PATHWAYS OF DISPERSION OF RNA VIRUSES THAT AFFECT HONEY BEES

REYNALDI FJ; SGUAZZA GH; GENCHI GARCIA M.L.; LUCIA M.; BRAVI ME. ; PECORARO MR; GALOSI CM

Estambul

Congreso; 45th Apimondia International Apicultural Congress; 2017

Apimondia

Honey bees, along with other species of wild pollinators, contribute to the pollination of natural systems as well as industrialized crops, which benefits for biodiversity, food production and the production of fiber used in our society. However, in the last decade, multiple cases of depopulation of bee colonies have been detected at the end of winter. Different factors seem to contribute to these reduction of bee populations, such as several pathogens and parasites, changes or even losses of their ecosystem, and the use of agrochemicals. All these factors alter the defense mechanisms of the immune system, and the viruses circulating take advantage of this situation in the colony generating disease.The objective of this work was to study the putative routes of viral dispersion in colonies of honeybees. In this trail, we used twenty-five bee colonies that were not treated for V. destructor mite in the last year. After a year without acaricide treatment, in the summer of 2015 the presence of V. destructor was quantified, samples of bees and mites were collected and the colonies were treated with commercial acaricides. Three samples were then taken in the autumn and winter of 2015 and summer of 2016. An mPCR RT was performed with bees and mites collected to detect 7 viruses, Israeli acute Paralysis Virus (IAPV), Deformed wings virus (DWV), sacbrood bee virus (SBV), Black Queen Cell Virus (BQCV), Acute Bee Paralysis Virus (ABPV), Kashmir bee Virus (KVB) and Chronic Bee Paralysis Virus (CBPV). In the 4 sampling periods, the 2 most common wild pollinator specimens in our region (Bombus pauloensis and Xylocopa augusti) were also sampled within 200 meters of the experimental apiary. At the beginning of the trail 100% of the hives had V. destructor (mean infestation level 11.85%). In autumn, after treatment with coumaphos, 10% of the hives were infested (3% of infestation level), in winter the mite was not detected and in the summer of 2016 60% of the hives were detected with a mean infestation of 1.03%.The presence of viral agents in these samples fluctuated independently of the amount of mites recorded. In wild pollinators of the SVB, BQCV and DWV were detected.We concluded that there is a relationship between the mite and the presence of certain viruses such as DWV or CBPV. In this sense, both mites and pollinators could explain the fluctuation of some viruses. However, other viruses such as ABPV or BQCV that were not detected neither in varroa nor in wild pollinators, increased their incidence in the absence of these possible vectors. For this reason, the study and understanding of the viral dispersion mechanisms in hives would allow us to designing alternatives for viral management.