Detecção, epidemiologia e análise molecular de rotavírus, picobirnavírus e reovírus em aves de corte criadas em granjas na mesorregião metropolitana de Belém, Pará, Brasil

This study aimed to investigate the occurrence of avian rotavirus (AvRV), picobirnavirus (PBV) and avian reovirus (ARV) in chickens raised on farms located in the Metropolitan mesoregion of Belém, Pará state, in the period of 2008 to 2011. For this purpose, 85 pools of fecal samples were collected from 37 farms belonging to eight counties. Viral RNA was extracted from fecal suspensions and subjected to polyacrylamide gel electrophoresis (PAGE) followed by RT-PCR. At least one sample was selected of each municipality wich positive result for nucleotide sequencing of the genes NSP4 (AvRV), RdRp (PBV) and S2 (ARV), and in the case of the PBV samples were cloned before sequencing. PAGE showed positive in 0/85 (0%) samples for AvRV group A, 13/85 (15.3%) samples for PBV and 01/85 (1.2%) samples for ARV. In the case of RT-PCR positive results was observed in 35/85 (41.2%), 42/85 (49.4%) and 28/85 (32.9%) of the samples for AvRV, ARV and PBV, respectively. Of the eight counties studied, seven showed positivity to PBV, and six for AvRV and ARV. Of the 37 farms studied the presence of these viral infections was observed in 19 (51.4%) to AvRV and ARV and 21 (56.8%) to PBV. NSP4 gene sequences had a similarity between 86.3 and 90.5% at the nucleotide level (nt) with prototypes from chicken and 93.5 and 100% similarity at the nt level when compared among them. RdRp sequences showed a high genetic heterogeneity with gene variants resulting between 56.1 and 100% similarity at the nt level with prototypes belonging to different species and sources of contamination and between 50.3 and 100% similarity at nt level when compared among them. S2 gene sequences analysis showed between 90.9 and 94.4% similarity at the nt level with chicken prototypes and 90.1 and 100% similarity at the nt level when compared each other. AvRV, ARV and PBV were detected in broiler farms of the Metropolitan mesoregion of Belém, being the detection by RT-PCR more efficient to detect at least one type of virus in the eight counties surveyed. Except for ...