Tick paralysis
What causes tick paralysis?
In eastern Australia, tick paralysis is caused mainly by the paralysis tick (Ixodes holocyclus). While feeding, the tick releases a toxin that interferes with communication between nerves and muscles.
Ticks are most common in warm, humid and wet conditions, but cases can occur throughout the year. Both dogs and cats can be affected, including pets that spend most of their time indoors.
What signs might I see?
Signs may begin subtly and can worsen quickly. Weakness often starts in the hind legs and progresses forward, but the toxin can also affect swallowing, breathing, the bladder and the eyes.
• A changed, softer or hoarse bark or meow
• Wobbliness, hind-leg weakness, difficulty standing or collapse
• Retching, gagging, drooling or regurgitation
• Reduced ability to swallow food, water or saliva
• Rapid, noisy or laboured breathing
• Weakness of the face, reduced blinking or dilated pupils
• Vomiting, restlessness or unusual quietness
• Difficulty urinating or a distended bladder
Important: Regurgitation can allow food or fluid to enter the lungs and cause aspiration pneumonia (lung inflammation or infection caused by accidentally inhaling food, fluid or saliva). Breathing muscles may also weaken, leading to respiratory failure.
What should I do if I find a tick or suspect paralysis?
• Remove any visible tick promptly with a tick-removal tool or fine-point tweezers, grasping close to the skin.
• Keep your pet calm, cool and as still as possible.
• Do not offer food or water if your pet is weak, gagging, retching, regurgitating or having difficulty swallowing.
• Transport your pet directly to the nearest veterinary hospital if any signs are present.
• Continue checking the entire body for additional ticks, but do not delay veterinary treatment to complete a prolonged search.
Common hiding places include the head, lips, ears, neck, between the toes, under the collar, around the armpits and groin, and beneath the tail. Ticks can be very small and more than one tick may be present.
How is tick paralysis diagnosed?
Diagnosis is based on the clinical signs, examination findings and identification of a paralysis tick or a recent tick attachment site. A tick is not always found, particularly if it has detached or is hidden under a thick coat.
Your veterinary team may grade the severity of paralysis and perform tests such as bloodwork, blood-gas analysis, chest radiographs, electrocardiography or blood-pressure monitoring, depending on your pet’s condition and suspected complications.
How is it treated?
Treatment combines rapid removal or killing of all ticks, administration of tick antiserum and intensive supportive care.
• Tick antiserum (TAS) to neutralise toxin that is still circulating in the bloodstream. TAS can neutralise unbound toxin but cannot immediately remove toxin that has already attached to the nerves. For this reason, some pets continue to deteriorate during the first 24-48 hours after treatment before improvement begins. TAS is a biological blood product made from donor horse plasma. Although it is not a red blood cell transfusion, please tell your veterinarian that your pet has received TAS before any future antiserum, antivenom or blood-product transfusion.
• A full-body tick search, often including clipping of longer coats
• Application of a fast-acting veterinary tick treatment to kill ticks that may have been missed
• Oxygen therapy and close monitoring of breathing
• Sedation and low-stress handling, because exertion and anxiety can worsen respiratory compromise
• Intravenous fluids and careful nutritional support when swallowing is unsafe
• Bladder care, eye lubrication and frequent repositioning for weak or paralysed patients
• Treatment of regurgitation, aspiration pneumonia, abnormal heart rhythm or other complications when required
Will my pet need intensive care?
Many affected pets require hospitalisation for several days. Pets with severe weakness, aspiration pneumonia or respiratory muscle fatigue may need high-flow oxygen, continuous monitoring or mechanical ventilation while the toxin clears.
Mechanical ventilation is intensive treatment, but dogs and cats with severe tick paralysis can recover when breathing is supported through the critical period.
What is the outlook?
The prognosis depends on how advanced the paralysis is when treatment begins and whether complications such as aspiration pneumonia or respiratory failure develop. Prompt TAS and supportive care improve the chance of recovery.
Most surviving pets improve over several days, but weakness can persist after discharge. Some pets can deteriorate despite treatment, and tick paralysis can be fatal.
Preventing tick paralysis
• Use an effective, species-appropriate paralysis-tick preventative all year round and give every dose on time.
• Never use a dog-only tick product on a cat unless your veterinarian has confirmed it is safe.
• Perform a fingertip search over the entire body every day, even when prevention is current.
• Check pets after walks, grooming, boarding or visits to bushland and coastal areas.
• Speak with your veterinarian about the most suitable product and dosing schedule for each pet.
No preventative product is guaranteed to stop every tick from attaching. Prevention and daily physical searching work best together.
Clinically reviewed and approved by Dr Giulia Agostini, Pet Emergency Senior Veterinarian and Clinical Manager, DVM MANZCVS (ECC) August 2026