scholarly journals Direct transmission by injection affects competition among RNA viruses in honeybees

2019 ◽  
Vol 286 (1895) ◽  
pp. 20182452 ◽  
Author(s):  
Emily J. Remnant ◽  
Niklas Mather ◽  
Thomas L. Gillard ◽  
Boris Yagound ◽  
Madeleine Beekman
Keyword(s):  
Varroa Destructor ◽  
Rna Viruses ◽  
Direct Injection ◽  
Direct Transmission ◽  
Black Queen Cell Virus ◽  
Virus Inoculation ◽  
Deformed Wing Virus ◽  
Viral Virulence ◽  
Queen Cell ◽  
Mode Of Transmission

The arrival of the ectoparasitic mite Varroa destructor on the western honeybee Apis mellifera saw a change in the diversity and prevalence of honeybee RNA viruses. One virus in particular, deformed wing virus (DWV) has become closely associated with V. destructor , leading many to conclude that V. destructor has affected viral virulence by changing the mode of transmission. While DWV is normally transmitted via feeding and faeces, V. destructor transmits viruses by direct injection. This change could have resulted in higher viral prevalence causing increased damage to the bees. Here we test the effect of a change in the mode of transmission on the composition and levels of honeybee RNA viruses in the absence of V. destructor . We find a rapid increase in levels of two viruses, sacbrood virus (SBV) and black queen cell virus (BQCV) after direct injection of viral extracts into honeybee pupae. In pupae injected with high levels of DWV extracted from symptomatic adult bees, DWV levels rapidly decline in the presence of SBV and BQCV. Further, we observe high mortality in honeybee pupae when injected with SBV and BQCV, whereas injecting pupae with high levels of DWV results in near 100% survival. Our results suggest a different explanation for the observed association between V. destructor and DWV. Instead of V. destructor causing an increase in DWV virulence, we hypothesize that direct virus inoculation, such as that mediated by a vector, quickly eliminates the most virulent honeybee viruses resulting in an association with less virulent viruses such as DWV.

scholarly journals Vector-mediated viral transmission favours less virulent viruses

2018 ◽  
Author(s):  
Emily J. Remnant ◽  
Niklas Mather ◽  
Thomas L. Gillard ◽  
Boris Yagound ◽  
Madeleine Beekman
Keyword(s):  
Alternative Explanation ◽  
Rna Viruses ◽  
Black Queen Cell Virus ◽  
Viral Titre ◽  
Exact Role ◽  
Deformed Wing Virus ◽  
Route Of Transmission ◽  
Queen Cell ◽  
Mode Of Transmission ◽  
Honeybee Health

AbstractWhile it is well-established that the ectoparasitic mite Varroa destructor is largely responsible for the widely-reported decline of populations of the Western honeybee Apis mellifera, the exact role the mite plays in honeybee health remains unclear. The last few years have seen a surge in studies associating RNA viruses vectored by the mite with the death of honeybee colonies. Varroa facilitates the spread of RNA viruses because it feeds on developing bee brood and transfers haemolymph from bee-to-bee. Such a change in transmission, from horizontal and vertical to vector-based, is predicted to lead to an increase in virulence of RNA viruses, thus potentially providing an explanation for the observed association between Varroa and certain viruses. Here we document the effect of changing the route of transmission of honeybee viruses contained in the haemolymph of honeybee pupae. We find that a change in mode of transmission rapidly increases viral titres of two honeybee viruses, Sacbrood virus (SBV) and Black queen cell virus (BQCV). This increase in viral titre is accompanied by an increase in virulence. In contrast, the virus most often associated with Varroa, Deformed wing virus (DWV), shows a reduction in viral titre in the presence of SBV and BQCV. In addition, DWV does not cause mortality to honeybee pupae in isolation. Most likely a change in mode of transmission due to the arrival of a vector quickly eliminates the most virulent honeybee viruses resulting in an association between Varroa and less virulent viruses such as DWV. Our work therefore provides empirical evidence for an alternative explanation for the widely-observed association between Varroa and DWV.

scholarly journals Mode of Transmission Determines the Virulence of Black Queen Cell Virus in Adult Honey Bees, Posing a Future Threat to Bees and Apiculture

