Veterinarian warns strychnine still out there despite Saskatchewan ban

Article content

A veterinarian is advising animal owners to remain vigilant a year after the province banned a poison commonly used for pest control.

“Even though strychnine has been banned, cases of poisoning have not disappeared. So, people just need to be aware of that, that it is still a possibility,” said Dr. Vanessa Cowan, an assistant professor and veterinary toxicologist at the Western College of Veterinary Medicine at the University of Saskatchewan.

Article content

Article content

Saskatchewan’s ban on strychnine came into force in March 2023, after a two-year phase out period.

Health Canada had previously de-listed strychnine as a rodenticide, largely over the poison’s tendency to linger in the carcasses of the gophers, ground squirrels and rats typically targeted by users, potentially poisoning other animals who scavenge or otherwise come into contact with them.

Cowan said she and her team saw six cases of dogs poisoned by strychnine in 2023, including five that happened after the provincial ban came into effect. She said this is an increase from typical years when “one or two” such cases would be the norm.

Cowan said about half the 2023 cases were in dogs from rural areas, while the other half came through Saskatoon — although she couldn’t confirm the poisonings happened within city limits.

Dogs can be exposed to strychnine accidentally, or through user negligence when it comes to safely storing and placing the poison away from pets, Cowan said.

Malicious poisonings do occur; Cowan said she’s seen instances in years past of owners bringing in poisoned dogs with samples of meat or other bait containing strychnine.

Article content

Article content

While she said none of the 2023 cases have included such direct evidence of malicious poisoning, she noted four of the cases were “suspicious” in that they occurred in late fall and winter — times of year when strychnine is not meant to be used for its intended purpose of killing pest rodents.

Cowan urges pet owners to be suspicious of any pieces of meat or other potential bait seen in yards, on walking routes or at dog parks. Samples can be submitted to Prairie Diagnostic Services at the veterinary college to check for dangerous substances.

The most common symptom of strychnine poisoning is seizures setting in within 15 to 20 minutes of exposure.

“The window of time to save that animal is narrow,” Cowan said.

Owners who think their pet may have been poisoned should immediately seek emergency veterinary care, even in the absence of symptoms, she added.

Apart from pets, Cowan said vets are still seeing strychnine poisonings in wildlife and livestock.

She expects poisonings will recede in time, as any stockpiles people may still have are depleted.

There are alternatives to strychnine, but all come with drawbacks, Cowan said.

Article content

She noted zinc phosphide is most commonly held up as a strychnine replacement, but added that while it reduces the risk of un-targeted exposure for wildlife, it carries risk for humans due to a chemical reaction in the stomachs of poisoned animals; this creates a gas that can potentially be inhaled by people coming into contact with carcasses.

Anti-coagulant poisons that stop poisoned animals’ blood from clotting are effective, but tend to be more expensive, Cowan said.

While she acknowledged this could make them a harder sell for people and businesses dealing with potentially large rodent problems, she said the advantage of this class of poisons is that antidotes are available, which makes it far easier to save animals that are exposed.

Article content