Prevalence and Seasonal Variations of Six Bee Viruses in Apis mellifera L. and Varroa destructor Mite Populations in France

A survey of six bee viruses on a large geographic scale was undertaken by using seemingly healthy bee colonies and the PCR technique. Samples of adult bees and pupae were collected from 36 apiaries in the spring, summer, and autumn during 2002. Varroa destructor samples were collected at the end of summer following acaricide treatment. In adult bees, during the year deformed wing virus (DWV) was found at least once in 97% of the apiaries, sacbrood virus (SBV) was found in 86% of the apiaries, chronic bee paralysis virus (CBPV) was found in 28% of the apiaries, acute bee paralysis virus (ABPV) was found in 58% of the apiaries, black queen cell virus (BQCV) was found in 86% of the apiaries, and Kashmir bee virus (KBV) was found in 17% of the apiaries. For pupae, the following frequencies were obtained: DWV, 94% of the apiaries; SBV, 80% of the apiaries; CBPV, none of the apiaries; ABPV, 23% of the apiaries; BQCV, 23% of the apiaries; and KBV, 6% of the apiaries. In Varroa samples, the following four viruses were identified: DWV (100% of the apiaries), SBV (45% of the apiaries), ABPV (36% of the apiaries), and KBV (5% of the apiaries). The latter findings support the putative role of mites in transmitting these viruses. Taken together, these data indicate that bee virus infections occur persistently in bee populations despite the lack of clinical signs, suggesting that colony disease outbreaks might result from environmental factors that lead to activation of viral replication in bees.     

Prevalence and seasonal variations of six bee viruses in Apis mellifera L. and Varroa destructor mite populations in France

A survey of six bee viruses on a large geographic scale was undertaken by using seemingly healthy bee colonies and the PCR technique. Samples of adult bees and pupae were collected from 36 apiaries in the spring, summer, and autumn during 2002. Varroa destructor samples were collected at the end of summer following acaricide treatment. In adult bees, during the year deformed wing virus (DWV) was found at least once in 97% of the apiaries, sacbrood virus (SBV) was found in 86% of the apiaries, chronic bee paralysis virus (CBPV) was found in 28% of the apiaries, acute bee paralysis virus (ABPV) was found in 58% of the apiaries, black queen cell virus (BQCV) was found in 86% of the apiaries, and Kashmir bee virus (KBV) was found in 17% of the apiaries. For pupae, the following frequencies were obtained: DWV, 94% of the apiaries; SBV, 80% of the apiaries; CBPV, none of the apiaries; ABPV, 23% of the apiaries; BQCV, 23% of the apiaries; and KBV, 6% of the apiaries. In Varroa samples, the following four viruses were identified: DWV (100% of the apiaries), SBV (45% of the apiaries), ABPV (36% of the apiaries), and KBV (5% of the apiaries). The latter findings support the putative role of mites in transmitting these viruses. Taken together, these data indicate that bee virus infections occur persistently in bee populations despite the lack of clinical signs, suggesting that colony disease outbreaks might result from environmental factors that lead to activation of viral replication in bees.     

北京地区六种蜜蜂病毒病的流行病学研究

【目的】对蜜蜂的6种病毒:以色列急性麻痹病毒(Israeli acute paralysis virus,IAPV)、残翅病毒(Deformed wing virus,DWV)、囊状幼虫病病毒(Sacbrood virus,SBV)、急性蜜蜂麻痹病毒(Acute bee paralysis virus,ABPV)、黑蜂王台病毒(Black queen cell virus,BQCV)、慢性麻痹病毒(Chronic bee paralysis virus,CBPV)在北京地区的流行情况进行调查,以期为该地区蜜蜂病毒病的防控提供一定的理论依据。【方法】应用多重RT-PCR法确定上述6种病毒在该地区的感染情况,并通过序列分析确定特异性。【结果】在所有检测样本中均未检测到急性麻痹病病毒和慢性麻痹病病毒,感染率最高的是以色列急性麻痹病毒,其次是残翅病毒。检测的样本普遍存在混合感染。【结论】以色列急性麻痹病毒、残翅病毒、囊状幼虫病病毒、黑蜂王台病毒4种病毒可能在北京地区广泛分布。     

