최근 국내에서는 꿀벌 대량소실 현상이 2022년부터 전국적으로 발생하고 있다. 우리나라 뿐 만 아니라, 전세계 적으로 양봉산업에 큰 위협이 되고 있는 봉군붕괴현상은 2016년 미국에서 세계 최초로 보고되었다. 국내에서는 2022년 민관 합동조사 결과, 이상기온, 응애, 말벌 등이 주요 원인으로 지목되었다. 대량소실 현상을 보인 양봉농 가와 정상 농가의 병원체 검출 비교 결과, 유의성있게 검출이 증가되는 병원체는 발견되지 않았다. 그러나, Tyrophagus mite, Trypanosome, Lake Sinai virus, Apis mellifera filamentous virus 등의 신종 응애, 원충 및 바이러 스 감염이 추가로 확인되었다. 국내에서 새롭게 감염이 확인된 기생충과 병원체가 대량소실, 나아가 봉군붕괴현 상에 직간접적으로 영향을 주었을 것으로 사료되며, 지속적인 조사와 연구개발을 통해 기후등 환경변화에 따른 신종 질병 검색과 대책을 마련해야 할 것이다.

Virus infections of the honeybee(Apis mellifera) have been increasingly investigated during the last decade. In general, honeybee viruses are widespread and most of them persist as inapparent infections. We screened honeybee colonies for the presence of several bee viruses, including deformed wing virus(DWV), black queen virus(BQCV), Kashmir bee virus(KBV), Israeli acute paralysis virus (IAPV), sacbrood virus(SBV), acute bee paralysis virus(ABPV), using uniplex RT-PCR. Frequently simultaneous infections with different viruses are diagnosed in seemingly healthy bee colonies. Therefore we developed a multiplex RT-PCR assay for the simultaneous detection of multiple bee viruses.

Sacbrood virus (SBV) is one of the most serious honeybee viruses. The virus causes failure to pupate and death in both larvae and adult bees. Recently, Korean Sacbrood virus (KSBV) caused a great loss in Korean honeybee (Apis cerana) colonies. Although KSBV shows high homology with SBV strains, it has unique motifs and causes different symptoms. Therefore, a simple, sensitive and specific method for detecting KSBV is needed urgently. In this study a reverse transcription loop-mediated isothermal amplification (RT-LAMP) and a novel micro PCR-based detection method, termed ultra-rapid real-time PCR (URRT-PCR) were applied for rapid detection for korean sacbrood virus (KSBV) from honeybees (Apis cerana) infected with SBV in Korea. The LAMP could be detect the virus in RT-LAMP reactions containing 102copies of pBX-KSBV within 30 min, which was 10 times more sensitive than a RT-PCR assay. The URRT-PCR showed high sensitivities which were able to detect 10 copies in the standard assays. In the application of URRT-PCR detection to an KSBV-infected honeybee, the shortest detection time was 10 min 12 sec, including reverse transcription. In addition, these methods could be distinguished between KSBV and other closely-related SBV strains, These rapid methods were rapid molecular-based diagnostic tools and useful tool for the rapid and sensitive diagnosis of KSBV infection of honeybees.

Sacbrood virus (SBV), a causative agent of larval death in honeybees, is one of the most devastating diseases in bee industry throughout the world. Lately the Korean Sacbrood virus (KSBV) induced great losses in Korean honeybee (Apis cerana) colonies. However, there is no culture system available for honeybee viruses, including SBV, therefore, the research on honeybee viruses is practically limited until present. In this study, we investigated the growth and replication of KSBV in cell cultures. The growth of KSBV was demonstrated by RT-PCR, quantitative real-time PCR, TEM and nucleotide sequence analysis. The results demonstrated that SBVshowed the replication signals in mammalian cell lines, including Vero cells without any signs of cytopathic effect (CPE). The results of RT-PCR, quantitative real-time PCR and in vivo infection with KSBV were also indicated the replication. Phylogenetic tree analysis shows our sequence included in distinct group with other SBV strains from China and Korea. It clearly showed the differenciation between field strain and attenuated strain through cell culture. The results of present study demonstrated for the first time that SBV like other animal viruses could be adapted and attenuated in cells through the sequential passages. The sequential adaptation through cell culture could result in discrepancy of pathogenicity of virus and morphological characterization. For this reason, the present results indicated that the cell adapted SBV could be a valuable tool to study the general properties of this emerging virus, including pathogenicity in the future.