Coral Snakebite Poisoning (Elapid Envenomation) in Dogs

Summary

Elapid envenomation occurs when a dog is bitten by a snake from the elapid family (e.g. coral snakes). The likelihood of occurrence is relative to the geographic range of elapid snake species. This class of snakebite is much less commonly reported than pit viper (rattlesnake, or crotalid) envenomation. Different species of coral snakes can be found across the southern US, Australia, and Asia.

Elapid venom causes muscle paralysis -including paralysis of the muscles that support breathing- and can be fatal. This makes venomous snake bites an emergency. Diagnosis is usually based on clinical signs and known or suspected exposure to snakes.

The best, most effective treatment for elapid venom is antivenin (antivenom). The availability of antivenin corresponding to different species of snakes varies across different regions. Envenomated dogs are treated with supportive care like IV fluids, oxygen, and ventilatory support. Pets with elapid envenomation require extensive monitoring after the bite to ensure any serious symptoms are identified in a timely manner.

Prognosis after envenomation depends on the amount of venom delivered by the bite, the size of the dog, the location of the wound, the species of snake, and how soon treatment is administered after the bite occurs. Most cases have a favorable prognosis with appropriate treatment.

Risk Factors

Elapid envenomation is a concern for dog owners living in regions where coral snakes are found, but elapid bites are rare.

Elapid snake bites are an emergency, as their venom contains toxins that prevent respiratory muscles from contracting. Dogs with suspected venomous snake bites need immediate medical attention.

Possible Causes

Elapid envenomation results when a dog is bitten by a snake from the elapid family. The most common species of elapid snakes in the US and Australia are:

• Coral snakes (Southern United States) • Black snakes (Australia) • Brown snakes (Australia) • Taipans (Australia) • Tiger snakes (Australia)

Elapids have short fangs and deliver neurotoxic venom.

Main Symptoms

Elapid snakebites typically have minimal pain and swelling at the bite location. The main symptoms of an elapid snake bite are:

• Limb weakness • Paralysis in all four limbs (tetraplegia) • Rapid breathing (tachypnea)

Dogs with suspected venomous snake bites require immediate veterinary attention.

Detailed Characterization

Other symptoms associated with elapid snake bites include:

• Irregular, wobbly gait (ataxia) • Excessive salivation and drooling (ptyalism) • Vomiting • Diarrhea • Pale or cyanotic gums

• Difficulty breathing (dyspnea) • Unequal pupils (anisocoria) • Collapse • Muscle tremors • Abnormal bleeding

Testing and Diagnosis

If the snake bite is witnessed, the diagnosis is self-evident. Identification of the species of snake involved may help expedite appropriate treatment. 

As with any penetrating wound, the veterinarian will first shave and clean the area of the snake bite thoroughly. Elapid snake bites often require:

• Supportive care, such as fluids and mechanical breathing on a ventilator

• Antivenin (antivenom), if available. Coral snake (elapid) antivenin is no longer manufactured in the United States, making it unavailable to most practitioners in North America. Elapid antivenin is widely available in Australia. 

Symptoms of elapid envenomation may take up to 48 hours to fully develop, so inpatient monitoring is advised until it is evident the dog’s condition is not deteriorating.

Steps to Recovery

The outcome of a snake bite depends on the species of snake, location of the bite, quantity of venom delivered, size of the dog, and how rapidly treatment was implemented. Specific identification of the biting snake may improve prognosis, as an appropriate antivenom can be selected, where available. 

Prognosis for elapid envenomation in dogs is fair to good with rapid treatment. Dogs who develop more serious complications like aspiration pneumonia have a worse prognosis. Muscle tissue damage after envenomation may take months to resolve in some cases.

Prevention

Snakebite envenomation is prevented by avoiding contact with poisonous snakes.

Is Elapid Envenomation Common in Dogs?

Elapid envenomation is globally uncommon, but likelihood of occurrence is relative to the geographic range of elapid snake species. Elapid envenomation is primarily reported in Australia and the southern United States.

Venom is injected as the coral snake chews on its victim. As a result, many times the snake is still attached to its victim upon presentation.  If the snake does not chew on the dog, the bite will be dry (without venom). Up to 60% of coral snake bites are dry.

Typical Treatment

• Antivenin (antvenom) - where available • IV fluids • Supplemental oxygen • Mechanical ventilation • Supportive care