Snake Bites in Dogs and Cats
Armed with curiosity and natural hunting instincts, it is not uncommon for our favourite four legged friends to cross paths with a snake.
Snake venom carries a large range of toxins that damage tissues and impair many of the body’s vital functions; they attack the nervous system and interfere with the body’s clotting mechanisms.
Venomous snakes in southern Africa can broadly be divided into 3 groups: cytotoxic, neurotoxic and those that can induce haemostatic toxic effects.
Several factors will determine what sort of reaction your pet has to a snake bite.
The type of snake, the amount of venom injected and the site of the snake bite all contribute.
Some, albeit broad, clinical signs include, sudden weakness followed by collapse, shaking or twitching of the muscles, localised swelling, vomiting and dilated pupils that aren’t responsive to light.
In the later stages, paralysis may occur.
On arrival at the veterinary practice, your veterinarian will examine your pet, assess the clinical signs they are showing and determine the best course of action.
Veterinary treatment varies with each individual case. Treatment usually consists of intravenous fluids and the administration of anti-venom to neutralise the snake venom in the pet’s body. Some patients require multiple vials of anti-venom.
Other supportive care may also be required – including oxygen supplementation and even breathing for the pet if they are not breathing well on their own.
Remember, anti-venom is not a “vaccination” or a preventative medication.
Five main clinical signs that most often occur are as follows:
Marked local pain and progressive swelling of the area.
Progressive paralysis (neurotoxicity), with minor local swelling.
Incoagulable blood, with negligible to mild local swelling.
Moderate to marked local swelling, associated with neurotoxicity.
Mild to moderate swelling, with negligible or absent systemic symptoms.
The occurrence of one or more of the aforementioned symptoms depends a great deal on the type of snake in question.
Types Of Interactions:
The toxins of cytotoxic snake venom lead to local swelling, blistering and oedema. Irreversible death of tissues may occur (necrosis).
Swelling usually begins early, often within 10 – 30 minutes. It may become extensive, involving the entire limb and even adjacent areas to the initial site.
Neurotoxicity is characterised by progressive paralysis. Early symptoms and signs include a transient “numb” sensation of the tongue and lips, pupillary abnormalities (e.g. dilated pupils), paralysis of facial muscles and other muscles innervated by the cranial nerves, leading to difficulty when swallowing.
In addition to the above neurotoxic effects, patients bitten by mambas may present with trembling and vomiting and excessive salivation.
Incoagulable blood accompanied with mild local swelling are caused by the boomslang.
Patients may present with nausea, vomiting and abdominal pain. Persistent oozing of blood from punctures or other wound sites is often observed. Bleeding usually manifests as gingival bleeding, bleeding from the nose, vomiting of blood, bloody diarrhoea, bloody urine and, in severe cases, haemorrhage into the brain and spinal cord. Severe, uncontrollable bleeding may lead to multiple organ failure. There is local pain with insignificant or mild local swelling.
Basic First Aid
If you suspect your pet has been bitten by a snake, you should immobilise your pet and try to keep him/her as quiet as possible. It is vital that you take your pet to a veterinarian as quickly as possible. The sooner your pet is treated, the better their chances of survival.
Some basic “first aid” tips are as follows:
Remember, the most important thing is to stay calm and to get your pet to a medical facility as soon as possible. Alert the medical facility or doctor ahead of arrival.
Avoid the many harmful and time-wasting traditional first-aid treatments.
A tight arterial tourniquet should NEVER be used!
DO NOT give your pet ANY human medicine unless you have direct instructions from your veterinarian, doing so may be extremely detrimental.
If your pet is bitten, DO NOT try to catch or kill the snake. A basic description of the snake is enough for the veterinarian to start treatment in the majority of cases. If the snake has already been killed, bringing it along will help a great deal.
Approximately 80% of pets survive snake bites if treated quickly. The survival rate is much lower, however, for pets that are left untreated and death is a distinct possibility.
Recovery from a snake bite usually takes 24 to 48 hours if the pet receives prompt veterinary attention and the snake bite is not severe. However, some pets will take substantially longer to make a full recovery due to tissue damage to internal organs or the skin and will require intensive and prolonged nursing care.
All About the Anti-Venom
Two snakebite anti-venoms are available.
Polyvalent anti-venom (SAIMR Polyvalent Snakebite Antiserum SAVP) is supplied in 10 ml ampoules. Venoms of the following snakes are used as antigens in the preparation of the polyvalent anti-venom: puff adder, rinkhals, green mamba, black mamba, Cape cobra, forest cobra, snouted cobra and Mozambique spitting cobra.
Polyvalent anti-venom is ineffective AND SHOULD NOT BE USED in treatment of bites caused by the berg adder, other dwarf adders, night adders and back-fanged snakes (boomslang and vine snake).
Boomslang anti-venom (SAIMR Boomslang Snakebite Antiserum SAVP) is supplied in 10 ml ampoules. It is effective against the venom of boomslang, but not against the venom of the vine snake.
Anti-venom neutralises a fixed amount of venom. It is infused slowly, rather than administration by bolus. This is recommended as a method of reducing serious anti-venom reactions.
For more information on snake bites in pets, check out our blog post – https://kimvet.co.za/snake-bites-in-south-africa/