MALICIOUS POISONINGS IN PETS
The malicious poisoning of pets is a serious problem in urban areas. It is however important to remember that there are also ways for animals to be accidentally poisoned. Always read the directions for use of any product used for pest control, whether it be for use on the pets or in the environment, or any other agricultural products used in the garden or home. If you are unsure about any products or ingredients, contact your vet before using where your pets have access to it.
For the topic of this piece, we will concentrate on the use of aldicarb (Temic or 2-Step) in malicious poisoning cases. Aldicarb is a carbamate which is extremely toxic. Carbamates and organophosphate products are related and work in the same way. The signs seen in cases of toxicity are also therefore similar.
Carbamates are synthetic pesticides used in agricultural pest control. It has been banned in this country, but can still be acquired very easily. Both the carbamates and organophosphates act by inhibiting esterase enzymes in the body. The function of these esterase enzymes is to detach the messenger molecules from the final receptors once a required message is delivered. If this does not occur, the message is not “cancelled” and continuous stimulation occurs. As an example; the acetylcholine esterase enzyme detaches the final messenger molecule (acetylcholine) from the receptor on a muscle that stimulates contraction. This leads to muscle relaxation. If this messenger is not “cancelled”, continuous stimulation is seen causing muscle twitching or fasciculation. Other common signs that are seen are excessive salivation, vomiting and diarrhoea; seizures; weakness and paralysis; slow heart rate (below 60 beats/minute) and small pupils. The cause of death is due to asphyxia and respiratory failure with a decrease in blood pressure and fatal heart block.
Exposure usually happens when bait containing the aldicarb is tossed into the garden/yard. It can be concealed in meat, sausages, etc which most dogs would eat readily. Aldicarb is found as a small, black, granular substance and only a small amount is needed for toxicity to be seen. The carbamates are fat soluble and can be absorbed via skin contact. If poisoning is suspected, take your pet to the nearest vet AS SOON AS POSSIBLE. Avoid contact with any bait, vomit, saliva or any other bodily fluids. Wrap your dog in a towel or blanket when bringing him/her to the vet. Cleaning up of any bait left behind or any body fluids should also be done wearing gloves to minimize any exposure and poisoning of people in the household. As it is fat soluble most house hold detergents work well for cleaning. If severe contamination is found, specialized cleaning services may be needed to decontaminate an area as re-exposure can occur if contaminated fluids or bait are ingested at a later stage.
Treatment is mainly symptomatic and your pet would need to admitted and placed on a drip to support circulation. Further treatment is aimed at increasing heart rate, stopping muscle tremors and seizures and trying to prevent further absorption of toxins from the intestines. With rapid and intensive treatment the prognosis is reasonable. Any delay can worsen the prognosis for recovery.
In some cases there is also chance of delayed symptoms being seen. These occur about 8 - 14 days after initial poisoning. The mechanism of action is not fully understood. This syndrome manifests as incoordination and weakness of the hind limbs. It is more commonly seen in cats, but can occur in dogs too. The changes are irreversible and permanent.