Molecular characterization of Marek's disease virus genomes isolated from white-fronted geese

为了鉴定从大雁中分离出的马立克病病毒血清型1 （MDV 1）的基因组特征，在2003-2005年期间收集了来自北海道200只尖尾鹅、63只豆鹅（Anser fabalis）、15只加拿大鹅（Branta canadensis）和50只俄罗斯远东地区白额鹅（Anser Albifrons）的羽毛尖和血液样本。2003-2005年在北海道采集了147只白额鹅样本。从这些样本中提取细胞总dna，并进行meq基因特异性巢式PCR检测MDV 1基因组。从这些鹅的尾羽中未检测到MDV基因组，但25-30%的样本中meq基因呈阳性。这些结果表明，尽管在这些鹅中没有观察到临床症状，但MDV - 1存在于雁群中。在接下来的实验中，对从白额鹅中获得的MDV1基因组进行核苷酸序列分析，以估计MDV1菌株的致病性。MDV1毒株的meq基因序列与先前报道的强毒MDV1毒株的meq基因序列非常相似。此外，在白额鹅的MDV1株中也发现了糖蛋白(g) L基因的缺失，这种缺失曾在毒性很强的MDV1株中报道过。这些结果表明，在白额鹅中检测到的MDV1毒株具有很强的毒力。然而，鹅源MDV1的gB基因序列与北海道地区鸡源MDV1的gB基因序列略有不同，说明目前鸡与鹅之间的MDV1传播并不频繁。值得注意的是，一株MDV1毒株的meq基因与北海道地区鸡中分离的毒性很强的MDV1毒株非常相似，有必要从鹅种群中进行更大量的样本研究。

To characterize the genomes of Marek's disease virus serotype 1 (MDV 1) isolated from wild geese, feather tips and blood samples were collected from 200 pintails in Hokkaido, 63 bean geese (Anser fabalis), 15 canada geese (Branta canadensis), and 50 white-fronted geese (Anser Albifrons) in the fareast area of Russia during 2003-2005. Samples were also collected from 147 white-fronted geese at Hokkaido during 2003-2005. Total cellular DNAs were extracted from these samples, and the meq gene-specific nested PCR was performed to detect the MDV 1 genome. The MDV genome was not detected from pintails, but 25-30% of samples from thses geese were positive for the meq gene. These results showed that MDV 1 is present in wild goose populations though no clinical signs were observed in these geese.In the next experiment, nucleotide sequence analysis of the MDV1 genomes obtained from white-fronted geese was done to estimate the pathogenicities of the MDV1 strains. The nucleotide sequences of the meq genes of the MDV1 strains were very similar to those of very virulent MDV1 reported previously. In addition, a deletion in the glycoprotein (g) L gene, which was reported in the very virulent MDV1, was also found in the MDV1 strains from white-fronted geese. These results suggested that the MDV1 strains detected in white-fronted geese are very virulent. However, nucleotide sequence of the gB gene of goose-derived MDV1 was slightly different from that of very virulent MDV1 isolated from chickens in the Hokkaido area, showing that the MDV1 transmission between chickens and geese is not so frequent at the present time. It should be noted that the meq gene of one MDV1 strain was very similar to that of very virulent MDV1 isolated from chickens in the Hokkaido area, and it will be necessary to study larger numbers of samples from goose populations.