Tick Paralysis. The Australian Paralysis Tick (Ixodes holocyclus)
Authored by Dr. Mark Tonzing & Dr. Romilly Haslam
A uniquely Australian emergency. Fast-acting, highly toxic, and potentially fatal if left untreated.
Found predominantly along the eastern seaboard of Australia, the Australian Paralysis Tick injects a potent neurotoxin as it feeds. Unlike ticks in the Northern Hemisphere—which are primarily vectors for diseases like Lyme—the venom of Ixodes holocyclus causes an acute, ascending motor paralysis in domestic pets.
Identification: Unfed, they are small (3-5mm) and egg-shaped. As they engorge on blood over several days, they turn a distinct bluish or light grey color. Where they attach, they deeply embed into the skin, often creating a highly irritable, raised red "crater".
This comprehensive guide serves as an essential resource for our local pet owners, as well as a clinical primer for visiting veterinarians unfamiliar with this unique toxidrome.
The Mt Coot-tha Corridor
Bardon Veterinary Hospital sits directly on the doorstep of Mt Coot-tha and the Brisbane Forest Park. This geographic proximity places our local pets in a high-risk "ground zero" for tick paralysis.
Native wildlife, particularly the long-nosed bandicoot and possums, are the natural hosts for the paralysis tick. As these animals forage through the dense bushland of Mt Coot-tha, Ithaca Creek, and adjacent suburban backyards in Bardon, they drop engorged ticks that subsequently breed. The peak risk season is spring through early summer, though cases present year-round in our clinic depending on winter temperatures.
High-Risk Local Zones:
- Mt Coot-tha Reserve & Walking Tracks
- Gap Creek Reserve
- Ithaca Creek corridors
- Bowman Park & Bardon bushland borders
- Properties adjoining natural scrub or dense foliage
Spotting the Signs
Tick paralysis is an ascending paralysis. It usually starts subtly at the back of the body and moves forward, eventually compromising the respiratory system.
Early Warning Signs
- Lethargy and reduced appetite
- A sudden change in voice (altered bark or meow)
- Weakness in the hind legs (wobbly, uncoordinated gait)
- Reluctance to jump, walk, or stand
- Gagging, retching, or bringing up frothy vomit
Advanced (Critical) Signs
- Inability to stand; full paralysis of limbs
- Labored breathing, grunting on exhalation or panting
- Inability to blink (leading to dry, damaged eyes)
- Blue or pale gums (cyanosis)
What to do if you find a tick:
- Remove it immediately. Grasp the tick as close to the skin as possible and pluck it off. Note: If the head breaks off, don't panic—it does not continue to pump venom once the body is removed.
- Do NOT use chemicals or fire. Do not try to burn the tick off or smother it with chemicals while attached.
- Keep the tick. Put it in a sealed ziplock bag or small container so we can identify the species.
- Do NOT offer food or water. Tick paralysis affects the ability to swallow. Giving water can cause fatal pneumonia.
- Call us immediately. Pets can continue to worsen for up to 3 days even after removal.
Prevention & Home Management
Tick paralysis is entirely preventable with the right combination of medication, physical checking, and environment management.
1. Medication
Routinely administer tick preventatives to your cats and dogs. Modern oral chews or topical treatments provide excellent coverage. For dogs over 6 months of age Bravecto Quantum is an annual slow-release injection that provides ongoing protection against ticks and fleas for 12 months.
⚠️ Crucial Warning for Cat Owners
Cats are highly sensitive to Permethrin, an insecticide used in many over-the-counter dog tick products. Applying a dog tick treatment to a cat can be rapidly fatal. Always use cat-specific preventatives.
2. Daily "Finger-Walk" Searches
Medication is highly effective, but daily physical checks are still mandatory in high-risk areas.
- Remove your pet's collar.
- Gently "finger-walk" your fingertips through the fur right down to the skin level.
- Start at the front: 90% of paralysis ticks attach forward of the shoulders (lips, chin, inside ears, under the collar, and between the front toes).
- If your pet has a long coat, consider clipping it short during tick season.
