Presence Of Deformed Wing Virus Research Articles

Prevalence and Molecular Characterization of Deformed Wing, Acute Bee Paralysis and Black Queen Cell Viruses Infecting Honey Bees and Varroa Mites

Abstract Surveys were conducted in Malatya and Elazığ provinces of Eastern Türkiye between 2018–2019 to detect the presence and distribution of Deformed wing virus (DWV), Acute bee paralysis virus (ABPV) and Black queen cell virus (BQCV) infecting honey bees and Varroa mites. Thirty Varroa mites feeding on honey bees and 147 honey bees were collected from twenty-five apiaries of Malatya and fifteen apiaries of Elazığ. The collected samples were subjected to reverse transcriptase-polymerase chain reaction. All tested viruses were found to be present in the samples singly or as mixed infections. The prevalence of the viruses were 23.81%, 12.93%, and 10.20% for DWV, ABPV and BQCV, respectively. Five out of thirty Varroa mites tested for the viruses were found to be infected only with DWV. Randomly chosen sequences of each detected virus’s partial polyprotein gene region were registered in GenBank under the accession numbers OP805878, OP805879, OP805880, OP805887, OP805888, OP805889, OP805890, OP805891 (DWV), OP805881, OP805882, OP805883, OP805884 (ABPV) and OP805885, OP805886 (BQCV). The phylogenetic tree of the viral isolates were compared with the world isolates. DWV isolates were found to be closely related to the UK, Lebanon, Türkiye, France, Germany and Israel isolates, whereas ABPV isolates were related to Türkiye, South Africa, Slovenia, Serbia, France, Hungary, Syria and USA isolates and BQCV isolates were related to China, South Korea, Czech Republic, France, Hungary, Poland, South Africa, Australia and Sweden isolates. The presence of DWV, ABPV and BQCV infections in Malatya and Elazığ provinces of Türkiye is revealed for the first time in this study.

Effects of Deformed Wing Virus Infection on Expressions of Immune- and Apoptosis-Related Genes in Western Honeybees (Apis mellifera).

Simple SummaryDeformed wing virus (DWV) is a widespread viral pathogen in western honeybees. This work investigated the effects of DWV on honeybee and host defense by analyzing the immune and apoptosis gene expressions. The results revealed that the mortality rates and deformed wing symptoms in newly emerged adult bees increased at high initial concentration of DWV injection. Moreover, abnormality of wings in DWV injected bees did not correlate with the virus levels nor the immune and apoptosis responses. After DWV injection, the immune response was activated in pupae and newly emerged adult bees. However, apoptosis genes were stimulated only in newly emerged adult bees but suppressed in honeybee pupae. The apoptosis gene suppression during the initial phase of infection may promote the DWV survival and parasitism in the honeybee host.Honeybees are globally threatened by several pathogens, especially deformed wing virus (DWV), as the presence of DWV in western honeybees is indicative of colony loss. The high mortality rate is further exacerbated by the lack of effective treatment, and therefore understanding the immune and apoptosis responses could pave an avenue for the treatment method. In this study, DWV was directly injected into the white-eyed pupae stage of western honeybees (Apis mellifera). The DWV loads and selected gene responses were monitored using the real-time PCR technique. The results showed that honeybee pupae that were injected with the highest concentration of viral loads showed a significantly higher mortality rate than the control groups. Deformed wings could be observed in newly emerged adult bees when the infected bees harbored high levels of viral loads. However, the numbers of viral loads in both normal and crippled wing groups were not significantly different. DWV-injected honeybee pupae with 104 and 107 copy numbers per bee groups showed similar viral loads after 48 h until newly emerged adult bees. Levels of gene expression including immune genes (defensin, abaecin, and hymenoptaecin) and apoptosis genes (buffy, p53, Apaf1, caspase3-like, caspase8-like, and caspase9-like) were analyzed after DWV infection. The expressions of immune and apoptosis genes were significantly different in infected bees compared to those of the control groups. In the pupae stage, the immune genes were activated by injecting DWV (defensin and hymenoptaecin) or Escherichia coli (defensin, abaecin, and hymenoptaecin), a positive control. On the contrary, the expression of apoptosis-related genes (buffy, caspase3-like, caspase8-like, and caspase9-like genes) was suppressed at 96 h post-infection. In DWV-infected newly emerged adult bees, abaecin, hymenoptaecin, Apaf1, and caspase8-like genes were upregulated. However, these genes were not significantly different between the normal and crippled wing bees. Our results suggested that DWV could activate the humoral immunity in honeybees and that honeybee hosts may be able to protect themselves from the virus infection through immune responses. Apoptosis gene expressions were upregulated in newly emerged adult bees by the virus, however, they were downregulated during the initial phase of viral infection.

Insight Into the Salivary Secretome of Varroa destructor and Salivary Toxicity to Apis cerana.

