Managing an outbreak of American foulbrood22 February 2023
Author: Jessica Bikaun (née Moran), Project Officer (Bees), Department of Primary Industries and Regional Development, Western Australia Recently I had the pleasure of speaking at the Western Australian Apiarists’ Society […]
Author: Jessica Bikaun (née Moran), Project Officer (Bees), Department of Primary Industries and Regional Development, Western Australia
Recently I had the pleasure of speaking at the Western Australian Apiarists’ Society about the bacterial brood disease American foulbrood (AFB). For the past four years, my PhD and life has revolved around AFB. I’ve dealt with it in hives, worked with it in the lab, conducted field tests, developed new methods for detecting it, smelled it, and, on one unfortunate occasion, even tasted it. I don’t recommend tasting AFB, but I do recommend that all beekeepers get familiar with the symptoms of the disease and have a clear picture of what steps to take if an outbreak occurs.
The Australian Honey Bee Industry Biosecurity Code of Practice (‘the Code’) has a number of requirements related to AFB – and for good reason. AFB is the most devastating bee disease in Australia and costs the industry millions of dollars each year. The disease is fatal to honey bee colonies, easily transmitted and can be incredibly persistent in apiaries – AFB spores can survive for over 50 years!
Historically, there has been a stigma about AFB, so beekeepers have been hesitant to talk about the disease or admit to having an outbreak. But let’s put that to rest, once and for all – anyone’s hives can get AFB. AFB does not discriminate; it can infect colonies that are weak or strong and affects both recreational and commercial beekeeping operations.
Industry reports and surveys have indicated that AFB has been on the rise for the past few decades – both here in Australia and overseas. In a New South Wales survey, almost 60% of beekeepers had a history of AFB in their apiary (NSWDPI, 2006) so chances are high that you will come across AFB at some stage. With this in mind, let’s break down the Code’s requirements for managing an AFB outbreak into three steps.
Step 1 – Make a report
Under the Code, beekeepers must notify their local apiary inspector within 48 hours of detecting AFB. Report an AFB outbreak in your state or territory by calling the Exotic Pest Hotline 1800 084 881.
Remember, we are here to help. If you suspect your hive may have AFB but don’t know how to proceed, get in touch with one of your Bee Biosecurity Officers. We can make a diagnosis and help you put together a management plan. Reporting incidences of AFB is important, as it helps monitor AFB levels and allocate biosecurity resources as needed.
Step 2 – Contain the outbreak: euthanise, burn, bury
Unfortunately, there is no cure for AFB. (See below for why antibiotics are not a cure). The AFB-diseased colony is lost but you will need to act quickly to protect nearby hives. Under the Code, outbreaks of AFB must be dealt with immediately to prevent the disease from spreading. In practise, this involves isolating the diseased hive and, after the field bees have returned, euthanising the bees, burning the hive in a pit and covering the remains in at least 30 centimetres of soil. Any contaminated equipment and hive parts must also be destroyed or sterilised.
Dealing with an AFB outbreak can feel like a nightmare and euthansing a colony is a horrible task but it’s important to dispose of contaminated material correctly. Leaving diseased hives in a pile behind the shed or dumping them at the rubbish tip poses a significant risk to nearby beekeepers and is a serious offence. Even if the outbreak has destroyed your entire apiary, you still have a responsibility to eradicate the spores and protect the rest of the industry.
If you can’t destroy or sterilise contaminated materials straightaway, it is crucial to make sure it is ‘bee-proof’ – that is, bagged or sealed in such a way that bees cannot access honey or other hive products. If given the chance, bees will rob from exposed equipment, unwittingly taking spores of AFB back to their colony. Just make sure that out of (bee) sight doesn’t mean out of (your) mind! Spores of AFB can lay dormant for decades before causing an infection so if you forget to dispose of contaminated frame and boxes, your outbreak could come back to haunt you or whoever inherits your beekeeping equipment. This has actually been common in the United States, where large outbreaks of AFB caused many to give up beekeeping between the 1930s-80s and stored equipment came back to cause problems for unsuspecting grandchildren. So if you’re storing equipment, don’t forget about it – or at the very least, label it clearly!
