Snakebite!!! What do I do?

If your pet has just been bitten

First things first: if you are reading this because your dog has just been bitten, or you think it might have been bitten, stop reading, pick up the phone and call us at the clinic on 07 4161 1404. If it is outside normal opening hours ring the mobile/home numbers directly. These numbers are 0488 0709 462 (Nathan’s mobile) and 07 4161 1899 (home number). The message on the office answering machine gives these numbers too. After Hours/Emergency Service

Overview of Treating Snake Bite

There are three things that must be achieved to effectively treat snakebites. They are:

  1. Use of the correct antivenom for the snake,
  2. Administered promptly,
  3. In adequate amounts.

To achieve these three things, we need to know:

  1. What species of snake it was. Ideally, bring the snake for identification. Don’t bring us live snakes and don’t get bitten yourself! Sometimes we just have to have an “educated guess” about what snake it was, based on symptoms. Snake Venom Detection Kits (SVDK’s) can help here. For more about SVDK’s, read further down.
  2. How much antivenom to give. We determine this based on response, but the response we are looking for varies depending on the type of snake we are treating. Anti-venom is antibodies which will attach to snake venom, coating it and stopping the venom molecules from functioning.
  3. How much our owner’s budget can afford. This is where pet insurance is invaluable. Unfortunately snake anti-venom is not cheap, and treating snake bites can get quite expensive. Not everyone can afford several thousand dollars to treat a severe snake bite. The really hard part is that when we start we don’t know how much anti-venom we need, and the only way to find out is to start the process and stop when we get the effect we want or run out of budget dollars, whichever comes first! Delaying anti-venom administration to save money is pointless, as delays can cause secondary effects (particularly blood clotting problems and paralysis) which are expensive to treat in themselves. These problems are often reduced, if not completely avoided, by giving the SAME AMOUNT of anti-venom sooner. It is best to do as much as can be afforded as soon as possible, then take our chances that it is enough. See the end of this page for a guide to possible costs.

First Aid for Snake Bite

Generally pets bitten by snakes are not good candidates for human-type first aid (bandage, splint the limb, don’t move, keep quiet). This is because they won’t sit still until they feel unwell, many bites are on the face and can’t be bandaged, and it is often very difficult to tell if an animal has been bitten or not, or even where the bite site is. It is impossible to provide first aid for a suspected snake bite in an unknown location by bandaging the whole dog! Most bites from snakes are only found because they are bleeding, and this is usually caused by the snake’s venom preventing the blood from clotting. This is a good indicator that emergency snakebite treatment is needed. If you think you have found a bite site, don’t wash it (we may swab it for a venom sample, used to determine the species of snake involved). We can do a couple of quick and relatively cheap blood tests to determine if an animal is beginning to be affected by snake venom. These tests will give us warning that treatment is required before the animal starts to show effects of the bite. As soon as you think a snake bite MIGHT have happened, pick up the phone and discuss it with us. The best outcome is much easier to achieve when we start early. Please don’t think that you will save dollars by waiting; we don’t want to over-service and will only advise treatment if it really is required, and early treatment is always better.

Snakes of the Central Burnett

Generally speaking, snakes in the Central Burnett fall into one of three categories:

  • Non-venomous, including carpet snakes, green tree snakes, etc.
  • Venomous but not dangerous, including whip snakes, brown tree snakes (also called night tigers), keelbacks, bandy-bandies, etc.
  • Dangerously venomous snakes, mainly Eastern (Common) Browns and Black snakes (mostly red-belly black snakes). We have historically had Death Adders, but they are extremely rare now.

Snakes we DON’T HAVE include: King Browns (these are actually a brown-coloured member of the black snake family) Tiger Snakes, and Taipans. There are persistent rumours of occasional taipans in the area but they are mostly based on false results from snake venom detection kits, which are notoriously unreliable.  Another cause of these rumours is mis-identification of brown tree snakes as taipans because of the similarity of body shape, and also mis-identification of common browns as taipans based on aggressive behaviour, speed of movement and size (body length).

From an animal health viewpoint we are not terribly interested in the harmless snakes.

The only venomous but not dangerous snake worth mentioning here is the whip snake. These snakes can look a lot like a common brown snake, but their venom only causes “local pain and swelling” according to the experts. Experience tells us that “local pain” would be better described as “excruciating pain” and “swelling” would be better described as “massive swelling of the bitten limb or body area.” These bites are effectively treated with anti-inflammatory and good pain relief.

Things NOT to do!

