Sacbrood Virus Research Articles

Honeybee colony disorder in crop areas: the role of pesticides and viruses.

As in many other locations in the world, honeybee colony losses and disorders have increased in Belgium. Some of the symptoms observed rest unspecific and their causes remain unknown. The present study aims to determine the role of both pesticide exposure and virus load on the appraisal of unexplained honeybee colony disorders in field conditions. From July 2011 to May 2012, 330 colonies were monitored. Honeybees, wax, beebread and honey samples were collected. Morbidity and mortality information provided by beekeepers, colony clinical visits and availability of analytical matrix were used to form 2 groups: healthy colonies and colonies with disorders (n = 29, n = 25, respectively). Disorders included: (1) dead colonies or colonies in which part of the colony appeared dead, or had disappeared; (2) weak colonies; (3) queen loss; (4) problems linked to brood and not related to any known disease. Five common viruses and 99 pesticides (41 fungicides, 39 insecticides and synergist, 14 herbicides, 5 acaricides and metabolites) were quantified in the samples.The main symptoms observed in the group with disorders are linked to brood and queens. The viruses most frequently found are Black Queen Cell Virus, Sac Brood Virus, Deformed Wing Virus. No significant difference in virus load was observed between the two groups. Three acaricides, 5 insecticides and 13 fungicides were detected in the analysed samples. A significant correlation was found between the presence of fungicide residues and honeybee colony disorders. A significant positive link could also be established between the observation of disorder and the abundance of crop surface around the beehive. According to our results, the role of fungicides as a potential stressor for honeybee colonies should be further studied, either by their direct and/or indirect impacts on bees and bee colonies.

Honey bee Apis mellifera parasites in the absence of Nosema ceranae fungi and Varroa destructor mites.

Few areas of the world have western honey bee (Apis mellifera) colonies that are free of invasive parasites Nosema ceranae (fungi) and Varroa destructor (mites). Particularly detrimental is V. destructor; in addition to feeding on host haemolymph, these mites are important vectors of several viruses that are further implicated as contributors to honey bee mortality around the world. Thus, the biogeography and attendant consequences of viral communities in the absence of V. destructor are of significant interest. The island of Newfoundland, Province of Newfoundland and Labrador, Canada, is free of V. destructor; the absence of N. ceranae has not been confirmed. Of 55 Newfoundland colonies inspected visually for their strength and six signs of disease, only K-wing had prevalence above 5% (40/55 colonies = 72.7%). Similar to an earlier study, screenings again confirmed the absence of V. destructor, small hive beetles Aethina tumida (Murray), tracheal mites Acarapis woodi (Rennie), and Tropilaelaps spp. ectoparasitic mites. Of a subset of 23 colonies screened molecularly for viruses, none had Israeli acute paralysis virus, Kashmir bee virus, or sacbrood virus. Sixteen of 23 colonies (70.0%) were positive for black queen cell virus, and 21 (91.3%) had some evidence for deformed wing virus. No N. ceranae was detected in molecular screens of 55 colonies, although it is possible extremely low intensity infections exist; the more familiar N. apis was found in 53 colonies (96.4%). Under these conditions, K-wing was associated (positively) with colony strength; however, viruses and N. apis were not. Furthermore, black queen cell virus was positively and negatively associated with K-wing and deformed wing virus, respectively. Newfoundland honey bee colonies are thus free of several invasive parasites that plague operations in other parts of the world, and they provide a unique research arena to study independent pathology of the parasites that are present.

Increased tolerance and resistance to virus infections: a possible factor in the survival of Varroa destructor-resistant honey bees (Apis mellifera).

