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Bombus terrestris workers with crippled (A) and normal (B) wings. Individual A shows yellow and white patches of anomalous pigmentation.
Source publication
The deformed wing virus (DWV) is one of the most common honey bee pathogens. The virus may also be detected in other insect species, including Bombus terrestris adults from wild and managed colonies. In this study, individuals of all stages, castes, and sexes were sampled from three commercial colonies exhibiting the presence of deformed workers an...
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... colonies had arrived from the breeding company with food supplies that were integrated onsite with frozen pollen from local honey bee colonies. On 17 January 2021, a routine check allowed for the detection in one of the colonies of one worker with crippled wings (Figure 1). As this observation was compatible with a DWV infection, a sampling plan created to collect and analyse all kinds of individuals present in the colonies. ...
Citations
... DWV) (e.g.Fürst et al., 2014;Cilia et al., 2021), Vairimorpha ceranae(Graystock et al., 2013), black queen cell virus (BQCV)(Tlak Gajger et al., 2021), and Israeli acute paralysis virus (IAPV)(Jones et al., 2021) among others.Doublet et al. (2024) found that IAPV only found at very low levels, also in the Nordic countries, and that the virus load does not increase in response to Varroa destructor infestation. IAPV is highly pathogenic in laboratory experiments, but does not seem to be of any importance in the Nordic countries and several other countries around the globe, as for now. ...
... Most tests have already been applied in ecological studies and diagnostic screenings [4,9,25,[43][44][45][46][47][48]. For the DWV virus, the analysis of published genome sequences suggested that PCR/qPCR detection of the virus can be unreliable since variant detection depends on the choice of appropriate oligonucleotide primers [24]. ...
Verifying the inclusivity of molecular detection methods gives indications about the reliability of viral infection diagnosis because of the tendency of viral pathogens to undergo sequence variation. This study was aimed at selecting inclusive probes based on reverse transcription–quantitative PCR (RT-qPCR) assays for the diagnosis of the most widespread and detrimental viruses infecting honeybees, namely the acute bee paralysis virus (ABPV), the black queen cell virus (BQCV), the chronic paralysis bee virus (CBPV), the deformed wing virus variants A (DWVA) and B (DWVB), and the sacbrood virus (SBV). Therefore, previously described detection methods were re-evaluated in silico for their specificity and inclusivity. Based on this evaluation, selected methods were modified, or new ones were designed and tested in duplex RT-qPCR reactions. The limits of detection (LODs), effect of multiplexing on sensitivity and the viral RNA quantification potential in bees and hive debris were assessed. This study made available diagnostic assays able to detect an increased number of virus variants compared with previously described tests and two viral pathogens in a single PCR reaction.
... Most tests were already applied in ecological studies and diagnostic screenings [4,9,25,[43][44][45][46][47][48]. ...
Verification of inclusivity of molecular detection methods gives indications on the reliability of viral infections diagnosis because of the tendency of viral pathogens to undergo sequence variation. This study was aimed to select inclusive probe based reverse transcription quantitative PCR (RT-qPCR) assays for the diagnosis of the most widespread and detrimental viruses infecting honeybees, namely the acute bee paralysis virus (ABPV), the black queen cell virus (BQCV), the chronic paralysis bee virus (CBPV), the deformed wing virus variants A (DWVA) and B (DWVB), and the sacbrood virus (SBV). Therefore, detection methods previously described were re-evaluated in silico for specificity and inclusivity. Based on this evaluation, selected methods were modified or new ones were designed and tested in duplex RT-qPCR reactions. The limits of detection (LODs), effect of multiplexing on sensitivity and viral RNA quantification potential in bees and hive debris were assessed. This study made available diagnostic assays able to detect an increased number of virus variants compared to previously described tests and two viral pathogens in a single PCR reaction.
... Nevertheless, we cannot exclude the possibility that DWV can develop into a systemic infection in bumblebees in a context-dependent manner. For example, Cilia et al. [38] detected DWV in the heads of commercial adult B. terrestris workers, which suggests bees suffered a systemic infection. Furthermore, bumblebee digestive tract parasites such as Apicystis bombi are known to penetrate the midgut wall after host ingestion [39]. ...
