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How to Protect your Cat from Tick Paralysis in Australia



How to cross a tick… and come out on top! 

Having decided that we would always keep our cat indoors, ticks are not an issue we expect to ever encounter but for all those kitties that enjoy the great outdoors, it's essential to keep them protected at all times.

The Tick Rap Sheet 

1) Ticks belong to a group of animals known as arthropods; they have no spine and are therefore invertebrates. They have an outer skeleton, a segmented body and pairs of jointed limbs. 

NB: Fleas are also arthropods, but whereas fleas are classified as insects, having three pairs of limbs, ticks are arachnids, with four pairs of limbs. (No, not all arachnids are spiders!) 

2) Contrary to popular belief, ticks do not have heads. What many people believe to be a head is actually the tick’s mouth part

3) In Australia, there are approximately 100 species of tick. These are broadly divided into “soft ticks” which affect birds and “hard ticks” which affect dogs and cats.
Most Common Ticks in Australia

4) The most commonly-encountered tick species in Australia are the Eastern paralysis tick (Ixodes holocyclus), Southern paralysis tick (Ixodes cornuatus), the brown dog tick, the bush tick, and other ticks affecting our wildlife species.

5) Worldwide, the incidence of tick-borne diseases is increasing due to climate change, urbanisation of rural areas and movement of animals such as domestic pet travel and bird migration. For example, tick preventative treatment is no longer a requirement of domestic pets travelling in and out of the UK. These diseases are caused by the bacteria, viruses, protozoa and other parasites that ticks carry and transmit to the hosts they feed off (Gunn-Moore, 2019).

6) One tick-borne disease of emerging importance is Lyme disease (Lyme borreli bacterium) which causes illness in dogs, cats, cattle and people (Lyme Australia). While many cats don’t show signs of illness, they can suffer lameness due to joint/limb inflammation, fever, anorexia, lethargy, heart complications and possibly neurological disease (Gunn-Moore, 2019)

7) Of major concern in some areas of Australia are the paralysis tick species. Approximately 10,000 cats and dogs present to veterinarians for treatment for paralysis tick each year in Australia. Paralysis ticks can also affect farm and wildlife species (Padula, 2018). The remainder of this article discusses paralysis ticks only.

Paralysis tick prevalence, life cycle and features:

Distribution of Ixodes holocyclus in Australia,
 and an engorged female paralysis tick. 
Image Credit: Boehringer Ingelheim Animal Health

Paralysis ticks can be found along most of the east coast of mainland Australia, as far south as Gippsland in Victoria.

They live in areas which are warm and moist enough to maintain their life cycle. 

Melbourne occasionally sees dogs and cats affected by paralysis ticks, usually when dogs or their owners return to Melbourne from a known tick area. Melbourne does not have a climate which supports tick populations all year-around, because during Summer it’s too dry for them. However, any stow-away ticks which hitch a ride to Melbourne can survive long enough to cause paralysis in the high-risk season (August-November)

The tick life cycle is complicated and involves multiple hosts at different stages of tick development. The entire life cycle takes a year.

Only adult female ticks are capable of causing signs of paralysis in our pets. They do this by feeding off the pet using specialised mouth parts. 3-6 days after attaching, the female tick engorges and produces a neurotoxin in its salivary glands which is transferred to the host. 

Male ticks can occasionally be seen crawling in a pet’s fur, but they have shorter mouth parts than females and do not feed off the host. It can be difficult to distinguish between different tick species, however in paralysis ticks the 1st and 4th sets of legs are darker than the middle legs, which aids identification.

What signs should I look out for in my cat?


Clinical signs in cats can vary from those in dogs. For example, cats affected by paralysis ticks often demonstrate signs of increased anxiety compared with dogs. Other signs in cats (
APTAP 2019) include: 

✔️ Obstruction of the upper respiratory tract (laryngeal paralysis). The larynx is often called the “voice box”; it plays a role in breathing, sound production and keeping food and other foreign matter from entering the respiratory tract. 

✔️ General respiratory distress, such as an increase in the rate of breathing or the effort required to breathe, especially on expiration (breathing out). 