A note on antibiotics and American foulbrood:
Controlling AFB with antibiotics is prohibited on the mainland under legalisation, as it can create more problems than it solves. Antibiotics do not kill the spores of AFB, unlike European foulbrood, and will only mask the symptoms of the disease. In some parts of North America, beekeepers have been allowed to routinely feed their bees antibiotics to suppress AFB. However, as soon as the antibiotics stop, the spores being new infections. Masking the symptoms, rather than removing the diseased colonies, can lead to high levels of spores throughout the entire system. For example, in a 2005 study by the United States Department of Agriculture, 70-80% of the 95 beekeeping operations pollinating almonds in California tested positive for AFB spores. Scary stuff! On another note, antibiotics are a health issue, as they can contaminate the honey and lead to antibiotic-resistant bacteria. Although replacing destroyed colonies is expensive, it would cost us far more to lose the Australian bee industry’s clean and green reputation.
Step 3 – Review your beekeeping practices
If you encounter AFB, tell other beekeepers – particularly those with apiaries nearby so they can check their hives for signs of the disease. Use the outbreak as talking point to help spread awareness about the disease and how to manage it. Conversely, if your bee buddy tells you about their AFB experience, remember to react with compassion. If you notice their beekeeping practices could be improved, let them know gently and avoid shaming. Remember – you are not a bad beekeeper if you get AFB. You are only a bad beekeeper if you get AFB and do nothing about it.
After an outbreak, take the time to think about how AFB entered your apiary and what steps you can take to prevent further outbreaks. AFB is commonly spread by beekeepers moving infected combs and hive components, or feeding contaminated honey or pollen. AFB can also spread naturally between colonies by worker bees robbing contaminated honey from diseased hives and – to a much lesser extent – bees drifting from diseased colonies into neighbouring colonies. With this in mind, consider the following when reviewing your beekeeping practices:
Are your bees hungry?
To put it simply, hungry bees spread disease. If nectar is scarce, bees will begin robbing honey from weaker colonies, which could be suffering from AFB. Avoid having hungry bees by leaving adequate stores of honey in the hive and, where necessary, feeding sugar. If you are adding protein to the hive, the best practice is to feed irradiated pollen or manufactured supplements. To minimise the risk of catching or spreading diseases, never feed honey or allow bees to rob from extraction equipment or exposed stickies.
Are you using a barrier system?
A good barrier system is the most effective way to minimise the effects of an AFB outbreak. Barrier systems involve dividing the apiary into clearly identified, isolated sub-units. Hive components (e.g. frames, boxes) stay within their designated subunit and tools are cleaned when moving between units. For example, a single-hive barrier system means that materials aren’t moved between hives and frames are returned to the same hive after honey-extraction. If a colony catches AFB, a working barrier system would minimise the chances of the infection spreading to other hives – saving bees and beekeeping businesses.
Can you identify bee diseases and are you inspecting regularly?
Under the Code, beekeepers must inspect each colony at least twice a year. This is the bare minimum – inspecting colonies regularly will allow you to discover symptoms earlier and minimise outbreaks. This only works if you know what you’re looking for, so make sure you are familiar with the signs and symptoms of honey bee pests and diseases. Check out beeaware.org.au/training to complete the free Biosecurity for Beekeepers course and learn more about bee pests and diseases.
Are you catching swarms?
Diseased colonies may abandon a hive (abscond) in an attempt to escape the infection, however, worker bees can still carry the spores and cause infections in future brood. In a 2006 WA survey, 3.3% of feral colonies and swarms tested positive for AFB – statistically, that’s one in 30 swarms that are likely to be carrying spores of AFB. When collecting feral colonies or swarms, avoid introducing AFB to your apiary by keeping new colonies isolated and monitoring for disease.
For more biosecurity information and tips, visit BeeAware
The National Bee Biosecurity Program is funded by the honey bee industry through a component of the Agricultural Honey Levy, with state governments contributing in-kind resources. Plant Health Australia manage the program on behalf of the Australian Honey Bee Industry Council.