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Woodford L, Steketee PC, Evans DJ. Doomed drones? Using passage experiments and mathematical modelling to determine Deformed wing virus population dynamics in male honeybees. Proc Biol Sci 2023; 290:20231010. [PMID: 37339741 PMCID: PMC10281807 DOI: 10.1098/rspb.2023.1010] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 05/25/2023] [Indexed: 06/22/2023] Open
Abstract
Varroa destructor is an ectoparasitic mite of honeybees which vectors a range of pathogenic viruses, the most notable being Deformed wing virus (DWV). Mites parasitise bees during pupal development and male honeybees, drones, have a longer development cycle than female workers (24 versus 21 days), allow for more progeny mites to develop per foundress (1.6-2.5 compared to 0.7-1.45). How this longer exposure time influences evolution of the transmitted virus population is unknown. Using uniquely tagged viruses recovered from cDNA we investigated the replication, competition and morbidity of DWV genotypes in drones. Assays examining virus replication and morbidity revealed drones are highly susceptible to both predominant genotypes of DWV. In virus passage studies using an equimolar inocula of major DNA genotypes and their recombinants, the recombinant form dominated but did not reach 100% of the virus population within 10 passages. Using an in-silico model of the virus-mite-bee system we examined bottlenecks during virus acquisition by the mite and subsequent injection of viruses into the host, which may play a significant role in shaping virus diversity. This study furthers our understanding of the variables influencing DWV diversity changes and provides insight into areas of future research in the mite-virus-bee system.
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Affiliation(s)
- Luke Woodford
- Department of Biology, University of St. Andrews, Biomedical Sciences Research Complex, St. Andrews, None KY16 9ST, UK
| | - Pieter C. Steketee
- The Roslin Institute, Easter Bush Campus, Midlothian, Edinburgh, EH25 9RG, UK
| | - David J. Evans
- Department of Biology, University of St. Andrews, Biomedical Sciences Research Complex, St. Andrews, None KY16 9ST, UK
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2
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Eliash N, Suenaga M, Mikheyev AS. Vector-virus interaction affects viral loads and co-occurrence. BMC Biol 2022; 20:284. [PMID: 36527054 PMCID: PMC9758805 DOI: 10.1186/s12915-022-01463-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 11/10/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Vector-borne viral diseases threaten human and wildlife worldwide. Vectors are often viewed as a passive syringe injecting the virus. However, to survive, replicate and spread, viruses must manipulate vector biology. While most vector-borne viral research focuses on vectors transmitting a single virus, in reality, vectors often carry diverse viruses. Yet how viruses affect the vectors remains poorly understood. Here, we focused on the varroa mite (Varroa destructor), an emergent parasite that can carry over 20 honey bee viruses, and has been responsible for colony collapses worldwide, as well as changes in global viral populations. Co-evolution of the varroa and the viral community makes it possible to investigate whether viruses affect vector gene expression and whether these interactions affect viral epidemiology. RESULTS Using a large set of available varroa transcriptomes, we identified how abundances of individual viruses affect the vector's transcriptional network. We found no evidence of competition between viruses, but rather that some virus abundances are positively correlated. Furthermore, viruses that are found together interact with the vector's gene co-expression modules in similar ways, suggesting that interactions with the vector affect viral epidemiology. We experimentally validated this observation by silencing candidate genes using RNAi and found that the reduction in varroa gene expression was accompanied by a change in viral load. CONCLUSIONS Combined, the meta-transcriptomic analysis and experimental results shed light on the mechanism by which viruses interact with each other and with their vector to shape the disease course.
