A study in the Abruzzo region on the presence of Paenibacillus larvae spores in honeys indicated underestimation of American foulbrood prevalence in Italy

American foulbrood (AFB) of Apis mellifera, caused by the bacterial spore former Paenibacillus larvae, is a notifiable disease in Italy and its spread is prevented by burning hives with clinical symptoms. 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 omitted, so that AFB transmission from infected apiaries is not prevented. 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. Spore numbers were significantly different for honeys produced in different environmental contexts and with varying management practices, suggesting to elucidate the caus...