title: Pathogenicity of a Marek's disease virus for chickens vaccinated with graded doses of herpesvirus of turkeys.
abstract: Six different groups of one-day-old chickens were vaccinated with herpesvirus of turkeys (HVT) vaccine at doses of 0, 4, 16, 64, 256 and 1,024 plaqueforming units. At 9 days of age they were challenged with an acute strain of Marek's disease herpesvirus (MDHV). Gross and microscopic lesions in nerves and gonads were investigated and combined for quantitative expression of MDHV pathogenicity. Including the microscopic lesions improved the accuracy of the HVT doses/MDHV response. The qualitative aspects of late microscopic lesions could be related to acquired resistance or to persistence of susceptibility in vaccinated chickens.
mesh_terms: D000818:Animals; D002645:Chickens; D006564:Herpesviridae / Q000276:immunology*; D007273:Injections, Intramuscular; D008380:Marek Disease / Q000473:pathology / Q000517:prevention & control*; D014422:Turkeys / Q000382:microbiology; D014611:Vaccination / Q000662:veterinary*; D014765:Viral Vaccines / Q000008:administration & dosage*
chemical_list: D014765:Viral Vaccines