Tick Paralysis in Cats

Summary

Tick paralysis is primarily a disease of Australian cats with only rare occurrences reported in North American domestic cats. Tick paralysis refers to widespread muscle paralysis that occurs in response to a neurotoxin present in the saliva of some species of ticks which are endemic to Australia. Cats with tick paralysis present with uncoordinated gait, weakness of the limbs, paralysis, and difficulty breathing. Symptoms usually appear 3-5 days after the tick bite occurs.

Tick paralysis is an emergency, and affected cats need immediate medical attention. Removal of ticks is critical to successful prevention and treatment of tick paralysis. Tick antitoxin may be indicated in some, but not all, cases. Cats who cannot breathe effectively are treated with supplemental oxygen and/or mechanical ventilation. Paralyzed cats require intensive nursing care while their muscles recover from the toxin. Cats suffering from tick paralysis are particularly susceptible to stress-induced airway obstruction, so anti-anxiety medications may be required. Most cats make a full recovery within 24-48 hours with appropriate treatment. Tick paralysis can be prevented by using vet approved flea and tick medication. Always consult with a veterinarian before using external parasite control.

Risk Factors

Tick paralysis in cats primarily occurs in Australia, with only rare reports in domestic cats elsewhere in the world. When tick paralysis does occur, it presents a life-threatening emergency. A cat showing weakness in the limbs, paralysis, difficulty swallowing, or difficulty breathing — even without known exposure to ticks — needs immediate medical attention.

Possible Causes

Tick paralysis is caused by a neurotoxin found in the saliva of certain species of ticks which are primarily found in Australia. While feeding on its host, the tick delivers the neurotoxin into the lymphatic system where it spreads throughout the body. The toxin affects muscle contraction, including the muscles involved in breathing. Tick paralysis is most common in the spring and early summer, when female ticks are most active.

Main Symptoms

Symptoms of tick paralysis usually appear 3-5 days after tick attachment, and worsen rapidly over the following 24-48 hours. In some environmental conditions, like cooler weather, it may take up to 14 days for symptoms to start. 

The primary symptoms are:

• Incoordination • Ataxia (difficulty walking) • Weakness • Collapse

• Lateral recumbency (the cat can not rise from lying on its side) • Paresis (partial paralysis) • Paralysis

• Increased breathing rate • Difficulty breathing (dyspnea)

Detailed Characterization

Other symptoms associated with tick paralysis in cats include:

• Changes to the character of the meow or difficulty vocalizing (dysphonia) • Inability to meow (aphonia) • Unkempt appearance • Dilated pupils (mydriasis)

Australian veterinarians have developed  a four-stage classification system for cases of tick paralysis. As the condition progresses, affected cats move through the following stages:

• Stage 1: the muscles are weak but the cat can still walk and stand

• Stage 2: the cat cannot walk but can stand

• Stage 3: the cat cannot stand but can still sit up

• Stage 4: the cat cannot sit up and lays flat

Animals in Stage 3 and 4 are considered to have a poor prognosis. 

Some cats show only respiratory symptoms and no obvious motor deficits.

Testing and Diagnosis

Note that the best treatment for any tick-related illness is prevention. Tick-borne illnesses are effectively prevented by year round veterinary preventative external parasite control. Always consult a vet before selecting external parasite control as some products on the market are not proven to be safe and effective for use.

In Australia where tick paralysis is most common, diagnosis is often presumptive and based only on presentation of typical symptoms and exposure to tick habitat. Routine tests like blood work and diagnostic imaging may provide more information about a cat’s condition and prognosis, but these are not always necessary. 

Ticks must be removed for the cat to recover from tick paralysis. Clipping the cat’s coat may be necessary to ensure all ticks are removed. External parasite control agents are used to kill any remaining ticks. 

In some cases, the tick(s) may have already dropped off of the cat, making diagnosis difficult. Even if a tick is not found, treatment must be administered promptly. Tick antitoxin is administered where indicated, allowing the neurotoxin to be expelled from the body without doing further damage. Tick antitoxin can have side effects, so it may not be administered to cats with mild symptoms that aren’t rapidly getting worse. Once the need for antitoxin is established, additional treatment to address the symptoms may include:

• Physical stabilization and support of the cat while waiting for the muscles to recover

• Supplemental oxygen and/or mechanical ventilation for cats who cannot breathe adequately

• Intensive nursing care to address hydration, nutrition, and elimination of body wastes (depending on the severity of paralysis)

• In-clinic monitoring: Symptoms may worsen significantly before recovery, so close monitoring is essential to prevent complications

• Cats with tick paralysis experiencing significant stress and anxiety may benefit from anti-anxiety medication

Steps to Recovery

Feline tick paralysis resulting from Australian paralysis tick bites generally has a good prognosis with appropriate early treatment. Most cats recover with no long-term effects. Cats that are severely affected with profound weakness, a low body temperature, or those who require mechanical ventilation are less likely to recover. The mortality rate, even with antitoxin treatment, is approximately 2%.

Prevention

Tick paralysis is not contagious, but ticks can transmit the neurotoxin to any animal they are attached to, including humans. This is why external parasite control is the best prevention against this and any other tick-borne illness.

Is Tick Paralysis Common in cats?

Tick paralysis is reported in approximately 10 000 domestic animals (including cats) per year in Australia. Australian cats who go outdoors, particularly in the spring and early summer, are most at risk of tick paralysis. Outside of Australia, tick paralysis is not commonly reported.

Typical Treatment

• Removal of ticks • Application of an external parasite control product • Tick antitoxin (where indicated) • Sedation

• Supportive care  • Mechanical ventilation (where indicated)