Detective Dog Sniffs Out Devastating Honeybee Disease

Earth Island Journal By Cherese Cobb January 28, 2019

Maryland's chief apiary inspector has trained her Labrador to inspect hives for harmful bacteria

Sure, dogs may not always wear capes, but they have a superpower — their superior sniffers. “They have up to 300 million olfactory receptors in their noses, versus only about 6 million for us. The part of their brains dedicated to interpreting smell is about 40 times larger than ours,” says Michael Nappier,an assistant professor at the Virginia Maryland College of Veterinary Medicine. “While we might notice if our coffee has a teaspoon of sugar added to it, a dog could detect a teaspoon of sugar in a million gallons of water, or two Olympic-sized pools,” writes Alexandra Horowitz, the author of Inside of a Dog: What Dogs See, Smell, and Know.

Cybil Preston, chief apiary inspector for the Maryland Department of Agriculture, does a training run with Mack. She sets up fake beehives and commands him to “find.” He sniffs each of them to check for American foulbrood. If he detects the disease, he is trained to sit to notify Preston. Photo by Morgan McCloy.

Cybil Preston, chief apiary inspector for the Maryland Department of Agriculture, does a training run with Mack. She sets up fake beehives and commands him to “find.” He sniffs each of them to check for American foulbrood. If he detects the disease, he is trained to sit to notify Preston. Photo by Morgan McCloy.

That's why canines can sniff out American foulbrood (AFB): the most serious bacterial disease impacting honeybees. Reported in the United States since the 1930s, it’s spread by beekeepers, drifting worker bees, and robber bees — often accompanied by killer wasps — who steal dangerous, spore-laden honey or bee bread and bring it back to their broods. Its spores can't be seen with the naked eye, but they can remain viable for over half a century. Caused by the spore-forming bacterium Paenibacillus larvae, AFB poses a major threat to American honeybees — and by extension, to US agricultural systems that rely on them. It's worsened by other factors like loss of habitat, use of pesticides, and climate change.

The disease doesn’t impact adult bees, but infected larvae turn chocolate-brown and melt into a gooey mass that looks like brown snot. “Once spores are in the midgut, the vegetative form of the bacterium takes over using the larvae as a source of nourishment,” says Rob Synder, a crop protection agent in Oroville, California. When the larvae dry out, they become black scales that are essentially glued to the hive’s floor. The scale from a single larvae can contain one billion spores. “It only takes 35 spores to trigger the disease,” says Spencer Gutierrez, the author of Beekeeping Secrets: 15 Facts You Need to Know That Will Save Your Life.

When hives are infected, beekeepers generally treat them with FDA-approved antibiotics like tylosin tartrate and lincomycin hydrochloride. They control the disease’s symptoms, but they don't destroy its spores. Under a vet’s supervision, the substances are mixed with powdered sugar. Four-to-six weeks before the start of the main honey flow (usually in the spring or fall), the sugary-antibiotic mixture is dusted across the top bars of the brood nest frame: a removable cell that holds the colony’s eggs, larvae, and pupae. From there, the worker bees pass the drugs on to the larvae during feeding.

“When you treat a beehive with antibiotics,” says Bryan Merrill, a researcher at Stanford University, “it'll knock down the population of all the healthy bacteria that bees need to survive.” With weakened immune systems, honeybees can’t fight off another bout of AFB, which often becomes antibiotic-resistant. “Everything else that can go wrong with the hives is fixable,” says Cybil Preston, who’s been keeping bees in Maryland since 1997 and working as an apiary inspector for over a decade, “but not that.”

American foulbrood poses a major threat to American honeybees. Infected larvae often turn chocolate-brown and melt into a gooey mass. Photo by  Tanarus / Wikimedia Commons .

American foulbrood poses a major threat to American honeybees. Infected larvae often turn chocolate-brown and melt into a gooey mass. Photo by Tanarus / Wikimedia Commons.

To save nearby colonies from infection, beekeepers frequently destroy their hives. They plug their entrances with newspaper and cover their sides with masking tape. Then they pour unleaded gasoline onto the hives and set them on fire with a blow lamp.

That’s where AFB-sniffing dogs come in — they make sure that infected hives are either isolated or destroyed.

“Detection and quarantine processes are essential to save our bees,” says Josh Kennett, the owner of Australia's first apiary dog.

It’s a big task for the canines to take on, particularly given declining honeybee numbers in the US: In 1947 there were an estimated 6 million hives, compared to today’s 2.4 million.