Occurrence and prevalence of seven bee viruses in Apis mellifera and Apis cerana apiaries in China

Populations of Apis mellifera and Apis cerana in China were surveyed for seven bee viruses: acute bee paralysis virus (ABPV), black queen cell virus (BQCV), chronic bee paralysis virus (CBPV), deformed wing virus (DWV), Kashmir bee virus (KBV), sacbrood virus (SBV), and Isreal acute paralysis virus (IAPV). No KBV was detected from any samples of the two species. In A. mellifera, DWV was the most prevalent virus, but in A. cerana, SBV was the dominant. Simultaneous multiple infections of viruses were common in both species. This is the first report of detection of IAPV and CBPV in A. cerana.     

Molecular and phylogenetic characterization of honey bee viruses,Nosema microsporidia,protozoan parasites,and parasitic mites in China

China has the largest number of managed honey bee colonies, which produce the highest quantity of honey and royal jelly in the world; however, the presence of honey bee pathogens and parasites has never been rigorously identified in Chinese apiaries. We thus conducted a molecular survey of honey bee RNA viruses, Nosema microsporidia, protozoan parasites, and tracheal mites associated with nonnative Apis mellifera ligustica and native Apis cerana cerana colonies in China. We found the presence of black queen cell virus (BQCV), chronic bee paralysis virus (CBPV), deformed wing virus (DWV), Israeli acute paralysis virus (IAPV), and sacbrood virus (SBV), but not that of acute bee paralysis virus (ABPV) or Kashmir bee virus (KBV). DWV was the most prevalent in the tested samples. Phylogenies of Chinese viral isolates demonstrated that genetically heterogeneous populations of BQCV, CBPV, DWV, and A. cerana‐infecting SBV, and relatively homogenous populations of IAPV and A. meliifera‐infecting new strain of SBV with single origins, are spread in Chinese apiaries. Similar to previous observations in many countries, Nosema ceranae, but not Nosema apis, was prevalent in the tested samples. Crithidia mellificae, but not Apicystis bombi was found in five samples, including one A. c. cerana colony, demonstrating that C. mellificae is capable of infecting multiple honey bee species. Based on kinetoplast‐encoded cytochrome b sequences, the C. mellificae isolate from A. c. cerana represents a novel haplotype with 19 nucleotide differences from the Chinese and Japanese isolates from A. m. ligustica. This suggests that A. c. cerana is the native host for this specific haplotype. The tracheal mite, Acarapis woodi, was detected in one A. m. ligustica colony. Our results demonstrate that honey bee RNA viruses, N. ceranae, C. mellificae, and tracheal mites are present in Chinese apiaries, and some might be originated from native Asian honey bees.     

Virus infections in Brazilian honey bees

This work describes the first molecular-genetic evidence for viruses in Brazilian honey bee samples. Three different bee viruses, Acute bee paralysis virus (ABPV), Black queen cell virus (BQCV), and Deformed wing virus (DWV) were identified during a screening of RNAs from 1920 individual adult bees collected in a region of southeastern Brazil that has recently shown unusual bee declines. ABPV was detected in 27.1% of colony samples, while BQCV and DWV were found in 37% and 20.3%, respectively. These levels are substantially lower than the frequencies found for these viruses in surveys from other parts of the world. We also developed and validated a multiplex RT-PCR assay for the simultaneous detection of ABPV, BQCV, and DWV in Brazil.     

