Tick paralysis is defined as a flaccid, lower motor neuron paralysis caused by salivary neurotoxins from certain species of female ticks. Said in other words, tick paralysis is a paralytic disease caused by the attachment and bite of some ticks under some circumstances in some dogs. The problem does not seem to occur in cats in the United States. Not all tick infested dogs develop tick paralysis and not all female ticks are capable of producing the neurotoxin.
In the United States, the disease is most commonly associated with the common wood tick, the Rocky Mountain wood tick, the lone star tick, and the Gulf coast tick – different genera and/or species of ticks. However, you would almost have to be a devoted parasitologist to be able to look at the ticks and know which one is which. In Australia, the disease is caused by a different genus of tick and the disease there is much more severe and more likely to be fatal.
The female tick attaches herself to the dog and begins to suck blood. In the process, some of her saliva is fed back into the dog and the neurotoxin (if present in that tick) affects the chemical mediators of nerve transmission. The disease begins with a weakness of the hind legs. The dog may initially wobble when walking but then rapidly progresses to a posterior paresis (weakness of the hind legs and hips) and then to a posterior paralysis (inability to use the hind legs). The paresis and paralysis then ascends the spinal cord (moves toward the head) and will ultimately cause the inability to use the front legs. Respiration is affected in severe cases and once the respiratory muscles are paralyzed, death is the result.
The affected dog usually remains mentally bright and alert and retains bowel and urinary function. Despite the muscular paralysis, pain reflexes are still in tact. The clinical appearance is usually that of a wide eyed, anxious dog lying on its sternum (chest) with all four legs spayed out in different directions and may or may not have swimming motion of the limbs. The dog is not in pain but is aware of the fact that it can’t get up and do what it would like to be doing. Respiration is usually not adversely affected. It is our experience that the causative tick is usually attached somewhere near or along the dorsal midline anywhere from the tip of the nose to the tip of the tail.
The condition must be differentiated from botulism (acutely fatal), coonhound paralysis, polyradiculoneuritis, and any of the several myopathies. Treatment involves removing (killing) all ticks and providing supportive care until the patient’s liver and kidneys have a chance to detoxify the neurotoxin. This supportive care ranges from a minimal effort to major life supporting actions. Recovery can occur with hours but may take several days.
The condition is most commonly seen during the heavy tick season in the spring and summer and less commonly in the fall. Prevention is achieved through tick control. There are only 3-4 good tick products on the market; most of the products out there are of minimal value. Remember that even the best of the tick preventing products has its limitations and downside. Owner unawareness of the limitations of the product that he/she has chosen will likely reduce the effectiveness of the product. Our staff can provide limited advice over the phone. If you have complicating factors or multiple pets, you may need an in-clinic consultation. In either case, we recommend that you consider some kind of effective tick control for your pet.