The job also comes with some risks. “[In 2013,] I realized that [my dog] Bazz was able to sniff out the disease, and save thousands of bees,” Kennet says. “But, he didn’t like being around them too much when he was getting stung.” Kennet designed the black Labrador his own beekeeper suit, which includes a homemade, mesh headpiece that’s similar to the cones dogs wear after a trip to the vet, only this one protects him from stingers.

Bazz may be Australia’s first bee-sniffing dog, but the tradition dates back further in the US. The Maryland Department of Agriculture (MDA) has kept a full-time “bee dog” on its staff since 1982. The only state agency in the nation that trains canines to detect AFB, the MDA keeps tabs on roughly 3.4 percent of the country’s pollinators, according to the USDA. The dogs assist with the state’s apiary inspections, a free service provided for commercial beekeepers and hobbyists. “Mack is our fifth bee dog,” Preston says. The 4-year-old yellow Lab is the only certified dog in the US that can sniff out “brown snot gunk."

Mack sits in front of a beehive, a sign that he's detected AFB. Photo by Cybil Preston.

Mack sits in front of a beehive, a sign that he's detected AFB. Photo by Cybil Preston.

Preston rescued Mack from a garage when he was a year-and-a-half old. When his family couldn’t care for him anymore, they called her. “I couldn’t resist,” she says. “I had to take him. I saw how cute he was.” While he’d been housebroken, he wasn’t fixed and was kind of wild, pouncing on people at the door.

Preston taught him basic commands. Then she partnered with Mark Flynn, the K-9 unit commander at the state’s Department of Public Safety and Correctional Services, to complete an eight-month training program. Whether dogs are searching for contraband cell phones, illegal drugs, or foulbrood in beehives, Flynn looks for the dogs that’ll jump into the water to get the ball, the ones completely obsessed with their toys. “Because when a dog is searching, he believes in his heart he’s trying to find his toy,” Flynn says.

Mack wasn’t motivated much by toys. “But there’s this phenomenon where you can actually build up the drive in a dog,” he says. And through reward, repetition, and play — wrestling, throwing balls, and tug of war — that’s what Preston did. Using rubber gloves, she also saturated his toys and blankets with AFB-infected honeycomb. “I did this indoors to decrease the chance of environmental infestation,” she says.

There are about 9,000 honeybee colonies scattered throughout Maryland. A single healthy colony may hold around 60,000 bees in mid-summer, 30,000 bees in the late fall, and closer to 20,000 by the end of the winter. Mack is cost-effective for Maryland. He only works in colder weather, usually from November to March, because bees are dormant or clustered when it’s below 54°F.

On long summer days, when the hives are busy with bees flying in and out to forage, Mack won’t even budge from his bed in the van. Preston still hides his training aids, and she runs drills to keep him on his toes. “When we're not [training], he's either swimming in the pool or sleeping on the couch. He's a Lab so he does that hanging out thing very well,” she says.

In the field, when Preston commands him to “find,” he moves from beehive to beehive, sniffing each one for the distinct odor of dead fish, the smell associated with AFB. If he smells the disease, he sits to alert Preston that a manual inspection is needed. Then Mack is praised and rewarded with a special ball that he doesn't get at any other time. “He’s incredibly efficient — in a span of three weeks, Mack inspected over 1,600 bee colonies that were being sent to California for almond pollination. And he is accurate —in field testing, he correctly identified 100 percent of infected hives,” she says. “It would take us a year to work on that many colonies.”

Preston, Mack, and Tukka — a young springer spaniel who’s still in training — are currently on the front lines, securing our country’s food supply. Grains are primarily pollinated by the wind. But fruits, nuts, and veggies — which comprise 70 of the top 100 human food crops — are pollinated by bees. That’s why beekeepers follow the bloom. For six months a year, they travel with their bees to fruit, vegetable, and nut farms in need of pollination.

“Every third bite of food we take would be thanks to the honeybees,” Preston says. “Without our canine program, beekeepers wouldn't be able to move their bees into West Virginia for strawberries and apples or into Delaware for cucumbers and pumpkins.” Tractor-trailers carry about seven million bees across the country to pollinate crops. They’re vulnerable. “AFB would be a lot more prevalent if we weren't doing dog inspections.”

