AFB has been detected in all Australian states and is present throughout Western Australia (WA).
Given the long-lasting and severe economic impact AFB can cause, it is a declared pest under the Biosecurity and Agriculture Management Act 2007. Reporting AFB is not only a legal requirement but a critical step in safeguarding your hives and those around you. Failing to report could result in widespread loss and affect the entire beekeeping community.
American foulbrood disease is caused by bacteria and is transmitted through spores. Very young larvae are highly susceptible to infection. As few as 10 spores can infect a larva less than a day old.
It is not a stress related disease and can infect the strongest to the weakest colony in an apiary.
Although not highly contagious, spores can be easily spread between hives and apiaries through the movement of equipment and infected combs.
Spores can remain viable for more than 50 years and are resistant to freezing and high temperatures. Beekeeping best practices and early detection and action is the best way to manage AFB.
AFB results in the loss of hive productivity and hive collapse which can lead to large numbers of infected or dead hives. This has the potential to impact crops that rely on the pollination services that honey bees provide.
Signs and symptoms of AFB include:
- patchy brood pattern with sunken and/or perforated cappings
- discoloured brood - typically light-dark brown and slumped on the bottom of the cell
- brood remains that are ropey (see rope test), or dried scales adhering to the bottom of the cell.
- a foul smell.
Infected larvae are killed by the bacteria before pupation and at this stage as many as 2.5 billion spores per larva may be released. These spores may survive at least 40 years. They are resistant to drying and boiling in hot water.
The spores may be introduced through contaminated equipment from other hives or from another bee colony by contaminated ‘robber’ or drifting bees. Unsterilised tools may also be a source of contamination.
Young larvae swallow the bacterial spores in infected food from nurse bees. The bacteria multiply in the larval tissue causing rapid death, and the spores are spread to other larval cells as well as the honey cells by worker bees attempting to remove the dead larvae. Eventually, numbers of adult bees decline and the hive becomes weak and dies out.
Bee colonies usually abscond (swarm) when this happens. This dead hive may attract robber bees from neighbouring hives which can spread the disease further.
Nosema ceranae produces spores in the stomach of infected bees allowing the fungus to spread.
Robbing or drifting bees can ingest AFB spores before taking them back to non-infected hives.
Accidental spread by humans occurs when combs or hive components from an infected colony are moved to a non-infected colony. Spores can also be transported on tools and beekeeping equipment. Honey and pollen harvested from hives with AFB contain spores and should not be fed to other colonies unless irradiated. AFB spores can survive for more than 50 years, infected material needs to be burnt or irradiated to insure spores are killed.
Legal duty to report
Paenibacillus larvae is a declared pest in WA. It is a prohibited organism under section 12 of the Biosecurity and Agriculture Management Act 2007.
This means that any person who finds or suspects the presence of American foulbrood must report it to DPIRD.
Reporting is not just a legal obligation; it's crucial for safeguarding your hives and nearby colonies. Early detection gives us the best chance to eradicate pests and diseases. By following best practices and reporting promptly, we can protect Western Australia’s healthy bee populations and stop the spread of harmful pests and diseases.
How to treat and manage
Euthanise diseased colonies
To contain an outbreak, colonies with clinical symptoms of AFB must be euthanised and sealed (made bee-proof) as soon as practicable. Under the Australian Honey Bee Industry Biosecurity Code of Practice, affected hives must be made bee-proof with 48 hours of detecting an outbreak.
Before euthanising the colonies, decide whether you intend to harvest the honey. AFB does not affect the safety of honey as a food product. However, it is important to consider the:
- risks of harvesting, i.e. spreading the infection further through robbing bees
- work required i.e. thoroughly cleaning extraction equipment to avoid contamination; and
- limited markets i.e. you must declare the contamination to honey packers.
To euthanise a colony in a hive:
- Seal all hive entrances in the evening, after field bees have returned for the night.
- Add half a cup of petrol under the lid, either pouring into the hive, or using a soaked rag.
- Burn in a pit, cover with 30cm soil.
Sterilise equipment
Monitor exposed colonies
Other live colonies in the apiary must be monitored for AFB. To reduce the likelihood of AFB-exposed colonies (including apiaries that have returned a positive honey culture test) from developing symptoms, a shook-swarm approach can be used to reduce spore loads. Shook-swarm involves shaking bees onto clean foundation and destroying old comb.
After an outbreak, take the time to think about how AFB entered your apiary and what steps you can take to prevent further outbreaks.
Do’s
- Inspect colonies regularly to detect problems early.
- Remove (i.e. shake) bees from brood frames during brood inspections.
- Complete bee biosecurity training, e.g. www.beeaware.org.au/training.
- Ensure bees have adequate hive stores for winter/periods of dearth.
- Provide artificial feed (sugar syrup, pollen substitutes) when required.
- Maintain a barrier system to avoid moving diseased material between hives.
- Seek help from other beekeepers and our department’s Bee Biosecurity Officer.
- Quarantine new colonies and caught swarms until satisfied with their health status.
- Gradually replace brood frames after 2-3 years.
- Sterilise hive tools and gloves between hive inspections.
Don’ts
- Let colonies go hungry.
- Feed bees pollen meant for human consumption.
- Feed bees supermarket honey or allow bees to rob from extraction equipment or exposed stickies.
- Illegally use antibiotics to mask symptoms of AFB.
- Use AFB-contaminated equipment without adequate sterilisation treatments
- Assume you will never get AFB.
Search Western Australian Organism List
The Western Australian Organism List (WAOL) provides the status of organisms which have been categorised under the Biosecurity and Agricultural Management Act 2007.
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DPIRD Apiary Team