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Affiliation(s)
- Nurit Eliash
- grid.18098.380000 0004 1937 0562Shamir Research Institute, University of Haifa, Katzrin, Israel ,grid.250464.10000 0000 9805 2626Okinawa Institute of Science and Technology, 1919-1 Tancha Onna-son, Okinawa, 904-0495 Japan
| | - Miyuki Suenaga
- grid.250464.10000 0000 9805 2626Okinawa Institute of Science and Technology, 1919-1 Tancha Onna-son, Okinawa, 904-0495 Japan
| | - Alexander S. Mikheyev
- grid.250464.10000 0000 9805 2626Okinawa Institute of Science and Technology, 1919-1 Tancha Onna-son, Okinawa, 904-0495 Japan ,grid.1001.00000 0001 2180 7477Australian National University, Canberra, ACT, 2600 Australia
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3
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Virus Prevalence in Egg Samples Collected from Naturally Selected and Traditionally Managed Honey Bee Colonies across Europe. Viruses 2022; 14:v14112442. [PMID: 36366540 PMCID: PMC9692946 DOI: 10.3390/v14112442] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 10/29/2022] [Accepted: 11/02/2022] [Indexed: 11/06/2022] Open
Abstract
Monitoring virus infections can be an important selection tool in honey bee breeding. A recent study pointed towards an association between the virus-free status of eggs and an increased virus resistance to deformed wing virus (DWV) at the colony level. In this study, eggs from both naturally surviving and traditionally managed colonies from across Europe were screened for the prevalence of different viruses. Screenings were performed using the phenotyping protocol of the 'suppressed in ovo virus infection' trait but with qPCR instead of end-point PCR and a primer set that covers all DWV genotypes. Of the 213 screened samples, 109 were infected with DWV, 54 were infected with black queen cell virus (BQCV), 3 were infected with the sacbrood virus, and 2 were infected with the acute bee paralyses virus. It was demonstrated that incidences of the vertical transmission of DWV were more frequent in naturally surviving than in traditionally managed colonies, although the virus loads in the eggs remained the same. When comparing virus infections with queen age, older queens showed significantly lower infection loads of DWV in both traditionally managed and naturally surviving colonies, as well as reduced DWV infection frequencies in traditionally managed colonies. We determined that the detection frequencies of DWV and BQCV in honey bee eggs were lower in samples obtained in the spring than in those collected in the summer, indicating that vertical transmission may be lower in spring. Together, these patterns in vertical transmission show that honey bee queens have the potential to reduce the degree of vertical transmission over time.
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4
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Transmission of deformed wing virus between Varroa destructor foundresses, mite offspring and infested honey bees. Parasit Vectors 2022; 15:333. [PMID: 36151583 PMCID: PMC9502634 DOI: 10.1186/s13071-022-05463-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 08/22/2022] [Indexed: 11/16/2022] Open
Abstract
Background Varroa destructor is the major ectoparasite of the western honey bee (Apis mellifera). Through both its parasitic life-cycle and its role as a vector of viral pathogens, it can cause major damage to honey bee colonies. The deformed wing virus (DWV) is the most common virus transmitted by this ectoparasite, and the mite is correlated to increased viral prevalence and viral loads in infested colonies. DWV variants A and B (DWV-A and DWV-B, respectively) are the two major DWV variants, and they differ both in their virulence and transmission dynamics. Methods We studied the transmission of DWV between bees, parasitic mites and their offspring by quantifying DWV loads in bees and mites collected in in vitro and in situ environments. In vitro, we artificially transmitted DWV-A to mites and quantified both DWV-A and DWV-B in mites and bees. In situ, we measured the natural presence of DWV-B in bees, mites and mites’ offspring. Results Bee and mite viral loads were correlated, and mites carrying both variants were associated with higher mortality of the infected host. Mite infestation increased the DWV-B loads and decreased the DWV-A loads in our laboratory conditions. In situ, viral quantification in the mite offspring showed that, after an initially non-infected egg stage, the DWV-B loads were more closely correlated with the foundress (mother) mites than with the bee hosts. Conclusions The association between mites and DWV-B was highlighted in this study. The parasitic history of a mite directly impacts its DWV infection potential during the rest of its life-cycle (in terms of variant and viral loads). Regarding the mite’s progeny, we hypothesize that the route of contamination is likely through the feeding site rather than by vertical transmission, although further studies are needed to confirm this hypothesis. Graphical Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-022-05463-9.
