Snakes and snake bites
Snakes are a significant spring and summer threat to our pets, particularly those with a strong prey drive and a highly investigative nature.
The Brown snake (pictured right* ) is most commonly involved in pet envenomation in the Dubbo district (around 95%). The Black snake (more commonly seen - but not exclusive to - the southern areas of the NSW) is responsible for less than 5% of bites in the Dubbo area. Its venom is not as potent when compared to Brown snakes and acts quite differently.
Here at the clinic, we have noticed that brown snakes are in general becoming blacker in colour. So distinguishing brown from black snakes is not always as simple as a quick "colour" check.
Other snakes are reported to be in the Dubbo area including Tiger snakes, Western Taipans and occasionally Death Adders in the Harvey Ranges. Anti-venom for the latter 2 snakes is not found in our veterinary practice.
The different type of snake causes different types of symptoms after a bite and the type of anti-venom used to treat the snakebite differs depending on the snake species.
Signs of Snake Bite
The most common signs of snake bite are:
weak wobbly back legs (dogs); or
lying on their side with only the tail tip occasionally flicking (cats) glazed staring eyes.
Other less common signs include drooling, bleeding, vomiting, constant licking somewhere on the body.
***One critical sign which occurs after serious snake bites is the pet (usually dogs), falls over suddenly onto its side, and paddles or briefly struggles to get up for a short period, then rises to run around normally again. These symptoms are sneaky and often fatal because if this important sign is missed, the pet will often run around as though nothing has happened. Then within 1-2 hours, these dogs will rapidly deteriorate and can often die.
How quickly signs and symptoms develop depends on the strength and volume of the venom, the bite location, the number of bites and how venomous the snake is.
Venom strength is high after the winter hibernation so early spring bites are nasty. The size of the snake and the number of strikes the snake has had in the preceding days, will influence the volume deposited. The length of time the snake is attached allows more venom deposition so if really angry (e.g. after a long fight with the pet), the snake will bite with attitude increasing the venom transfer.
Bite location makes an enormous difference to venom transfer. A mouth bite travels quickly into the blood stream and signs appear and progress more rapidly compared to a bite on the body. A number of bite sites on the body in areas with a poor blood supply, can delay the absorption of some venom. This allows signs to appear up to 24 hours after exposure to the snake. A tabby pussycat “Lucky” had absolutely no signs until exactly 24 hours under observation, then became paralysed for 3 days (excluding the tail tip) even after anti-venom administration.
Brown Snake Anti-venom can be very successful but if given too late, will not work. This anti-venom is produced using horses so allergic reactions can occur. Usually if given for the first time allergic reactions are less common. Strict rest following treatment is recommended from 24-48 hours in the clinic so we can observe how the pet is recovering especially if we are unable to identify the type or size of the snake.
Knowing the time of the bite and the size of the snake itself helps to determine what sort of dose of venom the dog/cat was likely to receive and in turn hopefully effective treatment. So if possible, (if the snake is dead of course) bringing it with you for identification is helpful, as is us phoning us on the way to the clinic letting us know if you have the dead snake with you. IF YOU ARE NOT SURE IF THE SNAKE IS DEAD OR ALIVE I recommend you LEAVE THE SNAKE ALONE and try to identify the type of snake and estimate it’s length, how thick he was and what time of day the bite occurred.
Get to the vet as quickly as humanly possible. Again, phoning ahead with a view to leaving the pet for observation is ideal.
Out and About During Snake Season
More pets are snake bitten on the outskirts of Dubbo and on surrounding properties than in residential yards in the city. However, that's not to say that snake encounters are unusual in town areas. In wet years snakes can come into sheds and yards chasing mice. During droughts snakes will do the same to locate water including your pets drinking bowl. Please be mindful of where you locate your pet's waterbowl. Talk to us about your options for locating the waterbowl during the snake season. Check also any potential snake hidey holes in your garden shed or any nooks and crannies in your garden.
