Ask the Expert - Primary and secondary rodent poisoning

Effective rodent control requires risk management, so it must involve the client. While anti-coagulants are effective and compassionate, there are risks when using toxic bait. Clients need to be aware of the dangers of primary and secondary poisoning. Understanding the risk keeps humans and companion animals safe during baiting programs.

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While anti-coagulants are effective and compassionate, there are risks when using toxic bait.

Primary and secondary poisoning – help clients understand the basics

  • “Primary poisoning is poisoning animals directly feeding on rodent bait” says Doug McCarron, Bayer. 

“Ideally, this should only be primary target pests - rats and mice. However, baits are non-specific, so non-target animals are always at risk.

As professionals, our responsibility is to secure baits so only targets can access them. The range of lockable stations available makes it easy.

If a station doesn’t suit, secure the bait block with wire or nail it to a secured beam so the rodent feeds but can’t remove it. Tracking powders are also an exceptional way of introducing bait without possible translocation to a non-target area,” Doug added.

  • “Secondary poisoning is when a non-target animal consumes a toxic dose while eating a previously poisoned rodent. 

As professionals, our responsibility is to secure baits so only targets can access them.
For Professional Pest Managers, this is a serious problem around residences with domestic animals. In commercial operations, areas such as piggeries can be particularly difficult to control.

Schedule multiple visits to quickly remove dead bodies, lowering the chances of secondary poisoning. Bayer recommends engaging customers and staff in the programme, getting as many eyes on the job as possible”, he said.

Tips for responsible baiting
Most active ingredients have a long residual life inside a dead rodent, making secondary poisoning an issue.

Coumatetryl and Warfarin rapidly degrade in an animal’s system but rodents need multiple feeds to obtain a toxic level. A diligent pest manager will ensure sufficient bait is always available. This safe degradation vastly reduces the chances of secondary poisoning. Always use this approach when working near sensitive animal enclosures such as Zoos.

Baits must be removed once the baiting programme has been successfully completed. Unintentional poisonings increase significantly when the program is not current. In commercial operations where permanent stations are required, regular bait checks limit the hazard.

At contract completion, remove the bait completely. This is also important for hygiene issues, as pests can emerge from old rodent bait, leading to pest infestation issues.

Rodilon®“Arguably the most palatable bait matrix available” 

A proven tool in rodent management, Bayer’s Rodilon®, combines difethialone, an anti-coagulant, with perhaps the most palatable rodent bait matrix available. Trials on rats and mice show higher levels of consumption than other wax or mini-block formulations. Fast, effective, ‘single feed’ treatment.

The bait matrix is enclosed in a paper sachet, reducing bait handling exposure without limiting efficacy (rodents chew through the sachet). Baits can easily be secured in stations (e.g. with wire). More importantly, Rodilon contains a human taste deterrent, Bitrex, and an antidote is available.

Talk about the problem….
Bayer recommends always discussing both primary and secondary poisoning with clients so they are fully aware of the implications associated with your program. The client’s involvement should be much more than just financial to protect the safety of humans and non-target animals. There are, of course, antidotes to most active ingredients and emergency application by a veterinary specialist can save the day - but why would you want to take the chance….