There are some things that don’t help with snakebites, but the old wives tales persist! Some of these are:

  • Cutting off the tips of the ears, and putting kerosene on the cuts
  • Putting kerosene, diesel, engine oil, even petrol all over the dog
  • Giving big doses of Vitamin C intra-venously (the most harmless of all these treatments really).
  • Cutting over the bites to “release the poison.” This doesn’t help, will cause bleeding, and may cause further problems treating the wounds inflicted.

Brown Snake Bites

By far the most common snake bites we see are by Common/Eastern Browns. In fact, during September 2017 we treated 5 separate snakebites in 7 days and in 2017 we treated about 40 cases of snakebite for the year, nearly one a week on average!

Usually the pet has attacked the snake, and the snake is found dead nearby. The fangs of the brown snake are tiny and the bite marks are never very obvious unless they are bleeding. Bite marks look like tiny scratches, about what you would expect by being scratched while pushing through/past a lantana bush. Most of them are on the face near the pet’s mouth, and sometime on a front leg.

Initial effects of brown snake bites can be seen within minutes. The fast acting part of the venom causes almost instant paralysis and sickness, and some animals will die within 2 minutes of a severe bite. Usually these are little animals bitten hard by a big snake. If the pet survives the initial “knockdown effect” they usually recover and appear normal within minutes and look quite ok for a time. Then the slower acting parts of the venom gradually cause paralysis, dilation of the pupils (commonly referred to as a “glassy-eyed” appearance) and blood clotting problems. This can start within ½ an hour, and in mild cases can take more than 12 hours to show. This “knockdown effect” is a good indicator that the clock is ticking on a snakebite that will need treatment. If your pet has been seen with a snake and been unwell or wobbly for a minute or two immediately after, click this link for our phone numbers: Contact Details and ring us straight away.

Brown snake venom is known as a “pro-coagulant.” It stimulates microscopic blood clots to begin forming inside the blood vessels throughout the whole body. The body has mechanisms to deal with clots in places they don’t belong, and clot breakdown enzymes come along to break up these clots, a bit like a cheese grater breaking up a block of cheese. The problem is that the little proteins in the blood called “clotting factors” cannot be recycled. Once they have formed into a clot and then been broken up they are gone forever. Brown snake venom can use them up at a prodigious rate, and when the supply runs out there is nothing left. Our bodies MUST have the ability to clot. If not, the continuous, normal damage to blood vessels cannot be repaired and the body begins to bleed abnormally. Bleeding is often seen around teeth, from the nostrils, from the bite sites, around needle puncture sites and as bruising under the skin. Sometimes this bleeding can be catastrophic, causing death within minutes of starting. Usually this involves bleeding into the lungs, with spectacular haemorrhage from the nostrils. The only way to stop this bleeding is to supply the patient with clotting factors by giving a plasma or blood transfusion. If enough anti-venom has been given this fixes the problem. If not enough anti-venom has been given the remaining snake venom will destroy the transfused clotting factors, requiring more anti-venom to neutralise the snake’s venom followed by more plasma/blood to plug the holes in leaky blood vessels again.

The other significant effect of brown snake venom is the ability to cause paralysis. The venom attaches to the receptors on muscle cells, preventing the neurotransmitters released by the nerve cells from activating the muscle. At first this effect is somewhat reversible with prompt anti-venom administration, but after a few hours the venom binding is “matured” and the venom cannot be dislodged. This paralysis results in animals having trouble jumping onto furniture, having wobbly hindquarters, falling over sideways, collapsing to the floor after a few steps, and going “splat” into the ground when jumping down from furniture or going down stairs. Sometimes local effects of the venom are seen in facial bites, where the eyelids and lips on the bitten side are not working properly. Left untreated the paralysis can progress to the point where the animal cannot move (although they can usually wag/flick their tail) and in severe cases paralysis of the respiratory muscles can cause death. This can occur despite treatment with anti-venom. Once the snake venom has been adequately neutralised with anti-venom the patient needs to be nursed until recovered. Nursing consists of keeping patients warm (they cannot warm themselves when paralysed), giving IV fluids because they cannot swallow or eat, and protecting the eyes from developing corneal ulcers because paralysis stops them from blinking, causing the eye to dry out.

Recovery from paralysis takes about 3 – 5 days, and is not complete for at least a week. The paralysed muscles cannot receive instructions from the nerves, a bit like having the telephone line to a house disconnected. The only way to “get connected” again is for the muscle cells to read the section of DNA titled “how to make a neurotransmitter receptor protein,” make the proteins, fold them to the right shape (done by other proteins, which also have to be made), transport them through the cell and bring them out to the surface where the nerve can then activate them to stimulate the muscle cell again, replacing the inactivated receptors. This takes about 48-72 hours to begin and then improvement of paralysis is rapid.

