Marek's Disease like Viruses (MDLV) are a group of highly contagious viruses that primarily infect birds, particularly chickens and other poultry species. MDLV belongs to the Herpesviridae family and is classified under the genus Mardivirus. Named after the veterinarian Josef Marek, who first discovered the disease, Marek's Disease (MD) primarily affects chickens and causes lymphoproliferative disorders characterized by tumor formation and immunosuppression.
MDLV shares genomic similarities and structural features with Marek's Disease Virus (MDV), the most well-known member of the group. MDLV is known to have diverse strains with varying pathogenicity levels, ranging from mildly pathogenic to highly virulent. The virus is transmitted horizontally from infected birds to susceptible individuals primarily through respiratory droplets or dander shedding.
Once the virus enters the host bird's body, it initially replicates within the respiratory tissues, followed by dissemination to lymphoid organs such as the spleen, thymus, and bursa of Fabricius. MDLV infection results in the transformation and uncontrolled proliferation of lymphocytes, leading to the development of various lymphoproliferative lesions and tumor formation, particularly in nerves, skin, and organs.
MDLV is known to cause severe economic losses in the poultry industry due to reduced egg production, decreased weight gain, immunosuppression, increased susceptibility to secondary infections, and mortality. Vaccination against MDV and other MDLV strains is crucial in disease management, with various vaccines available for prevention. However, the high genetic diversity and evolving nature of MDLV strains pose ongoing challenges in developing effective vaccines.
