After proviral DNA was extracted directly from infected cell culture or tumors, PCR with strain-specific primers was used to detect ALV-A, ALV-B, or ALV-J (4).
Of these samples, 150 (64.4%) were ALV-J positive, 28 (12.1%) were ALV-A positive, and 8 (3.4%) were ALV-B positive.
The newly isolated ALV-J strain from layer chickens was used to examine the pathogenicity in 1-day-old White Leghorn specific pathogen-free chicks soon after hatching in separate incubators and rooms in the experimental animal house facilities at Harbin Veterinary Research Institute, Harbin, China.
A previous study showed that meat-type birds infected with ALV-J retained a high level of viremia over their lifetime (7) but that layer chickens cleared the infection within a few weeks.
Fadly, the ARS veterinary medical officer who heads the ALV-J research team.
He says a typical call went like this: 'Although we removed all the hens infected with ALV-J, we're still finding new ALV-J cases in their penmates.'
He also wants to see if he can use chicken cells to produce ALV-J proteins for a possible vaccine.