Honey Bee Digestive Health
Viral, bacterial, fungal, and protozoal infection Monitoring
Also: This will be discussed by Jennafer Snyder at our Regular Meeting Thursday, May 21, 2026
Jennafer Snyder (our club secretary) will be discussing microscope diagnostics/monitoring for gut/digestive health at this meeting. She will be using our club microscope. Jennafer has a background in veterinary as a nurse in emergency/specialty care for 6 years and general practice for 3. She loved working on the microscope and slide prep.
PRESERVATION OF BEE SAMPLES FOR MONITORING
Marley E. Iredale, DVM, DACVP, MS
Northwest ZooPath
Northwest ZooPath
Marley states, "Preservation of bees is the same, regardless of what you're looking for. For most bee clubs, I recommend just collecting bees from the alcohol wash that you're already doing for Varroa monitoring. If the hive is showing clinical signs, then collecting some dead bees as well as live bees is also a good idea, but keep the samples separate. Ideally, the specimens should be kept in 70% ethanol until you're ready for your microscopic examination. If you don't have access to ethanol, this can be achieved using a clear alcohol from the liquor store that is at least 140 proof (like Everclear).
Preparation of bees depends on what you're looking for. If you're looking for gut pathogens, I recommend this protocol: https://ask.ifas.ufl.edu/publication/IN1431. If you need help getting hemocytometers, please let me know, and I can talk to the HBREL about where they got theirs. If you aren't sure what might be wrong, then please reach out to me, and we can talk about doing some histopathology.
The hemocytometer is important for quantifying infection, but you could probably do this protocol with just a slide and a cover slip and still be able to look for pathogens.
The main sign of an unhealthy gut is diarrhea (dysentery). I have attached a couple of pictures. It looks like runny feces on the front of the hive and on the frames. Bees are usually very fastidious about pooping outside the hive, so any frass inside the hive is an indication of gut disease. I'm happy to hear that none of your bees are showing signs of disease! I would be happy to help try to identify diseases as they pop up.
We think that the protozoa are contracted from the environment, like water sources. My impression is that they are probably endemic in the environment, but they overgrow (dysbiosis) when the gut microbiome is out of balance."
Marley E. Iredale, DVM, DACVP, MS
Preparation of bees depends on what you're looking for. If you're looking for gut pathogens, I recommend this protocol: https://ask.ifas.ufl.edu/publication/IN1431. If you need help getting hemocytometers, please let me know, and I can talk to the HBREL about where they got theirs. If you aren't sure what might be wrong, then please reach out to me, and we can talk about doing some histopathology.
The hemocytometer is important for quantifying infection, but you could probably do this protocol with just a slide and a cover slip and still be able to look for pathogens.
The main sign of an unhealthy gut is diarrhea (dysentery). I have attached a couple of pictures. It looks like runny feces on the front of the hive and on the frames. Bees are usually very fastidious about pooping outside the hive, so any frass inside the hive is an indication of gut disease. I'm happy to hear that none of your bees are showing signs of disease! I would be happy to help try to identify diseases as they pop up.
We think that the protozoa are contracted from the environment, like water sources. My impression is that they are probably endemic in the environment, but they overgrow (dysbiosis) when the gut microbiome is out of balance."
Marley E. Iredale, DVM, DACVP, MS
Bee Collection Recommended Protocol:
1. Collect ten live or dead bees from the front of each hive and place them into resealable bags labeled to identify the colony.
3. For simple detection (presence/absence), place a drop of liquid from the bag onto a microscope slide, apply a cover slip, and view with a light microscope. If you wish to quantify the contagion present to estimate the protozoal load, then you may use a hemocytometer to count M. mellificae spores in the same way you would use it to count Nosema spp. spores.
1. Collect ten live or dead bees from the front of each hive and place them into resealable bags labeled to identify the colony.
- Note: bees can be collected from anywhere in the hive, but selecting workers at the entrance may increase the likelihood of detecting the amoeba.
3. For simple detection (presence/absence), place a drop of liquid from the bag onto a microscope slide, apply a cover slip, and view with a light microscope. If you wish to quantify the contagion present to estimate the protozoal load, then you may use a hemocytometer to count M. mellificae spores in the same way you would use it to count Nosema spp. spores.