from APIS Volume 18, Number 1, January 2000 : Mr. Laurence Cutts of the Division of Plant Industry's Apiary Bureau (Florida) is burning more colonies that have become symptomatic than in past years. Many of these have been treated with antibiotic apparently to little avail. Tests at both the Florida and Federal Beekeeping Laboratory in Beltsville, Maryland have confirmed what appears to be a growing tolerance by the causative organism (Paenibacillus larvae larvae) for the only currently labeled antibiotic, Terramycin. This should be no surprise. It parallels what is happening in other livestock industries, as well as humans, signaling that the era of antibiotics as a wonder drug may be drawing to a close. The good news is that Dr. H. Shimanuki of the Beltsville Bee Laboratory sees a new era dawning such that we can expect to see advances made in the materials and methods available for detection, prevention and control of AFB. The bad news is that this may take some time, and those beekeepers having the problem now could be ill-equipped to deal with it. One of the reasons for this is that many are not familiar with the disease's etiology and detection. These have taken low priority in the face of 40 years of effective masking by Terramycin. --------------------------------------------------------------------------------------------------------------- The bee law in Pennsylvania allows for treatment of diseased colonies at the discretion of the inspector. An inspector who finds AFB will evaluate the situation and explain all the possible alternatives to the beekeeper, who will then decide how to treat the disease. If the colony is weak or heavily infested, the only alternative is to kill the bees and burn the frames and combs. If the disease is diagnosed in its early stages and the colony is strong, it may be treated with terramycin. A diseased colony treated with terramycin should be considered contaminated with spores forever and should be treated preventatively with terramycin indefinitely. A colony is not cleansed of AFB after treating for a year, 2 years or even 5 years. If a colony has had AFB and the terramycin treatment is discontinued the disease will come back. Terramycin (oxytetracycline) is the only drug approved for use against American Foul Brood. When present in the food given to susceptible larvae this antibiotic is effective in preventing germination of AFB spores. The bees are then able to develop and mature normally. Terramycin will not kill the spores and is not a means for sterilizing either the bees or the equipment. If a colony contains AFB spores and is maintained in a healthy condition through treatment with terramycin, the disease will recur when the drug treatment is discontinued. http://sites.state.pa.us/PA_Exec/Agriculture/bureaus/plant_industry/apiary/apiary_pests.html --------------------------------------------------------------------------------------------------------------- AFB is regulated by the Georgia Department of Agriculture, and infected colonies are normally burned by state inspectors. As state budgets allow, beekeepers may be indemnified for these losses. The spores of the AFB bacterium are extremely persistent in contaminated comb and hive parts. Although resistant bee colonies may clean up visible signs of infestation, it is more typical for AFB to be incurable and essentially doom the colony. Beekeepers should never maintain hospital yards in which they group AFB colonies together in isolation. Such yards simply serve as reservoirs of disease that will serve to contaminate apiaries for miles around. It is equally inadvisable to treat infected colonies with Terramycin. The antibiotic will simply obscure visible signs of the disease, but the symptoms will rapidly recur once the antibiotic is removed. http://www.ent.uga.edu/bees/Disorders/American_Foulbrood.htm --------------------------------------------------------------------------------------------------------------- -- Peter Borst <[log in to unmask]>