American Foulbrood - A Disease to Eradicate from Fiji
American foulbrood (AFB) is a severe bacterial brood disease of honey bees. AFB is lethal to bee colonies. The disease is distributed worldwide and can cause substantial economic losses. Foulbrood was first described in 1769 and although AFB has been in focus for decades it has recently become an increasing problem. In this week’s article, we explore the disease in Fiji and how it can be eradicated. AFB is caused by a spore-forming bacterium that is very hardy and can survive on used equipment or in honey for more than 30 years. The bacterium even survives boiling in water. The disease can exist in a colony as an unapparent infection for 12 – 18 months. During this time, beekeepers can inadvertently spread the disease by transferring frames of brood and bees, honey or honey supers to healthy hives.
Importance of early detection of AFB
Finding an AFB infection as early as possible and taking immediate action is critical to preventing its spread within the apiary. Therefore, regular thorough inspection of hives must be adapted as a management measure for early detection of the disease and reduction in economic losses. Moreover, AFB directly affects the production of honey thus it hinders the trade opportunities and subsequently will impact on livelihood of beekeepers.
Signs of the American foulbrood disease
1. Brood infected with AFB generally dies after the cells have been capped over and larvae are stretched out on their backs with their heads towards the cell capping. 2. Affected brood becomes discoloured, turning light brown at first then darker brown as the disease progresses 3. After 1 month, infected brood dries to a dark scale which adheres to the wall of the cell. 4. Cappings over dead brood cells sink inwards, become moist and have a discoloured dark chocolate or purple appearance. Some of these capped cells are punctured, the result of attempts by bees to remove the dead brood. Other cells may have the cappings totally removed, leaving the remains exposed. These remains are infective. 5. If a matchstick is thrust into the dead brood before the scale stage has developed, and then removed, the semi-fluid remains are drawn out in a ropy thread 3 – 5 cm long (see picture 4). This ropy consistency is characteristic of AFB. 6. In heavily infected colonies the brood has a scattered, uneven pattern due to the intermingling of healthy cells with uncapped cells, and capped cells of dead brood with punctured and sunken cappings. If you find any abnormality in your beehives, immediately contact BAF for inspection.
What beekeepers can adapt to prevent AFB?
Beekeepers must undertake strict precautionary measures to prevent their hives from contracting this disease and thereby helping to reduce further spread. The disease incidence can be kept as low as possible in a number of ways indicated below: • Beekeepers are the main defence against AFB. Monthly hive inspections are essential to identify weak colonies and diagnose any problems with the hive • Do not transfer brood combs between one colony and another or divide colonies without first checking carefully for AFB symptoms • Do not move frames of honeycomb from an infected colony to healthy colony. This most often happens when returning empty honey frames after harvesting honey • Do not feed bees honey or pollen from an unknown sources • Check for AFB signs on brood frames at least twice a year • Prevent honey robbing at all times • Arrange the hives in the apiary in such a way that drifting of bees is reduced to a minimum • Replace old brood combs (3 – 4 per brood box) every year with frames fitted with foundation to maintain a clean and healthy brood • Keep the colonies isolated at a distance from other colonies and inspect them for signs of AFB at least 3 months before incorporating them into the apiary • Do not purchase old combs or used beekeeping equipment as they may harbour spores for many years • Sterilize the hive tools, smoker or gloves after working on a hive you may suspect to be infected, so as not to spread the infection from colony to colony BAF activities to Eradicate AFB from Fiji 1. BAF is caring out survey in all divisions spectially targeting AFB hotspots 2. Affected areas of bee farm with AFB demarcated. Quarantine noticed issued to particular bee farm and still under quarantine. BAF officers are doing routine monitoring and inspection of hives. Trace back system to find out the source of infection 3. Infected bee hives are eradicated by burning and deep burial 4. Follow up visit to infected farms 5. Awareness on prevention, control and eradication of AFB is caring out by BAF-Eg: AFB survey, Emergency Declaration for AFB, AFB pamphlets As per the Emergency Declaration on AFB, any movement of bee hives, bee suits, bee products and bee keeping equipment within and from emergency areas is strictly prohibited unless BAF provides prior authorization for the movement.