Snakes Alive!

Spring has sprung and as we enter the warmer months, our resident snakes will become more active. Kangaroo Island is home to two prominent species of snake, the Black Tiger snake (not always black) and the Pygmy Copperhead snake. Both species exhibit a significant amount of variation in their appearance, however in general terms the Pigmy Copperhead adult snakes do not grow to greater than 1 metre in length.
 
Pet owners need to be vigilant about identifying if their dog has been bitten and seeking medical advice. The chances of a successful outcome from treatment will be greatly increased by prompt diagnosis and treatment. 
 
As you may not have seen your pet get bitten there are signs that are commonly seen post bite. These include:

• Lethargy, weakness or collapse
• Seizures, shaking or muscle twitching
• Large pupils
• Vomiting, diarrhoea or excessive drooling
• Difficulty blinking, swallowing or breathing
• Pink to dark brown coloured urine 

Symptoms can be noticed from between 10 minutes to 5-6 days after envenomation, depending on how effectively the pet has been bitten.

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This will determine the amount of venom that has been deposited in to the bite site and on to the skin and hair coat surrounding the bite site.
If you see your dog or cat with a snake, do not wait until you see symptoms to act as there may be a delay in onset. WASH YOUR PET FIRST - paying particular attention to the legs and head. These are the most common bite sites in dogs and cats but you will rarely find evidence of a bite wound. There is no need to apply pressure bandages to suspected bite sites. 
THEN call us immediately and arrange to bring the animal in. In some cases, acute onset clinical signs can be followed by a period of apparent recovery before relapsing. There are diagnostic tests available that can help confirm if venom is damaging muscle and internal organs before you might see any external signs and treatment can be given before that damage goes too far. 

A little about snake venom
Snakes use their venom to immobilise their prey and to start the digestion process. The venom of Kangaroo Island snakes contains 4 fractions in differing proportions in differing snakes – a fast acting neurotoxin, a slow acting neurotoxin, an anti-clotting agent and a muscle and organ damaging agent. The fast and slow acting neurotoxins paralyse their prey and the anti - clotting and muscle damaging fractions begin digestion – and that’s exactly what happens in our pets when they have free circulating venom in their bloodstream.

A little about antivenom
Antivenom is a biological product that binds to circulating venom (I molecule of antivenom binds to 1 molecule of venom) and inactivates its harmful effects. Tiger Snake antivenom, which successfully treats both Tiger Snake and Copperhead bites, is a more expensive antivenom to produce than the more common (on the mainland) Brown Snake antivenom.

There are two factors that can affect the success of treatment with antivenom. 
Time - Antivenom can only bind to circulating venom. The longer the venom circulates and binds to tissues in your pet’s body systems the more damage it will cause. 
Amount - a vial on antivenom contains enough antibodies to neutralise one average venom yield from a bite. However, the amount of antivenom needed can often be more than one vial. The subspecies of Tiger Snake found on Kangaroo Island contains more toxic venom than that of other Tiger Snakes in Australia with a higher venom yield. Also, if the snake has not fed for a while (such as at the end of Winter), the snake may deliver a larger volume of venom than the average bite when it bites your pet. In cases where a large amount of venom has been delivered in to your pet, up to 3 vials may be required to totally neutralise the bite.

After using antivenom, treatment is based on supportive care and there is often a prolonged recovery period of several weeks during which significant nursing care may be required.

Tips for keeping you and your dog safe
Walk your dog on a lead in snake habitats
Make your backyard a less appealing place for  snakes to live. You can remove shelter and food by clearing piles of rubbish and green waste, storing items off the ground, keeping the grass short and controlling rodents.