Varroa mites and honey bee health: can Varroa explain part of the colony losses?

Since 2006، disastrous colony losses have been reported in Europe and North America. The causes of the losses were not readily apparent and have been attributed to overwintering mortalities and to a new phenomenon called Colony Collapse Disorder. Most scientists agree that there is no single explanation for the extensive colony losses but that interactions between different stresses are involved. As the presence of Varroa in each colony places an important pressure on bee health، we here address the question of how Varroa contributes to the recent surge in honey bee colony losses.