The honey bee ectoparasitic mite, Varroa destructor, has a world-wide distribution and inflicts more damage than all other known apicultural diseases. However, Varroa-induced colony mortality is more accurately a result of secondary virus infections vectored by the mite. This means that honey bee resistance to Varroa may include resistance or tolerance to virus infections. The aim of this study was to see if this is the case for a unique population of mite-resistant (MR) European honey bees on the island of Gotland, Sweden. This population has survived uncontrolled mite infestation for over a decade, developing specific mite-related resistance traits to do so. Using RT-qPCR techniques, we monitored late season virus infections, Varroa mite infestation and honey bee colony population dynamics in the Gotland MR population and compared this to mite-susceptible (MS) colonies in a close by apiary. From summer to autumn the deformed wing virus (DWV) titres increased similarly between the MR and MS populations, while the black queen cell virus (BQCV) and sacbrood virus (SBV) titres decreased substantially in the MR population compared to the MS population by several orders of magnitude. The MR colonies all survived the following winter with high mite infestation, high DWV infection, small colony size and low proportions of autumn brood, while the MS colonies all perished. Possible explanations for these changes in virus titres and their relevance to Varroa resistance and colony winter survival are discussed.

Prevalence and distribution patterns of seven different honeybee viruses in diseased colonies: a case study from Croatia

The prevalence and regional distribution patterns of seven different honeybee viruses, i.e. Acute bee paralysis virus (ABPV), Sacbrood virus (SBV), Black queen cell virus (BQCV), Deformed wing virus (DWV), Kashmir bee virus (KBV), Chronic bee paralysis virus (CBPV), and Israeli acute paralysis virus (IAPV) were investigated using reverse transcription PCR (RT-PCR) analyses. Bee samples were collected in 82 apiaries located in 20 different districts of Croatia, mainly from bee colonies with various health problems. 9.75 % of investigated samples (apiaries) proved to be infected with CBPV, while ABPV, BQCV, SBV, and DWV were found in 10.97 %, 29.26 %, 40.24 %, and 95.12 % of apiaries, respectively. No samples tested positive for KBV and IAPV. Thus, the prevalences of BQCV, ABPV, SBV, and CBPV were generally lower in Croatia compared to other European Union member states, whereas the prevalence of DWV was similarly high. The possible reasons for these differences are discussed. This study provides the first molecular evidence for the presence of honeybee viruses in Croatian honeybees.

A novel strain of sacbrood virus of interest to world apiculture

This study has characterised a novel serotype of Sacbrood virus (SBV) infecting Apis mellifera in New Guinea that has emerged in the presence of the introduced European and Asian serotypes, which infect A. mellifera and Apis cerana, respectively. The New Guinea serotype appears to have evolved through mutation of the European serotype with no evidence of recombination between known strains, although recombination was detected in other SBV isolates from Asia. SBV was also confirmed for the first time causing disease in Apis dorsata (giant Asian honeybee) in Indonesia and found to be infected by the Asian serotype.

Differential Gene Transcription in Honeybee (Apis cerana) Larvae Challenged by Chinese Sacbrood Virus (CSBV)

Honey bees are economically important social insect. They are suffering from all kinds of pathogens, especially the virus. In response to pathogens, different immune pathways such as Toll, Imd, Jak-Stat and RNAi are involved. In the present study, the transcription analysis of 32 immune-related genes from Apis cerana challenged by Chinese sacbrood virus (CSBV), the most widely distributed virus in A. cerana, was carried out by qRT-PCR to provide cues for the antiviral mechanism and the effective control of bee viruses. The expression level of 22 genes were statistically changed, including 11 up-regulated genes (catus-2, lys-2, vir, s3a, mta1, faa, vhdl, co-1-iv, ago-1, ago-3, aub) in which 3 (ago-1, ago-3, aub) were related to RNAi pathway, and 11 down-regulated genes (kenny, pgrp-lc, pgrp-s2, abaecin, lys-1, lys-3, domeless, tepa, mlc, dscam, rpl8) related to Toll, Imd, and Jak-Stat pathways. The results indicated CSBV infection in A. cerana may activate a RNA-based antiviral immunity system. This work constituted the first report, under laboratory conditions, about induction of immune related genes in response to CSBV.

