Analytical sensitivity and specificity of a RT-PCR for the diagnosis and characterization of the spatial distribution of three Apis mellifera viral diseases in Spain

The occurrence and spatial distribution of deformed wing virus (DWV), black queen cell virus (BQCV), and Kashmir bee virus (KBV) were assessed in 294 honeybee colonies in Spain by employing a SYBR-Green based real time RT-PCR. 60% of them were positive for both DWV and BQCV, and those two viruses were detected in 84% and 68% of the samples, respectively. Conversely, KBV was detected in only 1.7% of the samples. Increments in the number of bee colonies per region, adjusted by the number of samples collected, were associated with increased risk of finding DWV, BQCV, and KBV, as estimated by mixed Bayesian regression models. The residual risk for DWV, BQCV, and KBV decreased northerly and westerly, suggesting that factors or forces that favour the presence of these viruses could be more prevalent in southern and eastern regions of Spain. Results will be useful in the design and implementation of effective honeybee viral disease control and surveillance programs in Spain.