Can it be treated:
Gamma Irradiation kills AFB by breaking down the bacterial DNA. This is the only method known to completely destroy the disease. Repeated antibiotic applications may treat the symptoms, however resistance of AFB to antibiotics is likely over time. The bacterium infects larvae and frequently leads to colony death.
Control of AFB is regulated in all States and Territories to ensure the monitoring of spread, record of incidence and disease colony and material destruction. Use of the antibiotic oxytetracycline as a control is permitted in Tasmania only. The State and Territory Government control of AFB is a key to ensuring the disease is managed and that the temptation for widespread antibiotic use in the industry is not required. This is a key competitive advantage for Australian honey.
How to Identify disease
The first step in disease identification is learning to recognize healthy brood. When inspecting colonies, make use of the sun to illuminate the contents of the brood cells whenever possible. As you inspect the brood combs, pay close attention to the color of the larvae. Healthy larvae are glistening and pearly white. Larvae that are dull, off-white, yellow, brown or black may be diseased and merit closer inspection. You should also pay attention to the brood pattern. A healthy brood pattern has very few empty cells; and the cappings are uniformly brown or tan in color, with a decidedly convex appearance. Combs with lots of scattered brood, combs with uncapped or partially capped cells, and combs with perforated, sunken cappings should always prompt a thorough inspection.
AFB is characterized by larvae or pupae that have melted down into a pool of light to dark brown liquid lying flat on the cell bottom. During this stage, the rope test can help identify it as AFB. Carefully insert a toothpick or twig etc into the infected bee, gently stir, then slowly withdraw. If the diseased material can be pulled out of the cell two cm or more before snapping back in, AFB is most likely the cause. Unfortunately, a negative rope test does not always guarantee that AFB is not present, so test several cells.
The only way to positively identify the disease is to send a sample for laboratory identification. The presence of a smooth, light to chocolate brown pupa in the cell with its tongue adhering to the roof of the cell is considered to be diagnostic for AFB. Eventually, the infected individual dries down to a black scale that adheres tightly to the bottom of the cell. The tongue may or may not be visible. A single scale may contain over 2.5 billion reproductive spores.
How does it spread:
If other bees rob a weakened or dying colony infected with AFB, or if combs or hive parts (lids, excluders, clearer boards) from an AFB colony are used or distributed to other colonies, the disease will spread. Spores may attach to your hive tool, gloves etc, and spread to the next hive you open. Therefore, it is critical that you take the right action when you identify it in your colonies.
What do I do with an infected hive:
The best response to a case of active AFB is to destroy the colony. Be sure to kill the colony when the bees are not flying.
If you can send the supers etc to be irradiated, you may re-use the supers, bottom boards, lids, frames, combs and honey. A pallet load of supers (with lids, bases, frames etc) cost aprox $8 per super to irradiate. If you do not have access to irradiation, all the material should be burned.