Prevalence and distribution of six bee viruses in Korean Apis cerana populations

The prevalence and distribution of six bee viruses was investigated in 527 Apis cerana samples which were collected from five provinces in South Korea. The most prevalent virus, black queen cell virus (BQCV), was present in 75.11% of 446 adult bee samples, followed by sacbrood virus (SBV) in 30.71%. Deformed wing virus (DWV), Kashmir bee virus (KBV), and chronic bee paralysis virus (CBPV) were present at lower levels of 8.07%, 1.56%, and 0.44%, respectively. The most prevalent virus in 81 larvae samples was SBV, with an incidence of 60.49%, followed by BQCV in 48.14%, DWV in 6.17%, and KBV in 1.23% of samples. CBPV infection was not detected in larvae samples, and acute bee paralysis virus (ABPV) was not present in both larvae and adult bee. Simultaneous infections with up to four viruses were also identified. Of these, infections with SBV and BQCV were most frequent in 25.61% of samples. The distribution of these viruses varied considerably throughout the geographic regions investigated. The three provinces of Gyeongbuk, Jeonnam, and Chungbuk had the highest frequency of bee viruses.     

The ectoparasitic mite Tropilaelaps mercedesae (Acari, Laelapidae) as a vector of honeybee viruses

The ectoparasitic mites Varroa destructor and Tropilaelaps mercedesae share life history traits and both infect honeybee colonies, Apis mellifera. Since V. destructor is a biological vector of several honeybee viruses, we here test whether T. mercedesae can also be infected and enable virus replication. In Kunming (China), workers and T. mercedesae mites were sampled from three A. mellifera colonies, where workers were exhibiting clinical symptoms of deformed wing virus (DWV). We analysed a pooled bee sample (15 workers) and 29 mites for the presence of Deformed wing virus (DWV), Black queen cell virus (BQCV), Sacbrood virus (SBV), Kashmir bee virus (KBV), Acute bee paralysis virus (ABPV), and Chronic bee paralysis virus (CBPV). Virus positive samples were analysed with a qPCR. Only DWV +RNA was found but with a high titre of up to 10⁸ equivalent virus copies per mite and 10⁶ per bee. Moreover, in all DWV positive mites (N= 12) and in the bee sample virus–RNA was also detected using RT-PCR and tagged RT-PCR, strongly suggesting virus replication. Our data show for the first time that T. mercedesae may be a biological vector of DWV, which would open a novel route of virus spread in A. mellifera. Received 6 June 2008; revised 14 August 2008; accepted 10 September 2008.     

Detection of chronic bee paralysis virus and acute bee paralysis virus in Uruguayan honeybees

Chronic bee paralysis virus (CBPV) causes a disease characterized by trembling, flightless, and crawling bees, while Acute bee paralysis virus (ABPV) is commonly detected in apparently healthy colonies, usually associated to Varroa destructor. Both viruses had been detected in most regions of the world, except in South America. In this work, we detected CBPV and ABPV in samples of Uruguayan honeybees by RT-PCR. The detection of both viruses in different provinces and the fact that most of the analyzed samples were infected, suggest that, they are widely spread in the region. This is the first record of the presence of CBPV and ABPV in Uruguay and South America.     

