American foulbrood

American foulbrood (AFB) is a devastating infectious disease affecting the brood of honey bees, caused by the spore-forming bacterium Paenibacillus larvae. While strictly a veterinary issue within the beekeeping sector, it remains a critical concern for agricultural sustainability, as healthy bee populations are essential for the pollination of diverse food and seed crops worldwide.

The causative agent, Paenibacillus larvae, is notable for its highly resilient endospores. These spores can remain viable on beekeeping equipment, in honey, and within old honeycomb for decades, facilitating easy transmission. The disease is spread when bees ingest spores while cleaning or tending to the infected brood, subsequently contaminating their food supply and other hive components.

Clinical signs are primarily observed in capped brood. Infected cells often feature sunken, darkened, and perforated cappings. The larval remains inside exhibit a characteristic ropey, glue-like consistency and a distinctive, foul odor reminiscent of old wood glue. Once the moisture evaporates, these remains dry into hard, dark scales that are firmly attached to the lower cell wall, making them nearly impossible to remove.

The progression of the disease is rapid and typically leads to the colony's collapse if left untreated. Spores thrive in stressful conditions and are easily spread by the drift of adult bees or the exchange of frames between weak and healthy colonies. The high infectiousness of the bacteria requires immediate and decisive action from beekeepers to prevent an epidemic.

Control and prevention revolve around stringent sanitary practices. Best management includes regular inspections, the use of sterile equipment, and the avoidance of feeding bees honey from unknown or suspicious sources. In many regions, confirmed cases require strict quarantine and the destruction of infected hives and equipment by fire to ensure total eradication of the bacterial spores.