A cat with Australian paralysis tick envenomation can keep getting weaker for 24 to 48 hours after the tick is off. That is the fact owners most often get wrong. Removal is necessary, and in most of the world it is also enough: with the Dermacentor ticks of North America and Europe, weakness usually starts to lift within 24 hours of removal and is gone by 72. Along Australia's east coast, where Ixodes holocyclus lives, the clock runs the other way.
What the salivary toxin does
Holocyclotoxin is a 5–6 kDa protein made in the tick's salivary glands. Output peaks on day 3–4 of attachment, which is exactly when the first signs appear. The toxin blocks presynaptic release of acetylcholine at the neuromuscular junction — the same final step botulism attacks. The nerve fires; the muscle never receives the order. Because the block sits at the nerve terminal rather than in the spinal cord, the cat stays conscious, feels pain and keeps normal sensation while its legs stop obeying. Weakness climbs in a fixed order: hind limbs, then forelimbs, then the throat and the muscles of breathing.
Why cats usually get off more lightly
Cats are resistant to most paralysis ticks. Merck lists them as unaffected by I. cornuatus and I. hirsti; only I. holocyclus produces the severe syndrome in this species, and even then the disease tends to be milder than in dogs, with fewer respiratory complications and a better prognosis. The word usually is load-bearing. In a retrospective series of 2,077 cats with tick paralysis, 6% were ill enough that mechanical ventilation was recommended — about 1 in 17.
The 24–48 hour paradox
Two tick groups, two sets of rules.
- Ticks outside Australia (Dermacentor andersoni, D. variabilis): signs appear 5–9 days after attachment and progress over the next 24–72 hours. Remove the tick and most patients improve within 24 hours, with complete recovery by 72.
- Ixodes holocyclus: signs appear 3–5 days after attachment (rarely up to 18) and progress rapidly over 24–48 hours. Removing the tick does not stop the process, because toxin already in the circulation keeps binding. In severe cases, death from respiratory muscle failure can follow within 1–2 days of the first sign.
Only female ticks cause paralysis; males do not feed. Larvae can paralyse cats. A tick under 4 mm is not a safe tick: 4 mm describes a typical fourth-day I. holocyclus, and smaller ones have caused signs.
Three signs the breathing muscles are involved
Leg weakness is frightening; respiratory weakness is what kills. Australian clinics grade breathing from A (normal) to D (severe). Three findings move a cat into the danger band.
- Effort at rest. An abdominal push with every breath, a stiff restrictive pattern, coughing, gagging or retching. That is grade C or worse.
- Throat and voice failure. A changed or missing meow, a grunt when the chest is squeezed, drooling, water returning through the nose. Laryngeal paresis is why these cats aspirate.
- Open-mouth breathing or a falling rate. Grade D covers severe dyspnoea, cyanosis, open-mouth breathing and a respiratory rate that drops. A slowing rate in a paralysed cat means fatigue, not improvement.
Cats bring their own trap: early in the disease they can develop asthma-like bronchoconstriction — expiratory wheeze, hard abdominal effort, exhaustion after a few steps. Many are treated for asthma first, because nobody has found the tick yet.
The hospitalisation window
Gait is graded 1 to 4. Stage 1 walks but is weak; stage 2 stands but cannot walk; stage 3 cannot stand but can right itself; stage 4 cannot right itself. Stages 3 and 4 account for roughly 30% of cases and carry a poor prognosis. A cat at stage 3, or at respiratory grade C, belongs in hospital now — not on the sofa being watched overnight. Among ventilated patients, survival to discharge is 52.6–77% when lung disease is present and 90.5% when it is not; median ventilation time runs 23–48 hours, with a range of 3 hours to 10 days. Cats are most often ventilated for hypoventilation rather than lung damage, which is why their outlook is better than the raw figures suggest.
Telling it apart from botulism and GBV
All three produce a flaccid, ascending, lower-motor-neuron paralysis. History and pupils separate them faster than any blood test.
| Feature | Tick paralysis | Botulism | Polyradiculoneuritis (GBV) |
|---|---|---|---|
| Tick or crater | Tick found, or a 1–3 mm crater | None | None |
| Onset | 3–9 days after attachment | 12–72 hours after carrion or raw meat | 1–3 days after a bite or vaccination |
| Pupils | May dilate late | Widely dilated, tear production down | Normal |
| Reflexes | Reduced to absent | Absent | Absent |
| Recovery | 24 hours (non-holocyclus); days with antiserum | About 3 days in the reported cat case | Weeks to months |
Botulism in cats is rare but documented: one outbreak among eight cats fed pelican carrion killed four. The tell is a clear exposure plus mydriasis and dry eyes. Polyradiculoneuritis involves no toxin at all; it is immune-mediated, and time is the treatment.
Find the tick, then leave the crater alone
Fine-tipped tweezers, gripped as close to the skin as possible, pulled straight up with steady pressure. No twisting, no kerosene, no alcohol, no lit match. Then search again: inside the ears, between the toes, under the collar, around the anus, inside the mouth. A crater 1–2 mm deep and 1–3 mm wide with a raised red rim proves a tick was there even when the tick is gone. Never put a permethrin or pyrethrin product made for dogs on a cat; that is a different poisoning, and a faster one.
The month after discharge
Before a cat goes home it should pass a drop test: released from 10–20 cm above a padded table, it should right itself and land with its chin up. Still-affected cats land heavily, chin first. After discharge, keep the cat out of heat, stress and strenuous play for at least a month, search the coat daily, and do not trust any product to be fully effective — one attached tick is enough to start the whole sequence again.
This article does not replace a veterinary diagnosis. Tick paralysis cannot be confirmed or excluded at home, and the gap between a cat that walks into the clinic and one that needs a ventilator can be a few hours. If you find a tick and any weakness, call an emergency hospital before you start reading further.
Terms mentioned in this article
Frequently asked
How long after a tick attaches do cats show signs of paralysis?
With Australian paralysis ticks (Ixodes holocyclus) the first signs usually appear 3 to 5 days after attachment, occasionally as late as 18 days. With North American Dermacentor ticks the interval is longer, about 5 to 9 days, and then signs progress over the following 24 to 72 hours. The toxin peaks around day 3 to 4 of feeding, which is why a tick you found yesterday may already have been attached for days.
Can a cat recover from tick paralysis without going to a vet?
For non-holocyclus ticks, many cats improve within 24 hours of correct removal and are normal by 72 hours, so removal is the treatment. You cannot identify the tick species reliably at home, though, and with Ixodes holocyclus the disease keeps progressing after removal. Any weakness, voice change, drooling or change in breathing means an emergency visit: cats at gait stage 3 or respiratory grade C are the ones that end up on a ventilator.
Does a tick have to stay attached for 24 hours to cause paralysis?
No. The famous 24-hour rule is about disease transmission, such as Lyme bacteria moving from the tick's gut after a day of feeding. Paralysis is different: the salivary toxin accumulates with feeding and reaches dangerous levels after roughly 72 hours of attachment, and a tick under 4 mm can still cause signs. Removing a tick quickly is always right, but a tick found within hours does not rule out toxin exposure.