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5
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Penn HJ, Simone-Finstrom MD, Chen Y, Healy KB. Honey Bee Genetic Stock Determines Deformed Wing Virus Symptom Severity but not Viral Load or Dissemination Following Pupal Exposure. Front Genet 2022; 13:909392. [PMID: 35719388 PMCID: PMC9204523 DOI: 10.3389/fgene.2022.909392] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 04/22/2022] [Indexed: 12/15/2022] Open
Abstract
Honey bees exposed to Varroa mites incur substantial physical damage in addition to potential exposure to vectored viruses such as Deformed wing virus (DWV) that exists as three master variants (DWV-A, DWV-B, and DWV-C) and recombinants. Although mite-resistant bees have been primarily bred to mitigate the impacts of Varroa mites, mite resistance may be associated with increased tolerance or resistance to the vectored viruses. The goal of our study is to determine if five honey bee stocks (Carniolan, Italian, Pol-Line, Russian, and Saskatraz) differ in their resistance or tolerance to DWV based on prior breeding for mite resistance. We injected white-eyed pupae with a sublethal dose (105) of DWV or exposed them to mites and then evaluated DWV levels and dissemination and morphological symptoms upon adult emergence. While we found no evidence of DWV resistance across stocks (i.e., similar rates of viral replication and dissemination), we observed that some stocks exhibited reduced symptom severity suggestive of differential tolerance. However, DWV tolerance was not consistent across mite-resistant stocks as Russian bees were most tolerant, while Pol-Line exhibited the most severe symptoms. DWV variants A and B exhibited differential dissemination patterns that interacted significantly with the treatment group but not bee stock. Furthermore, elevated DWV-B levels reduced adult emergence time, while both DWV variants were associated with symptom likelihood and severity. These data indicate that the genetic differences underlying bee resistance to Varroa mites are not necessarily correlated with DWV tolerance and may interact differentially with DWV variants, highlighting the need for further work on mechanisms of tolerance and bee stock–specific physiological interactions with pathogen variants.
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Affiliation(s)
- Hannah J. Penn
- United States Department of Agriculture, Agricultural Research Service, Sugarcane Research Unit, Houma, LA, United States
- *Correspondence: Hannah J. Penn, ; Michael D. Simone-Finstrom,
| | - Michael D. Simone-Finstrom
- United States Department of Agriculture, Agricultural Research Service, Honey Bee Breeding, Genetics and Physiology Research Unit, Baton Rouge, LA, United States
- *Correspondence: Hannah J. Penn, ; Michael D. Simone-Finstrom,
| | - Yanping Chen
- United States Department of Agriculture, Agricultural Research Service, Bee Research Laboratory, Beltsville, MD, United States
| | - Kristen B. Healy
- Department of Entomology, Louisiana State University and AgCenter, Baton Rouge, LA, United States
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6
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de Miranda JR, Brettell LE, Chejanovsky N, Childers AK, Dalmon A, Deboutte W, de Graaf DC, Doublet V, Gebremedhn H, Genersch E, Gisder S, Granberg F, Haddad NJ, Kaden R, Manley R, Matthijnssens J, Meeus I, Migdadi H, Milbrath MO, Mondet F, Remnant EJ, Roberts JMK, Ryabov EV, Sela N, Smagghe G, Somanathan H, Wilfert L, Wright ON, Martin SJ, Ball BV. Cold case: The disappearance of Egypt bee virus, a fourth distinct master strain of deformed wing virus linked to honeybee mortality in 1970's Egypt. Virol J 2022; 19:12. [PMID: 35033134 PMCID: PMC8760790 DOI: 10.1186/s12985-022-01740-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 12/31/2021] [Indexed: 01/11/2023] Open
Abstract
In 1977, a sample of diseased adult honeybees (Apis mellifera) from Egypt was found to contain large amounts of a previously unknown virus, Egypt bee virus, which was subsequently shown to be serologically related to deformed wing virus (DWV). By sequencing the original isolate, we demonstrate that Egypt bee virus is in fact a fourth unique, major variant of DWV (DWV-D): more closely related to DWV-C than to either DWV-A or DWV-B. DWV-A and DWV-B are the most common DWV variants worldwide due to their close relationship and transmission by Varroa destructor. However, we could not find any trace of DWV-D in several hundred RNA sequencing libraries from a worldwide selection of honeybee, varroa and bumblebee samples. This means that DWV-D has either become extinct, been replaced by other DWV variants better adapted to varroa-mediated transmission, or persists only in a narrow geographic or host range, isolated from common bee and beekeeping trade routes.