Viruses ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 535 ◽  
Author(s):  
Yahya Al Naggar ◽  
Robert J. Paxton
Keyword(s):  
Honey Bees ◽  
Horizontal Transmission ◽  
Well Being ◽  
Rnai Pathway ◽  
Viral Titer ◽  
Black Queen Cell Virus ◽  
Viral Pathogen ◽  
Viral Virulence ◽  
Queen Cell ◽  
Mode Of Transmission

Honey bees (Apis mellifera) can be infected by many viruses, some of which pose a major threat to their health and well-being. A critical step in the dynamics of a viral infection is its mode of transmission. Here, we compared for the first time the effect of mode of horizontal transmission of Black queen cell virus (BQCV), a ubiquitous and highly prevalent virus of A. mellifera, on viral virulence in individual adult honey bees. Hosts were exposed to BQCV either by feeding (representing direct transmission) or by injection into hemolymph (analogous to indirect or vector-mediated transmission) through a controlled laboratory experimental design. Mortality, viral titer and expression of three key innate immune-related genes were then quantified. Injecting BQCV directly into hemolymph in the hemocoel resulted in far higher mortality as well as increased viral titer and significant change in the expression of key components of the RNAi pathway compared to feeding honey bees BQCV. Our results support the hypothesis that mode of horizontal transmission determines BQCV virulence in honey bees. BQCV is currently considered a benign viral pathogen of adult honey bees, possibly because its mode of horizontal transmission is primarily direct, per os. We anticipate adverse health effects on honey bees if BQCV transmission becomes vector-mediated.

scholarly journals Presence and Prevalence of Viruses in Local and Migratory Honeybees (Apis mellifera) in Massachusetts

2009 ◽  
Vol 75 (24) ◽  
pp. 7862-7865 ◽  
Author(s):  
Anna Welch ◽  
Francis Drummond ◽  
Sunil Tewari ◽  
Anne Averill ◽  
John P. Burand
Keyword(s):  
Apis Mellifera ◽  
Black Queen Cell Virus ◽  
Deformed Wing Virus ◽  
Sacbrood Virus ◽  
Queen Cell ◽  
The Impact

ABSTRACT Migratory and local bees in Massachusetts were analyzed for seven viruses. Three were detected: black queen cell virus (BQCV), deformed wing virus (DWV), and sacbrood virus (SBV). DWV was most common, followed closely by BQCV and then by SBV. BQCV and SBV were present at significantly higher rates in the migratory bees assayed, bringing into question the impact that these bees have on the health of local bee populations.

scholarly journals The Pathogen Profile of a Honey Bee Queen Does Not Reflect That of Her Workers

Insects ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 382 ◽  
Author(s):  
Jessica L. Kevill ◽  
Katie Lee ◽  
Michael Goblirsch ◽  
Erin McDermott ◽  
David R. Tarpy ◽  
...  
Keyword(s):  
Honey Bee ◽  
Horizontal Transmission ◽  
Pathogen Transmission ◽  
Black Queen Cell Virus ◽  
Deformed Wing Virus ◽  
Israeli Acute Paralysis Virus ◽  
Queen Cell ◽  
Honey Bee Queen ◽  
Acute Bee Paralysis Virus ◽  
Paralysis Virus

Throughout a honey bee queen’s lifetime, she is tended to by her worker daughters, who feed and groom her. Such interactions provide possible horizontal transmission routes for pathogens from the workers to the queen, and as such a queen’s pathogen profile may be representative of the workers within a colony. To explore this further, we investigated known honey bee pathogen co-occurrence, as well as pathogen transmission from workers to queens. Queens from 42 colonies were removed from their source hives and exchanged into a second, unrelated foster colony. Worker samples were taken from the source colony on the day of queen exchange and the queens were collected 24 days after introduction. All samples were screened for Nosema spp., Trypanosome spp., acute bee paralysis virus (ABPV), black queen cell virus (BQCV), chronic bee paralysis virus (CBPV), Israeli acute paralysis virus (IAPV), Lake Sinai virus (LSV), and deformed wing virus master variants (DWV-A, B, and C) using RT-qPCR. The data show that LSV, Nosema, and DWV-B were the most abundant pathogens in colonies. All workers (n = 42) were LSV-positive, 88% were Nosema-positive, whilst pathogen loads were low (<1 × 106 genome equivalents per pooled worker sample). All queens (n = 39) were negative for both LSV and Nosema. We found no evidence of DWV transmission occurring from worker to queen when comparing queens to foster colonies, despite DWV being present in both queens and workers. Honey bee pathogen presence and diversity in queens cannot be revealed from screening workers, nor were pathogens successfully transmitted to the queen.

