Varroa destructor mites vector and transmit pathogenic honey bee viruses acquired from an artificial diet

PLoS One. 2020 Nov 24;15(11):e0242688. doi: 10.1371/journal.pone.0242688. eCollection 2020.

Abstract

The ectoparasitic mite Varroa destructor is one of the most destructive pests of the honey bee (Apis mellifera) and the primary biotic cause of colony collapse in many regions of the world. These mites inflict physical injury on their honey bee hosts from feeding on host hemolymph and fat body cells/cellular components, and serve as the vector for deadly honey bee viruses, including Deformed wing virus (DWV) and the related Varroa destructor virus-1 (VDV-1) (i.e., DWV-like viruses). Studies focused on elucidating the dynamics of Varroa-mediated vectoring and transmission of DWV-like viruses may be confounded by viruses present in ingested host tissues or the mites themselves. Here we describe a system that includes an artificial diet free of insect tissue-derived components for maintaining Varroa mites for in vitro experimentation. Using this system, together with the novel engineered cDNA clone-derived genetically tagged VDV-1 and wild-type DWV, we demonstrated for the first time that Varroa mites provided an artificial diet supplemented with engineered viruses for 36 hours could acquire and transmit sufficient numbers of virus particles to establish an infection in virus-naïve hosts. While the in vitro system described herein provides for only up to five days of mite survival, precluding study of the long-term impacts of viruses on mite health, the system allows for extensive insights into the dynamics of Varroa-mediated vectoring and transmission of honey bee viruses.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animal Diseases* / genetics
  • Animal Diseases* / metabolism
  • Animal Diseases* / transmission
  • Animal Feed / virology*
  • Animals
  • Bees* / metabolism
  • Bees* / parasitology
  • Bees* / virology
  • RNA Viruses* / classification
  • RNA Viruses* / genetics
  • RNA Viruses* / metabolism
  • Varroidae / virology*
  • Virus Diseases* / genetics
  • Virus Diseases* / metabolism
  • Virus Diseases* / transmission

Supplementary concepts

  • Deformed wing virus

Grants and funding

This research was supported in part by discretionary funds allocated to United States Department of Agriculture (USDA) Project 8042-21000-291-00D, a National Institute of Food and Agriculture (NIFA) grant 2017-06481 (EVR, YPC and JDE), a Department of Energy ORISE fellowship (FPF) and APHIS-ARS interagency agreement 19-8130-0745-IA (SCC and JDE). There was no additional external funding received for this study. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. USDA is an equal opportunity provider and employer.