What is the causative agent of American Foulbrood?

• A. Paenibacillus lactis
• B. Paenibacillus larvae
• C. Bacillus subtilis
• D. Escherichia coli

Answer: (B)

American Foulbrood is caused by Paenibacillus larvae, a spore-forming bacterium that specifically infects honeybee larvae. Its spores are extremely durable and can survive in hive equipment for many years, which is why the disease is so hard to eradicate. Infection happens when larvae ingest these spores, usually from contaminated brood food. The infected larvae die and decompose, leaving behind a dark, syrupy mass and a foul-smelling scale inside the brood cell. Because the spores persist in the environment, control often requires destroying affected hives or equipment rather than relying on treatment alone. The other organisms listed are different microbes not responsible for American Foulbrood: Paenibacillus lactis is not the bee pathogen here, Bacillus subtilis is a common soil bacterium with no specific role in this disease, and Escherichia coli is a gut bacterium of mammals and not involved in bee pathology.