Vaccine in development against deadly honeybee pathogen

Photo: C. Schüßler/Adobe Stock

Dalan Animal Health, Inc., the company responsible for the first honey bee vaccine in 2023, has announced positive findings regarding the efficacy of their new, innovative bacterial vaccine. The experimental vaccine has the potential to significantly reduce the threat of deformed wing virus (DWV) variant B in honey bee populations. The study showed DWV-B quantities to be reduced in vaccinated colonies, with an average reduction of 83%.¹

DWV-B is one of 3 major variants of deformed wing virus, alongside DWV-A and DWV-C, the latter of which is less common. DWV-B is becoming rapidly more prevalent worldwide, overtaking DWV-A in many regions.³ The disease, as the name implies, causes deformed wings in adult honey bees, which prevents them from leaving the hive to forage.¹

DWV is primarily spread by Varroa destructor mites, which feed on the fat bodies of adult honey bees, as well as pupae. Currently, there are no direct treatments or preventives for DWV. Instead, the primary method of reduction is vector control using acaracides.²

“I’ve seen firsthand the losses the DWV virus can cause and how increasingly widespread this population is for US beekeepers,” Tim Ferris, owner of Extract and Box, a Pennsylvania beekeeping business, said in a news release.¹ “Managing mite populations has become our primary focus, but seeing a potentially effective treatment on a vaccine [I have] already used for [American foul brood (AFB)] is extremely promising.”

The study tested the efficacy of vaccinating queen honey bees using killed Paenibacillus larvae (P larvae) bacterin, which is the causative agent of AFB.² Tests included 400 honey bee colonies, half with vaccinated queens, and the other half with unvaccinated queens. Researchers measured quantities of DWV-B immediately before vaccination, and again 4 months later.

Although the colonies recorded identical levels of DWV-B prior to vaccination, levels were significantly reduced 4 months later.² This indicates that reduction in virus load lasts from 4 months to an entire season. There was no difference in mite quantities between the groups.²

“To our knowledge, this is the first use of activating the immune system using a dead bacterium to provide protection against a virus in an invertebrate,” Annette Kleiser, PhD, CEO and cofounder of Dalan Animal Health, said.¹ “These results open exciting new possibilities for combating viral threats in honey bee populations, which have few methods for control available.”

In an interview with dvm360 at the 2024 American Veterinary Medical Association Convention in Austin, Texas, Kaitlyn Krebs, DVM, MBA, DABVP, spoke about topics that veterinarians should be aware of regarding honey bees.⁴ One of those topics: Varroa mites.

“…There’s so many other things that, as a veterinarian, we can advise people on, or that affect honey bees,” Krebs said.⁴ “Things like Varroa mites, the number 1 killer of honey bees. We don’t require veterinary intervention for those. But, as a veterinarian, I get asked from beekeepers about Varroa all the time…”

DWV is recorded in more than 90% of honey bee colonies worldwide. DWV is also transmissible to wild bee populations, including bumblebees.^1,2 The study by Dalan Animal Health is currently awaiting peer review. The company plans to continue their research in this area, noting that the current data does not constitute an efficacy claim for DWV-B for Dalan’s existing P. larvae product.¹ Their goal is to obtain a claim extension for DWV protection from the USDA and CFIA for the existing P larvae bacterin.¹

References

1. Company Behind the First Honeybee Vaccine Offers Hope for Beekeepers Against a Deadly Viral Pathogen. News release. Dalan Animal Health. September 10, 2024. Accessed September 10, 2024. https://prnmedia.prnewswire.com/news-releases/new-research-from-the-company-behind-the-first-honeybee-vaccine-offers-hope-for-beekeepers-against-a-deadly-viral-pathogen-302243458.html
2. Weinberg I., Floyd A., Reid N., Swift N. Reduction of Deformed Wing Virus-B levels in Colonies of the Honey bee Apis mellifera after Queen Vaccination with inactivated Paenibacillus larvae. bioRxiv. Preprint posted online July 3, 2024. https://doi.org/10.1101/2024.07.01.601551
3. Paxton R., Schäfer M., Nazzi F., et al. Epidemiology of a major honey bee pathogen, deformed wing virus: potential worldwide replacement of genotype A by genotype B. Int J Parasitol Parasites Wildl. 2022;18:157-171. https://doi.org/10.1016/j.ijppaw.2022.04.013
4. Coppock K. Common diseases in bees. dvm360. June 23, 2024. Accessed September 10, 2024. https://www.dvm360.com/view/common-diseases-in-bees