<figcaption class="figure-caption text-left"><strong>Figure 3:</strong> The chemical structure of fumagillin <a href="#ref10">[10].</a></figurecaption>
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<figcaption class="figure-caption text-left"><strong>Figure 3:</strong> The chemical structure of fumagillin <a href="#ref10">[10].</a></figcaption>
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Revision as of 12:07, 17 October 2018
Description
What is Nosema ceranae?
Nosema ceranae is a microsporidian parasite that infects the midgut of honeybees. N. ceranae invades the epithelial cells of the bee midgut and as it’s dependent on its honeybee host for its energy source, it causes debilitating energetic stress [1]. For individual honeybees, Nosema infections have symptoms which include shortened lifespans and weakened immune function. On the scale of a colony, the symptoms of Nosema infections greatly decrease hive productivity and contribute to colony failure [2][3][4].
Figure 1:Nosema ceranae spores imaged using phase contrast microscopy. The threadlike structures are polar filaments which spores use to penetrate honeybee epithelial cells. Pictured by Gisder S, et. al [5]
Figure 2: A Western honeybee worker (Apis mellifera)—the new host of N. ceranae.
Unfortunately, N. ceranae has recently spread to the major commercial honeybee species—the Western honeybee, Apis mellifera—and is now regarded as the dominant Nosema species infecting honey bees globally [6]. Through our conversations with Albertan beekeepers, we found that N. ceranae is a constant issue but when there is an outbreak it can lead to unsustainable rates of death. Some report over 80% hive loss due to Nosema. Nosema is also especially pervasive in cold climates, like the one found in Alberta, as colder temperatures contribute to increased hive losses in winter [7].
Previous Nosema Treatments
Previous methods of treating N. ceranae infections rely heavily on fumagillin, a potent antifungal agent that is not only expensive but is mutagenic and toxic to mammals. At low doses, fumagillin has actually been shown to increase N. ceranae spore count in honeybees [8][9]. Moreover, Medivet Pharmaceuticals Ltd., the only company that produced fumagillin for the whole of North America’s supply, went out of business earlier this year. This development led to the collapse of the fumagillin supply chain and means that there is no longer any protection available against Nosema. Thus, the issues with using fumagillin and its recent discontinuation motivate the development of alternative treatments for combating N. ceranae as a replacement is imperative to Alberta’s honey industry and the survival of honeybees. Interestingly, Medivet was based in Alberta and we were able to interview their former CEO, Ursula.
Figure 3: The chemical structure of fumagillin [10].
