TICK PARALYSIS IN DOMESTIC ANIMALS (IN AUSTRALIA)
Caused by Ixodes holocyclus (the Paralysis Tick)
1. What causes tick paralysis?
2. How do I recognize the signs of tick paralysis?
3. How can I recognize a paralysis tick?
4. When and where is my pet likely to pick up a tick?
5. What do I do if I find a tick on my pet?
6. Do animals develop immunity to the tick paralysis toxin?
7. How can I protect my pet against tick paralysis?
8. How effective is treatment of tick paralysis?
9. What do I need to do after my pet has been treated for tick paralysis?
1. What causes tick paralysis?
The adult female Ixodes holocyclus tick can attach to a dog or cat (the host) and burrow its mouthparts into the animal’s skin. The tick sucks the host’s blood and injects its neurotoxin (poison) into the host. On attachment this tick is quite small but it grows in size each day as it sucks blood. The toxin has several effects, most obviously acting on the animal’s muscles and respiratory (breathing) system. The host usually shows no signs of illness for about the first four days, in some cases for up to one or two weeks. However once the cat or dog starts to show signs of illness it can deteriorate quite rapidly and could die within 48 hours. It is important that veterinary treatment should be sought within 24 hours of the first signs of illness.
2. How do I recognize the signs of tick paralysis?
There are THREE main signs to look for:
(1) Weakness of the legs - slowness in walking, a wobbly gait, or a tendency to lose balance or fall over.
(2) Vomiting or dry retching.
(3) Difficulty in breathing, or a change in the breathing pattern.
(Important: Sometimes only ONE of these three signs is present, sometimes two, sometimes all three.)
If you see one or more of these signs, SEARCH your animals body for a tick. Search the whole body, but especially the head and neck areas, including around the ears. If you find a tick then your pet almost certainly has tick paralysis. You may find a little hole in the skin, like a crater or a small scab. This could be the place where a tick has been, in which case the problem is still likely to be tick paralysis. Or you may not find anything. However, if it is the right time of the year for ticks, and you are in a tick area, then it still could quite easily be tick paralysis. Ticks can be very difficult to find on an animal. If in doubt contact a veterinarian.
3. How can I recognize a paralysis tick?
Depending on where you are, Ixodes may be confused with other ticks common in that area. In northern NSW and Qld this would include the Cattle tick (Boophilus microplus) which is usually found only on cattle but may occasionally attach to dogs or other animals.
More commonly, in the coastal areas of NSW and Old, it is confused with the Bush Tick (Haemaphysalis longicomis) which is common on cattle, horses, dogs, and other animals. The size or degree of engorgement is of no use in differentiation. The terms ‘bottle tick‘ and ‘˜shell back‘ are also meaningless and not descriptive of any one species.
Ixodes is lighter in color than the other two ticks, has longer and stronger legs, and larger mouthparts. The male is a fiat, oval, yellowish-brown tick.
The unfed female is also yellowish in color, but, as it engorges, becomes grayish with a brown line (in the shape of a shield) encircling the body. A fully engorged female tick may be 15 to 18 mm in length. Its legs are in a V shape line from its snout down the sides of its body. Of the four pairs of legs, the front and back pairs are brown, the second and third pairs paler in color. If you have difficulty identifying a tick, take the tick to a veterinary clinic and they should be able to identify it for you.
4. What do I do if I find a tick on my pet?
First - Remove the tick. The best way is to first apply to the tick by dropper or spray a suitable insecticide effective against ticks e.g. Frontline or Permoxin. Then after a few minutes grasp the tick firmly between your finger and thumb, give a firm tug, and the tick should come out. Do not use irritant substances such as turpentine, kerosene, or petrol. These will kill the tick but not make it any easier to remove. They will also cause a very nasty sore at the site of the tick bite and cause your pet unnecessary pain.If the tick is too small to grasp with your finger and thumb, use a pair of fine tweezers or Allis forceps. If by any chance the head of the tick stays in the skin scratch it out with your fingernail. The head will not inject any more poison once the body is removed, but it may cause a foreign body reaction similar to a splinter. The spot where you remove a well attached tick is likely to leave a ‘crater’ or small hole in the skin. This will heal eventually. The local effects of a tick attachment are uncomfortable, but fairly insignificant compared with the potential fatal systemic effects caused by the tick toxin throughout the body.
Second - Is the dog showing any signs of tick paralysis? If it is, you should contact a vet as soon as possible, and describe the state of your pet. The vet or vet hospital staff can advise you on how urgently you need to obtain veterinary treatment. If it is outside normal business hours, leave your pet to rest quietly while you contact a vet by phone to make the necessary arrangements. Do NOT give anything (food, water, or medication) by mouth, as an animal affected by tick paralysis cannot swallow properly. If your animal appears normal and shows no signs of tick paralysis, be aware that the toxin can still work and produce a delayed reaction even after the tick has been removed. Keep an eye on your pet for the next 24 hours and if signs of toxicity develop then contact a veterinarian.
5. When and where is my pet likely to pick up a tick?
The likelihood of tick paralysis will depend on the number of ticks active at that time in the area, specifically of adult female ticks.
1. Areas of natural bush land which harbor native animals, particularly bandicoots, are the most likely areas. However an animal may be at risk anywhere close to such an area, as ticks can be carried by other animals and dropped in areas where you might not expect to find ticks. Ticks may also possible be carried by birds, or even possibly be blown short distances on the wind.
2. Anywhere along the coastal area of eastern Australia, from far north Qld. to around Lakes Entrance in Victoria, and also along the east coast of Tasmania. In northern NSW and Queensland this area extends quite a distance inland. Ixodes holocyclus also exists in Papua-New Guinea and portions of India and Indonesia.
