Snake Bites

Dear YourOwnVet,

We live in a rural area in South Africa and we have poisonous snakes on our property. What do I do if my dog gets bitten by a snake? The most common snake here is the Rinkhals.

Rinkhals in defensive position showing hood

The Rinkhals

Duduzile Dunicz,

South Africa

Hi Duduzile,

Dogs will tend to get bitten on their faces first and then their legs, or  get venom sprayed into their eyes, whereas cats may get bitten on the front legs or get venom sprayed into their eyes.  Most snakebites, whether by a venomous snake or not, will have a local effect. There is minor pain and redness in over 90% of cases, and many get infected. Snakebites occur most frequently in summer. If you see a snake, please do not kill it! It does a tremendous amount of good. (4)

This Staffie has venom sprayed in her eye

Venom may be sprayed into a dog's eye by a snake

First aid

Do:

Get the dog well away from the snake.(2)

Watch for the following signs:

  • Rapid swelling at the site of the bite
  • Intense pain
  • Oozing blood
  • Fang marks (can be difficult to identify in some animals)
  • Drooling
  • Rapid breathing
  • Dilated pupils
  • Pale gums
  • Weakness
  • Collapse
  • Tissue swelling is often worse 24 to 48 hours after the bite. Wound may drain and bleed for several days. Most snake bites require veterinary care. (10)

    Try to obtain a clear description of the snake.

    Keep the dog as still as possible and keep the bitten area lower than the heart (if your pet is bitten on its legs).

    If a snake spits into the eyes, rinse the eyes with large amounts of water, preferably by holding the head under a running tap. Use whatever liquid you have. Water, milk, beer, cooldrink – even urine.  (2)(6)

    Cover the area with a clean, cool compress or a moist dressing to minimize swelling and discomfort.

    Pressure bandages are used as first aid in humans. In practice with dogs, it should only be used if the dog does not panic, jump around and try to get its leg away from you which may do more harm than good. If your dog and allows you access to the leg you may wrap a bandage as tightly as you would bandage a sprained ankle beginning above the wound, going upwards then back down to the foot. Immobilize afterward with a splint.

    Call ahead to the vet. Most vets in South Africa do not stock anti-venom routinely, but in the US, many will. (4)

    Snakebites can cause death of the tissue round the bite

    Snakebites can cause death of the tissue round the bite

    Don’t:

    Use antivenom except in a hospital environment (2) as it may cause anaphylactic shock. (6)

    Cut the wound, (2) since it causes further damage and increases the risk of infection. (5) Then the venom will spread more rapidly (6)

    Apply a tourniquet.(2) Uninformed tourniquet use  can cut off circulation can lead to gangrene. The use of a compression bandage is as effective, and much safer(5)

    Try to kill the snake(2)

    Suck out venom, either by mouth or with a pump, as it does not work and may harm the area. You also release oral bacteria into the dog’s wound, leading to infection.(5) If you have cuts in your mouth there will be two patients where there was one. (6)

    Immerse the wound in warm water or sour milk, or apply snake stones, to draw off the poison. (5)

    Use electroshock therapy with a stun gun. It is useless and dangerous.(5)(6)

    Give drugs to the dog.

    Rub substances into the wound such as potassium permanganate or home remedies – perferably leave it alone.

    Apply heat or ice to the wound (6)

    Give the dog anything to eat or drink (5)

    At Your Vet

    If your vet has antivenom(antivenin) in stock it may be used. It is recommended for rattlesnake bites but can be expensive and cause anaphylaxis in some pets. For this reasons, pets are hospitalized and closely monitored.

    Diphenhydramine(antihistamine) is typically given to reduce some signs of allergic reaction associated with the snakebite.

    If the bite occurs in the area of the throat, airway support may be needed, including a temporary tracheotomy or ventilator.

    Hospitalization with continuous intravenous fluids may be recommended in severe cases.

    If your dog is bitten by a snake he will be given intravenous fluids

    Intravenous fluids prevent shock

    Treatment for pain and infection is also important. Sedatives may also be used

    Blood work may be done to evaluate coagulation times on a blood sample taken from an affected animal. Prolonged clotting times can indicate exposure to haemtoxic venom.(10) Blood may be transfused. (10)

    In the US, there is a vaccine against Rattlesnake bites that can be used in endemic areas. (11)

    Dog's leg a few days after being bitten by snake

    Dog's leg after a snake bite

    The following snakes have caused the most human injury or fatalities:

    Africa -  the puff adder

    The  Middle East – the coastal viper, Palestine viper, and Lebetine viper.

