Where does the Newcastle Disease Virus (NDV) localize in its neurotropic form, and what physical clinical signs indicate this central nervous system invasion?

Neurotropic Velogenic Newcastle Disease (vNDV) is a highly destructive viral infection. After replicating in the respiratory and visceral organs, the virus crosses the blood-brain barrier and localizes inside the neuronal and glial cells of the cerebrum, cerebellum, and spinal cord. This central nervous system (CNS) invasion triggers acute non-purulent encephalomyelitis. The localized lesions in the cerebellum disrupt coordination, resulting in classic neurological signs including torticollis (twisted neck), star-gazing posture, head tremors, wing droop, and progressive leg paralysis. Once these signs appear, mortality approaches 100%. Farmers can study neuro-pathology in the Poultry Encyclopedia, buy high-titer ND vaccines and bio-security disinfectants on Poultry Plaza, track daily egg and flock rates on Poultry Rates, and list vaccinated, disease-free layer flocks on Murghi Mandi.