Each spring brings with it cases of snail bait poisoning in dogs. Puppies in particular find snail bait irresistible, but even old animals can become poisoned.
There are two popular types of snail bait – Defender, which contains metaldehyde, and Baysol, which contains a poison which upsets the nervous control of the intestine. Both poisons can be fatal if a large amount is eaten, but of the two, Defender poisoning is the most difficult for the veterinarian to treat.
Metaldehyde (Defender) is a poison which causes no gastric irritation and therefore only when massive amounts have been eaten will the dog vomit. The first sign of poisoning is a lack of coordination in the dog’s movements. The dog will often be unable to climb stairs and will remain sitting.
On trying to get up tremors will be observed in the muscles of the legs. Depending on the amount of poison eaten these symptoms may take up to an hour to intensify. Eventually the muscle tremors become very marked and the dog will lie on its side with its muscles continually twitching.
These symptoms are similar to strychnine poisoning but with strychnine the muscle spasms are far more violent and tend to be intermittent, spasms often being induced by a loud noise or sudden movement.
Treatment of Defender poisoning must be undertaken by a veterinary surgeon. Attempts to make the dog vomit by giving emetics such as mustard and water are not successful. Where severe muscle spasms are present the dog may not be able to swallow and anything given by mouth can find its way into the dog’s lungs.
The veterinarian in these cases first anesthetizes the animal to counteract the nervous spasms. A stomach tube is passed and the stomach washed out to remove any free poison. Of course by this time quite large quantities of the poison have been absorbed and it is necessary to maintain anesthesia until no further nervous spasms occur. This often is for a period of 36 to 48 hours.
Whilst the animal is unconscious for such a prolonged period its body temperature must be maintained. Fluids are given by transfusion and the animal’s position changed regularly.
The success rate of this treatment is high but is dependent on the amount of poison absorbed before treatment was begun. Large dogs have a greater chance of survival from massive poisoning than small dogs. The margin of safety between the anesthetic dose and the lethal dose of the anesthetic used to counteract the effects of the poison is much greater in a large heavy dog than in a tiny dog weighing only a few kilos.
Poisoning with Baysol pellets produces a completely different picture. Baysol causes violent gastroenteric symptoms. In quite a short time the dog becomes very quiet, salivates profusely and soon starts to vomit. This is followed by severe purgation and straining, with the dog eventually passing only clear mucus.
If untreated the animal becomes very cold, depressed and weak and may die. Fortunately there is a specific antidote to the effects of this poison. Injections of Atropine sulfate quickly stop the violent muscular spasms of the intestinal tract and the animal rapidly recovers with apparently no lasting ill-effect.
Snail baits can be used where there are pets quite safely if certain precautions are followed.
- First lock your pets up before spreading the snail killer. Puppies will be encouraged to investigate if they see their owner busily spreading something in the garden.
- Avoid leaving the preparation in piles and follow the manufacturers recommendation as to the rate of application. It is almost impossible for even the most addicted pet to pick up a dangerous amount if the pellets are spread evenly and thinly.
- Be careful to store the packet well out of reach of the pet. Many dogs are poisoned by eating massive amounts of pellets from a spilled package.
- Seek veterinary advice if you see your pet eating the pellets. The veterinarian can make the animal vomit quite easily before serious symptoms develop.