Foulbrood – Still Smelling Foul

bee offWith so much attention on varroa destructors and nicotine-flavoured pesticides, we sometimes forget some of the other scourges of modern beekeeping.  Not long ago,  American Foulbrood (AFB) was the worst thing that could happen to your bees. If you were caught with the disease, an inspector might set your colonies upon a pit of fire. Your equipment – and bees – would burn, then collapse into the hole where the charcoal and melted wax would be buried under moist soil. I know. I was one of the bee inspectors, deputized by the state of Pennsylvania, and I was assigned the grizzly task of destroying infected colonies. It is little wonder that I was met several times by shotguns at farmers’ fences in the remote Appalachian hills.

That was the mid-1970s – I wasn’t yet twenty years old. Antibiotics (sulfathiazole and terramycin) had been discovered 30 years earlier and those chemicals usually put an end to the symptoms of the brown rotten smelly brood that gives foulbrood its name. But not all farmers cared to check their hives or invest in the inexpensive medicines. As a last resort, irresponsibly kept apiaries with irrecoverably sick bees were given the fire treatment. The bees were nearly dead anyway. If the equipment was not destroyed, healthy bees from miles around would find the dying hives, scoop up any remaining honey, and carry the disease back to their colonies. The robbing that ensued spread an AFB epidemic. Ugly as the burn-and-bury treatment seems, it was necessary. (A diligent beekeeper might shake the infected bees into new boxes with new equipment and foundation and perhaps save the bees. But a diligent beekeeper would not allow hives to collapse to the state that required destruction. When bees were seriously infected it almost always meant they were owned by a disinterested beekeeper who would not clean up the hives and keep them healthy. They (the bees, not the beekeeper) had to be destroyed.)

American foulbrood - stringy, dark brown, and (surprise) foul-smelling!

American foulbrood – stringy, dark brown, and (surprise) foul-smelling!

Ancient beekeepers were familiar with foulbrood. Aristotle complained that his bees were sometimes weak, dying, and had brood that smelled awful.  Such reports continued over the centuries. In 1906, two different flavours of foulbrood were distinguished – now known as European and American foulbrood. The European type is the less serious infection and can often be cured by replacing the queen and breaking the brood cycle. Although American foulbrood also originated in Europe, it was first identified by a North American scientist, hence its name: American foulbrood. AFB is much deadlier than EFB. A young developing larva dies if it ingests even a single Bacillus larvae spore. The body quickly decays and becomes a host for 100 million spores, each capable of causing the same bacterial outbreak in 100 million other larvae.

Before drugs were available in the 1940s, all colonies infected with AFB  died. If spotted early enough, the beekeeper might remove any frames with the infected brood and burn the bad combs. But the spores that had caused the infection had likely already spread throughout the hive. Good beekeepers in the 1920s and 30s sometimes found themselves out of business in weeks when foulbrood raced through their outfits.

Because foulbrood kills colonies and remedies didn’t exist for millennia, one might suppose that genetically resistant colonies would arise. Honey bees never developed reliable resistance to AFB (though some bees have more hygienic habits than others – they remove dead brood from the hive, slowing its inevitable spread). I suspect that bees survived alongside foulbrood because honey bees evolved an absconding reaction. Severely infected colonies sometimes leave their hive en masse, fly off to a new location, and start over again. The bees are able  to raise a few generations of offspring before the disease builds up to killer levels again. Although honey bees evolved this survival strategy to cope with the disease, it is no help to modern beekeepers – we can’t make honey if bees are sickly or if they abandon their hives entirely.

These days, American foulbrood is usually not a colony’s death sentence. Beekeepers control AFB with regular medicinal treatments. Better management caught on. Also, over the years, most farmers who were “let-alone beekeepers” gave up the sideline. In 1950, 2 million farms in the USA had a hive or two or more. (There were then over 6 million colonies kept in the USA.) Fifty years later, only 29,000 farmers owned beehives. Individual beekeepers began to manage thousands of hives each. With a change in beekeeping habits, AFB was under better control.

However, the control of American foulbrood in the Americas and Europe is tenuous and the disease could erupt if habits become lax again – or if antibiotics fail to protect evolving strains of the Bacillus larvae bacterium. South Africa offers an example of the devastation that may result when AFB is not fought effectively.  In April of this year, South African officials announced that an outbreak of American foulbrood had killed 40% of all the bees in the West Cape area. This is a big deal – the Cape is an important agriculture district where bee-pollinated crops valued at $1.5 billion (US) are grown. Without bees, the West Cape farmers are in trouble.

Killer bees are notoriously tough. )

Killer bees are notoriously tough.
(Credit: Wikipedia)

How did this happen? The arrival of AFB is recent. The disease appeared in a single province in 2009. Six years ago, a beekeeper spotted AFB and began losing colonies. Since then, it has spread. An article in South Africa’s Mail and Guardian suggests that South African beekeepers are generally rather cocky in their attitude towards bee diseases.

We are informed that nobody worries much about pests and diseases because the African bees are notoriously tough and hardy. But not, it appears, when they are confronted by the microscopic spores of American foulbrood. Although harmless to humans, AFB spores found in honey will infect bee larvae.  It is suspected that tainted honey was imported into South Africa in 2008, introducing the malady.

Besides a cavalier attitude on the part of some beekeepers, South Africa seems to have an ineffective bee inspection program. From the Guardian article again, it seems that there are adequate inspection regulations. But – claims the news story –  there’s a paucity of inspectors and compliance. The country seems to lack bee inspectors of the type Pennsylvania once had – inspectors willing to face the occasional shotgun in the face as part of their job. Unless South African beekeepers and their government proactively fight American foulbrood, it will destroy the country’s honey bees. But North American beekeepers should take the African experience as a reminder and a warning – the same could happen here again, too.

About Ron Miksha

Ron Miksha is a bee ecologist working at the University of Calgary. He is also a geophysicist and does a bit of science writing and blogging. Ron has worked as a radio broadcaster, a beekeeper, and Earth scientist. (Ask him about seismic waves.) He's based in Calgary, Alberta, Canada.
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5 Responses to Foulbrood – Still Smelling Foul

  1. Pingback: A Look Back at 2015 | Bad Beekeeping Blog

  2. Deb Corcoran says:

    I recently lost 9 hives to AFB. Apparently it was in a frame in a nuc that I had bought a few years ago when I first started in 2012. At that time Beekeepers were starting to rotate old black combs out of their apiaries. I noticed that there were some black combs in the nuc and figured the commercial beek I bought it from was trying to save money by putting the old combs in nucs he was selling. I put the old combs in a swarm trap and didn’t use them till this year when doing splits this past Spring and
    I ran out of equipment, so took and used those old combs. I never noticed anything. Those splits were going like gangbusters! All queens mated and healthy hives going strong but one. That’s when I found it, July 4th; I had infected the other hives by my hive tool and equalizing the splits by trading frames. I would find just one funky cell in a perfectly good frame; had to burn them all.


  3. Pingback: Cutting Out the Messy – Site Title

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