The transmission of pathogens from reservoir to recipient host species, termed pathogen spillover, can profoundly impact plant, animal, and public health. However, why some pathogens lead to disease emergence in a novel species while others fail to establish or do not elicit disease is often poorly understood. There is strong evidence that deformed wing virus (DWV), an (+)ssRNA virus, spills over from its reservoir host, the honeybee Apis mellifera, into the bumblebee Bombus terrestris. However, the low impact of DWV on B. terrestris in laboratory experiments suggests host barriers to virus spread in this recipient host. To investigate potential host barriers, we followed the spread of DWV genotype B (DWV-B) through a host’s body using RT-PCR after experimental transmission to bumblebees in comparison to honeybees. Inoculation was per os, mimicking food-borne transmission, or by injection into the bee’s haemocoel, mimicking vector-based transmission. In honeybees, DWV-B was present in both honeybee faeces and haemolymph within 3 days of inoculation per os or by injection. In contrast, DWV-B was not detected in B. terrestris haemolymph after inoculation per os, suggesting a gut barrier that hinders DWV-B’s spread through the body of a B. terrestris. DWV-B was, however, detected in B. terrestris faeces after injection and feeding, albeit at a lower abundance than that observed for A. mellifera, suggesting that B. terrestris sheds less DWV-B than A. mellifera in faeces when infected. Barriers to viral spread in B. terrestris following oral infection may limit DWV’s impact on this spillover host and reduce its contribution to the community epidemiology of DWV.
... . A total reaction volume of 10 µl was produced for each target gene using SYBR™ green assays with forward and reverse primers and nucleic acid extract adding 2 µl of extracted DNA or RNA, as reported in previous studies 21,57 . The SYBR PowerUp™ SYBR™ Green Master Mix (ThermoFisher, Waltham, MA, USA) and the Power SYBR™ Green Cells-to-CT™ Kit (ThermoFisher Scientific) were used for the DNA and RNA, respectively. ...
The interspecific transmission of pathogens can occur frequently in the environment. Among wild bees, the main spillover cases are caused by pathogens associated with Apis mellifera, whose colonies can act as reservoirs. Due to the limited availability of data in Italy, it is challenging to accurately assess the impact and implications of this phenomenon on the wild bee populations. In this study, a total of 3372 bees were sampled from 11 Italian regions within the BeeNet project, evaluating the prevalence and the abundance of the major honey bee pathogens (DWV, BQCV, ABPV, CBPV, KBV, Nosema ceranae, Ascosphaera apis, Crithidia mellificae, Lotmaria passim, Crithidia bombi). The 68.4% of samples were positive for at least one pathogen. DWV, BQCV, N. ceranae and CBPV showed the highest prevalence and abundance values, confirming them as the most prevalent pathogens spread in the environment. For these pathogens, Andrena, Bombus, Eucera and Seladonia showed the highest mean prevalence and abundance values. Generally, time trends showed a prevalence and abundance decrease from April to July. In order to predict the risk of infection among wild bees, statistical models were developed. A low influence of apiary density on pathogen occurrence was observed, while meteorological conditions and agricultural management showed a greater impact on pathogen persistence in the environment. Social and biological traits of wild bees also contributed to defining a higher risk of infection for bivoltine, communal, mining and oligolectic bees. Out of all the samples tested, 40.5% were co-infected with two or more pathogens. In some cases, individuals were simultaneously infected with up to five different pathogens. It is essential to increase knowledge about the transmission of pathogens among wild bees to understand dynamics, impact and effects on pollinator populations. Implementing concrete plans for the conservation of wild bee species is important to ensure the health of wild and human-managed bees within a One-Health perspective.
... The resulting suspension was used to extract the total RNA, using a Quick RNA Microprep Plus Kit (Zymo Research). During this process, a modification of the manufacturer's instructions for solid tissue processing was followed [55,56]. Each RNA sample was eluted in 100 µL of DNase-RNase-free water, and the extracts were stored at -80 °C until used for qPCR assays. ...
... For each target gene, a total reaction volume of 25 µL was prepared as described previously [43,50,55], using a Power SYBR Green Cells-to-CT Kit (Thermo Fisher Scientific, Waltham, MA, USA) with forward and reverse primers (2 µM) and 3 µL of nucleic acid extract. qPCR was performed using a QuantStudio 3 Real-Time PCR System (Thermo Fisher Scientific), following the specific protocol for each gene [6,57]. ...
... For each target gene, a standard curve was generated by amplifying serially diluted recombinant plasmids containing the pathogen-specific RNA fragment from 1 × 10 1 to 1 × 10 9 copies in a qPCR assay using a QuantStudio 3 Real-Time PCR System (Thermo Fisher Scientific) as described previously [48,50,55,56], following the amplification and quantification protocols [6, 57]. ...