American Foulbrood Disease

Thank you to Jaime E. Garza, Apiary/Agricultural Standards Inspector, Department of Agriculture, Weights & Measures, County of San Diego for the following:

"To help improve the overall health of our honey bee community it is important for beekeepers to familiarize themselves with healthy brood conditions and types of brood diseases.

I have attached a helpful resource on American Foulbrood Disease which is a highly contagious bacteria with no cure. The disease weakens and in most cases kills a bee colony. During times of dearth a weakened infected bee colony may be susceptible to robbing by other honey bees from other colonies which can cause the bacteria to be spread. The disease can be spread by bees, honey, propolis, hive tools, frames and other beekeeping equipment."

Watch: This Dog's Nose Saves Bees

National Geographic    Via Swindon & District Beekeepers Association  January 14, 2015

Klinker is a one-of-a-kind dog. She's the only dog in the U.S. certified to detect a damaging bacteria in beehives. Along with her handler, Bill Troup, she inspects up to a thousand honeybee colonies a day for the contagious and lethal bacteria called American foulbrood.

View at National Geographic:

Guelph Scientists One Step Closer to Inhibiting Destructive Bee Disease

The Globe and Mail    By Eric Atkins  December 16, 2014

The honeybees responsible for pollinating one-third of the food we eat face a host of threats, from bloodsucking mites and viruses to pesticides and climate change.

But researchers at the University of Guelph have taken a big step toward fighting the most destructive and widespread killer of honeybee larvae, a disease known as American foulbrood.

For the first time, scientists have identified a toxin released by the pathogen, and come up with a drug that could stop the disease that is prevalent in North America, Europe and other parts of the world.

“What we’ve found is an important factor that we can inhibit in this honeybee disease,” said Rod Merrill, a Guelph biochemist and co-author of the study to be published in the December issue of the Journal of Biological Chemistry.

American foulbrood, named for the smell of infected hives and the country in which it was first identified more than a century ago, is spread easily among honeybee colonies by spores carried by adult bees. The spores are eaten by larvae, which die but also spread millions more spores into the hive.

“The next generation is kaput. It’s not toxic to the adults, but that ultimately destroys the hive,” Prof. Merrill said in an interview. “And then what happens is robber bees go into the hive and steal the honey, which is contaminated with the bacterial spores, and then they drag it over to their hive, so it just proliferates.”

Hives infected with the bacteria quickly fail, and beekeepers must burn the hive and all associated equipment to ensure the spores are destroyed.

There is no cure for American foulbrood. Antibiotics used to control the disease have proven ineffective as resistant strains have developed.

Field tests to be conducted on hives in the spring will show whether the drug is effective at controlling American foulbrood, said Prof. Merrill, who began the research more than two years ago.

The drug that could treat the disease is not an antibiotic, but an anti-virulence compound that controls the toxin that kills the larvae but does not prompt the bacteria to mutate by threatening their survival.

“Research takes a long time. So right at this moment I can’t say what the impact will be in treating American foulbrood,” Prof. Merrill said. “However, I can say it’s going in the right direction that we need to characterize the toxins produced by the organism that causes American foulbrood or the impending crisis for the honeybee is going to get worse.”

Long winters, virus-bearing varroa mites and pesticide exposure have contributed to declines in honeybee populations in North America and Europe. In Ontario, declining honey production and mounting costs of replacing dead bees have been blamed in part on neonicotinoid pesticides that are used to grow corn and soybeans.

In response, the Ontario government recently said it plans to impose rules that would reduce the use of the systemic pesticide by 80 per cent by 2017. Farmers who plant seeds treated with neonics would have to show their fields are susceptible to grubs, worms and other yield-destroying pests.

The move is opposed by the chemical companies that sell the pesticide-treated seeds and the Grain Farmers of Ontario, which says the restrictions will take away an important tool farmers use to protect their harvests.

A new poll of 1,000 Ontarians shows nearly 80 per cent support the provincial government’s plans to restrict the use of neonics, which scientists say impair bees’ foraging abilities and contribute to colony failure.

The poll, released by the Canadian Association of Physicians for the Environment, Friends of the Earth Canada and the Ontario Beekeepers’ Association, found support for the restrictions was strongest (85 per cent) in Southwestern Ontario, the heart of Canada’s corn-and-soybean region. Support was weakest, 60 per cent, in the central part of the province.

“Our food security depends on healthy pollinators,” said Gideon Forman of the Canadian Association of Physicians for the Environment. “Ontarians are aware of the current crisis and want the government to take action to protect bees.”