✔️ Cyanosis, which is a bluish appearance to the skin, particularly the mucous membranes such as the lips. This indicates a lack of oxygen being delivered to the body’s tissues. Veterinary advice should be sought immediately for any cat experiencing breathing difficulties and/or cyanosis. 

✔️ Coughing 

✔️ Voice changes

✔️ Difficulties controlling the legs, although the tail can be unaffected. 

✔️ Difficulties with urination

How do I perform a tick search on my cat?

If your cat is at risk of encountering ticks due to geographic location, climate conditions, time of year, lifestyle or contact with other at-risk animals, you should perform a thorough daily tick search. Because female ticks don’t produce their neurotoxin until 3-6 days after attaching to a host, any ticks found during a daily search are unlikely to cause signs of paralysis.

Some cats will resent being “body frisked”, so don’t force them and reward them for allowing you to offend their sense of dignity (food often works well). Turn the search into a patting session, be gentle, and some cats will enjoy the attention and affection! If your cat is a long-haired breed, it is sometimes easier to keep their fur clipped during the tick season, to make searching easier (your local vet can help with this because most cats need to be sedated for clipping).

The majority of ticks are found around the head, neck and front legs of the host, but they can be found anywhere on the body, so a thorough head-to-tail search is required. 

Pay particular attention to small crevices including the eyes, inside the nostrils, ears and mouth, under the cat’s collar, under the armpits, between the shoulder blades, between the toes and around the bottom area / under the tail, where ticks can lodge and be hidden from view. 

In addition to keeping a sharp eye out for crawly imposters, use your fingers to “walk” through the fur and feel for lumps and other inconsistencies on your cat’s skin. 

It’s not uncommon to find skin tags and other growths such as fatty lumps; if you find anything that concerns you, even if it’s not a tick, contact your veterinary professional for advice. If you feel anything unusual, part your cat’s fur and have a closer look. As well as ticks, you might find tick craters where a tick was previously attached.

It’s a good idea to have different people search your cat because everyone has their own method of searching, therefore one person might find a tick or a crater that another person misses.

What should I do if I find a tick on my cat?

If you find a tick on your cat, they are easy to remove using either a commercially available tick hook, or by using your fingers in a twist-and-pull action - don’t be squeamish! 

Many people are worried about “leaving in the tick’s head” but remember ticks don’t have heads! If any of the mouth parts happen to be left in the skin, they will cause much less damage than if you delay removing the tick.

If you do find a tick, it’s worth saving it in a small container to show your veterinary professional, who can assist with species identification if needed (the most common tick species have a similar appearance), and estimate how long the tick was attached to your cat by the level of engorgement.

It’s also crucial that you keep searching the entire cat after finding a tick, because there is no rule that specifies only one tick per host! It might have associates lurking nearby.

It’s not recommended that you use any chemicals or alcohol-based products to kill a tick while it’s still attached to your cat, as this method can do more harm than good.

If you find one or more ticks or a tick crater, contact your local veterinarian for advice. Depending on your cat’s individual circumstances, they might advise you to administer an acaricide (tick preventative product) immediately. They might also advise that you withhold food and water from your cat for 12-24 hours (don’t do this unless advised accordingly). 
(APTAP, 2019)

If your cat is not showing any signs of being unwell (as described above), your vet might recommend that you monitor your cat closely and seek veterinary attention if clinical signs develop. If you’re not able to monitor your cat, or you prefer to err on the side of caution, you can arrange to leave him/her at your local vet clinic for monitoring.

The author’s personal opinion is that if your cat needs hospitalisation for monitoring or treatment of tick paralysis, ensure the clinic is staffed 24 hours a day

If not, I strongly recommend that you transfer your cat to a 24-hour facility where it can be closely monitored overnight, because paralysis ticks don’t just work from 9-5, and respiratory distress and failure can’t be treated if there’s no one on duty to notice. 

It’s crucial to remember that signs of paralysis can occur for up to 72 hours after a tick has been removed, which is why ongoing monitoring and tick searches are so important (search every 6-12 hours for the first 3 days if you’ve found a tick or crater). Because cats also experience increased anxiety, it’s important to keep them in a quiet and stress-free environment, which is temperature-controlled if possible, because additional stress makes breathing more difficult (APTAP, 2019).

