Chronological study of ultrastructural changes in the peripheral nerves in Marek's disease

• Published in: Neuropathology and applied neurobiology Vol. 5; no. 6; p. 485
• Main Authors: Lawn, A M, Payne, L N
• Format: Journal Article
• Language: English
• Published: England 01.11.1979
• Subjects: Animals; Brachial Plexus - ultrastructure; Chickens; Demyelinating Diseases - etiology; Demyelinating Diseases - pathology; Herpesvirus 2, Gallid; Lymphoid Tissue - ultrastructure; Marek Disease - complications; Marek Disease - pathology; Peripheral Nerves - ultrastructure; Sciatic Nerve - ultrastructure; Specific Pathogen-Free Organisms; Vagus Nerve - ultrastructure
• ISSN: 0305-1846
• DOI: 10.1111/j.1365-2990.1979.tb00645.x

A chronological study was made of the ultrastructural changes in peripheral nerves following inoculation of 1-day-old chicks with a neurogenic strain of Marek Disease virus. No virus particles were found in nerves. Cellular infiltration of nerves was detected as early as 5 days after inoculation and by 3 weeks some nerves contained proliferative lesions which possessed many of the ultrastructural features characteristic of normal, reactive lymphoid tissue. About 4 weeks after inoculation, coinciding with the onset of neurological signs, areas of widespread demyelination appeared within these lesions; lymphocytes and macrophages penetrated and destroyed the myelin sheath, but spared Schwann cells and most axons. Later oedematous, sparsely infiltrated B type lesions were observed, some of which contained demyelinated nerve fibres undergoing repair; these were therefore a stage in the regression of the proliferative lesions. Our observations do not favour the hypothesis that cellular infiltration of nerves in Marek's disease is the direct result of auto-sensitization to normal myelin. They are consistent with the hypothesis that demyelination is a secondary feature and that the primary lesions are preferential sites for immune demyelination.