Evaluation of the effectiveness of control measures against American and European foulbrood in honey bees

The study aimed to evaluate the clinical and epizootiological characteristics of American foulbrood and European foulbrood in honey bees and to assess the practical effectiveness of veterinary-sanitary and therapeutic control measures. Investigations were conducted at the Scientific-Research Institute of Veterinary and in different beekeeping farms. The epizootiological situation was assessed in affected and conditionally healthy colonies using clinical observation, laboratory diagnostics, and epizootiological monitoring. The findings indicated that the long-term persistence of Paenibacillus larvae spores in the environment complicates elimination of American foulbrood infection sources. European foulbrood was characterized mainly by damage to unsealed brood and by a more pronounced course under nutritional deficiency and unfavorable hive microclimate. Colonies infested with Varroa destructor showed a more severe clinical course of foulbrood. Veterinary measures, including transferring affected colonies to disinfected hives, removing contaminated combs, disinfection, and queen replacement, produced favorable practical outcomes. Antibiotic treatments reduced clinical signs, but uncontrolled use is inappropriate because of the risks of antimicrobial resistance and residues in bee products. Whey-based treatments showed promising supportive effects at the early stages of European foulbrood. Overall, combined biosecurity and veterinary-sanitary measures were identified as the central approach to disease control.