American foulbrood (Terramycin® antibotic)
Terramycin (oxytetracycline) is the only drug approved for use as a preventive treatment against American foulbrood. This antibiotic does not kill Bacillus larva spores. However, when it is present in low concentrations in the food fed by workers to susceptible larvae, terramycin prevents AFB spores from germinating to the vegetative stage and delays vegetative growth in larvae. While this treatment allows individual larvae to survive, it has no effect on the virulent spores in the contaminated equipment. Thus, AFB often reappears once terramycin treatment stops.