A severe sacbrood virus outbreak in a honeybee (Apis mellifera L.) colony: a case report

A honeybee colony, part of an apiary of nine, showed abnormalities in brood pattern and was thus presented for study. A classic veterinary medicine approach has allowed the diagnosis of a severe case of sacbrood virus (SBV) confirmed by a high viral load in affected larvae. SBV is known to infect larvae of the honeybee (Apis mellifera), resulting in failure to pupate and ultimately death of infected larvae. Several contributing factors combined, among them the parasite Varroa destructor, have been identified in this particular affected colony to explain the clinical outbreak of the disease whereas, in the majority of cases, infected colonies remain asymptomatic. As no specific cure of honeybee viruses is available, the management of these contributing factors is essential, including feeding of colonies and control of the Varroa parasite. After implementation of management solutions, the colony rapidly recovered in six weeks, but did not recommence honey production and remained at higher risk of a winter collapse. An earlier control management would have been more effective: regular visits of the colonies by the beekeepers should be the rule in order to detect abnormalities and also to detect and eliminate as early as possible the combination of factors that contribute to the proliferation of the virus.