3. Yard & Environment
Reduce the tick population near your home by making your yard less hospitable to native wildlife.
- Clear leaf litter, tall grass, and brush around the house and lawn edges.
- Keep grass mowed frequently.
- Restrict your pet's access to bushy environments or creeks bordering your property.
- Create a dry mulch barrier around the perimeter of properties backing onto bushland.
Veterinary Protocol: Ixodes holocyclus
Pathophysiology
The salivary glands of the engorging tick secrete holocyclotoxin. This acts rapidly at the presynaptic neuromuscular junction, inhibiting the calcium-dependent release of acetylcholine.
The clinical picture is an acute, ascending, symmetric lower motor neuron paresis/paralysis. The toxin also causes profound autonomic dysfunction (megaesophagus, loss of gag reflex, excessive salivation, mydriasis/anisocoria, and compromised myocardial contractility).
Diagnostic Markers
- Tick crater: Even if the tick is gone, a highly erythematous, crater-like eschar is usually palpable.
- Respiration: Distinctive expiratory grunt due to laryngeal paresis and fatigue of intercostal muscles.
- Gastrointestinal: Regurgitation of frothy mucus (due to megaesophagus). High risk of aspiration pneumonia.
- Pupillary response: Check for anisocoria or delayed PLR.
Standard Treatment Protocol
1. Neutralize the Toxin
Administer Tick Antiserum (TAS). Note: TAS only neutralizes circulating, unbound toxin. It cannot reverse toxin already bound at the motor endplate. Clinical deterioration for 12-24 hours post-TAS administration is common.
Pre-medicate: Atropine (optional, check HR), an antihistamine (e.g., chlorpheniramine), and often a corticosteroid (e.g., dexamethasone) to mitigate anaphylaxis risk from the hyperimmune serum.
2. Search & Destroy
Comprehensive whole-body clip (especially long-haired breeds). Apply fluralaner spot-on (Bravecto spot-on) for dogs and cats. Remove any located ticks.
3. Respiratory & GI Support
Strict NPO (Nil Per Os). Do not attempt oral medications or fluids. Maintain sternal recumbency to prevent aspiration. Suction airways PRN. Intubation/ventilation may be required in Stage 4 paralysis.
4. Nursing Care
Maintain IV fluid therapy for hydration and perfusion. Bladder expression every 4-6 hours (loss of detrusor function). Regular turning to prevent decubital ulcers and atelectasis. Eye lubrication (diminished blink reflex).
Frequently Asked Questions
Common questions from our Bardon pet owners about tick paralysis.
How quickly does tick paralysis happen in dogs and cats?
A tick usually needs to be attached and feeding for 3 to 4 days before symptoms become noticeable. However, once symptoms begin (like weakness or a change in bark), they can progress to life-threatening respiratory failure within hours.
What is the best tick preventative for pets living near Mt Coot-tha?
Modern isoxazoline chews and spot-ons (such as Bravecto, NexGard, and Simparica) are highly effective against paralysis ticks. However, in high-risk bushland areas like Bardon and Mt Coot-tha, daily physical "finger-tip" tick searches of your pet's coat are still mandatory.
What does a paralysis tick look like?
Unfed, they are small (3-5mm), flat, eight-legged, and egg-shaped. As they feed, they become engorged with blood, changing color from whitish to a bluish or light grey. They deeply embed into the skin, often leaving a raised, red "crater".
I removed the paralysis tick, why is my pet getting worse?
The tick continuously pumps toxin into your pet's bloodstream while attached. Even after the tick is removed, the toxin already in the body will continue to bind to nerve endings for up to 24-48 hours, causing your pet to deteriorate. Veterinary treatment with tick antiserum is essential.
Can a cat get tick paralysis?
Yes, cats are highly susceptible to the Australian Paralysis Tick. While they are meticulous groomers and often remove ticks themselves, ticks hidden around the head, neck, and under the collar can easily cause fatal paralysis in cats.
Tick Paralysis is a Medical Emergency
If you have found a tick on your pet, or if they are displaying any signs of weakness, retching, or breathing difficulty, do not wait. Early administration of tick antiserum is critical for survival.