Caracterização de vírus associados a varroa destructor no Rio Grande do Sul

Abstract

Beekeeping is the economic activity derived from the management of honeybees. Such activity has been increasing and taking up space in the market, with trading of both honey and other bee products and the rent of hives, which are used in the pollination of many crops. However, some factors, such as the climate change and the presence of insecticides in the crops, can interfere with this activity because they are responsible for decreasing the number of individuals in the colonies. One of the probable reasons for this phenomenon is the interference of the above stated factors on the immune system of bees, making them more susceptible to pathogens and parasites. Amongst the pathogens, RNA viruses can cause high mortality rates of individuals, reducing the bee population, and consequently reducing the production of honey. However, it is known that viral transmission from individual to individual rarely occurs or does not occur at all, depending on the virus type. Thus, transmission occurs primarily via vectors such as the mite Varroa destructor. The presence of this parasite in free-of-viruses hives does not cause significant damage, but can cause high rates of mortality and abandonment of the colony if associated to viruses. Therefore, it is necessary to identify which viruses are associated to the mites and, possibly, use these parasites as vectors. Within this context, this work aims to identify which viruses are associated to V. destructor mite specimens collected in apiaries from different regions of Rio Grande do Sul. We collected 15 V. destructor mite specimens per hive in apiaries located in São Gabriel, Vila Nova do Sul, Santa Margarida do Sul, Bagé, Hulha Negra, Candiota, Don Pedrito and Barão do Triunfo cities. A total of 5 hives per apiary were used. From these samples, total RNA was extracted and cDNA was synthesized. cDNA samples were subjected to PCR using specific primers for eight viral types (ABPV, BQCV, CBPV, IAPV, KBV, SBPV e SBV, beyond DWV, KV and VDV that make up a multispecific primer) that affect bees. After the PCR reaction, samples were subjected to electrophoresis on agarose gel. The presence or absence of PCR product bands denoted the presence or absence of a specific viral type, respectively. In this work, we identified which are the presence of SBV, DWV and VDV- associated virus V. destructor mite in the apiaries of São Gabriel, Bagé e Barão do Triunfo. That possibly use the ectoparasite mite as a vector for transmission. The data presented herein will be useful in determining the health status of the apiaries in Rio Grande do Sul and in defining more accurate practices in the apiaries. In addition, this work will 9 contribute to the scientific knowledge regarding bee virus associated to V. destructor mites in the state of Rio Grande do Sul, not existent to date.