If your cat is showing signs of tick paralysis, seek veterinary treatment immediately. In particular, any breathing difficulties can be life-threatening, especially if your cat is stressed or anxious. They need careful and calm handling during transport to a veterinary clinic, in a quiet and darkened environment (such as a towel over their carrier).

Treatment for tick paralysis:

Detailed protocols are in place (APTAP, 2019) to aid veterinarians in the treatment of tick paralysis, and treatment recommendations vary depending on the severity of clinical signs. It is beyond the scope of this article to discuss treatment in detail, but your veterinary team will concentrate on addressing clinical signs and providing supportive care for your cat (and for you!) 

Treatment might include sedation or general anaesthesia to minimise stress, Tick Antitoxin Serum (see below), intravenous fluid therapy (a “drip”), oxygen therapy, monitoring of blood and urine, and other tests and procedures. Patients with severe respiratory distress might need to be put onto a mechanical ventilator to help them breathe until signs of paralysis improve.

Veterinarians utilise two primary methods for assessing dogs and cats affected by paralysis ticks. These are the gait (walking) score and the respiratory score:

The Gait Score: 

1. Mild weakness.

2. Can stand but not walk.

3. Cannot stand but can right itself and maintain sternal recumbency (lying with the breastbone in contact with the floor/horizontal surface).

4. Unable to right itself; cannot maintain sternal recumbency.

The Respiratory Score: 

A. Normal

B. Mild: increased respiratory rate and effort.

C. Moderate: any respiratory disease or difficulty breathing, restrictive breathing pattern, coughing, gagging or retching.

D. Severe: severe difficulty breathing, cyanosis (blue gums and other mucous membranes), progressive reduction in respiratory rate, open-mouth breathing. (Leister et al, 2018)

These scores vary between individual pets and will change depending on whether the pet’s condition is improving or deteriorating. Some pets might experience mild clinical signs only, and might be given a score of 1B (mild weakness and mild respiratory signs), whereas more severely-affected pets might be scored as 3D or 4C. These scores will guide your vet in providing the most appropriate treatment, and monitoring response to treatment.

A common component of treatment in dogs and cats is the administration of Tick Antitoxin Serum (TAS). While many people have heard of TAS, not everyone understands exactly what it is. TAS is a hyperimmune canine serum, taken from the blood of dogs which have developed an immunity to paralysis ticks.

This is not a “tick vaccine” and doesn’t provide future immunity, nor will it affect toxin which is already bound (causing damage) to the host’s nervous system, so it doesn’t result in immediate improvement of clinical signs in affected patients. The role of TAS is to neutralise any unbound toxin circulating in the host, preventing further signs of paralysis.

Because TAS is a blood product, patients can have an anaphylactic reaction, similar to reactions associated with some other blood product transfusions. This risk is increased in cats because TAS comes from dogs’ blood.

Not all dogs and cats will require TAS. If required, the dose rate (how much TAS is given) and the number of doses depends on the animal’s body size and the severity of clinical signs.

Mortality rates in cats:

There is an increased risk of mortality (death):

✔️ in cats with higher gait scores or respiratory scores (as described above)
✔️ if a cat has a low body temperature at initial presentation to a veterinary clinic
✔️ if there is an anaphylactic reaction to the TAS. This risk is higher in cats than dogs and higher still if a cat has received a previous canine antiserum

The risk of mortality is reduced:

✔️ if fur is clipped (enabling ticks to be spotted sooner)
✔️ if a cat receives TAS where necessary
✔️ if the cat is put onto a mechanical ventilator for respiratory failure, to enable effective breathing. (APTAP, 2019)

While this might suggest a grim prognosis, with appropriate veterinary treatment there is a 2% mortality rate in cats, as opposed to 6.9% in dogs. The most common cause of death in cats is respiratory failure; for cats who require mechanical ventilation due to tick paralysis, the survival rate is 83.3% (APTAP, 2019). 

Mild cases which receive early treatment have a >90% survival rate (Padula, 2018). Therefore, bear in mind that life-saving treatment is available, but with extreme cases of intoxication this treatment can be complicated, take time and be very expensive (not to mention extremely traumatic for you and your feline friend). By following simple preventative guidelines, the risks to your cat are greatly reduced.