ПОРАЖЕНИЕ МЕДОНОСНОЙ ПЧЕЛЫ Apis melifera caucasica Gorb. ВИРУСАМИ И ПАРАЗИТАМИ И СОСТОЯНИЕ ПЧЕЛИНЫХ СЕМЕЙ В РАЗНЫХ ЭКОЛОГО-ГЕОГРАФИЧЕСКИХ УСЛОВИЯХ БОЛЬШОГО КАВКАЗА

Honeybees, mainly Apis mellifera, remain the most important pollinator of crops requiring animal pollination. However, bee colony declines reported around the globe, termed «Colony Collapse Disorder», show an objective need for studying causes of this phenomenon. Bee colony collapses are reported both in Russia and ex-Soviet Union countries each year. However, official reports are not available due to the lack of adequate data and tools. This work is believed to be the first in Azerbadjan looking into potential causes of bee losses in this country. PCR results indicate the presence of deformed wing virus, black queen cell virus, and viruses from the family Iflaviridae (Kashmir virus and/or Israeli bee paralysis virus) and never reported before Nosema ceranae in Azerbaijani bees. Interestingly, сhronic and acute bee paralysis viruses, sacbrood virus and N. apis were not detected. Honey was demonstrated to contain the organophosphate diazinon and the organochlorides hexachlorocyclohexane and hexachlorobenzene. Taken together, no correlation was found between bee losses and the presence of viruses, parasites, pesticides and varroa infestation (р > 0.05).

First molecular detection of co-infection of honey bee viruses in asymptomatic Bombus atratus in South America.

Pollination is critical for food production and has the particularity of linking natural ecosystems with agricultural production systems. Recently, losses of bumblebee species have been reported worldwide. In this study, samples from a commercial exploitation of bumblebees of Argentina with a recent history of deaths were studied using a multiplex PCR for the detection of the honey bee viruses most frequently detected in South America. All samples analysed were positive for co-infections with Deformed wing virus, Black queen cell virus and Sacbrood virus. This is the first report of infection of Bombus atratus with honey bee viruses. A better understanding of viral infections in bumblebees and of the epidemiology of viruses could be of great importance as bumblebees can serve as possible viral reservoirs, resulting in pathogen spillover towards honey bees and native bumblebees.

Nosema ceranae and RNA viruses in European and Africanized honeybee colonies (Apis mellifera) in Uruguay

Nosema ceranae is one of the causative agents of Nosemosis, a severe disease that affects the honeybee Apis mellifera. The aim of the present work was to compare N. ceranae and RNA virus infections in Africanized bees (hybrid of Apis mellifera scutellata and A. m. mellifera) and European (Italian) bees (A. m. ligustica) under field conditions. Africanized and Italian healthy colonies were relocated to an Eucalyptus grandis plantation, a place where colonies inevitably acquire Nosemosis. Fifteen and 30 days after that, all colonies presented N. ceranae spores although Africanized bees were less infected than Italian bees. Sacbrood virus (SBV) and Black queen cell virus (BQCV) were detected in both races of bees, although Africanized bees presented a lower level of BQCV infection than Italian bees. At the end of the flowering period, Africanized colonies had a larger honeybee population and produced more honey than Italian colonies. These results suggest that Africanized bees may be able to limit N. ceranae and BQCV infections within the colony, and that this may allow them to be more productive.

