Monocytosis is associated with the onset of leukocyte and viral infiltration of the brain inchickens infected with the very virulent Marek's disease virus strain C 12/130

Abstract

Marek's disease (MDV) virus is mainly known for the induction of visceral lymphomas and lymphoidinfiltration of peripheral nerves. Recently, additional tropism for the central nervous system has been recognisedas a distinct feature of disease induced by very virulent MDV isolates. During the analysis of changes in theperipheral blood leukocyte subpopulations in chickens infected with either a virulent (HPRS-16) or a veryvirulent (C12/130) strain of MDV, we observed a marked monocytosis in chickens infected with C12/130.Perivascular cuffing in brain and mononuclear cell infiltration into the meninges of chickens infected with C12/130 were associated with the appearance of the monocytosis from 6-10 days post-infection. Our results showthat a peripheral blood monocytosis may be a contributory factor in establishing or accelerating the severity ofmononuclear infiltration into the meninges and perivascular spaces in the brain during infection by very virulentC12/130 strain of MDV.