The world’s first insect vaccine is here, and it could help with stopping a fatal bacterial disease in honeybees. A study published on October 17 in the journal Frontiers in Veterinary Science found honeybees born from vaccinated queens were more resistant to American Foulbrood (AFB) infection than hives with unvaccinated queens. Not only would the vaccine help in improving colony health, but it might increase commercial beekeeping to make products, such as honey and medical wax.
Several factors have contributed to declining honeybee populations—higher temperatures from climate change, pesticides, and drought to name a few. “Bee health is a multifaceted problem and many factors play into the survival or perishing of a beehive,” says Dalial Freitak, associate professor at the University of Graz in Austria and senior author of the study. “As in any organism, diseases can cause havoc, especially if other stressors are at play.” The current vaccine tackles AFB, a devastating disease that’s caused early outbreaks in US beehives since the early 1900s.
AFB is caused by the spores of the larva of the bacteria Paenibacillus. Young honeybees ingest the spores in their foods and in one to two days, the spores take root in their gut, sprouting out rod structures. Like an aggressive cancer tumor, the rods quickly multiply before invading the blood and body tissues and killing the young insect larva from the inside. By the time they die, new spores have formed to infect the bees that come in to clean up the honeycomb cells where the deceased laid. Beekeepers may also accidentally spread the disease by exposing contaminated honey or equipment to other bees. Freitak estimates at least 50 percent of beehives globally have AFB. While cultivators may not see any noticeable symptoms of the disease at first, it can feel like a ticking “time bomb” with an outbreak potentially happening at any moment, she says.
The recent study tests the safety and effectiveness of an oral breeder vaccine—an immunization that’s passed down from parents—to increase resistance against Paenibacillus larva. The oral vaccine is mixed into a new queen’s food which she ingests before being introduced into the hive. Once digested, the vaccine contents are transferred into the fat body, the storage organ in insects. Vitellogenin, or the yolk proteins that provide nutrients for growing embryos, bind to pieces of the vaccine and deliver it to eggs in the ovaries. “A little piece of vaccine into the ovaries stimulates an immune response and it’s where you need it the most,” says Annette Kleiser, the CEO of biotech company Dalan Animal Health that created the vaccine. “A lot of these diseases are when the larvae get infected in the first few days when they hatch.”
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In the current study, two queen honeybees were vaccinated with either the vaccine or the placebo before entering their hive and laying eggs. After the eggs hatched, the two hives were brought to the lab (to avoid infecting other colonies in the wild) and exposed to AFB spores for several days. The team found that vaccinating the queen decreased the risk of AFB by 30 to 50 percent. What’s more, the vaccine did not impact the health of bee colonies. The study authors saw no difference in hive losses between the placebo and vaccinated groups before spore exposure.
“They have shown a proof-of-concept,” says Ramesh Sagili, a professor of apiculture at Oregon State University who was not affiliated with the study. He notes, however, the study took place in an isolated, lab-controlled setting and the challenge with this type of technology is the lack of success when tested in the field. One suggestion is to conduct large-scale field studies, expanding from two honeybee hives to thousands split between vaccine and placebo groups. Other questions Sagili would like answered in future research is how the vaccine fares against different AFB strains and how long immunity lasts in the long-run.
“I’m convinced they have something promising here, but only if they do some large-scale field studies with the beekeeping industry,” adds Sagili. If successful, he says this could open doors to the production of vaccines for other viral diseases plaguing honeybees.
Still, finding solutions to assist honeybees with illness is important: “A declining honeybee population has made it difficult to pollinate enough food for everyone to eat,” explains Kleiser.
Honeybees pollinate one-third of food in the US. Beyond honey, they are essential for the production of apples, broccolis, melons, and even your favorite cup of java. But as much service honeybees provide, humanity has provided them a disservice in keeping them safe and alive. Beekeepers estimated a 45.5 percent loss in honeybee colonies from April 2020 to April 2021, which is largely associated with human activity. According to the United Nations, if bees continue to disappear, we may see permanent disruptions in our food supply chain and the disappearance of fruits, vegetables, and other crops heavily dependent on pollination.
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There are other options currently on the table to mitigate the spread of AFB. Once beekeepers notice the first signs of disease, they can burn the honey, tools, and other equipment in contact with the hive. Additionally, they could quarantine the hive to prevent infected bees from swarming nearby colonies. However, both options aren’t ideal because they slow down honey production and affect the food supply chain. “You have a withdrawal period where you have to wait and that costs money to beekeepers,” says Kleiser. “The flowers won’t wait so if you miss the season you miss your entire yield.”
Another option is antibiotics. Sagili explains that antibiotics are effective against AFB, and beekeepers have been using antibiotics to manage the spread of spores. Because of its availability, he says it doesn’t rise to the level of other challenges that honeybees presently face. That said, there is always a risk of antibiotic resistance that could lower honeybees’ protection against the bacterium. “Beekeepers have options, but it would be nice to have a vaccine for [AFB] so they have one less problem to deal with,” Sagili says.
Right now, the vaccine is pending conditional license by the US Department of Agriculture Center of Veterinary Biologics. Kleiser emphasizes the vaccine would not only benefit bees, but the larger ecosystem as well. “It’s a survival issue,” she says. “We have to understand the critical importance of these animals.”