Basil visited the south coast recently with his family and another canine friend. It was a week after they returned to Sydney that his family noticed his tongue was protruding a little and he seemed weak in the back legs. They rushed him to the emergency hospital, where an engorged tick was found and he was treated for tick paralysis. He then came to stay with us for the next few days while he recovered. Basil has been a lovely patient, and is a good example of a common problem at this time of year, tick paralysis.

Where Do Ticks Occur?
Tick paralysis occurs mainly on the east coast of Australia from Cairns to just about the Victorian border. In the more southern parts of Australia, tick season extends from spring to autumn. In northern Australia, due to the warmer climate, ticks can be found year round. Ticks can be found anywhere there is wildlife, particularly coastal scrub. Bandicoots and possums are the main hosts, but other wildlife and even birds can spread ticks. Wildlife tend to develop good natural immunity to ticks, so can carry hundreds of ticks without developing paralysis. Ticks are usually waiting on long grasses, bushes, or trees and will fall onto your pet or climb on as your pooch passes by. In some cases ticks can hitchhike on towels, sheets hung outdoors or similar items that can then be brought into the home.

What Do Ticks Look Like?
There are three main ticks in Australia, the cattle tick and bush tick are of lesser concern, it is the paralysis tick Ixodes holocyclus that we need to watch for. Ticks are easy to identify, as they have a round bulbous body which will protrude from the skin and 6 or 8 legs. The body varies in size and colour depending on the age of the tick and the stage of feeding, it can be the size of a pin-head or up to 1cm in diameter. The paralysis tick has brown legs and white legs (one brown leg closest to the head, then two white legs, then one brown leg closest to the body) on each side, whereas the cattle tick has only pale coloured legs, and the bush tick has just brown legs. Leg colour is the best way to identify ticks, as their body colour can vary. If you find a tick, carefully remove it and show a veterinarian to check whether it is a paralysis tick.

How Do I Prevent Tick Paralysis?
If you are going to a tick area, use Frontline every 2 weeks, Advantix, or Proban. Ensure that you tick search daily even if you are using a preventative, as it only takes one tick to cause paralysis and none of the products are 100% effective. A tick search should always begin at the front of the body, where most ticks are found. Search in a systematic way, ensuring you look up inside the lips, in the ears and between the toes. If you have a long-haired dog, clipping may make it easier to search.

Removing a Tick
If you find a tick, place a drop of Frontline or Advantix on the tick and wait until its legs stop moving before removing it. Do not put anything irritant like methylated spirits on the tick, and certainly don’t try to burn it! If you don’t have any tick prevention handy, don’t delay in removing the tick, simply use a pair of tweezers to grab around the head (not the body) and twist to remove it. It will be latched on tightly, so be prepared to use some force to twist and pull. The toxin is located in the body of the tick, so it doesn’t matter too much if part of the head/mouth parts are left in the skin, no more toxin will be injected. Ticks can spread disease to humans so please be careful when handling them.

So What Happens When a Tick Attaches?
When a tick attaches, it starts injecting a toxin that binds to nerves where they join to muscles, causing paralysis. It is the female tick that attaches to feed, and intially the rate of engorgement of the tick is slow, as is the rate of toxin injection. After 4 days, feeding increases, and a great deal of toxin is injected. This is why it is often 5-7 days after visiting a coastal area that tick paralysis develops.

Clinical Signs
Initially the signs of tick paralysis are somewhat vague, your pet may be a little quiet and lethargic and not want to eat. An altered bark, coughing, drooling, gagging, vomiting and large dilated pupils may be apparent. Ultimately paralysis occurs, which initially appears as just a little lameness or wobbliness in the back legs or a slightly ‘drunken’ gait. This progresses to a complete inability to move, and includes the muscles involved in breathing. The tick toxin also has a direct effect on the heart and can cause a build-up of fluid in the lungs. After the tick is removed, and even after tick serum is administered, signs can worsen for 24- 48 hours, and many pets can die despite treatment. Never give a pet with tick signs food or water.

Treatment
The earlier your pet receives treatment for tick paralysis, the better the prognosis. Hospitalisation is essential to reduce activity and limit activation of muscles that can lead to more tick toxin binding. Some pets require a ventilator to help them breathe. Because muscles are weak and the gag/swallow reflex that stops food going down into the lungs is often absent, it is not safe to give food or water by mouth. Intravenous fluids are required until a good strong gag reflex returns. Basil was extremely lucky that his owners noticed his tick paralysis promptly and sought veterinary attention when they did! He required hospitalisation and fluids and could not be fed, but recovered relatively quickly from his experience.

© Eloise Cotton, Livingstone Road Animal Health Centre