In some severe cases of brown snake bites the venom will also cause the outside membrane of red blood cells to break (haemolysis). This releases haemoglobin into the blood, which can be seen as pink-reddish brown discolouration of the serum. This effect is not important to treating the snake bite, but can make determining the type of snake bite more difficult as haemolysis and myolysis (destruction of red blood cells and muscle cells) is a feature of black snake bites. Generally if haemolysis is present in a brown snake bite the clotting effect of the venom is pronounced, which black snakes do not cause.

Another possible effect of brown snake bites is necrosis (dying) of the skin around the bite sites. Usually this occurs on the flanks of the animal, and starts becoming evident as the animal recovers from the paralysis a few days after the bite. It is not common but can cause severe scarring when it does occur.

Black Snake Bites

Black snakes are much less aggressive and offensive/defensive and do not bite nearly so many pets as brown snakes, but the effects can still be lethal. Bitten pets have almost always killed the snake involved, even if the owner has not found it. The flies and smell usually help to find them a day or two later. Black snakes can cause a similar “knockdown effect” to browns. Once recovered from the knock down effect the venom causes mild to moderate paralysis, severe haemolysis/myolysis (seen as pink-reddish brown disclouration of the serum, and red-black discolouration of the urine). This pigment will cause kidney damage as it is filtered from the blood, so giving large volumes of IV fluids to “flush” the kidneys is an essential part of nursing these patients. Most pets bitten by black snakes “just look sick, as if they feel like they are dying” and this effect is almost instantly reversed when adequate anti-venom is administered. The difficulty can be that this quick effect of the anti-venom is spectacular, and owners (and vets!) can be tricked into thinking treatment is completed. If the bite site still contains un-absorbed snake venom this venom can continue to trickle into the body through the lymphatic system. Once the anti-venom has run out the patient can deteriorate again, requiring more anti-venom. Monitoring for at least 6 hours is required after administration of anti-venom.

Interestingly black snake bites are treated with tiger snake anti-venom, because it works quite well for black snakes too! Then just to add to the confusion, King Browns are a brown coloured member of the black snake family, and so King Brown bites are treated with tiger snake anti-venom as well.

Snake Venom Detection Kits (SVDK’s)

SVDKs are a bit expensive (about $250 per test) and take up to 20 minutes to run. Usually we don’t have time to run a test before needing to start giving anti-venom, so we guess first and then confirm our guess later, if possible. Unfortunately the results of an SVDK are not always a black and white answer. They are not useful for determining if a bite has happened or not, and they are not useful for determining if treatment is required or not. They are prone to false positive and false negative results. The main use for an SVDK is to distinguish between species of snake to select the appropriate anti-venom. Even then, samples containing lots of venom are prone to “cross-reacting” and indicating more than one species.  The procedure then is to dilute the sample, and repeat the test (and the cost)! Sometimes a sample may not have enough venom to activate the SVDK, and even though the patient is obviously affected the SVDK gives negative results.

Snake vennom detetcion

A positive for brown snake on one of our in house SVDK

Expected Cost of Treatment

There is no such thing as an “expected cost”. We often ask owners without pet insurance to decide on a budget, and we agree not to exceed that budget. Setting a reasonable budget depends on what the owners can afford, and can later be revised upwards by the owner if they wish.

Minor bites without antivenom: Some animals will survive with no treatment at all, and some will survive with supportive care such as rest, IV fluids, keeping warm if paralysed, etc. These can cost between $100 for a consult and some drugs, up to $500 for a paralysed animal nursed in the clinic for several days.  This type of treatment is not appropriate for every patient.

Minor snake bites with antivenom: Some bites are mild, and only need a little bit of anti-venom and not much else. These will usually fall between $800 and $1,200, most will be around $900-$1,000.

More Serious Bites: This is where it gets difficult, with many factors coming into play. For example, if we treat a brown snake bite early, preventing paralysis and blood clotting problems, and so don’t have to nurse them for days or give plasma to help blood to clot again, this can save over $1,000 off the total costs. The same animal treated with the same amount of anitvenom a few hours later will need a lot of extra medicines and care (which all adds to the cost). Some severe bites treated here have cost over $4,000 dollars (and because of pet insurance the owners only paid 20% of this).

We understand that snake bites can happen at the worst possible times, and if finances are not immediately available discuss the situation frankly with us. We can usually come to an arrangement that allows treatment immediately and delays some of the payment, providing we are confident of owner’s good intentions to pay as they can. Unfortunately, because people not paying for snake bite treatment have been one of our largest causes of bad debts, an initial deposit will be requested before we can agree to a payment plan. We would much rather agree to a smaller, regular payment weekly or fortnightly than larger payments less often.