• GekkoVet Team

European viper bites in dogs and cats




European vipers commonly bite pets and are a yearly cause of worry to many pet owners. Their poison is often more detrimental to dogs than to cats. The prognosis of a pet bitten by a viper is often good but can be fatal in some cases. A pet bitten by a viper must be seen by a veterinarian as soon as possible.

The European viper or European adder (Vipera berus) often lies in warm and sunny places, such as rocks. Although vipers are often linked to summer, they can also be encountered during early fall. In Southern Europe vipers hibernate for only a few months and can thus be encountered for the majority of the year. One may recognize a viper by its gray or gray-brown coloring and the black jigsaw pattern on its back. 

A threatened viper usually bites a dog on its legs, nose, or head. Cats are usually bitten on the paws. The bite site often swells, becomes sore to touch and may appear blue. The bite marks may be visible to the eye. After being bitten, the pet appears sluggish and apathetic. A large dose of venom can cause diarrhea and vomiting. Some dogs may present with heart palpitations and murmurs. Damage to the heart, kidneys, and liver is also possible.

After a bite the owner can make their pet more comfortable by calming them down and maintaining them in a rested position. The owner should also remain calm. However, the most important thing is to contact a veterinarian immediately and follow the given instructions. You must not give your dog a cortisone pill. Cortisone can mask or worsen the effects of the venom, as well as interfere with treatment. Other medications such as non-steroidal anti-inflammatory drugs (NSAIDs) should also be avoided. A veterinarian can suggest giving a cortisone pill to a pet that is in respiratory distress or has severe swelling in the head area. 

A pet that has been bitten by a viper must be brought to a veterinarian as soon as possible. The pet should be carried to the car. Touching and moving around of the bite site should be avoided. This delays the spread of the venom into other organ systems. The bite site should also not be bound. 

The venom of a viper contains several toxic compounds. The composition of the venom has remained unclear for a long time. In recent years, it has been more thoroughly researched. The toxins of highest concentration are A2 phospholipases and serine- and metalloproteinases. These enzymes cleave fatty acid and peptide bonds in tissues, blood cells, and blood vessel walls. The enzymes cause damage to the structure of cells. This is followed by tissue damage, shock, and blood coagulation disorders.

The danger a bite possesses is determined by the amount of venom relative to the size of the pet. Thus, being bitten by a viper is more dangerous for a small dog than it is for a bigger dog. It’s also been determined that the body of a dog reacts to the venom faster than the body of a cat. This is because dogs’ coagulation cascade is more sensitive to overactivation and failure. The better the circulation at the bite site, the easier it is for the venom to spread to the rest of the body. Juvenile vipers use their venom more recklessly compared to their fully grown counterparts.

The treatment for viper bites includes intravenous fluids and strong painkillers, usually opioids. The pain medication is continued at home. The treatment aims to maintain normal bodily functions and relieve the pain. A known antivenom exists but its efficacy has limited research data. However, the use of antivenom has become more common. Antibiotics are prescribed if the bite wound gets infected. Heavy exercise should be avoided for at least a month after the bite. Control blood samples are taken at a later date to determine normal liver and kidney function. 

Bites can be prevented by watching the pet, especially during warm and sunny weather. The pet should be kept on a leash during the first days after arriving at a summer house or another premise that has not been visited for a while. Vipers prefer open yards; they can feel the vibration of the ground and usually flee in the presence of humans. It’s good to be aware of the mechanism of transport and route to the nearest veterinary clinic when traveling away from the city. The prognosis of the pet is good when the owner is familiar with the symptoms and what to do in the case of a viper bite.

A tip! Don’t get rid of the viper cortisone pills you have at home or at your summer house. They can be used with wasp or bee stings. Cortisone pills help to reduce the allergic reaction and swelling caused by the sting. However, the pill should be administered only under the advice of a veterinarian.

Sources:

R. I. Al-Shekhadad, K. S. Lopushanskaya, Á. Segura, J. M. Gutiérrez, J. J. Calvete, and D. Pla. (2019). Vipera berus berus Venom from Russia: Venomics, Bioactivities and Preclinical Assessment of Microgen Antivenom. Toxins 2019, 11(2), 90. Available at: https://doi.org/10.3390/toxins11020090

H. J. Harjen, A. A. Bjelland, J. Harris, T. K. Grøn, K. P. Anfinsen, E. R. Moldal, R. Rørtveit. (2020). Ambulatory electrocardiography and serum cardiac troponin I measurement in 21 dogs envenomated by the European adder (Vipera berus). Journal of Veterinary Internal Medicine. 2020, 34(4), 1369–1378. Available at: https://doi.org/10.1111/jvim.15817

J. B. Lervik, I. Lilliehöök, J. HM. Frendin. (2010). Clinical and biochemical changes in 53 Swedish dogs bitten by the European adder - Vipera berus. Acta Veterinaria Scandinavia. 2010, 52(1), 26. Available at: https://doi.org/10.1186/1751-0147-52-26

J. Puig, M. Vilafranca, A. Font, J. Closa, M. Pumarola, J. Mascort. (1995). Acute intrinsic renal failure and blood coagulation disorders after a snakebite in a dog. Journal of Small Animal Practice, 1995, 36(7), 333-336. Available at:  https://doi.org/10.1111/j.1748-5827.1995.tb02942.x

C. N. Zdenek, J. Llinas, J. Dobson, L. Allen, N. Dunstan, L. F. Sousa, A. M. Moura da Silva, B. G. Fry. (2020). Pets in peril: The relative susceptibility of cats and dogs to procoagulant snake venoms. Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology. 2020, Volume 236, 108769. Available at: https://doi.org/10.1016/j.cbpc.2020.108769