If your dog is on a tick preventative, you likely know the dangers of tick diseases. But you may not know about one of the most dangerous among them.

Tick paralysis is caused by a poison injected when a certain type of tick feeds on a dog. The toxin goes straight to the dog’s nervous system, damaging nerves that route messages from the spinal cord to the muscles. A single tick can cause a dog to progressively become completely paralyzed.

Tick paralysis is most common during warm weather. Within a week of tick exposure, a dog can become unsteady on its feet or have trouble barking or breathing. Eventually — unless the tick is found and removed — the dog will need to be on a ventilator to stay alive.

So stick with tick preventative, but still be sure to examine your dog frequently — and thoroughly — for ticks.