Development and validation of a real-time two-step RT-qPCR TaqMan® assay for quantitation of Sacbrood virus (SBV) and its application to a field survey of symptomatic honey bee colonies

Sacbrood virus (SBV) is the causal agent of a disease of honey bee larvae, resulting in failure to pupate and causing death. The typical clinical symptom of SBV is an accumulation of SBV-rich fluid in swollen sub-cuticular pouches, forming the characteristic fluid-filled sac that gives its name to the disease. Outbreaks of the disease have been reported in different countries, affecting the development of the brood and causing losses in honey bee colonies. Today, few data are available on the SBV viral load in the case of overt disease in larvae, or for the behavioural changes of SBV-infected adult bees. A two-step real-time RT-PCR assay, based on TaqMan® technology using a fluorescent probe (FAM-TAMRA) was therefore developed to quantify Sacbrood virus in larvae, pupae and adult bees from symptomatic apiaries. This assay was first validated according to the recent XP-U47-600 standard issued by the French Standards Institute, where the reliability and the repeatability of the results and the performance of the assay were confirmed. The performance of the qPCR assay was validated over the 6 log range of the standard curve (i.e. from 102 to 108 copies per well) with a measurement uncertainty evaluated at 0.11log10. The detection and quantitation limits were established respectively at 50 copies and 100 copies of SBV genome, for a template volume of 5μl of cDNA. The RT-qPCR assay was applied during a French SBV outbreak in 2012 where larvae with typical SBV signs were collected, along with individuals without clinical signs. The SBV quantitation revealed that, in symptomatic larvae, the virus load was significantly higher than in samples without clinical signs. Combining quantitation with clinical data, a threshold of SBV viral load related to an overt disease was proposed (1010 SBV genome copies per individual).

Detection of Sac Brood and Black Queen Cell Viruses from Honeybee Colonies of Jordan Using RT- PCR Technique

The Reverse Transcription-polymerase Chain Reaction (RT-PCR) is an excellent technique for the detection of honeybee viruses. In this study, the presence of Sac Brood Virus (SBV) and Black Queen Cell Virus (BQCV) was demonstrated in 100 samples, collected from Jordanian honeybee colonies by employing RT-PCR. The collected samples represented infected (depopulation, paralysis, or dark coloring), dead, and apparently healthy honeybees of different developmental stages (adult and larvae). SBV was detected in 37% of the samples, whereas BQCV was detected in 5%. Nucleotide sequences of the PCR products from each virus was determined and found to be 433 and 309 nucleotides in SBV and BQCV, respectively. The identities to the Gene Bank were 95% for SBV and 91% for BQCV. This is the first record of BQCV in Jordan.

Intérêt diagnostique des séquences IRM dynamiques de perfusion et de diffusion dans le bilan des tumeurs parotidiennes

Using standard epidemiological methods, this study set out to quantify the risk associated with exposure to easily diagnosed factors on colony mortality and morbidity in three migratory beekeeping operations. Fifty-six percent of all colonies monitored during the 10-month period died. The relative risk (RR) that a colony would die over the short term (∼50 days) was appreciably increased in colonies diagnosed with Idiopathic Brood Disease Syndrome (IBDS), a condition where brood of different ages appear molten on the bottom of cells (RR = 3.2), or with a “queen event” (e.g., evidence of queen replacement or failure; RR = 3.1). We also found that several risk factors—including the incidence of a poor brood pattern, chalkbood (CB), deformed wing virus (DWV), sacbrood virus (SBV), and exceeding the threshold of 5 Varroa mites per 100 bees—were differentially expressed in different beekeeping operations. Further, we found that a diagnosis of several factors were significantly more or less likely to be associated with a simultaneous diagnosis of another risk factor. These finding support the growing consensus that the causes of colony mortality are multiple and interrelated.

