American Foulbrood (AFB) is an infectious brood disease caused by the spore-forming bacterium Paenibacillus larvae subsp. larvae.
It is the most destructive and widespread of the honeybee brood diseases. AFB disseminates rapidly through the colony and, if left unchecked, spreads quickly to other healthy colonies both in the same apiary and those nearby. Untreated, AFB can result in the death of the hive in a very short time.
It is vitally important to detect foulbrood as early as possible and distinguishing between AFB and EFB can be difficult.
In colonies infected with either European or American Foulbrood the brood pattern can appear very patchy and irregular (sometimes termed 'pepper-pot') in distribution. [Fig 1]
Unlike with EFB, cadavers of AFB infested larvae can be stretched (or 'roped out') with a matchstick or similar instrument. [Fig 2]
Cadavers of larvae infected with AFB die in the late larval stage. As the cadaver decays it becomes gelatinous.
American Foulbrood can be identified by costly and time consuming laboratory tests but perhaps the best, and easiest, method is to use Vita's AFB Diagnostic Kit - a simple to use field kit that gives a clear result in just three minutes.
Since stresses on the colony can be a contributing factor to infestation, these should be removed wherever possible.
American Foulbrood can be controlled by the use of antibiotics but this can leave residues in wax and honey and is banned in many European countries.