The world’s first insect vaccine is here, and it could help prevent a deadly bacterial disease in honey bees. The study, published Oct. 17 in the journal Frontiers in Veterinary Science found that honeybees born from vaccinated queens were more resistant to American Foulbrood (AFB) infection than hives with unvaccinated queens. Vaccination will not only help improve colony health, but can also increase commercial beekeeping to make products such as honey and medical wax.
Climate change, pesticides and warmer temperatures from drought are several factors that have contributed to the decline in honey bee numbers. Dalial Freitak, associate professor at the University of Graz in Austria and lead author of the study, says: “Bee health is a multifaceted problem and many factors influence the survival or destruction of a beehive. “As with any organism, diseases can wreak havoc, especially if other stressors are involved.” The current vaccine fights AFB, a devastating disease that has caused early outbreaks in US beehives since the early 1900s.
AFB is caused by spores of bacterial larvae Paenibacillus. Young honeybees ingest the spores in their food, and within a day or two, the spores take root in their guts and sprout rod structures. Like an aggressive cancerous tumor, the rods multiply rapidly before penetrating the blood and body tissues and killing the young insect larvae from the inside. When they die, new spores are formed to infect bees that come to clean the hive cells left by the deceased. Beekeepers can also accidentally spread the disease by giving contaminated honey or equipment to other bees. Freitak estimates that at least 50 percent of beehives worldwide contain AFB. He says that even if growers don’t see any noticeable symptoms of the disease at first, it can feel like a “ticking time bomb” with an outbreak potentially occurring at any moment.
A recent study examines the safety and efficacy of an oral breeding vaccine to boost immunity—an immunization passed down from the parents. Paenibacillus larva. Oral inoculation is mixed into the new queen food she eats before being introduced into the hive. After digestion, the contents of the vaccine are transferred to the fat body, which is a storage organ in insects. Vitellogenin, or yolk proteins that nourish growing embryos, binds to fragments of the vaccine and delivers them to the eggs in the ovaries. “A small piece of vaccine in the ovaries stimulates an immune response, and it’s where you need it most,” says Annette Kleiser, CEO of Dalan Animal Health, the biotech company that developed the vaccine. “Many of these diseases occur when the larvae are infected within the first few days of hatching.”
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In the current study, two queen bees were inoculated with either a vaccine or a placebo before entering their hives and laying eggs. After the eggs hatched, two hives were brought into the laboratory (to avoid infecting other colonies in the wild) and exposed to AFB spores for several days. The team found that vaccinating the queen reduced the risk of AFB by 30 to 50 percent. Moreover, the vaccination did not affect the health of bee colonies. The study authors saw no difference in hive losses between the placebo and vaccinated groups before spore exposure.
“They proved a concept,” says Ramesh Sagili, a beekeeping professor at Oregon State University who was not involved in the research. However, he notes that the research was conducted in an isolated, controlled laboratory setting, and the problem with this type of technology is the lack of success when tested in the field. One suggestion is to conduct large-scale field studies, from two honeybee hives to dividing thousands between vaccine and placebo groups. Other questions Sagili wants to answer in his future research are how the vaccine works against different strains of AFB and how long immunity lasts in the long term.
“I’m sure they have something promising here, but only if they do large-scale field research with the beekeeping industry,” adds Sagili. If successful, he said, it could open the door to developing vaccines for other viral diseases that plague honey bees.
However, it’s important to find solutions to help honey bees with disease: “Dwindling honey bee populations have made it difficult to pollinate enough food for everyone to eat,” explains Kleiser.
Honeybees pollinate one-third of the food in the United States. Apart from honey, they are essential for the production of apples, broccoli, melons and even your favorite cup of java. But as much service as honey bees have provided, humanity has done them a disservice in keeping them safe and alive. Beekeepers estimate a 45.5 percent loss in honey bee colonies from April 2020 to April 2021, largely due to human activity. According to the United Nations, if bees continue to disappear, we could see permanent disruptions in our food supply chain and the disappearance of fruits, vegetables and other crops that depend heavily on pollination.
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There are other options currently on the table to reduce the spread of AFB. When beekeepers see the first signs of disease, they can burn honey, tools and other equipment that come into contact with the hive. Additionally, they can quarantine the hive to prevent infected bees from congregating in nearby colonies. However, neither option is ideal, as they slow honey production and affect the food supply chain. “You have a waiting period, and it costs beekeepers money,” says Kleiser. “The flowers won’t wait, so if you miss the season, you’re missing out on your entire harvest.”
Another option is antibiotics. Sagili explains that antibiotics are effective against AFB and that beekeepers use antibiotics to control the spread of spores. Because of its existence, he says, it hasn’t risen to the level of other challenges honey bees currently face. However, there is always the risk of antibiotic resistance, which can reduce honey bees’ defenses against bacteria. “Beekeepers have options, but it would be nice to have a vaccine [AFB] therefore, they have one less problem to solve,” says Sagili.
The vaccine is currently awaiting conditional licensure by the US Department of Agriculture’s Center for Veterinary Biology. Kleiser emphasizes that the vaccine will not only benefit the bees, but also the larger ecosystem. “It’s a matter of survival,” he says. “We need to understand the critical importance of these animals.”