> It appears that the prevalent DWV strain in the population is DWV-B. This may in-fact prove to be a less virulent strain and may be part of the survival story.


The opposite may also be true. The science around replacing DWV-A with B is still ongoing, and since DWV-B replicates at greater speeds than A, its eventual dominance over A seems inevitable. In terms of virulence, the viral landscape is unpredictable.  


> Subsequent experimental comparison of the virulence of DWV-A versus DWV-B (Tehel et al., 2020; Al Naggar and Paxton, 2021) have supported the initial demonstration of higher virulence and viral loads reached by DWV-B over DWV-A in adult honey bees. 

> We conclude from the experimental evidence of impacts on individual bees that DWV-B likely has an equal or somewhat higher virulence than DWV-A.

>What impact DWV-B will have on honey bee populations, if and when it replaces DWV-A  is currently unclear. As we have pointed out above, experiments on individual honey bees suggest that DWV-B is more virulent than DWV-A, at least in adult hosts (McMahon et al., 2016), suggesting that it may lead to greater colony losses in the future.

Open source: 

Epidemiology of a major honey bee pathogen, deformed wing virus: potential worldwide replacement of genotype A by genotype B

Robert J. Paxton et al. 

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