Molecular detection of black queen cell virus and Kashmir bee virus in honey

Vesna Milićević, Sonja Radojičić, Jasna Kureljušić, Milanko Šekler, Ksenija Nešić, Ljubiša Veljović, Jelena Maksimović Zorić, Vladimir Radosavljević

Considering the intensive trading nowadays, the honey from the local market was tested for the presence of the six most common bee viruses. To prove the suitability of honey as a sample for the bee viruses detection, the set of different sample types taken directly from the hives we comparatively tested. The study included 30 samples of domestic and 5 samples of imported honey. Additionally, we tested 40 sets of samples including live bees, dead bees, and the honey taken from four apiaries for the evaluation of honey suitability for the virus detection, Two out of the six most common bee viruses were detected in the samples of honey from the market. Black queen cell virus (BQCV) genome was found in 24 domestic honey samples and Kashmir bee virus (KBV) genome was detected in one sample of imported honey. The nucleotide sequences of 24 BQCV isolates showed the highest identity (86.4%) with strains from Europe at the polyprotein gene, whilst the Serbian isolates between each other showed 98.5% similarity. By comparative testing of the different type of samples, in three out of four apiaries BQCV genome was detected in both bees and honey. Evaluating the suitability of honey for the detection of the viral disease by simultaneous testing of live, dead bees, and honey from the same hive, it was shown that the honey can be successfully used for the detection of BQCV. Since, as of yet, there has been no evidence of KBV circulation in Serbia, after its detection in imported honey, there is a substantial risk of its introduction and consequently the need for its surveillance. Therefore, the programs of bee diseases screening should be included in the regular control procedures for the international trade. In addition to this benefit, honey gives an opportunity to beekeepers for continuous monitoring of bees' health status.