Acute bee paralysis virus (ABPV), Kashmir bee virus (KBV), and Israeli acute paralysis virus (IAPV) usually persist as covert infections in honey bee colonies. They can cause rapid bee mortality in cases of severe infection, often associated with high Varroa destructor infestation, by which they are transmitted. In various countries, these viruses have been associated with colony collapse. Despite their potential danger, these viruses are often disregarded, and little information is available on their occurrence in many countries, including Italy. In 2021, 370 apiaries representing all of the Italian regions were investigated in four different months (June, September, November, and March) for the presence of ABPV, KBV, and IAPV. IAPV was not found in any of the apiaries investigated, whereas 16.45% and 0.67% of the samples tested positive for ABPV and KBV, respectively. Most ABPV cases occurred in late summer-autumn in both northern and southern regions. We observed a scattered pattern of KBV-positive colonies that did not allow any seasonal or regional trends to be discerned. Differences observed among regions and months were potentially related to the dynamics of varroa infestation, viral genetic variations, and different climatic conditions resulting in variations in bee behaviour. This study improves our understanding of the circulation of bee viruses and will contribute to better disease prevention and preservation of bee health.
... Even if cases of exploitative competition between B. terrestris and wild pollinators have been suggested (e.g., Smith-Ramirez et al., 2021;Wignall et al., 2020) the main negative effect of B. terrestris on local native populations is the spillover of shared pathogens (e.g., Aizen et al., 2019). Bombus terrestris commercial colonies have been shown to be infected by multiple pathogens and parasites (e.g., Nosema-Trillo et al., 2019; deformed wing virus (DWV)- Cilia et al., 2021;Crithidia spp.-Murray et al., 2013-see Graystock et al., 2013. Commercialized colonies have been long suspected to have introduced parasites and pathogens in invaded area (e.g., Arismendi et al., 2021;Cameron et al., 2016;Keum et al., 2021), affecting local wild pollinators through spillover (e.g., Aizen et al., 2019;Arismendi et al., 2021). ...
Introducing any species in a large number into an ecosystem is never a zero-sum game. In this paper, we assessed what are the main advances on the known impacts of Massively Introduced Managed Species (MIMS) on plant–pollinator communities and networks. We first focused on the raising body of literature studying the effects of the introduction of honey bees (Apis mellifera) in ecosystems. We then presented the growing concerns around emerging MIMS, be they plants or pollinators, with a highlight on oceanic islands. Finally, we proposed a roadmap to construct solutions with local actors as an incentive to regulate MIMS, notably in protected areas.
... The replicative form of DWV was also detected in NW alates in addition to DW alates. The finding that NW alates also carry the replicative form of DWV mirrors what other research groups have found in honey bees [28,29], bumble bees, Bombus terrestris, [30], and the wasp, Vespa crobro [31]. For the first time, the presence of replicative DWV in S. invicta has been confirmed. ...
Simple Summary
Deformed wing virus (DWV) is a major honey bee pathogen found throughout the world. DWV, in association with the varroa mite, causes wing deformity, a shortened abdomen, and neurological impairments, leading to the mortality of millions of honey bee colonies worldwide. At least 12 ant species have been shown to harbor DWV, including the red imported fire ant, one of the most invasive and detrimental pests in the world. To date, there have been no reports in the literature of DWV causing symptoms in ants. In this study, we observed the classic honey-bee-like symptoms of deformed wings in laboratory and field colonies of the red imported fire ants and verified the presence and replication of DWV. This is the first report of the co-occurrence of DWV-like symptoms and DWV in ants. However, more research is needed to determine whether DWV is indeed the causative agent of DW syndrome in S. invicta.