    Europe, the viper.

    Australia – the kraits, tiger snake and Eastern brown snake.

    The USA – The diamondback rattlesnake. [4]

    the rattlesnake causes many fatalities in the U.S. haemotoxic venom

    The Eastern diamondback Rattlesnake

    Snakes can be divided into three categories:

    Harmless or non-venomous species have solid teeth.

    Back fanged snakes have grooved fangs for conveying venom i.e. the boomslang and the twig snake.

    Front-fanged snakes – cobras, mambas and adders – their fangs are near the front of the upper jaw, and are swivelled forwards for a maximum effect.

    Rattlensnake is a front fanged snake

    Front Fanged Snake

    Venom

    Snake venom is made in modified salivary glands, stored in sacs behind the eyes, and ejected through hollow fangs (5) (1) and consists of a mix of toxins, proteins and enzymes. (6)

    Neurotoxic venom – most cobras, mambas and berg adders – attacks the central nervous system, paralysing the muscles. It affects movement, breathing, swallowing, and sight.(1)  The pupils dilate and do not respond to light. Fast acting.(6)

    Haematoxic venom – rattlesnakes, boomslang and twig snakes – affects the blood, so it does not clot and causes bleeding into the tissues.(1) Huge “bruises” develop all over the body. Blood oozes from all mucous membranes. Blood transfusions may be necessary. Slow acting. (6)

    the Boomslang has a haemotoxic venom

    The Boomslang

    Cytotoxic venom – adders, spitting cobras and rinkhals – attacks the body cells or tissues, causes a very painful bite with swelling and shock.(1) It usually causes death of large parts of flesh. (6)

    Myotoxic venom – yellow-bellied sea snakes – attacks the muscles and can lead to death from kidney and heart failure.(1)

    It is now thought that most snake venom affects every organ system in the body and can be a combination of many different combinations of  cytotoxins, hemotoxins, neurotoxins, and myotoxins.  (5)

    Recovery from a bite depends on the amount of venom injected, the site and depth of the bite, the size, physical condition and temperature of the snake as well as the health and size of the patient. The type of first aid given and time it takes to receive treatment also play a role. (2)(5) A bite may also trigger anaphylactic shock, which can be fatal. (5)If a venomous snake bites your pet, it is unlikely that he will learn from the experience and he probably won’t voluntarily avoid snakes in the future. Future venomous snakebites may result in much more severe toxic signs and might even result in death. (10)

    The Rinkhals

    Rinkhals has a characterstic stripe on the underside of its neck

    The Rinkhals has a characteristic stripe on the underside of it's neck

    The Rinkhals is a smallish snake rarely exceeding 1.2 metres.  If threatened, it will rear up and spread a hood. If this does not scare an attacker off it will spit venom, quite accurately. Should the venom enter the eyes it will burn fiercely – and complications may arise if not treated rapidly.

    The Rinkhals seldom bites – and those usually only occur when it is handled as it tends to sham death.  Rinkhals are nocturnal, but may occasionally be seen basking during the day. (9) Symptoms of bites are local  swelling / bruising,  drowsiness, nausea, vomiting, violent abdominal pain and a mild fever. Difficulty breathing may be seen. THIS SNAKE IS NOT CONSIDERED A MAJOR THREAT DUE TO ITS WEAKER VENOM (6) (5)

    Most snakebites occur in large breed primarily outdoor dogs with the majority of bites located on the legs or head, especially the muzzle. Most bites occur during the spring and summer seasons. It is estimated that 90% of bites occur between April and mid October. Bites from these snakes are generally the result of aggressive or curious actions while playing in snake-infested areas.

    References

    1. http://home.intekom.com/ecotravel/southern-african/wildlife-guides/snakes-list.htm

    2. http://www.health24.com/medical/Condition_centres/777-792-2557-2561,32367.asp

    3. http://www.umm.edu/non_trauma/snake.htm

    4. http://www.surviveoutdoors.com/reference/snakes/snake-bites.asp

    5. http://en.wikipedia.org/wiki/Snakebite

    6. http://www.seanthomas.net/oldsite/venom.htm

    7. http://en.wikipedia.org/wiki/Rinkhals

    8. http://home.intekom.com/pharm/saimr/snake.html

    9. http://www.venomousreptiles.org/articles/34

    10.http://www.petplace.com/dogs/snakebites-from-a-copperhead-pit-viper-snake-venom-rattlesnake-crotalidae/page1.aspx

    11.http://www.marvistavet.com/html/body_rattlesnake_bites_in_californi.html

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