The Honey Bee Pathosphere of Mongolia: European Viruses in Central Asia

Parasites and pathogens are apparent key factors for the detrimental health of managed European honey bee subspecies, Apis mellifera. Apicultural trade is arguably the main factor for the almost global distribution of most honey bee diseases, thereby increasing chances for multiple infestations/infections of regions, apiaries, colonies and even individual bees. This imposes difficulties to evaluate the effects of pathogens in isolation, thereby creating demand to survey remote areas. Here, we conducted the first comprehensive survey for 14 honey bee pathogens in Mongolia (N = 3 regions, N = 9 locations, N = 151 colonies), where honey bee colonies depend on humans to overwinter. In Mongolia, honey bees, Apis spp., are not native and colonies of European A. mellifera subspecies have been introduced ~60 years ago. Despite the high detection power and large sample size across Mongolian regions with beekeeping, the mite Acarapis woodi, the bacteria Melissococcus plutonius and Paenibacillus larvae, the microsporidian Nosema apis, Acute bee paralysis virus, Kashmir bee virus, Israeli acute paralysis virus and Lake Sinai virus strain 2 were not detected, suggesting that they are either very rare or absent. The mite Varroa destructor, Nosema ceranae and four viruses (Sacbrood virus, Black queen cell virus, Deformed wing virus (DWV) and Chronic bee paralysis virus) were found with different prevalence. Despite the positive correlation between the prevalence of V. destructor mites and DWV, some areas had only mites, but not DWV, which is most likely due to the exceptional isolation of apiaries (up to 600 km). Phylogenetic analyses of the detected viruses reveal their clustering and European origin, thereby supporting the role of trade for pathogen spread and the isolation of Mongolia from South-Asian countries. In conclusion, this survey reveals the distinctive honey bee pathosphere of Mongolia, which offers opportunities for exciting future research.     

Lower Virus Infections in Varroa destructor-Infested and Uninfested Brood and Adult Honey Bees (Apis mellifera) of a Low Mite Population Growth Colony Compared to a High Mite Population Growth Colony

A comparison was made of the prevalence and relative quantification of deformed wing virus (DWV), Israeli acute paralysis virus (IAPV), black queen cell virus (BQCV), Kashmir bee virus (KBV), acute bee paralysis virus (ABPV) and sac brood virus (SBV) in brood and adult honey bees (Apis mellifera) from colonies selected for high (HMP) and low (LMP) Varroa destructor mite population growth. Two viruses, ABPV and SBV, were never detected. For adults without mite infestation, DWV, IAPV, BQCV and KBV were detected in the HMP colony; however, only BQCV was detected in the LMP colony but at similar levels as in the HMP colony. With mite infestation, the four viruses were detected in adults of the HMP colony but all at higher amounts than in the LMP colony. For brood without mite infestation, DWV and IAPV were detected in the HMP colony, but no viruses were detected in the LMP colony. With mite infestation of brood, the four viruses were detected in the HMP colony, but only DWV and IAPV were detected and at lower amounts in the LMP colony. An epidemiological explanation for these results is that pre-experiment differences in virus presence and levels existed between the HMP and LMP colonies. It is also possible that low V. destructor population growth in the LMP colony resulted in the bees being less exposed to the mite and thus less likely to have virus infections. LMP and HMP bees may have also differed in susceptibility to virus infection.     

Viral impacts on honey bee populations: A review

Honey bee is vital for pollination and ecological services, boosting crops productivity in terms of quality and quantity and production of colony products: wax, royal jelly, bee venom, honey, pollen and propolis. Honey bees are most important plant pollinators and almost one third of diet depends on bee’s pollination, worth billions of dollars. Hence the role that honey bees have in environment and their economic importance in food production, their health is of dominant significance. Honey bees can be infected by various pathogens like: viruses, bacteria, fungi, or infested by parasitic mites. At least more than 20 viruses have been identified to infect honey bees worldwide, generally from Dicistroviridae as well as Iflaviridae families, like ABPV (Acute Bee Paralysis Virus), BQCV (Black Queen Cell Virus), KBV (Kashmir Bee Virus), SBV (Sacbrood Virus), CBPV (Chronic bee paralysis virus), SBPV (Slow Bee Paralysis Virus) along with IAPV (Israeli acute paralysis virus), and DWV (Deformed Wing Virus) are prominent and cause infections harmful for honey bee colonies health. This issue about honey bee viruses demonstrates remarkably how diverse this field is, and considerable work has to be done to get a comprehensive interpretation of the bee virology.     

