Isolation and some characteristics of a subgroup J-like avian leukosis virus associated with myeloid leukosis in meat-type chickens in the United States.
Several subgroup J-like avian leukosis viruses (ALV-Js) were isolated from broiler breeder (BB) and commercial broiler flocks experiencing myeloid leukosis (ML) at 4 wk of age or older. In all cases, diagnosis of ML was based on the presence of typical gross and microscopic lesions in affected tissues. The isolates were classified as ALV-J by 1) their ability to propagate in chicken embryo fibroblasts (CEF) that are resistant to avian leukosis virus (ALV) subgroups A and E (C/AE) and 2) positive reaction in a polymerase chain reaction with primers specific for ALV-J. The prototype strain of these isolates, an isolate termed ADOL-Hc1, was obtained from an adult BB flock that had a history of ML. The ADOL-Hc1 was isolated and propagated on C/AE CEF and was distinct antigenically from ALV of subgroups A, B, C, D, and E, as determined by virus neutralization tests. Antibody to ADOL-Hc1 neutralized strain HPRS-103, the prototype of ALV-J isolated from meat-type chickens in the United Kingdom, but antibody to HPRS-103 did not neutralize strain ADOL-Hc1. On the basis of both viremia and antibody, prevalence of ALV-J infection in affected flocks was as high as 87%. Viremia in day-old chicks of three different hatches from a BB flock naturally infected with ALV-J varied from 4% to 25%; in two of the three hatches, 100% of chicks that tested negative for virus at hatch had evidence of viremia by 8 wk of age. The data document the isolation of ALV-J from meat-type chickens experiencing ML as young as 4 wk of age. The data also suggest that strain ADOL-Hc1 is antigenically related, but not identical, to strain HPRS-103 and that contact transmission of ALV-J is efficient and can lead to tolerant infection.
Fadly
A M
AM
USDA-Agricultural Research Service, Avian Disease and Oncology Laboratory, East Lansing, MI 48823, USA.
Smith
E J
EJ
D000818:Animals; D000956:Antigens, Viral / Q000032:analysis; D001353:Avian Leukosis / Q000175:diagnosis* / Q000473:pathology; D001354:Avian Leukosis Virus / Q000145:classification / Q000254:growth & development / Q000302:isolation & purification*; D002642:Chick Embryo; D002645:Chickens / Q000821:virology*; D007668:Kidney / Q000473:pathology; D008099:Liver / Q000473:pathology; D008460:Meat / Q000821:virology*; D016133:Polymerase Chain Reaction; D014481:United States
D000956:Antigens, Viral