The Varroa destructor (Acari Varroidae) mite is a serious threat to honey bee due to hemolymph feeding and virus transmission. Mite salivary proteins are involved in these interactions. However, the salivary secretome has not been previously characterized. In this paper, the saliva of V. destructor was found to be toxic to the worker larvae of Apis cerana (Hymenoptera Apidae) in the absence of deformed wing virus (DWV) and to stimulate the development of deformed wings in Apis mellifera (Hymenoptera Apidae) adults in the presence of DWV. The salivary secretome was analyzed by nano-liquid chromatography coupled to tandem mass spectrometry (nano-LC-MS/MS). A search of the resulting data against peptide databases using the software Mascot yielded 356, 53, and 9 matched proteins from V. destructor, A. mellifera, and DWV, respectively. The saliva contained Varroa mite proteins identified as important for potential virulence to A. cerana larvae, for the inhibition of harmful microorganisms, for the utilization of bee nutrients, and for antioxidant, oxidation-reduction and detoxification functions as well as A. mellifera proteins identified as nutrients important for mite reproduction. The saliva proteins also contained viral proteins from one virus, DWV. These results provide a strong foundation for understanding the interactions among the Varroa mite, honeybee, and DWV.

Metagenomic analysis of Varroa-free Australian honey bees (Apis mellifera) shows a diverse Picornavirales virome.

The viral landscape of the honey bee (Apismellifera) has changed as a consequence of the global spread of the parasitic mite Varroa destructor and accompanying virulent strains of the iflavirus deformed wing virus (DWV), which the mite vectors. The presence of DWV in honey bee populations is known to influence the occurrence of other viruses, suggesting that the current known virome of A. mellifera may be undercharacterized. Here we tested this hypothesis by examining the honey bee virome in Australia, which is uniquely free of parasitic mites or DWV. Using a high-throughput sequencing (HTS) approach, we examined the RNA virome from nine pools of A. mellifera across Australia. In addition to previously reported honey bee viruses, several other insect viruses were detected, including strains related to aphid lethal paralysis virus (ALPV) and Rhopalosiphum padi virus (RhPV), which have recently been identified as infecting honey bees in the USA, as well as several other viruses recently found in Drosophila spp. A further 42 putative novel insect virus genomes spanning the order Picornavirales were assembled, which significantly increases the known viral diversity in A. mellifera. Among these novel genomes, we identified several that were similar (but different) to key A. mellifera viruses, such as DWV, that warrant further investigation. We propose that A. mellifera may be preferentially infected with viruses of the order Picornavirales and that a diverse population of these viruses may be representative of a Varroa-free landscape.

First detection of honey bee viruses in stingless bees in North America

Here, we report the first molecular detection of two honey bee viruses (deformed wing virus (DWV) and black queen cell virus (BQCV)) in stingless bees of the genus Scaptotrigona. This is the first molecular report of the presence of DWV and BQCV in stingless bees in North America and the first in S. mexicana.

First detection and complete genome sequence of Deformed wing virus in Chilean honeybees

Deformed wing virus (DWV) is one of the most common viruses affecting honey bee specimens. Although the presence of DWV has been reported in many countries, there is no data of the current situation in Chile. In this report, we detected the presence of DWV in apiaries from two different locations in central Chile. Furthermore, the genome of a Chilean DWV isolate was completely sequenced. This is the first report of the presence of a honey bee virus in Chile.

Prevalence and persistence of deformed wing virus (DWV) in untreated or acaricide-treated Varroa destructor infested honey bee (Apis mellifera) colonies

SummaryThe ectoparasitic mite Varroa destructor is a serious pest of the honey bee Apis mellifera. The naturally occurring virus known as deformed wing virus (DWV) has long been linked with the collapse of mite infested honey bee colonies. We therefore surveyed the prevalence and persistence of DWV in four heavily infested untreated colonies (Survey 1), and five heavily infested colonies that were treated with an acaricide (Survey 2). The presence of DWV in samples of adult bees, sealed brood and mites was detected using an Enzyme Linked Immunosorbent Assay (ELISA). Twenty individuals of each type were sampled monthly from each colony over the course of the study. During the summer, the proportion of adults, sealed brood and mites in which DWV was detected increased until either the colony died or was treated. When colonies were treated, thus removing mites from the colony, DWV became undetectable in the sealed bee brood at a similar rate to the loss of mites. The speed at which DWV became undetectable in adult workers depended, however, on the season, reflecting differences in life span between adult workers emerging in summer or winter. If treatment was delayed until October, DWV was still detected in adult bees during the winter even in the absence of mites. To reduce the viral load of the colony, therefore, mite treatment should be started no later than the end of August in order to remove the mites before production of the overwintering bees begins.

Deformed wing virus is not related to honey bees' aggressiveness

Guards of Cyprian honey bee colonies, Apis mellifera cypria, display a great defensive behaviour against hornets' attacks. The deformed wing virus (DWV) and the kakugo virus (KV) genomes are very similar, but unlike KV, the presence of DWV is not related to honey bees' aggressiveness. This discrepancy is further discussed.