Phylogenetic analysis of subgroup J avian leucosis virus from broiler and native XXXX in Taiwan during 2000-2002.

@entity1573 @entity3322 @entity72448
Subgroup J avian leucosis virus ( @entity3322 -J) causes great economic losses in the poultry industry. One in 3 grandparent farms was closed due to @entity3322 -J infection in 1998 in Taiwan. The remaining 2 farms were forced to import breeding chicks from different breeding companies afterwards. We report on the @entity3322 -J infection status among these breeders, their progeny and Taiwan native @entity1573 during 2000-2002. The weekly mortality for the male line among the infected breeders was higher than that for the female line. Sixty-three percent (5/8) of the broiler flocks were infected with @entity3322 -J. The surface (SU) portion of the @entity72448 gene from the @entity3322 -J field isolates was cloned and sequenced. The phylogenetic results show that all of the isolates fell into 2 clusters. Unexpectedly, the isolates from the same breeds fell into different clusters, with a cluster including isolates from different breeding companies. @entity3322 -Js from native @entity1573 crossbred with imported @entity1573 were placed into the same clusters as those from the imported breeds. The high similarities observed in different @entity3322 -J isolates suggest that different @entity3322 -Js were mixed in the pedigree generations in different breeding lines.
