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Powdered Sugar Examination as a Tool for the Assessment of Paenibacillus larvae Infection Levels in Honey Bee
Stefano Bassi1, Giorgio Galletti1, Emanuele Carpana2
1Istituto Zooprofilattico Sperimentale della Lombardia e dell' Emilia Romagna "Bruno Ubertini", Brescia, Italy.
Abstract:
American Foulbrood (AFB) is a contagious and severe brood disease of honey bees caused by the spore-forming bacterium Paenibacillus larvae. The identification of honey bee colonies infected by P. larvae is crucial for the effective control of AFB. We studied the possibility of identifying the infection levels by P. larvae in honey bee colonies through the examination of powdered sugar samples collected in the hives. The powdered sugar was dusted on the top bars of honeycombs and collected from a sheet paper placed at the bottom of the hive. Three groups of honey bee colonies were examined: Group A1- colonies with clinical symptoms of AFB (n = 11); Group A2 - asymptomatic colonies located in apiaries with colonies showing symptoms of AFB (n = 59); Group B - asymptomatic colonies located in apiaries without cases of the disease (n = 49). The results showed that there was a significant difference in spore counting between Groups and that the spore load in sugar samples was always consistent with the clinical conditions of the colonies and with their belonging to AFB-affected apiaries or not. Based on the obtained results the cultural examination of powdered sugar samples collected from hives could be an effective tool for the quantitative non-destructive assessment of P. larvae infections in honey bee colonies.
Insights
Powdered sugar samples can detect American Foulbrood (AFB) in honey bees. This method quantifies Paenibacillus larvae spores, aiding in early detection and control of this severe bee disease.
Area of Science:
- Apiculture
- Bacteriology
- Veterinary Entomology
Background:
- American Foulbrood (AFB) is a significant honey bee brood disease caused by Paenibacillus larvae.
- Early and accurate identification of P. larvae is essential for managing AFB outbreaks.
Purpose of the Study:
- To evaluate the efficacy of analyzing powdered sugar samples for detecting P. larvae infection levels in honey bee colonies.
- To determine if spore counts in powdered sugar correlate with clinical AFB symptoms and apiary disease status.
Main Methods:
- Powdered sugar was dusted on top bars and collected from hive floors.
- Samples were analyzed for P. larvae spore loads.
- Three groups of colonies were tested: clinically affected, asymptomatic in affected apiaries, and asymptomatic in disease-free apiaries.
Main Results:
- Significant differences in spore counts were observed between the study groups.
- Spore loads in sugar samples consistently reflected the clinical status of colonies and apiary disease presence.
- The method demonstrated consistency between spore load and clinical presentation of AFB.
Conclusions:
- Cultural examination of powdered sugar samples offers a viable non-destructive method for assessing P. larvae infection.
- This technique can be an effective tool for quantitative, non-invasive monitoring of AFB in honey bee colonies.
- The findings support the use of powdered sugar analysis for improved AFB management strategies.