scholarly journals Phylogenetic analysis of black queen cell virus and deformed wing virus in honeybee colonies infected by mites in Van, Eastern Turkey

2018 ◽  
Vol 74 (1) ◽  
pp. 5990-2018 ◽  
Author(s):  
ZEYNEP KARAPINAR ◽  
BEKİR OĞUZ ◽  
ENDER DİNÇER ◽  
CİHAT ÖZTÜRK
Keyword(s):  
Phylogenetic Analysis ◽  
Analysis Data ◽  
Parasitic Infections ◽  
Black Queen Cell Virus ◽  
Deformed Wing Virus ◽  
Eastern Turkey ◽  
Geographical Regions ◽  
Queen Cell ◽  
Colony Loss ◽  
Paralysis Virus

This study aimed to determine the presence and prevalence of viral and parasitic infections causing high rates of colony loss in honey bee colonies in Van province, eastern Turkey. Twenty-six different apiaries were collected from five counties in Van province. These samples were tested by Reverse-Transcriptase PCR (RT-PCR) for acute bee paralysis virus (ABPV), chronic bee paralysis virus (CBPV), black queen cell virus (BQCV) and deformed wing virus (DWV). Selected positives were sequenced, phylogenetically analyzed and investigated in terms of Varroa. DWV and BQCV were identified in 69.23% (18/26) and 88.46% (23/26) of the bees respectively whereas ABPV and CBPV were not detected in the sampled apiaries. Results of the phylogenetic analysis of DWV and BQCV sequences showed 94–100% similarity to DWV and BQCV isolates obtained from Genbank. Prevalence of varroasis was 89% (23/26) in Van. The obtained samples were identified as V. Varroa destructor by morphological investigation. The study showed that viral and parasitic agents commonly infect honeybees in Van province, with high prevalence rates for BQCV and DWV. There was also a high degree of conservation of DWV and BQCV sequences distinct from DWV and BQCV isolates from other geographical regions. These findings, including current prevalence and phylogenetic analysis data for DWV, BQCV and varroazis in honeybees, are useful for future studies. .

scholarly journals Virus Status, Varroa Levels, and Survival of 20 Managed Honey Bee Colonies Monitored in Luxembourg Between the Summer of 2011 and the Spring of 2013

2015 ◽  
Vol 59 (1) ◽  
pp. 59-73 ◽  
Author(s):  
Antoine Clermont ◽  
Matias Pasquali ◽  
Michael Eickermann ◽  
François Kraus ◽  
Lucien Hoffmann ◽  
...  
Keyword(s):  
Honey Bee ◽  
Varroa Destructor ◽  
Principal Component ◽  
Deformed Wing Virus ◽  
Sacbrood Virus ◽  
Queen Cell ◽  
Varroa Mites ◽  
Kashmir Bee Virus ◽  
Bee Colonies ◽  
Paralysis Virus

Abstract Twenty managed honey bee colonies, split between 5 apiaries with 4 hives each, were monitored between the summer of 2011 and spring of 2013. Living bees were sampled in July 2011, July 2012, and August 2012. Twenty-five, medium-aged bees, free of varroa mites, were pooled per colony and date, to form one sample. Unlike in France and Belgium, Chronic Bee Paralysis Virus (CBPV) has not been found in Luxembourg. Slow Bee Paralysis Virus (SBPV) and Israeli Acute Paralysis Virus (IAPV) levels were below detection limits. Traces of Kashmir Bee Virus (KBV) were amplified. Black Queen Cell Virus (BQCV), Varroa destructor Virus-1 (VDV-1), and SacBrood Virus (SBV) were detected in all samples and are reported from Luxembourg for the first time. Varroa destructor Macula- Like Virus (VdMLV), Deformed Wing Virus (DWV), and Acute Bee Paralysis Virus (ABPV) were detected at all locations, and in most but not all samples. There was a significant increase in VDV-1 and DWV levels within the observation period. A principal component analysis was unable to separate the bees of colonies that survived the following winter from bees that died, based on their virus contents in summer. The number of dead varroa mites found below colonies was elevated in colonies that died in the following winter. Significant positive relationships were found between the log-transformed virus levels of the bees and the log-transformed number of mites found below the colonies per week, for VDV-1 and DWV. Sacbrood virus levels were independent of varroa levels, suggesting a neutral or competitive relationship between this virus and varroa.

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