Abstract
Deformed wing virus (DWV), a major honey bee pathogen, is a generalist insect virus detected in diverse insect phyla, including numerous ant genera. Its clinical symptoms have only been reported in honey bees, bumble bees, and wasps. DWV is a quasispecies virus with three main variants, which, in association with the ectoparasitic mite, Varroa destructor, causes wing deformity, shortened abdomens, neurological impairments, and colony mortality in honey bees. The red imported fire ant, Solenopsis invicta Buren, is one of the most-invasive and detrimental pests in the world. In this study, we report the co-occurrence of DWV-like symptoms in S. invicta and DWV for the first time and provide molecular evidence of viral replication in S. invicta. Some alates in 17 of 23 (74%) lab colonies and 9 of 14 (64%) field colonies displayed deformed wings (DWs), ranging from a single crumpled wing tip to twisted, shriveled wings. Numerous symptomatic alates also exhibited altered locomotion ranging from an altered gait to the inability to walk. Deformed wings may prevent S. invicta alates from reproducing since mating only occurs during a nuptial flight. The results from conventional RT-PCR and Sanger sequencing confirmed the presence of DWV-A, and viral replication of DWV was confirmed using a modified strand-specific RT-PCR. Our results suggest that S. invicta can potentially be an alternative and reservoir host for DWV. However, further research is needed to determine whether DWV is the infectious agent that causes the DW syndrome in S. invicta.
... Before the extraction of total RNA, all samples were washed by full immersion in 95% ethanol for 10 s to remove any external viral contamination (Cilia et al., 2021). Each sample was processed individually, placed in a 2 mL microtube with 300 µL of DNA/RNA Shield (Zymo Research, Irvine, CA, USA) and crushed with a TissueLyser II (Qiagen, Hilden, Germany) for 3 min at 30 Hz, as previously reported (Cilia et al., 2022b). ...
... Previous surveys detected DWV in various bumblebee species worldwide, where it may be contributing to the decline of both wild and managed populations (McMahon et al., 2015;Meeus et al., 2011). DWV infections were reported in B. terrestris (Arismendi et al., 2021;Cilia et al., 2021;Dalmon et al., 2021;Evison et al., 2012;Fürst et al., 2014;Jabal-Uriel et al., 2017;Tehel et al., 2016), B. pascuorum (Scopoli, 1763, B. impatiens Cresson, 1863 (Levitt et al., 2013;Li et al., 2011;Sachman-Ruiz et al., 2015;Singh et al., 2010;Tehel et al., 2016), B. atratus Franklin, 1913(Gamboa et al., 2015Reynaldi et al., 2013), B. vagans Smith, 1853(Levitt et al., 2013Singh et al., 2010), B. huntii Greene, 1860(Li et al., 2011), B. ruderatus (Fabricius, 1775 (Arismendi et al., 2021), B. ternarius Say, 1837(Singh et al., 2010), B. lapidarius (L., 1758), B. lucorum (L., 1761), and B. monticola Smith, 1848(Fürst et al., 2014. ...
... Although DWV was frequently detected in B. terrestris (Gisder and Genersch, 2017;Tehel et al., 2016), symptomatic adults were seldom described. Only a few studies found B. terrestris specimens and B. pascuorum workers both showing symptoms attributable to a DWV infection and reporting replicative viral RNA (Cilia et al., 2021;Genersch et al., 2006). ...
... Though DWV is a key pathogen in managed honey bees and spillover to other species, e.g. bumble bees, has been reported repeatedly, more data are required before deriving general conclusions on the role of spillover of viruses contributing to solitary bee decline (Fürst et al., 2014;Alger et al., 2019;Gusachenko et al., 2019;Tehel et al., 2020;Burnham et al., 2021;Cilia et al., 2021 For example, solitary bees cannot rely on social immunity and must therefore entirely rely on individual immune responses (Wilson-Rich et al., 2009;Meunier, 2015). These individual immune responses may be better developed compared to workers in social insects, which can be considered analogous to somatic cells. ...
Virus spillover from managed to unmanaged bees and vice versa may be one mechanism driving colony losses of the former and declines of the latter. There is clear evidence that the ubiquitous Deformed wing virus (DWV) is a major driver of honey bee (Apis mellifera) colony mortality. Although DWV has been detected in the solitary bee Osmia bicornis, data on DWV infectivity and virulence from solitary bees are scarce. Here, we used microinjection to investigate whether DWV genotype A (DWV-A) obtained from honey bees can replicate in O. bicornis. DWV-A titers and intermediate strand analyses suggest that DWV-A does not replicate in O. bicornis and thus is probably not infectious for this solitary bee species. Interestingly, the data demonstrate that DWV-A recovered from O. bicornis 16 days post-microinjection remains infectious for A. mellifera. Therefore, despite the lack of apparent virulence of DWV in this solitary bee species, O. bicornis has the potential to act as a virus spillover host and may contribute to increased colony losses of managed honey bees and declines in populations of other managed or unmanaged bee species.
