Can humans catch bee dysentery?

No. Honey bee dysentery is not caused by a pathogen, so it is not “catchable.” Honey bee dysentery arises when the food a winter bee eats is high in solids, usually known as ash. These solids hold water in the gut and cause it to become distended. When the bees endure long periods of time when they cannot fly out of the hive to relieve themselves, they end up defecating inside the hive.

A common disease caused by the microsporidian Nosema apis, also causes dysentery-like symptoms. Nosema apis is a type of fungi that lives in the honey bee gut. The infected bees are unable to properly digest their food, which causes diarrhea and distended abdomens. Symptoms usually show up in late winter or early spring after long periods of confinement. As a result, the disease causes more problems in areas with long winters. A laboratory analysis is required for positive identification of a Nosema infection but, in any case, Nosema is not transmissible to humans.


  • So how would fermented open stores (a known cause of dysentery) suddenly increase their “ash”? Solids would not be increasing as the hygroscopic properties of honey would be pulling in water and the fermentation process gives alcohol…

    • Trisha,

      You forgot one thing. Fermentation is caused by yeast that land on the open honey. The yeast reproduce like crazy and give off alcohol and carbon dioxide. They multiply exponentially, at least for a while, and their dead bodies accumulate in the substrate they are living in. For example, the slurry at the bottom of an unfiltered ale is dead yeast bodies. The yeast bodies contribute to the solids that cause the dysentery.

  • The funny things people want to know! When I was revising nosema for a bee diseases exam recently, my books said dysentery was not a symptom of nosema but can spread it quickly, due to worker bees cleaning the hive coming into contact with nosema spores in the dysentery faeces. Would you disagree with this and say that dysentery is a direct symptom of nosema apis?

    • Emily,

      The book, Honey Bee Parasites, Pests, Predators and Diseases, published by Penn State University and The Mid-Atlantic Apiculture Research and Extension Consortium says this about Nosema apis: “Damage to the digestive tract may produce symptoms of dysentery (diarrhea).” So your book is probably correct in that Nosema may produce dysentery. Also, the sentence implies that it is the damage to the digestive tract—not the pathogen itself—that causes the dysentery, so dysentery is more or less a secondary symptom.

      • Thanks Rusty. A lot of sources seem to say that dysentery is more associated with nosema apis than nosema ceranae, perhaps the two have different effects on the digestive tracts of bees.

        • Emily,

          As far as I know, Nosema ceranae is not associated with dysentery at all. It’s confusing because N. ceranae is more of a summer affliction and N. apis is a winter one. Plain dysentery is definitely a winter problem, so it’s hard to tell what is what without lab tests.

    • I assume you mean Nosema, and not honey bee dysentery since honey bee dysentery is not “catchable.” As for Nosema, I don’t think the screened floor makes much difference. Once a colony is infected, the bees pass it around via trophallaxis, even before they start to defecate.

  • Hi,

    I am not sure what my hive has, as it seems too late in the season for Nosema. My bees have been dying for the past 5 days. It starts mainly after noon, and they begin to collapse from 1-6 feet from the hive. They squirm and crawl, but cannot fly. They are defecating everywhere outside the hive, on the hive and on the ground outside the hive. I performed an inspection of the hive after 4 days of this and there is only one spot of feces within the hive. There is a ton of capped brood and larvae. Not a ton of honey at this point in the season, however. What is this and is there anything I can do? Do bees eventually recover from dysentery?

    • Elizabeth,

      Nosema in summer, usually Nosema ceranae, is not normally associated with dysentery. In fact, dysentery from any source is unusual in summer. My guess (and I can only guess from this information) is that your bees are getting into a pesticide-laced crop. It sounds like they may be foraging on it in the afternoon, flying home, but then not entering the hive because they know they are sick. The poison may be causing the dysentery-like symptoms as well as the squirming, crawling, and inability to fly. Even one neighbor with a passion for insecticide could cause a big loss.

  • Just a side note to the problem of insecticides being brought home in the pollen stores, even after the initial kill off, one has to bee careful in that they might have stored insecticide pollen inside the hive and when they start to uncap it and feed it, another disaster takes form and happens. This happened to me, so I thought I would warn. I think you hit the nail on the head as this seems to mimic what happened with my one hive a few years back and then I had another kill off a week or two later from inside the hive. I had to take all pollen frames out, scrape and clean them before I inserted them back into the hives. Some of the frames I just burned if I thought they needed it. People and their Seven Dust!

  • Hi. If my colony is decimated with dysentery can I re populate with new queen/bees
    And if so is the existing honey etc safe or do I discard said frames ? Novice

    • Hi John,

      The thing to remember is that honey bee dysentery is not caused by disease organisms the way human dysentery is. It is caused by a wintertime diet that is too high in fiber and/or water. With that in mind, the honey is perfectly safe for you and the bees. You can also repopulate the hive with new bees and a new queen. Scrape off the frames, if you can. Otherwise, just leave the mess for the new bees to clean up. It won’t take them long.

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