All too often when people hear that I am a beekeeper they ask me, “What’s killing the bees?” Of course there is no one reason but viri spread by Varroa mites is one reason I bring up along with a couple other reasons. Here is a good summary by Prime Bees of what’s happening with the mites and the viri they spread. – Sassafras Bee Farm

Deformed wing virus (DWV) is a highly viral disease transmitted by Varroa destructor. The disease is commonly found in colonies infested with mites. Deformed Wing Virus is regarded as deadly due to its ability to spread fast in any colony. It causes massive wing deformation in bees making it difficult for them to live normally. DWV which is regarded as a low-grade infectious disease is commonly triggered by mite infestations. It has a reputation for being massively destructive leading to the decimation of well-established colonies globally. The deformed wing virus is common in late summer and early fall. A high concentration of mites can be overwhelming for any bee colony.

DWV occurs when varroa mites which are external parasites feed on the hemolymph of both developing and mature bees after attacking them. Consequently; it reduces their lifespan drastically while spreading the deadly disease to the rest of the colony members. The Varroa mite can trigger the virus transmission from one infected bee to the entire colony within a very short span of time. Their vectored viruses are notorious at affecting honeybees immune systems hence leaving them exposed to risks of DWV. This wing deformity is a sign of a high viral load on the bees, and ultimately, bees need their wings to survive. Those with deformed wings cannot forage. 

Read full article here: Deformed Wing Virus — Prime Bees – College Station Bee & Honey Farm