• Open Access

Do the honeybee pathogens Nosema ceranae and deformed wing virus act synergistically?

Authors

  • Stephen J. Martin,

    Corresponding author
    • School of Environment and Life Sciences, University of Salford, Greater Manchester, UK
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  • Jennifer Hardy,

    1. Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK
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  • Ethel Villalobos,

    1. Department of Plant and Environmental Protection Sciences, University of Hawaii at Manoa, Honolulu, HI, USA
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  • Raquel Martín-Hernández,

    1. Centro Apicola Regional, Consejeria de Agricultura, Junta de Comunidades de Castilla-La Mancha, Marchamalo, Guadalajara, Spain
    2. Instituto de Recursos Humanos para la Ciencia y la Tecnología (INCRECYT), Fundación Parque Científico y Tecnológico de Albacete, Albacete, Spain
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  • Scott Nikaido,

    1. Department of Plant and Environmental Protection Sciences, University of Hawaii at Manoa, Honolulu, HI, USA
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  • Mariano Higes

    1. Centro Apicola Regional, Consejeria de Agricultura, Junta de Comunidades de Castilla-La Mancha, Marchamalo, Guadalajara, Spain
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For correspondence. E-mail s.j.martin@salford.ac.uk; Tel. (+44) (0)161 2952476; Fax (+44) (0)161 2955999.

Summary

The honeybee pathogens Nosema ceranae and deformed wing virus (DWV) cause the collapse of honeybee colonies. Therefore, it is plausible that these two pathogens act synergistically to increase colony losses, since N. ceranae causes damage to the mid-gut epithelial ventricular cells and actively suppresses the honeybees' immune response, either of which could increase the virulence of viral pathogens within the bee. To test this hypothesis we exploited 322 Hawaiian honeybee colonies for which DWV prevalence and load is known. We determined via PCR that N. ceranae was present in 89–95% of these colonies, with no Nosema apis being detected. We found no significant difference in spore counts in colonies infected with DWV and those in which DWV was not detected, either on any of the four islands or across the entire honeybee population. Furthermore, no significant correlation between DWV loads (ΔCT levels) and N. ceranae spore counts was found, so these two pathogens are not acting synergistically. Although the Hawaiian honeybees have the highest known prevalence of N. ceranae in the world, with average number of spores been 2.7 million per bee, no acute Nosema related problems i.e. large-scale colony deaths, have been reported by Hawaiian beekeepers.

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