Having recently had a case referred to us following an Adder bite, we thought that a reminder about the possibility of this type of injury might be timely.
Adders are the only venomous snakes native to the UK. Varying in size from around 40 to 70 cm long, they can be distinguished from other, non-poisonous snakes, like the grass snake and slow worm, by the zigzag pattern on their back and V- or X-shaped markings on their head. They hibernate during the winter and reappear in spring as their environment warms up.
It is relatively uncommon for dogs to be bitten by Adders with only around 100 cases reported each year in the UK. Generally speaking, they will attack only in self-defence but, unfortunately, dogs are unaware of the danger and can often provoke an attack through their excessive curiosity. If an Adder does attack a dog, it will inject venom – most commonly into the face or forelimbs.
Signs of an Adder bite usually appear within 2 hours and can include local swelling, pain, bleeding and lameness. If venom is absorbed into the lymphatic system, it can cause a widespread inflammatory reaction leading to symptoms such as lethargy, fever, increased heart and respiratory rates, drooling, vomiting and a ‘wobbly gait’.
Most cases make a full recovery but, occasionally, more severe effects are seen such as breathing problems, collapse, convulsions, kidney failure, bleeding disorders or abnormal heart rhythms.
Treatment of Adder bites is aimed at supporting the circulation and hence preserving organ function, minimising the swelling, reducing the pain and preventing secondary infections. It is likely that fluids will be given via a catheter; and steroids, possibly anti-histamines and/or antibiotics may be given. Following treatment, cage rest is recommended to reduce the absorption of venom into the circulatory system. There is an anti-venom available, which can also be useful in severe cases. However, this can induce an allergic reaction and should be used only when absolutely necessary.
The most important factor in a dog’s response to an Adder bite is rapid and appropriate treatment. The dog should be taken to a veterinary surgery as soon as possible, utilising the emergency service if it occurs outside of normal hours. If possible, he/she should be carried rather than allowed to walk. This reduces the chance of venom entering the lymphatic and circulatory system.
Although the risk of Adder bites is quite low, it is advisable to be cautious at this time of year, especially in areas where the snakes are known to be present. These can include sand dunes, moorland and woodland edges.