Isolation, identification, and complete genome sequence of an avian reticuloendotheliosis virus isolated from geese

Naturally occurring lymphoreticular tumors in geese have been found from time to time in Taiwan, but their etiology has not been determined except through morphological descriptions. This study observed a reticuloendotheliosis virus (REV) infection occurring in a white Roman goose (Anser anser) farm in Yunlin, Taiwan in 2006. These geese showed growth-retarded and nodular lymphoma-like tumors in the liver, lung, kidney, and pancreas. Thirty blood samples were taken for REV detection and 21 (70%) of them contained REV genetic sequences using polymerase chain reaction (PCR). Virus isolation was attempted from 11 blood samples by inoculating the buffy coat onto DF1 cells. Nine (81%) REVs were isolated after three blind passages. The complete proviral sequence from one isolate was determined for phylogenetic analysis by direct sequencing using overlapping PCR products. The length of the provial genome is 8284 nucleotides. By comparing with other published REV complete sequences, the nucleotide percent identity ranged from 93.5% to 99.8% with most LTR varieties, ranging from 74.9% to 99.8%. The present isolated goose REV is most close to REV APC-566, a REV isolated from Attwater's Prairie chickens.