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Affiliation(s)
- Joachim R de Miranda
- Department of Ecology, Swedish University of Agricultural Sciences, 750-07, Uppsala, Sweden.
| | - Laura E Brettell
- Hawkesbury Institute for the Environment, Western Sydney University, Locked Bag 1797, Renrith, NSW, 2751, Australia.,School of Environment and Life Sciences, University of Salford, Manchester, M5 4WT, UK.,Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, L3 5QA, UK
| | - Nor Chejanovsky
- Institute of Plant Protection, The Volcani Center, PO Box 15159, 7528809, Rishon Lezion, Israel
| | - Anna K Childers
- Bee Research Laboratory, Beltsville Agricultural Research Center, USDA, Beltsville, MD, 20705, USA
| | - Anne Dalmon
- Abeilles et Environnement, INRAE, 84914, Avignon, France
| | - Ward Deboutte
- Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory for Clinical and Epidemiological Virology, University of Leuven, 3000, Leuven, Belgium.,Max Planck Institute of Immunobiology and Epigenetics, Stübeweg 51, 79108, Freiburg, Germany
| | - Dirk C de Graaf
- Laboratory of Molecular Entomology and Bee Pathology, Ghent University, 9000, Ghent, Belgium
| | - Vincent Doublet
- College of Life and Environmental Sciences, University of Exeter, Penryn, TR10 9FE, UK.,Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Haftom Gebremedhn
- Laboratory of Molecular Entomology and Bee Pathology, Ghent University, 9000, Ghent, Belgium.,Tigray Agricultural Research Institute, P.O. Box 492, Mekelle, Ethiopia
| | - Elke Genersch
- Institut Für Mikrobiologie Und Tierseuchen, Fachbereich Veterinärmedizin, Freie Universität Berlin, Berlin, Germany.,Department of Molecular Microbiology and Bee Diseases, Institute for Bee Research, Hohen Neuendorf, Germany
| | - Sebastian Gisder
- Department of Molecular Microbiology and Bee Diseases, Institute for Bee Research, Hohen Neuendorf, Germany
| | - Fredrik Granberg
- Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, 750-07, Uppsala, Sweden
| | - Nizar J Haddad
- Bee Research Department, National Agricultural Research Center, Baq'a, Jordan
| | - Rene Kaden
- Department of Ecology, Swedish University of Agricultural Sciences, 750-07, Uppsala, Sweden.,Clinical Microbiology, Department of Medical Sciences, Uppsala University, 753 09, Uppsala, Sweden
| | - Robyn Manley
- College of Life and Environmental Sciences, University of Exeter, Penryn, TR10 9FE, UK
| | - Jelle Matthijnssens
- Department of Microbiology, Immunology and Transplantation, Rega Institute, Laboratory for Clinical and Epidemiological Virology, University of Leuven, 3000, Leuven, Belgium
| | - Ivan Meeus
- Laboratory of Agrozoology, Department of Plants and Crops, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Hussein Migdadi
- Bee Research Department, National Agricultural Research Center, Baq'a, Jordan
| | - Meghan O Milbrath
- Department of Ecology, Swedish University of Agricultural Sciences, 750-07, Uppsala, Sweden
| | - Fanny Mondet
- Abeilles et Environnement, INRAE, 84914, Avignon, France
| | - Emily J Remnant
- Behaviour, Ecology and Evolution (BEE) Lab, School of Life and Environmental Sciences, The University of Sydney, Camperdown, 2006, Australia
| | - John M K Roberts
- Commonwealth Scientific and Industrial Research Organisation, Canberra, 2601, Australia
| | - Eugene V Ryabov
- Bee Research Laboratory, Beltsville Agricultural Research Center, USDA, Beltsville, MD, 20705, USA
| | - Noa Sela
- Institute of Plant Protection, The Volcani Center, PO Box 15159, 7528809, Rishon Lezion, Israel
| | - Guy Smagghe
- Laboratory of Agrozoology, Department of Plants and Crops, Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Hema Somanathan
- School of Biology, Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala, 695551, India
| | - Lena Wilfert
- College of Life and Environmental Sciences, University of Exeter, Penryn, TR10 9FE, UK.,Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Owen N Wright
- Centre for Research in Animal Behaviour, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QG, UK
| | - Stephen J Martin