Read at:

Using Microscopic Bugs to Save the Bees

Bee    Brigham Young University   October 27, 2014 

Some Viruses can be used to protect bees against the bacterial infection, American Foulbrood. Check out this fascinating video

Undergraduate BYU student on the path to treating deadly bee-killing bacteria

BYU researchers have identified five new phages that can potentially treat honeybee hives infected with American Foulbrood, a deadly disease that costs the industry millions of dollars each year.

For decades, honeybees have been battling a deadly disease that kills off their babies (larvae) and leads to hive collapse. It’s called American Foulbrood and its effects are so devastating and infectious, it often requires infected hives to be burned to the ground.

Treating Foulbrood is complicated because the disease can evolve to resist antibiotics and other chemical treatments. Losing entire hives not only disrupts the honey industry, but reduces the number of bees for pollinating plants.

Now an undergraduate student at BYU, funded by ORCA grants, has produced a natural way to eliminate the scourge, and it’s working: Using tiny killer bugs known as phages to protect baby bees from infection.

“Phages are the most abundant life form on the planet and each phage has a unique bacteria that it will attack,” said Sandra Burnett, BYU professor of microbiology and molecular biology. “This makes phage an ideal treatment for bacterial disease because it can target specific bacteria while leaving all other cells alone.”

Although phages are plentiful in nature, finding the perfect phage for the job takes a lot of hunting. That’s where student Bryan Merrill comes in.

Merrill has been researching ways to treat American Foulbrood since joining a “Phage Hunters” class his freshman year at BYU. Merrill loved the class, which introduced him to the process of phage identification, and so he approached Burnett with hopes of researching treatment for the disease under her tutelage.

“This bacteria has been a problem in honeybees for a long time,” Merrill said. “It infects the larva when they’re teeny tiny. Even a few spores will infect and they’ll start eating the larva from the inside out. It doesn’t hurt the adult bees, but all of the sudden the bees can’t replenish the population and the hive just collapses.”

When hives are infected, beekeepers generally treat their hives with antibiotics. However, this is usually only a temporary solution. If the bacteria returns, it will most likely develop to be resistant to the antibiotics. From there, bee owners have the option to burn the hive or try phage treatment.

“Phage is a great alternative to antibiotics, and it’s a natural alternative because phages exist in nature on their own,” Burnett said. “And just the nature of a phage itself is that it’s self-replicating at the expense of the bacteria. It multiplies itself so there are more of them to hunt down the bacteria. Then as soon as the host is gone, the phage just disappears.”

Once they identify the perfect phage, Burnett, Merrill and other students replicate it in the lab so it can be applied to the hive with a sugar-water solution. Like a virus, the phage get to work infecting the harmful bacteria until it is gone.

After a lot of gene sequencing and analyzing, Merrill has identified five phage candidates for honeybee treatment, cleverly named after former BYU basketball stars (Abouo, Davies, Emery, Jimmer1 & Jimmer2). His findings appear in a recent issue of high ranking biotechnology journalBMC Genomics.

Merrill has received two ORCA grants to fund his research over the years and has raised several successful beehives for himself.

Read more here:

New Drug for American Foulbrood (AFB)

In March 2012, FDA approved LINCOMIX Soluble Powder, sponsored by Pharmacia and Upjohn Co., a Division of Pfizer, Inc. to control American Foulbrood 

By Melanie McLean, DVM, Center for Veterinary Medicine, FDA

American Foulbrood – A Foul Disease

When beekeepers utter the three-letter acronym “AFB,” they’re not referring to the closest air force base. Rather, they’re talking about American foulbrood, a serious infectious disease of honey bees. Caused by the spore-forming bacteria Paenibacillus larvae and found worldwide, AFB is one of the most widespread diseases affecting honey bee brood, and the most destructive. The disease does not pose any health risks to people, but it wrecks havoc among bees. Severe outbreaks can weaken or kill entire colonies.

American foulbrood affects the larval and pupal stages of brood development, leaving adult bees safe from infection. Young larvae may die quickly when they are curled at the base of their uncapped cells. Worker bees remove these dead larvae, leaving empty cells. Most often, death occurs after the cell has been capped. By this time, the older larvae or young pupae have stretched out lengthwise and are upright, filling most of their cell. Read more...

(The above brought us by CATCH THE BUZZ (Kim Flottum) Bee Culture, The Magazine of American Beekeeping, published by A.I. Root Company.)