The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
The causative agent of MD is a cell-associated lymphotropic alphaherpesvirus. The virion has a spherical structure consisting of an electron-opaque core containing viral DNA, an icosadeltahedral capsid surrounding the core, an amorphous tegument surrounding the capsid, and an outer envelope containing viral glycoprotein spikes on the surface. MDV DNA is a linear double-stranded molecule of about 170 kb consisting of a unique long region (UL) flanked by a set of inverted repeat (TRL and IRL) regions and a unique short region (US) flanked by another set of inverted repeat (IRS and TRS) regions (Ross, 1999). The complete genomic sequence of MDV has recently been described (Lee et al., 2000; Tulman et al., 2000). The viral genomes in the infected cells are maintained either as circular episomes or as integrated forms. Three serotypes of MDV are recognised. Serotype 1 includes all the pathogenic or oncogenic strains of MDV, as well as the attenuated strains of these viruses. Serotype 2 includes naturally occurring non-pathogenic strains of MDV. Serotype3 includes turkey herpesvirus (HVT), the non-oncogenic MDV-related virus isolated from turkeys. A large diversity exists within serotype 1, with viruses varying in their virulence and oncogenicity. On the basis of their ability to induce MD lesions in vaccinated chickens, serotype 1 viruses are classified as mild (mMDV), virulent (vMDV), very virulent (vvMDV) and very virulent + (vv+MDV) pathotypes.
Lee LF; Wu P; Sui D; Ren D; Kamil J; Kung HJ; Witter RL, 2000. The complete unique long sequence and the overall genomic organization of the GA strain of Marek's disease virus. Proceedings of the National Academy of Sciences USA, 97(11):6091-6096.
OIE Handistatus, 2002. World Animal Health Publication and Handistatus II (dataset for 2001). Paris, France: Office International des Epizooties.
OIE Handistatus, 2003. World Animal Health Publication and Handistatus II (dataset for 2002). Paris, France: Office International des Epizooties.
OIE Handistatus, 2004. World Animal Health Publication and Handistatus II (data set for 2003). Paris, France: Office International des Epizooties.
OIE Handistatus, 2005. World Animal Health Publication and Handistatus II (data set for 2004). Paris, France: Office International des Epizooties.
Ross LJN, 1999. T cell transformation by Marek's disease virus. Trends in Microbiology, 7:22-29.
Tulman ER; Afonso CL; Lu Z; Zsak L; Rock DL; Kutish GF, 2000. The genome of a very virulent Marek's disease virus. Journal of Virology, 74(17):7980-7988.
CABI, Undated. CABI Compendium: Status inferred from regional distribution. Wallingford, UK: CABI
OIE Handistatus, 2005. World Animal Health Publication and Handistatus II (dataset for 2004)., Paris, France: Office International des Epizooties.