WVDA Apiary Program
American Foulbrood Cause, Detection and Prevention
American foulbrood (AFB) is a honey bee disease, which infects the brood while it is in the larval and pupa stages. The bacterium which causes AFB is Bacillus larvae. AFB occurs in two forms; vegetative (rod-shaped bacterial cells) and spores. The spore stage is unique and may persist in a dormant state for
many decades. AFB can be detected by examining the appearance of the brood. Dark, sunken or punctured cells with a spotty brood pattern is a tell tale sign of infection. Healthy brood should be white and curved completely in the bottom of the cell while in the uncapped or larval stage. After the cells are capped (pupal stage), the brood capping’s should be of a uniform color with a slightly dome shape. Any variations should be investigated further. To test a punctured cell for AFB, insert a small stick (about the size of a match) into the cell and gently stir the sample. If, when the stick is removed, the sample has a stringy consistency, you should contact the West Virginia Department of Agriculture’s Apiary Program immediately.