Review of Bee Health

As its name indicates, deformed wing virus causes shrunken or crumpled wings in bees, which often die from the disease when they become adults.
Varroa mites transmit the virus to bees, and killing varroa with a miticide remains the best way to control the virus.

However, University of Manitoba entomologists published a paper last year on an alternative method to control deformed wing virus using a technique called RNA interference.

In cellular biology, RNA acts as a messenger carrying information from DNA to form the necessary proteins of life. RNA interference is a technique to silence the messenger and prevent the expression of a particular gene.

Humans and other animals have complex immune systems to fight off viruses, but plants, fungi and invertebrates such as bees use RNAi to protect themselves against viruses.

The U of M researchers replicated RNA from the deformed wing virus, converted it to double stranded RNA and fed it to bees in the form of a syrup. The double stranded RNA silences the invading deformed wing virus by blocking expression of the virus genes.

Adult bees that were fed the treatment had lower levels of deformed wing virus and fewer incidences of deformed wings than a control group.

“Deformed wing virus is a common virus affecting bees, which is linked with severe winter mortality in bee colonies,” said Suresh Desai, a researcher who works with Rob Currie, a U of M entomologist.

“Having a means to prevent or suppress the expression of the virus would be a valuable addition to our bee health toolkit.”

Currie said the tests were done on caged bees, and they must now show that it works at a hive scale.

“You need to prove it has a really effective role in pest control, so there’s a lot of further study that needs to be done before you’d want to invest a huge amount of money,” he said.

“That’s what we hope to be working on.”

The researchers will have to partner with industry to commercialize a product if they establish that RNAi is an effective tool to fight deformed wing virus.

Finding an investor could prove challenging because the bee industry is tiny compared to other sectors of agriculture. Therefore, it’s hard to convince companies to invest in a product that will be used solely on bees.

However, Currie said a biotech company may want to invest to protect other parts of its business.

“A lot of the chemical companies that are producing hybrid seed have a huge stake in pollination,” he said.

“If they don’t have (bees) they’re in big trouble, so they might have to take it on and do it that way, rather than thinking of it as a way of getting sales (from the bee industry).”

Saskatchewan Beekeepers Association president Corey Bacon said apiarists need this kind of technology because only one remaining miticide is effective on varroa mites.