GENETIC DIFFERENTIATION OF POPULATIONS OF HONEY BEE (Apis mellifera L.) AND DISTRIBUTION OF RNA-CONTAINING VIRUSES AT THE BACKGROUND OF EPIZOOTIA OF Varroa destructor ON THE TERRITORY OF UDMURTIA

GENETIC DIFFERENTIATION OF POPULATIONS OF HONEY BEE (Apis mellifera L.) AND DISTRIBUTION OF RNA-CONTAINING VIRUSES AT THE BACKGROUND OF EPIZOOTIA OF Varroa destructor ON THE TERRITORY OF UDMURTIA Alexander E. Kalashnikov*, Ivan V. Maslennikov**, Ludmila M. Kolbina**, Irina G. Udina* *N.I. Vavilov Institute of General Genetics RAS **Udmurt Research Institute of Agriculture Abstract The bees of dark forest species (Apis mellifera mellifera L.) are winter-hardy. These bees are able to effectively use a short honey harvest. Introgression of southern bee species in the Russia affects ro the economic quality of local northern species of bees. Introgression of species reduces their immunity, thereby It was enhancing susceptibility bees to infection with ectoparasites, as well as distribution of various viral diseases. Varroa destructor mite infestations on bees may predispose to infection by viruses. We have presented data about population differentiation of bees of dark forest species in Udmurtia, which were obtained based on the study using PCR method, morphometric parameters (cubital index of wing) and estimation of variability in intergenic locus of the CO-I-CO-II of mtDNA. Based on the analysis of the mtDNA the hybridization degree in samples of bees from Udmurtia 1UD_S and 5UD_S (maternal line) was 15.4 and 60.0%, respectively. Sample 2D_S-4UD_S meet the standards of dark forest bee species. For all analyzed samples (1UD_S-5UD_S) obtained average rating of cubital index> 0.55. These data confirmed the high probability of belonging of bees of sample data to the dark forest bee species. However, the variability analysis (according to the length of the intergenic locus CO-I-CO-II) with Southern species hybridization was observed only in samples 2UD_S-4UD_S, whereas in the other samples 1UD_S 5UD_S hybridization has occurred. This indicates a greater degree of reliability of molecular techniques in the evaluation of the degree of hybridization when samples of bees were studied. It's interesting that in one of the samples 2UD_S we founded a heteroplasmy PQ/P3*Q. In bees exposed to Varroa destructor defeat was detected deformed wing virus (DWV) (23,3% of families), chronic bee paralysis virus (CBPV) and sacbrood bee virus (SBV) (13, 3%). Keywords honey bee, Apis mellifera L., mitochondrial DNA, cubital index, deformed wing virus, sacbrood virus, chronic paralysis virus, Varroa destructor Introduction The dark forest bee Apis mellifera mellifera L. and related subspecies of Central Russian bee breed was widespread in Russia (1), including Udmurtia (2) and Bashkortostan (3). These bees have winter hardiness, resistance to several diseases, the ability efficiently uses a short honey harvest. The proboscis of these bees is short (6.0-6.4 mm). They have a dark color of the body. For these bees is a characteristic light dry seal of honey. However, these bees are aggressive and have a tendency to increase swarming. The cubital index value of the breed standard of these bees is in the range 0.60-0.65 (4). Under the influence of anthropogenic factor in Russia, like in Western Europe and North America, there was observes a hybridization of A. m. mellifera subspecies with subspecies, which are spread in the more southern latitudes. Integration of the southern subspecies effect on economic quality of the local northern species, as well as have a negative impact on their adaptability to environmental conditions. It also reduces immunity, thereby enhancing susceptibility of bees to infection of ectoparasites and distribution of various diseases, including viral (5). Infection bee mite Varroa destructor bees predispose to infection by viruses (5-7). Mite serves as a reservoir for virus bee mite infestation therefore weaken their immunity and promotes viral infection (8). Six of the studied viruses of the honey bee cause serious consequences if infected, up