- School of Environment and Life Sciences, University of Salford, Manchester, M5 4WT, UK.,Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Brenda V Ball
- Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
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7
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Ray AM, Davis SL, Rasgon JL, Grozinger CM. Simulated vector transmission differentially influences dynamics of two viral variants of deformed wing virus in honey bees ( Apis mellifera). J Gen Virol 2021; 102. [PMID: 34816791 PMCID: PMC8742989 DOI: 10.1099/jgv.0.001687] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Understanding how vectors alter the interactions between viruses and their hosts is a fundamental question in virology and disease ecology. In honey bees, transmission of deformed wing virus (DWV) by parasitic Varroa mites has been associated with elevated disease and host mortality, and Varroa transmission has been hypothesized to lead to increased viral titres or select for more virulent variants. Here, we mimicked Varroa transmission by serially passaging a mixed population of two DWV variants, A and B, by injection through in vitro reared honey bee pupae and tracking these viral populations through five passages. The DWV-A and DWV-B variant proportions shifted dynamically through passaging, with DWV-B outcompeting DWV-A after one passage, but levels of both variants becoming equivalent by Passage 5. Sequencing analysis revealed a dominant, recombinant DWV-B strain (DWV-A derived 5′ IRES region with the rest of the genome DWV-B), with low nucleotide diversity that decreased through passaging. DWV-A populations had higher nucleotide diversity compared to DWV-B, but this also decreased through passaging. Selection signatures were found across functional regions of the DWV-A and DWV-B genomes, including amino acid mutations in the putative capsid protein region. Simulated vector transmission differentially impacted two closely related viral variants which could influence viral interactions with the host, demonstrating surprising plasticity in vector-host-viral dynamics.
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Affiliation(s)
- Allyson M Ray
- Molecular, Cellular, and Integrative Biosciences Graduate Program, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA.,Department of Entomology, Center for Infectious Disease Dynamics, Center for Pollinator Research, Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Sheldon L Davis
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, USA
| | - Jason L Rasgon
- Molecular, Cellular, and Integrative Biosciences Graduate Program, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA.,Department of Entomology, Center for Infectious Disease Dynamics, Center for Pollinator Research, Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Christina M Grozinger
- Molecular, Cellular, and Integrative Biosciences Graduate Program, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA.,Department of Entomology, Center for Infectious Disease Dynamics, Center for Pollinator Research, Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA, USA
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8
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Norton AM, Remnant EJ, Tom J, Buchmann G, Blacquiere T, Beekman M. Adaptation to vector-based transmission in a honeybee virus. J Anim Ecol 2021; 90:2254-2267. [PMID: 33844844 DOI: 10.1111/1365-2656.13493] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 04/06/2021] [Indexed: 11/27/2022]
Abstract