WHEN -The danger period is spring and early summer. However, animals living in or visiting areas of natural bush land can pick up ticks in ANY MONTH of the year. The incidence will be higher in periods of increased warmth or humidity, or in years of higher rainfall than average.
6. Do animals develop immune to the tick paralysis toxin?
Native animals which are the natural hosts of Ixodes holocyclus appear (when in their natural environment) to develop immunity to the harmful effects of the tick toxin, arid can carry large numbers of ticks without ill effect.Dogs and cats which live in areas where they regularly pick up ticks will also tend to develop their own immunity. This depends on them getting small doses of tick toxin initially, not enough to cause severe illness, but enough to start the production of antibodies by the animal’s immune system. As they pick up more ticks and are injected by gradually increasing doses of toxin this immunity can become quite strong. Unfortunately this immunity is not long lasting and can be lost from one season to the next if there are no ticks on the animal in the time between. A previously immune dog can therefore suddenly become affected by tick paralysis. Owners should be aware of this risk.Owners are also commonly misled by the fact that a dog frequently carries ticks of the genus Haemaphysalis (Bush Ticks) which resemble Ixodes to some degree but do not inject a toxin. These dogs may have no immunity at all to the Ixodes toxin and can easily be affected by tick paralysis.Dogs or cats which have been given Anti-Tick Serum as treatment for tick paralysis should not be expected to have any increased immunity after treatment.
7. How effective is treatment of tick paralysis?
Some animals which are only mildly affected may recover without treatment by a veterinarian. However to leave an animal untreated is taking a risk with the life of the animal. If you are thinking of NOT treating, at least contact a veterinary clinic for advice and preferably have the animal examined by a veterinarian. Veterinary treatment will significantly improve the chances of survival of any affected animal. However some will die even with the best treatment. The ones which die usually have had a larger amount of toxin injected than normal (as occurs if more than one tick is present) or have been left too long and become severely ill before the owner presents the pet for treatment. Very young and very old animals also tend to be more severely affected, or animals suffering from any other disease or stress at the same time. In my early years of treating dogs and cats with tick paralysis I had 41 deaths out of 415 cases presented (10.1%) over a three year period. In later years I got this down to 36 deaths out of 691 treated (5.2%) over a six year period.In every case the more severely the animals were when presented for treatment, the higher the mortality rate. Treatment of animals showing only mild wobbliness of the legs was 100% successful, with no failures. The most seriously affected group (animals which were paralyzed and unable to lift their head at time of presentation for treatment) had a 36% mortality rate despite treatment. However we still saved 64% of these severely affected animals, all of which would certainly have died without treatment.
8. What do I need to do after my pet has been treated for tick paralysis?
Depending on the severity of toxicity, your dog may have required a stay in Hospital for tick poisoning caused by Paralysis Tick. At the time of going home, the dog may be walking and breathing normally and appear outwardly normal, or alternatively may still be showing some of the signs of tick paralysis (e.g. paralysis or leg weakness).
In either case, the following instructions are VERY IMPORTANT:
(1) FOOD & WATER: Tick poisoning prevents the dog from swallowing properly. Food or water given too early may cause choking, coughing, or inhalation pneumonia which can be fatal. Unless the dog has already been eating or drinking in Hospital, we recommend the following:
(a) The first 24 hours offer water only, in small amounts. If vomiting or coughing occurs, stop offering water.
(b) The second day you can offer soft easy to swallow foods in small amounts. a little often is better than one big meal. If coughing or occurs, stop. In any case the pet’s total food intake should not exceed half of its normal daily food intake, at this stage.
(c) The third day, if there have been no problems, return to normal daily feeding and make water freely available.
(2) PROGRESSION OF SIGNS: When a dog is first treated with Tick Hyperimmune Serum, there is a time lag before it becomes effective, so that the pet’s condition may still deteriorate for a day or more following initial treatment. After this it will normally stabilize or start to recover. Following a stay in Hospital of 24 hrs or more, when a pet is sent home it should not get any worse than it is at the time of discharge from Hospital. lf it does get any worse, for example if it has greater difficulty walking, or starts coughing or vomiting, you should contact your veterinarian as soon as possible.
(3) SEARCH FOR MORE TICKS: Although veterinary and nursing staff search every pet thoroughly for ticks while it is in Hospital, it is impossible to guarantee that one may not be missed. It is also possible for a dog to pick up more ticks as soon as it goes home. You should search the coat thoroughly for ticks every day and remove any you find, if you find any large ones (over 2 mm long), call your vet.
(4) AVOID STRENUOUS EXERCISE OR UNNECESSARY EXCITEMENT: For up to 2 months after suffering from Tick paralysis, your pets body will be slowly recovering from the effects of the poison, even though outwardly it may seem to have made a quick recovery. Its heart, lungs, muscles, and nerves will not be as strong as they were before the disease. Recovery is gradual, and given time, should be complete without any permanent after-effects. However it is important to avoid strenuous exercise or excitement, especially in the first few days. Taking a dog for a long run, for example, could cause a heart attack. We suggest confinement and rest for the first few days, and avoidance of serious exercise (as with working dogs) for four to six weeks.
(5) PREVENT RE-INFESTATION WITH TICKS: Following treatment for Tick poisoning, you might expect your pet to develop an immunity, but the passive short term immunity (a few days) conferred by the serum prevents the development of any long term effective immunity. During the two-month recovery period, the pet is actually more susceptible to another bout of Tick Poisoning if an adult female Paralysis tick attaches and injects her poison. Therefore it is important to keep ticks off your pet especially during this period.
How to protect your dog from tick paralysis
(6) SEEK EARLY TREATMENT: Remember that if an animal is affected by tick poisoning, the earlier treatment is given the higher will be the pet’s chance of survival. Contact your vet immediately if the signs of paralysis reoccur.