Deformed Wing Virus
Krankheiten
The deformed wing virus, DWV for short, is one of the most significant viruses of the honey bee.
The deformed wing virus, DWV for short, is one of the most significant viruses of the honey bee. It occurs in several variants, mainly DWV-A and DWV-B. Without the Varroa mite, an infection usually goes unnoticed, as the virus is passed on via brood food and social feeding. It becomes critical as soon as the Varroa mite acts as a vector: it transmits the virus directly into the hemolymph of larvae and pupae, bypassing the bee's natural barriers. In addition, the virus also multiplies within the mite itself.
The typical picture is freshly hatched bees with crippled, stub-like wings, a shortened abdomen, and often darker coloring. These bees are unable to fly, are rejected by the guard bees, and crawl around in front of the hive or on the landing board. Even without visible wing damage, a high viral load significantly shortens the bees' lifespan, which is especially fatal for the winter bees.
Studies show the close connection with the mite very clearly: in colonies without Varroa infestation, infection rates are low, while in heavily parasitized colonies they rise many times over. Crippled bees in late summer and autumn are therefore not a disease picture of their own but an alarm signal for a far too high mite infestation and the imminent collapse of the colony.
There is no medication against the virus. The only effective measure is consistent, timely, and controlled Varroa control, in particular the summer treatment before the winter bees are reared. Renewing the comb structure, young vigorous queens, and avoiding robbing, through which mites and viruses are carried between colonies, also help.
Crippled bees should not be dismissed as a merely cosmetic problem, and treatment should not be postponed any further. Combs and bees from collapsing colonies should likewise not be moved into healthy colonies. There is no reporting requirement, but the finding is a good reason to review one's own Varroa strategy and document mite drop.