Global pollinator declines as a result of emerging infectious diseases are of major concern. Managed honeybees Apis mellifera are susceptible to numerous parasites and pathogens, many of which appear to be transmissible to sympatric non-Apis taxa. The ectoparasitic mite Varroa destructor is considered to be the most significant threat to honeybees due to its role in vectoring RNA viruses, particularly Deformed wing virus (DWV). Vector transmission of DWV has resulted in the accumulation of high viral loads in honeybees and is often associated with colony death. DWV has two main genotypes, A and B. DWV-A was more prevalent during the initial phase of V. destructor establishment. In recent years, the global prevalence of DWV-B has increased, suggesting that DWV-B is better adapted to vector transmission than DWV-A. We aimed to determine the role vector transmission plays in DWV genotype prevalence at a colony level. We experimentally increased or decreased the number of V. destructor mites in honeybee colonies, and tracked DWV-A and DWV-B loads over a period of 10 months. Our results show that the two DWV genotypes differ in their response to mite numbers. DWV-A accumulation in honeybees was positively correlated with mite numbers yet DWV-A was largely undetected in the absence of the mite. In contrast, colonies had high loads of DWV-B even when mite numbers were low. DWV-B loads persisted in miticide-treated colonies, indicating that this genotype has a competitive advantage over DWV-A irrespective of mite numbers. Our findings suggest that the global increase in DWV-B prevalence is not driven by selective pressure by the vector. Rather, DWV-B is able to persist in colonies at higher viral loads relative to DWV-A in the presence and absence of V. destructor. The interplay between V. destructor and DWV genotypes within honeybee colonies may have broad consequences upon viral diversity in sympatric taxa as a result of spillover.
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Affiliation(s)
- Amanda M Norton
- Behaviour, Ecology and Evolution (BEE) Laboratory, School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Emily J Remnant
- Behaviour, Ecology and Evolution (BEE) Laboratory, School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Jolanda Tom
- Wageningen University and Research, Wageningen, The Netherlands
| | - Gabriele Buchmann
- Behaviour, Ecology and Evolution (BEE) Laboratory, School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
| | | | - Madeleine Beekman
- Behaviour, Ecology and Evolution (BEE) Laboratory, School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia.,Wissenschaftskolleg zu Berlin, Berlin, Germany
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9
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Virus Prospecting in Crickets-Discovery and Strain Divergence of a Novel Iflavirus in Wild and Cultivated Acheta domesticus. Viruses 2021; 13:v13030364. [PMID: 33669085 PMCID: PMC7996529 DOI: 10.3390/v13030364] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/18/2021] [Accepted: 02/22/2021] [Indexed: 12/19/2022] Open
Abstract
Orthopteran insects have high reproductive rates leading to boom-bust population dynamics with high local densities that are ideal for short, episodic disease epidemics. Viruses are particularly well suited for such host population dynamics, due to their supreme ability to adapt to changing transmission criteria. However, very little is known about the viruses of Orthopteran insects. Since Orthopterans are increasingly reared commercially, for animal feed and human consumption, there is a risk that viruses naturally associated with these insects can adapt to commercial rearing conditions, and cause disease. We therefore explored the virome of the house cricket Acheta domesticus, which is both part of the natural Swedish landscape and reared commercially for the pet feed market. Only 1% of the faecal RNA and DNA from wild-caught A. domesticus consisted of viruses. These included both known and novel viruses associated with crickets/insects, their bacterial-fungal microbiome, or their plant food. Relatively abundant among these viral Operational Taxonomic Units (OTUs) was a novel Iflavirus, tentatively named Acheta domesticus Iflavirus (AdIV). Quantitative analyses showed that AdIV was also abundant in frass and insect samples from commercially reared crickets. Interestingly, the wild and commercial AdIV strains had short, extremely divergent variation hotspots throughout the genome, which may indicate specific adaptation to their hosts’ distinct rearing environments.
