Review on Virulence and Diagnostic Methods of Mareks Disease Virus in Chickens

Abstract

Marek’s Disease is a highly contagious oncogenic and neuropathic disease of chickens caused by Marek’s Disease Virus which is a highly cell-associated Alpha herpes virus that replicates in chicken lymphocytes and establishes a latent infection within T cells. Evolution of Marek’s Disease Virus towards higher virulence have been a concern over the years from mild to virulent, very virulent and very virulent plus. Mareks Disease is diagnosed by clinical examination of infected chickens accompanied with demonstration of postmortem lesions. The technique for diagnosis of infection with Marek’s Disease Virus involves isolation and identification of Marek’s Disease Virus from infected tissues. Virus isolation is usually by virus propagation in cell culture and identification/ quantification by cytopathic changes. Further confirmatory diagnosis of Marek’s Disease Virus can be done by serological test such as Agar Gel Immuno Diffusion Test and Enzyme Linked Immuno Sorbent Assay and molecular based technique such as Polymerase Chain Reaction. High-throughput sequencing technology which is a second-generation sequencing, provide the possibility to rapidly obtain the full sequence of pathogen genome at once for studying virus evolution and development of novel vaccines. Mareks Disease can be controlled by live-attenuated vaccines. In Ethiopia, reports coming from various regions of the country indicated that Marek’s Disease possesses a great threat to the flourishing young poultry industry.