Peer review of: Chronic bee paralysis as a serious emerging threat to honey bees (2020)

Reviewers' Comments: 
 
Reviewer #1: 
Remarks to the Author: 
This paper aimed to determine if chronic bee paralysis virus is an emerging infectious disease of 
honeybees in England and Wales. By using governmental data on inspections, the authors show an 
exponential increase of cases in the last decade with cases that clustered spatially but not temporally, 
suggesting that the pathogen was spreading locally but did not persist in the same spot between 
years. The overall increase across the region in the last decade is convincing that this is indeed an 
emerging infectious disease. It is interesting that they found the highest increase in prevalence among 
professional beekeeper’s hives in comparison to amateur beekeepers, as well as beekeepers that 
imported hives. The authors attempted to track the potential origin of the virus by determining what 
regions the hives were imported from and which were associated with the highest rates of increase. 
My sense is that this paper is important because the authors try to understand the large scale spatial 
and temporal trends of patterns in viruses in a region, along with piecing apart what practices are 
causing higher risks. Overall it is a well written, with clear logic and justification and results. At its 
heart it is a descriptive, observational paper that will be interesting to the field. 
Comments 
Line 37-38: Honeybee’s globally have been increasing in population across that time span right? 
Line 48: Add in common name for Apis cerana like you do for Apis mellifera. 
Line 49: clarify that they are new diseases for the western honeybee specifically. 
Line 172 – p=0.0000 – is a nonsense – be consistent with <0.001 – again 2 lines later – these 
analyses are pretty pointless. – this is against random? 
Line 232-233: Could add in the aspect of a sampling bias. Are the professional beekeepers more likely 
to inspect and report issues in their hives since that is their main form of income, in comparison to 
amateurs. 
Line 282: Clarification about the details and shortcomings of the disease data set. When are these 
health inspections occurring? On a regular time interval basis or when they are requested? 
Line 299-300: how were the putative cases checked? Were there genetic tests to validate infection? 
What about asymptomatic cases? 
 
 
 
Reviewer #2: 
Remarks to the Author: 
The manuscript "The Chronic bee paralysis: A serious emerging threat to honey bees", is an very 
interesting work on the epidemiology in honeybee and reads well. Using geo-statistical methods the 
authors present a picture of the distribution of the specific syndrome (hairless and grease) in time and 
space. I think this manuscript present novel epidemiological data using a geostatic approach that can 
be of a broad interest. I am not an expert in the geo-statistics and thus can't judge the accuracy of 
the methodology used and the conclusions, but from what is described the information is important 
and needs to be published. 
However, as the data are entirely summary of records collected based on the symptoms alone without 
any molecular conformation of the CPPV diagnostics the conclusions need to be more careful 
addressed. Indeed the symptoms described fit well those of CBPV, but do they entirely exclude other 
possibilities? Can we really claim CBPV infection without the clear diagnostics of the CBPV viral load by 
RTPCR and more so it's replication? This is especially relates to the sources of the inoculum and the 
modes of its spread. What do we know about the spread of the virus in these countries? Are there any 
variants of the virus that could help us to trace the source/s? Can the differences between large and 
amateur beekeepers come from the fact that the former provide pollination services, thus exposing 
the bees to various stress factors? 

As it is clear that the records of the past can't be validated by molecular methods I suggest the 
authors either confirm the presence of CBPV in the current samples or at least be very careful in their 
conclusions. I also suggest to refer to recent review about bee viruses by Grozinger & Flenniken in 
Annu. Rev. Entomol. 2019. 64:205–26. 
Some small technical comments are bellow: 
Fig 2 is not clear. This graph is not informative and somewhat confusing. The meaning of the 
distance's is not clear. In its legend line 102 remove second "cases". 
Fig 5 legend is not informative enough. How exactly the risk was assessed? 
L. 205 you list possible ways of transmission, what about the possibility of sexual transmission?