Detecção e identificação molecular de vírus e Nosema spp. que acometem Apis mellifera

Abstract

Bees are very important insects in agriculture, playing a very important role in pollination and renewal of the ecosystem. However, in several countries’ significant colony losses and declining honey bee populations have been reported. In Brazil, few data are available on the causes of these losses, especially in the southern region of the country, where the highest bee mortality has been reported. The decrease in the number of bees is related to multifactor, being the pathogens, such as viruses, Varroa mite and microsporidium Nosema spp., one of the possible causes. The main bee viruses belong to the order Picornavirales and are classified in the family Iflaviridae and Dicistroviridae. The chronic paralysis virus (CBPV) was not classified as family. The present study aimed to present a bibliographic review about the viruses that affect bees and to determine the occurrence of the main viruses in southern Brazil. With the first study it was concluded that viruses affect bee health and contribute to the loss of colonies and that understanding the role of the pathogen in the hosts will lead to the discovery of new viruses, as well as clarifying the routes of transmission, the association with other parasites, disease symptoms and the development of prevention strategies. In a second study, the occurrence of black queen virus (BQCV) in apiaries in southern Brazil was determined. BQCV was identified in 37.9% (25/66) of Apis mellifera colonies collected from 13 apiaries in the cities of Canguçu, Piratini and Arroio do Padre. The presence of viral RNA was identified only in adult bee samples. In a third study, the occurrence of ABPV, BQCV, CBPV, DWV, IAPV and SBV with multiplex RT-PCR and Nosema ceranae and Nosema apis with multiplex PCR were determined in municipalities of Rio Grande do Sul (RS) and Santa Catarina (SC). BQCV was detected in 36% (38/105) of apiaries in the state of RS, ABPV in 3% (3/105) and DWV in 1% (1/105). In the state of SC, BQCV was identified in 8.5% (5/59) of the samples and DWV in 1.7% (1/59). Nosema ceranae DNA was identified in 59% (59/100) and 23% (23/100) associated with BQCV. Thus, the results show the high occurrence of BQCV and Nosema ceranae in apiaries in southern Brazil, and the presence of ABPV and DWV. This study is expected to contribute to the epidemiology of bee viral diseases, assisting in the diagnosis and the search for prevention and control measures.