Detection of multiple viruses in queens of the honey bee Apis mellifera L

Individual honey bee Apis mellifera L. queens were examined for the presence of six honey bee viruses including acute bee paralysis virus, chronic bee paralysis virus, black queen cell virus, deformed wing virus, Kashmir bee virus, and sacbrood virus. All viruses, except ABPV, were detected in the samples. Among queens examined for virus infections, 93% had multiple virus infections. The detection of viruses in queens raises the possibility of a vertical transmission pathway wherein infected queens can pass virus through their eggs to their offspring.     

Prevalence of honeybee viruses in the Czech Republic and coinfections with other honeybee disease

Six bee viruses, which occur in Apis mellifera, were monitored in the Czech Republic between 2006 and 2009. Samples of larvae and pupae collected from hives where American foulbrood was detected were screened for bee viruses and in the 125 samples of larvae, there was no confirmed case of a larva infected with both American foulbrood and a bee virus. Of 145 samples infected with the protozoan Nosema apis, there were 23 cases of coinfections with the BQCV virus, 18 with the DWV virus and 11 with the ABPV virus. All coinfections with three or four viruses were also statistically significant apart from the one between ABPV with CBPV and DWV. The PCA ordination diagram indicates that BQCV occurs mainly with Nosema apis and DWV mainly with ABPV.     

Sudden deaths and colony population decline in Greek honey bee colonies

During June and July of 2009, sudden deaths, tremulous movements and population declines of adult honey bees were reported by the beekeepers in the region of Peloponnesus (Mt. Mainalo), Greece. A preliminary study was carried out to investigate these unexplained phenomena in this region. In total, 37 bee samples, two brood frames containing honey bee brood of various ages, eight sugar samples and four sugar patties were collected from the affected colonies. The samples were tested for a range of pests, pathogens and pesticides. Symptomatic adult honey bees tested positive for Varroa destructor,Nosema ceranae, Chronic bee paralysis virus (CBPV), Acute paralysis virus (ABPV), Deformed wing virus (DWV), Sacbrood virus (SBV) and Black queen cell virus (BQCV), but negative for Acarapis woodi. American Foulbrood was absent from the brood samples. Chemical analysis revealed that amitraz, thiametoxan, clothianidin and acetamiprid were all absent from symptomatic adult bees, sugar and sugar patty samples. However, some bee samples, were contaminated with imidacloprid in concentrations between 14 ng/g and 39 ng/g tissue. We present: the infection of Greek honey bees by multiple viruses; the presence of N. ceranae in Greek honey bees and the first record of imidacloprid (neonicotonoid) residues in Greek honey bee tissues. The presence of multiple pathogens and pesticides made it difficult to associate a single specific cause to the depopulation phenomena observed in Greece, although we believe that viruses and N. ceranae synergistically played the most important role. A follow up in-depth survey across all Greek regions is required to provide context to these preliminary findings.     

克什米尔蜜蜂病毒(KBV)研究进展

克什米尔蜜蜂病毒(Kashmir bee virus, KBV)作为一种毒力较强的蜜蜂急性病毒,自20世纪70年代被分离鉴定以来,已发现其广泛侵染世界各地的东方蜜蜂Apis cerana和西方蜜蜂Apis mellifera。KBV在蜂群内通过垂直和水平两种方式进行传播,且狄斯瓦螨Varroa destructor在其中扮演着重要角色,这使得KBV的分布范围持续扩散。目前已报道的病毒宿主除蜜蜂外,其还可侵染熊蜂、胡蜂等多种野生授粉昆虫。同时,KBV作为一种典型的双顺反子病毒科病毒,由于其在分子生物学上与同科的蜜蜂急性麻痹病毒(acute bee paralysis virus, ABPV)和以色列急性麻痹病毒(Israeli acute paralysis virus, IAPV)间的高相似性,对该病毒流行性的调查与检测、分类等研究的混乱局面也接踵而至。本文对过去40多年来的KBV相关研究进行综述,以期为KBV及类似昆虫病毒的后续研究提供一定的参考和借鉴,促进养蜂业的健康发展。