Other diagnostics include PCR of CNS tissues and immunohistochemistry. Rabid horses may present in a number of ways, and can have any of a wide variety of clinical signs, and like several neurologic diseases in horses, be difficult to diagnose. The spinal cord form and the dumb form are the most common. The spinal cord form is characterized by ataxia, fever and hyperesthesia followed by ascending paralysis, recumbency and loss of anal sphincter tone. The dumb form is characterized by drooling, phayngeal paralysis, depression and anorexia.
Death is usually by cardiorespiratory failure.
After the onset of signs, survival ranges from 2 to 5 days with rare horses surviving for 2 weeks. Diffuse perivascular cuffing with leukocytes in meninges and throughout the parenchyma. Neuronal degeneration, neuronophagia, gliosis and malacia may be present. The rabies virus-specific fluorescent antibody test is most widely used method for confirmating rabies infection. Due to the zoonotic potential of this virus, specialized laboratories are set up for diagnosing this disease.