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What is idiopathic brood disease syndrome?

A new research paper by vanEnglesdorp et al. titled “Idiopathic brood disease syndrome and queen events as precursors of colony mortality in migratory beekeeping operations in the eastern United States” is getting a lot of attention. Boiled down to its essence, it states (among other things) that colonies diagnosed with idiopathic brood disease syndrome (IBDS) have a risk of dying in the short term that is 3.2 times greater than average.

So what is IBDS? According to The New Oxford American Dictionary, idiopathic means “relating to or denoting any disease or condition that arises spontaneously or for which the cause is unknown.” We already know what brood is and we know what disease is. That leaves us with “syndrome,” which means “a group of symptoms that consistently occur together or a condition characterized by a set of associated symptoms.”

All put together, it means IBDS is a brood disease with a recognizable set of symptoms for which we don’t know the cause. It’s a fancy way of saying “we don’t know much.”

What we do know is the following:

  • In many ways, IBDS looks similar to American foulbrood, European foulbrood, or even sacbrood, but with some differences.
  • Brood of various ages appears “molten” (meaning liquified) on the bottom of the cells.
  • Parasitic mites may or may not be present.
  • According to Randy Oliver, the dead brood smells very bad but different than American foulbrood.

The syndrome is not necessarily new—it was once known under the name “parasitic mite syndrome.” The name was changed to reflect the fact that parasitic mites may not be present. At this point, it is not known whether mites transmit the disease or not. It is possible the disease is transmitted by mites but is able to persist after the mite population has been eradicated.


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