Comparative pathological analysis of systemic atherosclerosis in two cases of Japanese bantams infected with Marek's disease virus.

Infection with Marek's disease virus (MDV) primarily causes neurological disorders and lymphomas; however, vascular syndrome rarely occurs. We herein report two cases of Japanese bantams submitted for a pathological examination, with multiple atherosclerotic lesions observed in the muscular arteries throughout the body. In the first case, diffuse proliferative lesions of neoplastic lymphocytes were formed in the spleen and liver and were considered Marek's disease (MD) with vascular syndrome. In contrast, in the second case, no obvious diffuse proliferative lesions of neoplastic lymphocytes were observed. Viral proteins expressed upon MDV infection, such as MDV-EcoRI-Q (Meq) and phosphoprotein 38 (pp38), were detected by immunohistochemical staining, confirming that vascular syndrome can occur with MDV infection, regardless of the presence of diffuse proliferation of neoplastic lymphocytes characteristic of MD. In addition, it was confirmed that MDV-infected lymphocytes infiltrated the arterial lesions, and viral proteins were observed in the smooth muscle cells of the arterial lesions, suggesting that the infected lymphocytes may be transporting MDV to the arterial lesion sites.