Tick paralysis is the only tick-borne disease that is not caused by an infectious organism. The illness is caused by a neurotoxin produced in the tick’s salivary gland. Symptoms usually begin to appear around 6-9 days after a tick (Dermacentor variabilis) has attached to the skin of the dog. This disease is somewhat seasonal and more prevalent in the summer time in certain areas of the U.S. After prolonged attachment, the engorged tick transmits the toxin to its host.
The toxins released by ticks cause lower motor neuron paralysis, which is defined as a loss of voluntary movement and which is caused by a disease of the nerves that connect the spinal cord and muscles. With lower motor neuron paralysis the muscles stay in an apparent state of relaxation. The paralysis ascends to the trunk, arms, and head within hours to days and may lead to respiratory failure and death. On a neurologic exam the dog will appears very weak and possibly paralyzed. Spinal reflexes will be decreased to absent and there could be compromise to the respiratory muscles.
Identifying and detaching the ticks is the first step to preventing the further release of toxins and aggravating the symptoms. Even if no ticks are found, an insecticidal bath may be given to your dog to kill any ticks that may be hidden in the folds of the skin. In some cases, this is the only treatment required and the dog will soon start showing signs of recovery. However, in cases with respiratory paralysis, oxygen supplementation or some other form of artificial ventilation will be required to keep the dog breathing.
The prognosis for this disease is generally good if respiratory failure does not exist. Rapid improvement in neurologic signs typically occurs within a day of removing the tick.
Veterinary Neurology 