Cross-species transmission of honey bee viruses in associated arthropods

There are a number of RNA virus pathogens that represent a serious threat to the health of managed honey bees (Apis mellifera). That some of these viruses are also found in the broader pollinator community suggests the wider environmental spread of these viruses, with the potential for a broader impact on ecosystems. Studies on the ecology and evolution of these viruses in the arthropod community as a whole may therefore provide important insights into these potential impacts. We examined managed A. mellifera colonies, nearby non-Apis hymenopteran pollinators, and other associated arthropods for the presence of five commonly occurring picorna-like RNA viruses of honey bees – black queen cell virus, deformed wing virus, Israeli acute paralysis virus, Kashmir bee virus and sacbrood virus. Notably, we observed their presence in several arthropod species. Additionally, detection of negative-strand RNA using strand-specific RT-PCR assays for deformed wing virus and Israeli acute paralysis virus suggests active replication of deformed wing virus in at least six non-Apis species and active replication of Israeli acute paralysis virus in one non-Apis species. Phylogenetic analysis of deformed wing virus also revealed that this virus is freely disseminating across the species sampled in this study. In sum, our study indicates that these viruses are not specific to the pollinator community and that other arthropod species have the potential to be involved in disease transmission in pollinator populations.

천안·아산지역 양봉농가 꿀벌질병 감염률 조사

This study was carried out to investigate the prevalence of honeybee (Apis mellifera) disease in cheonan and asan area. From September to November in 2012, 33 samples were collected from 33 apiculture farms in the regions and reverse transcriptase-polymerase chain reaction (RT-PCR) and polymerase chain reaction (PCR) was conducted. Among 33 samples, prevalence rate was 42% in Sac Brood Virus (SBV), 52% in Nosema, 21% in American foulbrood (AFB), 70% in European foulbrood (EFB), 97% in Stonebrood, 3% in Chalkbrood. The result indicate that stonebrood was most prevalent disease in apiculture farms in cheonan and asan area.

Genetic characterization of VP1 gene of seven Sacbrood virus isolated from three provinces in northern China during the years 2008–2012

The genetic diversity of seven northern China isolated Sacbrood virus strains (SBV) has been analyzed, and hypervariable regions of the VP1 gene of 7 SBV were sequenced and characterized, in order to obtain epidemiological and immunological information, and to suggest typing criteria for SBV. Sequence analysis of hypervariable regions of the VP1 gene in the genome of these isolates revealed a sequence homology of 91.0–99.3% among all seven local SBV isolates from Apis cerana from China, with a similarity of 93.3–100.0% in deduced amino acid sequences. These local isolates shared 87.4–92.8% sequence homology with six SBV reference strains in GenBank (including two SBV reference strains from Apis cerana from China), which represents a 91.8–97.6% similarity in deduced amino acid sequences. Genetic analysis also showed that five SBV strains from Apis cerana from China had a 13-amino-acid deletion at amino acid positions 287–299, and two SBV strains infecting the Korean honeybee had a 17-amino-acid deletion at amino acid positions 284–300 in comparison with other SBV. Phylogenetic analysis revealed two major groups (AC genotype SBV infecting Apis cerana and AM genotype SBV infecting Apis mellifera). The AC genotype could be further divided into subgroups. Based on the results of phylogenetic analysis, a similarity scan of SBV nucleotide sequences was carried out by using Simplot software and results in similar results. Our results suggest possible typing criteria for SBV based on the phylogenetic tree and sequence homology, and also that the virus has host specificity and regional variations.

경북 동부지역 꿀벌에서 주요 병원체의 분자생물학적 검출

Abstract The ecologically and economically important honeybee species are susceptible to infections by various pathogens. This study was investigated to detect infectious pathogens in honeybee colonies reared in eastern Gyeongbuk province by PCR in 2010∼2011. A total of 11 infectious pathogens, including 6 viruses, 2 bacteria, 2 fungi, and 1 parasite, were investigated in honeybee colonies suffering from symp-toms of sudden collapse, depopulation, or paralysis. The infectious pathogens and infection rates among 24 honeybee colonies detected were as follows: sacbrood virus (66.7%), deformed wing virus (4.2%), black queen cell virus (12.5%), Kashmir bee virus (29.2%), American foulbrood (41.7%), European foulbrood (12.5%), stonebrood (45.8%), chalkbrood (4.2%), and Nosema (33.3%), respectively. Since the coinfection rates of multiple pathogens were detected high in honeybee colonies reared in eastern Gyeongbuk province, large-scale investigation and appropriate control programs need to be established in this region.

