Sampling of adult bees for detection of American foulbrood (Paenibacillus larvae subsp. larvae) spores in honey bee (Apis mellifera) colonies
Anders Lindstrom and Ingemar Fries
Fifty-nine apiaries with a total of 489 honey bee colonies belonging to a beekeeping operation in central Sweden with a previous history of American foulbrood (AFB) were inspected. For each colony the clinical disease status was visually inspected and the number of brood cells clinically diseased by AFB estimated. From 94 of these colonies, individual samples of >100 live honey bees from the brood chamber and supers were collected. Two composite samples consisting of >100 adult bees from each individual colony in each inspected apiary were also taken from (1) all brood chambers and (2) all supers, respectively. Samples were taken on both the individual colony level and the apiary level and analysed for presence of Paenibacillus larvae subsp. larvae by culturing. Spores were found in 100% (n = 21) of the bee samples from clinically diseased colonies and in 77% of the supers and 82% of the brood chambers in colonies without clinical symptoms (n = 73). On the apiary level, 100% of the samples from clinically diseased apiaries were positive (n = 32). In the apiaries that showed no clinical disease, 70% of the composite samples from supers and 67% of the samples from brood chambers were positive for AFB (n = 27). Spore load differed only slightly between bees in brood chambers and in supers, suggesting that sampling bees from supers when screening apiaries for AFB is a fast and satisfactory alternative to sampling brood chambers.
American foulbrood, Paenibacillus larvae subsp. larvae, spores, Apis mellifera, honey bees, colonies, Sweden