeeper there is good news; Nosema can be controlled by feeding sugar water treated with Fumagillin in either the fall or early spring. Placing bee hives facing the south where the sun warms the hive entrance encourages flying. Considerable advantage in fighting Nosema disease can be gained by regularly changing out old honeycomb, thus removing the disease-causing spores. Today’s photo shows hive-top feeders in use.


  1. Richard, I have used no chemicals whatsoever in my hive. But if I could find some natural supplement, I would be glad to try it. I see that some beekeepers use Nozevit, made with herbs and minerals. Would you recommend using it at all or are my North Carolina winters be mild enough, albeit cold snaps from time to time, to keep Nosema at bay?

  2. nice plant here. good working on honey bee.. thanks for sharing this with us.

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  3. The microbe that causes Nosema disease has been reclassified several times, and it closely resembles a fungus. The effects of Nosema apis could largely be held in check if the hives had good hive ventilation and the bees were able to fly. Less is known about Nosema ceranae; but both strains of Nosema can be controlled by Fumagillin, an antibiotic. Even though Fumagillin has been in use for quite a while, Nosema has not shown to have developed a resistance to it. It remains the only treatment.

    The use of herb and essential oil-based honey bee food additives and supplements is increasing. There is anecdotal evidence of health benefits associated with plant-based agents. Some stimulate feeding by meeting the bees’ behavior of sharing the taste of food with other foragers. For this they may be useful. This area of bee nutrition is promising; much more information will be known in the future as studies are conducted to determine the effectiveness of different additives.

  4. A paper on the subject of Nosema ceranae infection in honeybees, and how it can lead to CCD, can be found at

    Apparently Nosema ceranae has been identified in French and other European honey bee hives, as well as in Costa Rican killer bee colonies. It may be that Nosema ceranae hitches a ride into the bee colonies on foraged pollen.

    Also, it seems that Nosema ceranae was first described as an infectious agent at least as far back as 1995 by visiting a researcher studying bees in China. But little more was reported on the subject or much further inquiry made.

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