Vaccine for Honeybees Could Be a Tool to Fight Population Decline

https://www.nytimes.com/2018/12/23/science/bee-vaccine-honeybee.html

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At a time when some beekeepers are struggling to keep their colonies alive and pollinating, the prospect of a vaccine for honeybees has offered a flicker of hope.

The scientists behind the project say the vaccine is designed to protect honeybees from microbial diseases that can decimate bee populations. If the technology can be adapted to fight a multitude of infections, experts hope it can provide one solution for the array of problems facing bees, which pollinate about one-third of food in the United States.

The work that honeybees do for people — pollinating food as they gather pollen and nectar for themselves — is estimated to produce about $15 billion worth of crops in the United States each year.

“This is a very new way of thinking about how we can help bee health,” said Dennis vanEngelsdorp, an entomologist with the University of Maryland. “As a proof of concept, this is really exciting.”

The crisis that inspired calls to “save the bees” is multilayered. Bee experts like to sum up the crisis with the “4 Ps”: parasites, poor nutrition, pathogens and pesticides. Beekeepers in the United States lost an estimated 40 percent of their honeybee colonies in one year, according to data from April 2017 to April 2018 kept by Bee Informed Partnership, a consortium of universities and research laboratories.

Dalial Freitak, one of the scientists behind the vaccine, said she hoped it can make bees more resilient in a perilous environment. Because of regulatory hurdles, such as safety testing, it will be years before a vaccine hits the market, Dr. Freitak said. Some experts were wary about getting too excited about the vaccine because it is still in the developmental stages.

Unlike vaccinations for humans, the one for bees does not involve needles. Rather, it is edible in the form of a sugar solution that honeybees are attracted to. (It recalls the way children were given the polio vaccine through sugar cubes.)

Based on the prototype, the product — marketed under the name PrimeBEE — involves vaccinating a queen bee and sending her to the beekeeper, said Dr. Freitak, who is now an associate professor in honeybee research at Karl-Franzens University of Graz in Austria.

The beekeeper would then introduce the vaccinated queen bee to the hive, heralding a new generation of bees with immunity to the disease.

Creating a vaccine for insects was not always believed to be possible. Before the early 2000s, conventional wisdom was that insects could not acquire immunity because they lacked antibodies, the protein that helps many animals recognize and fight bacteria and viruses.

“Vaccinations have always been more associated with vertebrates and being dependent on the presence of antibodies,” Dr. Freitak said. “That’s why vaccinations have never been considered.”

Once scientists understood that insects could acquire immunity and pass it to their offspring, the remaining questions were how they did so and whether that process could be replicated in a lab. In 2015, Dr. Freitak, who was then with the University of Helsinki in Finland, published a study with two other scientists that explained this process. After that, a vaccine for insects seemed feasible.

The study, published in the journal PLOS Pathogens, found that in honeybees, a protein called vitellogenin binds to bacteria and carries it to the eggs, prompting immune responses in the offspring. The researchers realized they could cultivate immunity in a bee population with a single queen.

The scientists’ first goal was targeting American foulbrood, a bacterial disease that turns larvae dark brown and makes the hive give off a rotting smell. It is typically a death sentence for an infected colony, which can amount to about 60,000 bees at its peak in the middle of summer and 10,000 at the low point in winter.

Although antibiotics exist to control the disease, the treatment recommended to address an outbreak of American foulbrood is to burn the infected colony and all the equipment used.

During the late 1800s and early 1900s, the disease devastated bee colonies in parts of the United States. The threat was so serious that beekeepers who did not comply with laws requiring they burn all infected colonies and equipment were fined or even put in jail, according to a 2009 paper in the Journal of Invertebrate Pathology.

American foulbrood is under far better control than it was a century ago. Rob Snyder, who inspects commercial beehives in Northern California, said treatments like burning infected populations and antibiotics have staved off the spread of the disease. Some officials have even trained dogs to sniff out the bacteria in an effort to avoid spreading it across state lines.

In California, where vast numbers of honeybees are needed for almond production, Mr. Snyder said he has not seen American foulbrood in several years. He said a much bigger threat to honeybee populations there is the Varroa mite, a parasite that sucks blood of the adult honeybees and their brood.

No vaccine can eradicate mites, but a vaccine might be able to protect honeybees from the viruses associated with the mites, including deformed-wing virus, said Keith S. Delaplane, the director of the Honey Bee Program at the University of Georgia. Scientists still have to demonstrate the efficacy of a vaccine to treat those kinds of viruses, he said.

“If an oral vaccine for deformed-wing could be combined with effective mite controls, that would be, in my opinion, a huge leap forward for honeybee health,” he said.