The American Foulbrood

The American Foulbrood is considered one of the most dangerous and fatal diseases that affect the bee brood. This is typical brood disease. It does not affect adult honey bees. The adult individuals can have spores on them without catching the disease. The cause of this lethal disease is a bacterium, scientifically named Paenibacillus Larvae. It can be found either in a spore form or in a vegetative state. The bacterium is dangerous for the honey bees only when it is in its spore form.

These spores have developed a remarkable resistance to extreme temperatures and even to chemicals that used for killing various types of bacteria. They can survive in a dormant state up to forty years within old combs, hive and even in honey and beeswax. The spores also contaminate the honey and the pollen extant in combs. There is no treatment for an American Foulbrood infested colony. Prevention is the key for saving bee colonies from this deadly bacterium.

The disease spreads easily and rapidly inside a hive due to the spores at the bottom of the cells. The spores are move from here and there due to house bees that clean the brood and larvae cells. When a hive is infected there are high chances for the ones in its vicinity to be infected as well. The American Foulbrood can be transmitted from family to family through beekeeping activities such as the transfer of brood and honey combs or introduction of a queen bee that comes from an infested hive. The drifting and the robber bees are also disease carrier and spreaders. The disease can be spread by artificial swarms that are taken from ill families. The contaminated beekeeping tools contribute a lot to the spreading of the disease within an apiary.


The American Foulbrood is a very contagious disease that spreads fast and can lead to the extinction of bee colonies. For this reason, each beekeeper should be able to correctly identify the disease according to its symptoms. If the disease is detected in its early stage, the beekeeper can avoid its spreading and thus he/she can reduce the damages.

The infection takes place the moment the bee larvae eat the spores of Paenibacillus Larvae. The spores reach the rod stage and manage to destroy the gut wall. They enter the bee larvae tissues, feed there leading to the death of the respective larva. The larvae that die due to this disease are dark brown and have the aspect of gluey mass with a foul odor. The dead larva adheres powerfully to the bottom of the cell and it is impossible for the bees to remove it. This is an enormous source of infection since there are millions of spores in a single cell.

The honeybees cannot fight the disease by themselves. In the absence of human intervention the colony will eventually die. The death might occur any time throughout the year.

The American Foulbrood infested hives have spotty brood and cell that have scales. Another sign of the disease is the pepper-pot pattern of the brood. The capping of the cells that have infested larvae are moist and colorless. In the beginning the infected larva have a yellowish color but as the disease advances they turn to light brown and then to brown or black. The ill larvae are sticky and soft while the dead ones are either brown or black and lay upright. There are open cells that present scales at their bottom. It is quite easy to recognize American Foulbrood in an advanced stage due to its pungent, foul odor. Another sign of the disease is the honey and pollen stored in brood cells.

The American Foulbrood can be identified with the help of the matchstick test. In order to do this, the beekeeper needs a matchstick to inspect the ill larva. The match is stuck inside the comb cell and the slowly taken out. If the larva is contaminated then its tissues are brown and sticky. The disease can also be identified using the Vita Diagnostic Kit.


There is no medication for an already infested family. However, oxy-tetracycline and tylan can be used for the prevention of the disease. The treatment is applied at the beginning of spring and has to be stopped four weeks before the first important honey flow. Honey with traces of antibiotics cannot be sold for human consumption. The antibiotic treatment can be done once gain in autumn after the last honey crop. The medicine has to be administered according to the indications on the label. The antibiotics do not have the power to kill the Paenibacillus Larvae spores; they only prevent their development. When the medication is stopped the American Foulbrood disease emerges. A contaminated hive must be permanently under observation and medication. In the UK, the Netherlands and other country no medication is allowed for the treatment of the American Foulbrood disease. The infected hives are burnt thus reducing the risk of contamination and disease spreading.

Another method used by beekeepers implies the movement of the adult bees that belong to the infested hive, in a new hive boxes with new frames and new combs. The brood combs and the honey combs are burnt down so as to avoid any disease spreading. This method is quite efficient since it saves the adult members of a bee family.


The American Foulbrood is a very dangerous disease, difficult to be kept under control. If a hive has been infested with American Foulbrood it is better to burn it down, frames and combs included. If you decide to burn the adult bees as well, then you should better kill them before setting the fire. It is also very important to clean and sanitize all beekeeping tools. The sterilization of the beekeeping equipment can be done through gamma irradiation, heating in a box designed for this purpose only or through scorching.


The American Foulbrood can cause lots of damages to a country's apiculture. For example ten years after the identification of AFB in New Zeeland, it managed to destroy seventy percent of the country's bee population. Therefore prevention is better than both treatment and control. Thus, it is very important to pay attention to the type of food given to the honeybees. Colonies should not be fed with AFB infested honey and pollen. The re-queening should be done with queens that belong to powerful, healthy colonies. The combs must be inspected and replaced regularly and the bee families should be fed with sugar syrup when there is no nectar flow. The beekeeping tools must be cleaned and sanitized. When purchasing bees one must make sure they are not infested with AFB. If they are and you have already purchased them you must not stop the antibiotic treatment. The minute the treatment stops, the American Foulbrood spreads.

Honey bee disease > Acarine mites > Acute bee paralysis virus > American Foulbrood > Black Queen Cell Virus > Bee louse> Chalkbrood > Chilled Brood > Chronic Bee Paralysis Virus > Cloudy wing virus > Colony Collapse Disorder > Deformed Wing Virus > Bee Dysentery > European Foulbrood > Israelii acute paralysis virus > Kashmir Bee Virus > Nosema > Sacbrood virus > Bee septicemia > Stonebrood > Varroa Mite >

Copyright ©