An Integrated Proteomics Reveals Pathological Mechanism of Honeybee (Apis cerena) Sacbrood Disease

Viral diseases of honeybees are a major challenge for the global beekeeping industry. Chinese indigenous honeybee (Apis cerana cerana, Acc) is one of the major Asian honeybee species and has a dominant population with more than 3 million colonies. However, Acc is frequently threatened by a viral disease caused by Chinese sacbrood virus (CSBV), which leads to fatal infections and eventually loss of the entire colony. Nevertheless, knowledge on the pathological mechanism of this deadly disease is still unknown. Here, an integrated gel-based and label-free liquid chromatography-mass spectrometry (LC-MS) based proteomic strategy was employed to unravel the molecular event that triggers this disease, by analysis of proteomics and phosphoproteomics alterations between healthy and CSBV infected worker larvae. There were 180 proteins and 19 phosphoproteins which altered their expressions after the viral infection, of which 142 proteins and 12 phosphoproteins were down-regulated in the sick larvae, while only 38 proteins and 7 phosphoproteins were up-regulated. The infected worker larvae were significantly affected by the pathways of carbohydrate and energy metabolism, development, protein metabolism, cytoskeleton, and protein folding, which were important for supporting organ generation and tissue development. Because of abnormal metabolism of these pathways, the sick larvae fail to pupate and eventually death occurs. Our data, for the first time, comprehensively decipher the molecular underpinnings of the viral infection of the Acc and are potentially helpful for sacbrood disease diagnosis and medicinal development for the prevention of this deadly viral disease.

TaqMan MGB Probe Fluorescence Real-Time Quantitative PCR for Rapid Detection of Chinese Sacbrood Virus

Sacbrood virus (SBV) is a picorna-like virus that affects honey bees (Apis mellifera) and results in the death of the larvae. Several procedures are available to detect Chinese SBV (CSBV) in clinical samples, but not to estimate the level of CSBV infection. The aim of this study was develop an assay for rapid detection and quantification of this virus. Primers and probes were designed that were specific for CSBV structural protein genes. A TaqMan minor groove binder (MGB) probe-based, fluorescence real-time quantitative PCR was established. The specificity, sensitivity and stability of the assay were assessed; specificity was high and there were no cross-reactivity with healthy larvae or other bee viruses. The assay was applied to detect CSBV in 37 clinical samples and its efficiency was compared with clinical diagnosis, electron microscopy observation, and conventional RT-PCR. The TaqMan MGB-based probe fluorescence real-time quantitative PCR for CSBV was more sensitive than other methods tested. This assay was a reliable, fast, and sensitive method that was used successfully to detect CSBV in clinical samples. The technology can provide a useful tool for rapid detection of CSBV. This study has established a useful protocol for CSBV testing, epidemiological investigation, and development of animal models.

Complete Genome Sequence of Sacbrood Virus Strain SBM2, Isolated from the Honeybee Apis cerana in Vietnam

Here we report the complete genomic sequence of the SBM2 strain (VSBV-SBM2) of the sacbrood virus (SBV) that was isolated from the Asian honeybee (Apis cerana) in Northern Vietnam. The entire sequence excluding the 3′ poly(A) tail is 8,834 nucleotides in length and contains a single large open reading frame (ORF) of 8,580 nucleotides (position 178 to 8757), encoding 2,859 amino acids. VSBV-SBM2 shared 90 to 93% nucleotide identity and 95 to 96% amino acid homology to six complete genomes of SBV currently available in GenBank (two from China, three from Korea, and one from the United Kingdom). A hypervariable domain (amino acid [aa] position 712 to 729) and a conserved motif (position 2124 to 2143) in the precursor polypeptide of all seven SBVs are also described.