Marek Disease like Viruses (MDLVs) are a group of highly contagious viruses that belong to the family Herpesviridae and are primarily associated with causing diseases in birds, especially chickens. Named after the veterinarian József Marek who first described the disease in chickens in the early 20th century, MDLVs are known for their ability to induce malignant lymphomas, nerve damage, and immunosuppression.
MDLVs are characterized by their particular affinity for lymphoid tissues, nervous system, and feather follicles. They can be divided into serotypes based on their antigenic properties, and different serotypes of MDLVs may cause varying degrees of symptoms and lesions in affected birds. The transmission of MDLVs can occur through the inhalation of viral particles shed from infected birds or through contact with contaminated environmental surfaces, such as litter, feathers, or dander.
In infected chickens, MDLVs may cause varying clinical signs depending on the serotype and host immunity, ranging from increased mortality rates to more subtle symptoms like weight loss, paralysis, tumors, or feather abnormalities. MDLVs are often associated with immunosuppression, making affected birds more susceptible to other secondary infections.
Control and prevention of MDLVs mainly involve vaccination programs and strict biosecurity measures. Vaccination is crucial in poultry flocks to reduce the incidence and severity of the disease, and various vaccines have been developed for different serotypes of MDLVs.
Overall, MDLVs are a significant concern in the poultry industry due to their potential economic impact caused by reduced productivity, increased mortality, and the need for disease control measures.
