Evolutionarily diverse origins of deformed wing viruses in western honey bees
Nonno Hasegawa, Maéva Angélique Techer, Noureddine Adjlane, Muntasser Sabah al-Hissnawi, Karina Antúnez, Alexis Beaurepaire, Krisztina Christmon, Hélène Delatte, Usman H Dukku, Nurit Eliash, Mogbel A. A. El‐Niweiri, Olivier Esnault, Jay D. Evans, Nizar Haddad, Barbara Locke, Irene Muñoz, Grégoire Noël, Delphine Panziera, John M. K. Roberts, Pilar De la Rúa, Mohamed A. Shebl, Zoran Stanimirović, David A. Rasmussen, Alexander S. Mikheyev
Abstract
). They provide an opportunity to explore how novel transmission routes shape disease epidemiology. As the principal driver of the spread of deformed wing viruses (mainly DWV-A and DWV-B), varroa infestation has also driven global honey bee health declines. The more virulent DWV-B strain has been replacing the original DWV-A strain in many regions over the past two decades. Yet, how these viruses originated and spread remains poorly understood. Here, we use a phylogeographic analysis based on whole-genome data to reconstruct the origins and demography of DWV spread. We found that, rather than reemerging in western honey bees after varroa switched hosts, as suggested by previous work, DWV-A most likely originated in East Asia and spread in the mid-20th century. It also showed a massive population size expansion following the varroa host switch. By contrast, DWV-B was most likely acquired more recently from a source outside East Asia and appears absent from the original varroa host. These results highlight the dynamic nature of viral adaptation, whereby a vector's host switch can give rise to competing and increasingly virulent disease pandemics. The evolutionary novelty and rapid global spread of these host-virus interactions, together with observed spillover into other species, illustrate how increasing globalization poses urgent threats to biodiversity and food security.