Marek’s diseaseA highly contagious, viral-induced (caused by Gallid herpesvirus 2) neoplastic process affecting poultry.
• Classical Marek's disease—causes asymmetric paralysis of one or more limbs and, with vagus nerve involvement, difficulty in breathing or dilation of the crop.
• Acute Marek's disease—an epidemic illness that affects uninfected or unvaccinated flocks, characterised by depression, paralysis and death in a large number of birds (up to 80% mortality).
• Cutaneous Marek’s disease— causes round, firm lesions at the feather follicles.
• Other findings—immunosuppression, atherosclerosis, ocular lymphomatosis.