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10
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Woodford L, Evans DJ. Deformed wing virus: using reverse genetics to tackle unanswered questions about the most important viral pathogen of honey bees. FEMS Microbiol Rev 2020; 45:6035241. [PMID: 33320949 DOI: 10.1093/femsre/fuaa070] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 12/11/2020] [Indexed: 12/31/2022] Open
Abstract
Deformed wing virus (DWV) is the most important viral pathogen of honey bees. It usually causes asymptomatic infections but, when vectored by the ectoparasitic mite Varroa destructor, it is responsible for the majority of overwintering colony losses globally. Although DWV was discovered four decades ago, research has been hampered by the absence of an in vitro cell culture system or the ability to culture pure stocks of the virus. The recent developments of reverse genetic systems for DWV go some way to addressing these limitations. They will allow the investigation of specific questions about strain variation, host tropism and pathogenesis to be answered, and are already being exploited to study tissue tropism and replication in Varroa and non-Apis pollinators. Three areas neatly illustrate the advances possible with reverse genetic approaches: (i) strain variation and recombination, in which reverse genetics has highlighted similarities rather than differences between virus strains; (ii) analysis of replication kinetics in both honey bees and Varroa, in studies that likely explain the near clonality of virus populations often reported; and (iii) pathogen spillover to non-Apis pollinators, using genetically tagged viruses to accurately monitor replication and infection.
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Affiliation(s)
- Luke Woodford
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews, KY16 9ST, UK
| | - David J Evans
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews, KY16 9ST, UK
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11
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OneHealth implications of infectious diseases of wild and managed bees. J Invertebr Pathol 2020; 186:107506. [PMID: 33249062 DOI: 10.1016/j.jip.2020.107506] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 10/27/2020] [Accepted: 11/20/2020] [Indexed: 01/23/2023]
Abstract
The OneHealth approach aims to further our understanding of the drivers of human, animal and environmental health, and, ultimately, to improve them by combining approaches and knowledge from medicine, biology and fields beyond. Wild and managed bees are essential pollinators of crops and wild flowers. Their health thus directly impacts on human and environmental health. At the same time, these bee species represent highly amenable and relevant model organisms for a OneHealth approach that aims to study fundamental epidemiological questions. In this review, we focus on how infectious diseases of wild and managed bees can be used as a OneHealth model system, informing fundamental questions on ecological immunology and disease transmission, while addressing how this knowledge can be used to tackle the issues facing pollinator health.
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Yañez O, Piot N, Dalmon A, de Miranda JR, Chantawannakul P, Panziera D, Amiri E, Smagghe G, Schroeder D, Chejanovsky N. Bee Viruses: Routes of Infection in Hymenoptera. Front Microbiol 2020; 11:943. [PMID: 32547504 PMCID: PMC7270585 DOI: 10.3389/fmicb.2020.00943] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Accepted: 04/20/2020] [Indexed: 11/13/2022] Open
Abstract
Numerous studies have recently reported on the discovery of bee viruses in different arthropod species and their possible transmission routes, vastly increasing our understanding of these viruses and their distribution. Here, we review the current literature on the recent advances in understanding the transmission of viruses, both on the presence of bee viruses in Apis and non-Apis bee species and on the discovery of previously unknown bee viruses. The natural transmission of bee viruses will be discussed among different bee species and other insects. Finally, the research potential of in vivo (host organisms) and in vitro (cell lines) serial passages of bee viruses is discussed, from the perspective of the host-virus landscape changes and potential transmission routes for emerging bee virus infections.
