ABSTRACT
Bees are fundamental in several aspects, especially in relation to plant biodiversity and pollination. Recently, immense losses are being faced in the number of Brazilian colonies, mainly in southern states of the country, which has a strong beekeeping activity. There are indications that, among the reasons for the losses, pathogens that affect the health of bees may be involved. Among them, the microsporidium Nosema and the black queen cell virus (BQCV) stand out for their prevalence. In this study, 92 colonies of 17 apiaries from southern Brazil were evaluated for infection by Nosema ceranae, Nosema apis and BQCV. Nucleic acid extractions and cDNA synthesis were performed from adult bee samples, followed by Reverse Transcription Polymerase Chain Reaction (RT-PCR) and multiplex PCR. Eight BQCV positive samples were subjected to sequencing. The results showed that N. ceranae and BQCV are circulating in the Southern region of the country, which may be the reason for the loss of colonies. N. apis was not found. N. ceranae was found in 57.6% (53/92) of the colonies and BQCV in 32.6% (30/92). Co-infection was found in 25% (23/92) of the colonies studied, a factor that is suggested to be reducing the hosts' longevity due to the synergistic action of the pathogens. The samples submitted to sequencing indicated similarity of 96.8 to 100% between them, in addition to strong similarity with sequences from Asia, United States, Germany and Peru. This study reports the circulation of N. ceranae and BQCV in apiaries in southern Brazil, in addition to being the first phylogenetic analysis of the Brazilian BQCV sequence.(AU)
As abelhas mostram-se fundamentais em diversos aspectos, especialmente com relação à biodiversidade de plantas e polinização. Recentemente, estão sendo enfrentadas imensas perdas no número de colônias brasileiras, principalmente nos estados do sul do país, com forte atividade apícola. Há indicativos de que, dentre as razões para as perdas, possam estar envolvidos patógenos que afetam a saúde das abelhas. Dentre eles, o microsporídio Nosema e o vírus da realeira negra (BQCV) destacam-se pela prevalência. Neste estudo, foram avaliadas 92 colônias, de 17 apiários do sul do Brasil, a respeito da infecção por Nosema ceranae, Nosema apis e BQCV. Foram realizadas extrações de ácidos nucleicos e síntese de cDNA a partir de amostras de abelhas adultas, seguidos de Reação em Cadeia da Polimerase-Transcriptase Reversa (RT-PCR). Oito amostras positivas para BQCV foram submetidas a sequenciamento. Os resultados mostraram que N. ceranae e BQCV estão circulando na região sul do país, podendo ser a razão para as perdas de colônias. N. apis não foi encontrado. N. ceranae foi encontrado em 57.6% (53/92) das colônias e BQCV em 32.6% (30/92). Foi encontrada coinfecção por ambos em 25% (23/92) das colônias estudadas, fator que sugere a diminuição da longevidade do hospedeiro por ação sinérgica dos patógenos. As amostras submetidas ao sequenciamento indicaram similaridade de 96.8 a 100% entre elas, além de forte similaridade com sequências da Ásia, Estados Unidos, Alemanha e Peru. Este estudo relata a circulação de N. ceranae e BQCV nos apiários do sul do Brasil, além de ser a primeira análise filogenética da sequência do BQCV brasileiro.(AU)
Subject(s)
Animals , Bees/microbiology , Nosema/isolation & purification , Microsporidiosis/epidemiology , Dicistroviridae/isolation & purification , Coinfection , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
In Argentina, bee virus studies are still incipient, and there are no studies regarding the climatic effect. The aim of this study was to assess and compare the presence of honeybee viruses in different climatic regions from Argentina. A total of 385 colonies distributed in five Argentinean eco-regions were examined to evaluate the percentage of infestation with Varroa destructor and the presence of seven virus species (Deformed wing virus, DWV; Acute bee paralysis virus, ABPV; Chronic bee paralysis virus, CBPV; Black queen cell virus, BQCV; Kashmer bee virus, KBV; Israeli acute bee paralysis virus, IAPV; and Sacbrood bee virus, SBV) after honey yield. Two viruses, KBV and IAPV, were not detected. The other five viruses were found in different prevalences: DWV (35%), ABPV (21.5%), BQCV (8.0%), CBPV (2.2%), and SBV (1.1%). We found double and triple viral associations in approximately 25% of the sampled colonies. The mean V. destructor infestation in the colonies prior to the acaricide treatment was 7.12% ± 8.7%. The knowledge of the prevalence of these viruses in the region and their relation with the mite and other possible influencing factors is important for preventing colony losses. Further studies are necessary to identify the risk factors associated with virus presence and its relationship with other pathogens such as V. destructor.
En Argentina, los estudios sobre prevalencia de virus en abejas continúan siendo incipientes y no existen reportes acerca de cómo inciden sobre dicha prevalencia las variables climáticas. El objetivo de este estudio fue evaluar y comparar la presencia de virus en abejas melíferas en diferentes regiones agroecológicas de Argentina. A tal fin se evaluaron 385 colmenas distribuidas en 5 regiones agroecológicas de las provincias de Chaco y Santa Fe; en ellas se analizó el porcentaje de infestación con Varroa destructor (ácaro patógeno de abejas) y la presencia de 7 especies de virus (DWV, virus de las alas deformadas; ABPV, virus de la parálisis aguda de la abeja; CBPV, virus de la parálisis crónica de la abeja; BQCV, virus de celda negra de la reina; KBV, virus de la abeja de Cachemira; IAPV, virus israelí de la parálisis aguda y SBV, virus de la cría ensacada). luego de la cosecha de miel. Dos virus (KBV y IAPV) no fueron detectados. Las otras 5 especies de virus se encontraron con prevalencias variables: DWV (35%), ABPV (21,5%), BQCV (8%), CBPV (2,2%) y SBV (1,1%). Fue posible identificar la presencia de 3 y hasta 3 virus simultáneamente en el 25% de las colmenas evaluadas. El promedio de infestación por V. destructor en las colmenas luego de la cosecha de miel y antes del tratamiento con acaricidas fue de 7,12% (±8,7). Conocer la prevalencia de virus en las diferentes regiones agroecológicas y su relación con la presencia del ácaro V. destructor e identificar otros posibles factores que podrían influir en su presencia es relevante para definir estrategias que reduzcan la mortandad de colmenas. Es necesario realizar estudios adicionales para identificar los factores de riesgo asociados a la presencia de virus en las colmenas y su relación con otros patógenos, como V. destructor.