Long grass, wood and garden rubbish piles offer affordable housing for snakes. Slashing or mowing and regular disposal of accumulated green waste lessens the chances of snakes breeding on your property. The Black snakes are found around water courses like creeks, rivers and dams.
When walking your dog in spring and summer, encourage them to stay close particularly in the country areas. Your pet is far safer anywhere if on a lead by your side. (N.B. The widespread use of fatal fox baits like 1080 - which has no antidote or cure if dog poisoning occurs- emphasises the importance of using leads even when out of town). Strong lessons which ensure your pets only eat after voice command, pays long term dividends under these circumstances. Let your pet investigate more even off lead, during the autumn and winter months when the threat of snake encounters significantly lessens.
If you are out and about in an isolated area, cooling the pets in a dam or trough may slow the venom's absorption however, this may simply delay the inevitable. Tourniquets definitely help in people but anyone who has bandaged their own cat or dog’s leg will know this may stir them up more than benefit them. In my experience bites aren’t common on the toes or tail tip, so bandages are likely to be less effective in pets anyway, even if you’re lucky enough to locate the bite.
If a pet has killed a snake, or bailed one up it doesn’t necessarily mean it will be envenomated. The problem with snakes’ fangs is they are so narrow and sharp, they often barely leave a noticeable mark on the coat or skin. This makes accurate checking for a bite site very difficult.
On bush walks, let your pet investigate more during the Autumn and Winter months. In Spring and Summer go “walkies” using a collar and lead.
Never put yourself in danger where snakes are concerned. You are not much help to your pet if you also get bitten.
If in an isolated situation, remain calm and try not to stress the pet, call a vet clinic for further advice. Remember some pets haven’t been bitten during their encounter.
If available, phone ahead to your vet, and inform them you are coming and if possible, which snake was involved.
Snake bite can be a lethal and nervewrecking moment for both human’s and pets alike. There’s further reading below to understand how the venom can affect pets and how the symptoms come about. I encourage you to read this information as awareness and education is every bit as important as knowing what to look out for and what to do during the dramatic event of a snake bite.
What the Snake Venom Does:
Brown snake bites signs are mainly neurotoxic (attacks the nervous system) with wobbly back legs progressing to paralysis seen in the target (victim). Blinking motion can be delayed with the eyes appearing to be staring as the pupils dilate. The unfortunate instance of the interruption to the heart and the blood clotting process is what takes the life of the target of snake bite.
Blood clotting is delayed after the venom rapidly consumes the fibrinogen (a very important protein in the blood). During this process, the heart dramatically slows as large clots coagulate inside the heart's chambers. Due to widespread clotting, fibrinogen levels become critically low. The heart rate speeds up again and internal bleeding can occur anywhere in the body, including the bladder and brain. A clotting test performed at this stage will be delayed. Recently a brown snake bitten Labrador had a test take over 10 minutes to clot! (normally 90 seconds).
Since venom travels through the lymphatics, slowing the heart rate will generally slow the venom's passage through the body and delay the onset of signs if you think your pet has been bitten.
Black snake (pictured right*) venom is not as potent when compared to Brown snakes and acts quite differently causing a blood disorder rupturing Red Blood Cells (RBC’s) leading to urine to become port wine coloured. Gut pain also appears to be a feature of black snake bite. The venom appears to begin digestion of the victim’s major organs as they die. There is a neurotoxin also present but in lower levels of brown snake bites. Black snake venom also contains Cytotoxin which will cause pain, swelling and inflammation at the bite site but usually takes 24-48 hours to develop so may not be apparent on initial presentation. Black snakes (both red and blue bellied), King brown snakes and Tiger snakes have similar venom. Tiger snake anti-venom can be used to treat these bites, or black snake anti-venom is combined with brown snake in a bivalent (double–acting) anti-venom.
*Pic source: Wikipaedia