Marek's Disease Virus
Blanca M. Lupiani, Yifei Liao, Di Jin, Yoshihiro Izumiya and Sanjay M. Reddy
from: Avian Virology: Current Research and Future Trends (Edited by: Siba K. Samal). Caister Academic Press, U.K. (2019) Pages: 345-364.
Marek's disease virus (MDV) is a highly oncogenic alphaherpesvirus that infects chickens, causing enormous economic losses to the poultry industry. MDV belongs to the genus Mardivirus and is classified into three serotypes. Only viruses belonging to serotype 1 cause disease in chickens. In susceptible chickens, T-lymphocytes undergo neoplastic transformation. The manifestation of the disease depends on the distribution of the neoplastic lesions. Typically, the disease is manifested by visible lymphomas in various visceral organs and paralysis. Highly pathogenic MDV also causes neurological disease and immunosuppression. MDV is controlled by vaccination using live attenuated vaccines, but vaccinated chickens do not provide sterilizing immunity and cannot block virus transmission of field strains. Vaccination is generally believed to have contributed to increase in virulence of the filed strains leading to vaccine breaks. Among several genes encoded by MDV, meq, which encodes a bZIP protein, appears to play a critical role in the transformation of lymphocytes. With the availability of genome manipulation tools and a natural host system, MDV provides a relevant model to explore the molecular mechanisms of viral oncogenesis. In this chapter, we summarize the current knowledge of MDV molecular biology, pathogenesis and control, as well as the role of individual viral genes in replication and transformation read more ...