Not about the USA or Canada, but of interest:

Official epidemiological data indicate a very low number of annual outbreaks in the country, therefore this investigation was carried out to evaluate whether notification to the veterinary authority is [being] omitted, so that AFB transmission from infected apiaries is not [being] prevented.

None, or very few, annual AFB outbreaks were reported by the National Informative System for Animal Diseases (SIMAN, https://www.vetinfo.sanita.it) in most regions since 2010, year in which the reporting system became active. This could indicate underreporting and an ineffective disease control.

Presence and number of P. larvae spores were analyzed in 122 honey samples, each from a different apiary, collected in the Abruzzo region in years 2014 and 2015. P. larvae spores were found in 40% of the samples and the spore numbers allowed to infer a prevalence of AFB of at least 22.7% among beekeepers, indicating the necessity to improve the surveillance system. 

Results are not only in contrast with the official AFB annual reports but also with the Epilobee European surveillance study, the closest in terms of localization and time of execution to the present investigation. The latter showed a prevalence of clinical signs in at most 6% apiaries inspected in Italy in year 2014.

The series of average spore counts for beekeepers were statistically different between beekeepers with apiaries of 100–200 hives and beekeepers with apiaries with more than 200 hives. A possible explanation is that operators with smaller apiaries are less technically specialized than those with larger apiaries for whom apiculture is a more relevant source of income.

Ricchiuti, & al (2019): A study in the Abruzzo region on the presence of Paenibacillus￿larvae spores in honeys indicated underestimation of American foulbrood prevalence in Italy, Journal of Apicultural Research, DOI: 10.1080/00218839.2018.1541651

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What they showed is that official reporting is not remotely accurate, AFB spore presence is much higher than thought, and the group with the highest spore count is the 100-200 colony set (58.6% of their apiaries tested positive versus 30% for both the group >200 and the group <200 which showed 30%).

Peter 🐝

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