RESUMO
Este estudo teve como objetivo determinar a frequência de anticorpos e detectar o genoma viral do vírus da Doença Infecciosa Bursal em criações de frangos de corte e em criações de subsistência localizadas em duas regiões do polo avícola da Bahia. Foram coletadas 758 amostras de soro de frangos de corte e 320 amostras de galinhas de quintal para avaliação da frequência de anticorpos utilizando ELISA indireto. Para a detecção e caracterização do vírus foram coletados 6 pools de bursas de Fabrícius em frangos de corte e 3 pools em criações de subsistência, analisados posteriormente com PCR/RFLP. Os resultados revelaram que não há proteção uniforme na criação comercial nas duas regiões estudadas, sugerindo falha na vacinação e desafio com vírus no ambiente. Também observaram-se altos títulos em galinhas de quintal não vacinadas, com variação nos títulos relacionada com desafios de campo. Nos testes moleculares, verificaram-se que três pools de frangos de corte eram positivos, sendo dois para cepa vacinal (G3) e um para cepa variante (G15). Nas criações de subsistência, houve uma amostra positiva para cepa variante (G15). Os resultados demonstram a necessidade de monitoramento em ambas as criações.
The aim of this study was to determine the frequency of antibodies anti-Infectious Bursal Disease Virus as well as to detect the virus in broilers and chicken backyard, raised in two different regions at Bahia's poultry production area. A total of 758 serum samples were collected from broilers and 320 from chicken backyard, in order to assess the frequency of antibodies using an indirect ELISA. For virus detection and characterization it was collected 6 bursal pools from broilers and 3 from chicken backyard, which were further analyzed with PCR/RFLP. The results showed that there is no uniform protection in commercial flocks of the two different regions, suggesting that it may be occurring vaccination errors and that it may be occurring challenge from viruses at the environment. High titers were observed in no vaccinated chicken backyard. Molecular tests revealed that 3 broilers pools were positive in which 2 matched the vaccine strain (G3) and 1 a variant strain (G15). One sample from free-ranging chickens was positive for the variant strain (G15). These results demonstrate the need for monitoring both types of exploration.
RESUMO
The cDNA nucleotide sequence of genome segment B encoding the VP1 protein was determined for the aquatic birnavirus GC1 isolated from the rockfish Sebastes schlegeli in Korea. The VP1 protein of GC1 contains a 2,538 bp open reading frame, which encodes a protein comprising 846 amino acid residues that has a predicted MW of 94 kDa. The sequence contains 6 potential Asn-X-Ser/Thr motifs. Eight potential Ser phosphorylation sites and 1 potential Tyr phophorylation site were also identified. GC1 contains the Leu-Lys-Asn (LKN) motif instead of the typical Gly-Asp- Asp (GDD) motif found in other aquatic birnaviruses. We also identified the GLPYIGKT motif, the putative GTPbinding site at amino acid position 248. In total, the VP1 regions of 22 birnavirus strains were compared for analyzing the genetic relationship among the family Birnaviridae. Based on the deduced amino acid sequences, GC1 was observed to be more closely related to the infectious pancreatic necrosis virus (IPNV) from the USA, Japan, and Korea than the IPNV from Europe. Further, aquatic birnaviruses containing GC1 and IPNV have genogroups that are distinct from those in the genus Avibirnaviruses and Entomo-birnaviruses. The birnavirusstrains were clustered into 5 genogroups based on their amino acid sequences. The marine aquatic birnaviruses (MABVs) containing GC1 were included in the MABV genogroup; the IPNV strains isolated from Korea, Japan, and the USA were included in genogroup 1 and the IPNV strains isolated primarily from Europe were included in genogroup 2. Avibirnaviruses and entomobirnaviruses were included in genogroup 3 and 4, respectively.