Prevalence of Four Common Bee RNA Viruses in Eastern Bee Populationsin Yunnan Province, China

Deformed wing virus (DWV), black queen cell virus (BQCV), sacbrood virus (SBV), Kashmir bee virus (KBV), acute bee paralysis virus (ABPV) and chronic bee paralysis virus (CBPV) are the most common RNA viruses in bee population worldwide. To determine the prevalence of these viruses in Apis cerana in Yunnan Province, China, 270 adult Eastern worker bee (A. cerana) samples have been collected from nine major bee breeding regions in Yunnan province for screening. Our data showed that BQCV, DWV, KBV and SBV are widely prevalent in Yunnan Province. The total prevalence rates of KBV, DWV, SBV and BQCV in Yunnan province were 3%, 14.8%, 24.1% and 36.3%, respectively. BQCV was detected in all selected regions except Jinghong City. The prevalence of KBV in Tengchong County is the first evidence, to our knowledge, showing that Eastern bees could be infected by KBV. The highest infection rate of SBV was found in Kunming city (56.7%). Sequence analysis demonstrated high nucleotide homology between the isolated BQCV, DWV, KBV and SBV strains. Phylogenetic analysis showed that except SBV (YNO7), Yunnan isolates can be likely clustered into independent branches, which indicates the possibility of geographic origins.