Colony Collapse Disorder (CCD) – latest suspects

Bees Here at MicrobiologyBytes I like to report each and every time someone claims to have found “the” cause of Colony Collapse Disorder (CCD) of bees. This isn’t the first such report, and it won’t be the last:

Iridovirus and Microsporidian Linked to Honey Bee Colony Decline. (2010) PLoS ONE 5(10): e13181. doi:10.1371/journal.pone.0013181
Background: In 2010 Colony Collapse Disorder (CCD), again devastated honey bee colonies in the USA, indicating that the problem is neither diminishing nor has it been resolved. Many CCD investigations, using sensitive genome-based methods, have found small RNA bee viruses and the microsporidia, Nosema apis and N. ceranae in healthy and collapsing colonies alike with no single pathogen firmly linked to honey bee losses.
Methodology/Principal Findings: We used Mass spectrometry-based proteomics (MSP) to identify and quantify thousands of proteins from healthy and collapsing bee colonies. MSP revealed two unreported RNA viruses in North American honey bees, Varroa destructor-1 virus and Kakugo virus, and identified an invertebrate iridescent virus (IIV) (Iridoviridae) associated with CCD colonies. Prevalence of IIV significantly discriminated among strong, failing, and collapsed colonies. In addition, bees in failing colonies contained not only IIV, but also Nosema. Co-occurrence of these microbes consistently marked CCD in bees from commercial apiaries sampled across the U.S. in 2006–2007, bees sequentially sampled as the disorder progressed in an observation hive colony in 2008, and bees from a recurrence of CCD in Florida in 2009. The pathogen pairing was not observed in samples from colonies with no history of CCD, namely bees from Australia and a large, non-migratory beekeeping business in Montana. Laboratory cage trials with a strain of IIV type 6 and Nosema ceranae confirmed that co-infection with these two pathogens was more lethal to bees than either pathogen alone.
Conclusions/Significance: These findings implicate co-infection by IIV and Nosema with honey bee colony decline, giving credence to older research pointing to IIV, interacting with Nosema and mites, as probable cause of bee losses in the USA, Europe, and Asia. We next need to characterize the IIV and Nosema that we detected and develop management practices to reduce honey bee losses.


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One Response to Colony Collapse Disorder (CCD) – latest suspects

  1. Ed Rybicki says:

    As a sometime contributor to the “THIS is the cause of CCD!!” bandwagon, I am rapidly getting to the point where I think it is going to be found to be a multifactorial syndrome, rather than “a” disease – and that it will be found that everything from pesticides (various) to fertilisers to diesel fumes and microwaves, to picornaviruses, iridoviruses, bacteria and fungi will be found to contribute – to varying degree, and in varying mixtures.

    The only cure will be to stop civilisation / agriculture as we know it. Or breed better bees…Africanise them!! I mean, we live with the real thing quite happily, instead of some wimpy hybridised version, and no-one I know has ever died of a bee sting. Been chased, mind, and stung, but not dead yet…and ironically, in our neck of the woods, Apis capensis – the Cape honeybee – is aggressively displacing the African honeybee. Wait till the Yanks get wind of that…B-)

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