Molecular detection and partial phylogenetic analysis of Deformed Wing Virus and Acute Bee Paralysis Virus in Varroa destructor samples

Varroa destructor is a significant mite that adversely affects honey bee health, both directly and as a vector for various pathogens. This study aimed to detect Deformed Wing Virus (DWV) and Acute Bee Paralysis Virus (ABPV) by reverse transcription polymerase chain reaction (RT-PCR) and to perform sequence and phylogenetic analyses of field isolates obtained from V. destructor samples collected in Burdur, Southwestern Türkiye. Mites were collected from five research regions (Karaçal, Kumluca, Akyaka, Yazıköy, and Çendik), with one apiary selected per region; colonies within each apiary were screened, and 25 colony-level pools were prepared by collecting approximately 50–60 V. destructor mites from the colonies exhibiting the highest infestation. In one pooled V. destructor sample from the Çendik apiary (Pool III), nucleic acids specific to both DWV and ABPV were detected. Phylogenetic analysis of the BUR/ABPV/Varroa/2022 isolate revealed a close genetic relationship with isolates from other regions of Türkiye, as well as from Northern Europe and Asia. Additionally, the BUR/DWV/Varroa/2022 isolate was identified within the DWV genotype A cluster. Point mutations and motif variations in amino acid sequences of the analyzed strains were also identified. These findings contribute to understanding the viral evolution and epidemiology of ABPV and DWV and underscore the importance of continuous monitoring and effective control strategies against Varroa infestations to mitigate their direct and indirect impacts on honey bee health.