Written by Dr David Allen
It’s not often that we see a disease disappear, but that is what is happening right now around Australia.
Only three years ago every summer we would see quite a few cases of dogs (sometimes cats) brought in by their distressed owners because the dog had become paralysed.
The culprit was a tiny (less than 5mm) tick that had lodged in the dog’s skin and was sucking blood, and at the same time injecting a toxin into the animal.
The Ixodes paralysis tick lives in Tasmania in the bush and coast, and also all along the Eastern seaboard of the mainland.
After a few days of the tick feeding on the dog the toxin takes affect, and the dog begins to lose strength in the back legs, initially swaying like he was drunk and then being completely unable to stand.
The toxin then affects the front legs and also the voice box and finally the chest muscles.
These paralysed dogs were brought to vet clinics where they were hospitalised and treated with a tick antiserum to try to neutralise the toxin in the dog’s body.
These dogs needed to be kept very quiet in hospital as excitement or exercise would bring back the paralysis.
Those dogs badly affected by the paralysis tick sometimes even needed to be placed on ventilators for days to keep them alive.
So why is this disease disappearing?
The paralysis tick is still around in the bush, it’s toxin is just as deadly as before, but what has changed is that there are new drugs available for owners to give to their pets to keep them healthy.
These medicines are mainly used to kill fleas of dogs and cats, but they have a second purpose - they kill ticks fast, so fast that the ticks don’t even have time to inject the toxin into the dog or cat.
The drugs are easy to give and depending on the manufacturer, one tablet lasts for one month, or three months, and now there is even a spot-on liquid that lasts for six months.
As vets quickly realised how effective these drugs were in preventing tick paralysis, we advised our pet owners to give these medications to their dogs and cats.
Each summer now we see less tick paralysis cases brought in than the year before.
Hopefully in a year or two the tick antiserum we keep in our fridge will not be needed at all.