How can I reduce the risk of tick paralysis in my cat?

The good news is that like so many illnesses, the best treatment for ticks is prevention. This is aided by:

✔️ reducing exposure to ticks by minimising outdoor access, particularly during peak times of the year

✔️ keeping grass cut short and trim back overgrown foliage in your garden, where ticks are more likely to be found

✔️ regular application of an acaricidal (tick) product, all year around. There are numerous products on the market, some of which are combination products to prevent multiple parasite species. 

Talk to your veterinary team about which product will work best for you and your cat, and ensure you only use a product which is licenced for use in cats and which is effective against Ixodes Holocyclus species.

Image of the female Paralysis Tick 
(Ixodes Holocyclus)


Some dog products contain permethrin or similar chemicals which are toxic to cats

Also take note of the “speed of kill” claims on the product label. 
These can vary for paralysis ticks as opposed to other tick species, and remember to follow all manufacturer directions for product use .

✔️ treating all in-contact pets with an appropriate tick prevention product

✔️ performing a daily tick search, following a set pattern and utilising multiple people

✔️ keeping your cat’s fur short during high-risk times of the year

Summary:

If you do find a tick(s) on your cat, early removal of the tick, +/- immediate treatment, results in a successful outcome in the majority of cases. If your cat is severely affected and requires intensive treatment and a long hospital stay, the chances of survival are still high.

One barrier to successful (intensive) treatment is the associated cost, so ensure you have a contingency plan for veterinary emergencies, such as pet insurance or other financial source. It’s additionally devastating to lose a beloved pet when the treatment is available but not affordable.

The take-home message is that the risk of tick paralysis is significantly reduced with effective preventative measures, and always contact your veterinarian if you’re concerned your cat has come into contact with a tick.

If you have these measures in place, your cat will award you the Tick of Approval!

written by Candice Drew, November 2020 for Australian Cat Lover (all rights reserved).

About the Writer

Candice qualified as a veterinary nurse in Australia in 2005, being awarded the Novartis Award for Outstanding Achievement in Veterinary Nursing in her qualifying year. 
She has worked extensively in Australia and the UK, and is a UK Registered Veterinary Nurse. Candice is experienced in general practice, shelter nursing and referral nursing (Surgery and Emergency & Critical Care [ECC]). 

She attained the Diploma of Veterinary Nursing (surgical) in 2009, qualified as a trainer & assessor in 2015, and completed the ISFM Diploma in Feline Nursing in 2018. Candice is interested in most aspects of veterinary nursing but her passions are feline nursing, ECC and working with students.
Candice is the happy slave of a 10-year-old rescue cat named “Maggie”, whom she adopted in January 2018.


References:

Australian Paralysis Tick Advisory Panel (APTAP), 2019: Tick Paralysis of Dogs and Cats. An Updated Guide to Diagnosis, Management, Treatment and Prevention, 2020 update. Boehringer Ingelheim Animal Health Australia Pty Ltd.

Boehringer Ingelheim Animal Health Academy for Nurses: Vet Nurse Technical Advisor in Parasitology Programme module 3 (access for veterinary professionals only), www.animalhealthacademy.com.au

Gunn-Moore, D.: “Beneath the fur: Tick talk – the risks of ticks to cats”, International Society of Feline Medicine webinar, aired on 12.06.19

Leister, E., et al: “Clinical presentations, treatments and risk factors for mortality in cats with tick paralysis caused by Ixodes holocyclus: 2077 cases (2008-2016)”, Journal of Feline Medicine and Surgery, 2018, Vol. 20 (6), 465-478. DOI: 10.1177/1098612X17733628
Lyme Australia: Lyme borelliosis: Clinical Disease in Animals, www.lymeaustralia.com/clinical-lyme-disease-in-animals.html

Padula A.M. (2018) Tick Paralysis of Animals in Australia. In: Gopalakrishnakone P., Vogel CW., Seifert S., Tambourgi D. (eds) Clinical Toxinology in Australia, Europe, and Americas. Toxinology. Springer, Dordrecht. doi.org/10.1007/978-94-017-7438-3_65 
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