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Affiliation(s)
- Orlando Yañez
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Agroscope, Swiss Bee Research Centre, Bern, Switzerland
| | - Niels Piot
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Anne Dalmon
- INRAE, Unité de Recherche Abeilles et Environnement, Avignon, France
| | | | - Panuwan Chantawannakul
- Environmental Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
- Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
| | - Delphine Panziera
- General Zoology, Institute for Biology, Martin-Luther-University of Halle-Wittenberg, Halle (Saale), Germany
- Halle-Jena-Leipzig, German Centre for Integrative Biodiversity Research (iDiv), Leipzig, Germany
| | - Esmaeil Amiri
- Department of Biology, University of North Carolina at Greensboro, Greensboro, NC, United States
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, NC, United States
| | - Guy Smagghe
- Laboratory of Agrozoology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Declan Schroeder
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN, United States
- School of Biological Sciences, University of Reading, Reading, United Kingdom
| | - Nor Chejanovsky
- Entomology Department, Institute of Plant Protection, The Volcani Center, Rishon LeZion, Israel
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Roberts JMK, Simbiken N, Dale C, Armstrong J, Anderson DL. Tolerance of Honey Bees to Varroa Mite in the Absence of Deformed Wing Virus. Viruses 2020; 12:E575. [PMID: 32456246 PMCID: PMC7290856 DOI: 10.3390/v12050575] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 12/31/2022] Open
Abstract
The global spread of the parasitic mite Varroa destructor has emphasized the significance of viruses as pathogens of honey bee (Apis mellifera) populations. In particular, the association of deformed wing virus (DWV) with V. destructor and its devastating effect on honey bee colonies has led to that virus now becoming one of the most well-studied insect viruses. However, there has been no opportunity to examine the effects of Varroa mites without the influence of DWV. In Papua New Guinea (PNG), the sister species, V. jacobsoni, has emerged through a host-shift to reproduce on the local A. mellifera population. After initial colony losses, beekeepers have maintained colonies without chemicals for more than a decade, suggesting that this bee population has an unknown mite tolerance mechanism. Using high throughput sequencing (HTS) and target PCR detection, we investigated whether the viral landscape of the PNG honey bee population is the underlying factor responsible for mite tolerance. We found A. mellifera and A. cerana from PNG and nearby Solomon Islands were predominantly infected by sacbrood virus (SBV), black queen cell virus (BQCV) and Lake Sinai viruses (LSV), with no evidence for any DWV strains. V. jacobsoni was infected by several viral homologs to recently discovered V. destructor viruses, but Varroa jacobsoni rhabdovirus-1 (ARV-1 homolog) was the only virus detected in both mites and honey bees. We conclude from these findings that A. mellifera in PNG may tolerate V. jacobsoni because the damage from parasitism is significantly reduced without DWV. This study also provides further evidence that DWV does not exist as a covert infection in all honey bee populations, and remaining free of this serious viral pathogen can have important implications for bee health outcomes in the face of Varroa.
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Affiliation(s)
- John M. K. Roberts
- Commonwealth Scientific and Industrial Research Organisation, Canberra 2601, Australia;
| | - Nelson Simbiken
- Coffee Industry Corporation Ltd., Goroka 441, Papua New Guinea;
| | - Chris Dale
- Department of Agriculture, Water and the Environment, Canberra 2601, Australia;
| | - Joel Armstrong
- Commonwealth Scientific and Industrial Research Organisation, Canberra 2601, Australia;
| | - Denis L. Anderson
- Research and Development Division, Abu Dhabi Agriculture & Food Safety Authority, Al Ain, UAE;
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Harwood GP, Dolezal AG. Pesticide-Virus Interactions in Honey Bees: Challenges and Opportunities for Understanding Drivers of Bee Declines. Viruses 2020; 12:E566. [PMID: 32455815 PMCID: PMC7291294 DOI: 10.3390/v12050566] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 02/07/2023] Open
Abstract
Honey bees are key agricultural pollinators, but beekeepers continually suffer high annual colony losses owing to a number of environmental stressors, including inadequate nutrition, pressures from parasites and pathogens, and exposure to a wide variety of pesticides. In this review, we examine how two such stressors, pesticides and viruses, may interact in additive or synergistic ways to affect honey bee health. Despite what appears to be a straightforward comparison, there is a dearth of studies examining this issue likely owing to the complexity of such interactions. Such complexities include the wide array of pesticide chemical classes with different modes of actions, the coupling of many bee viruses with ectoparasitic Varroa mites, and the intricate social structure of honey bee colonies. Together, these issues pose a challenge to researchers examining the effects pesticide-virus interactions at both the individual and colony level.
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Affiliation(s)
- Gyan P. Harwood
- Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA;
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