If a cat eats a mouse that has eaten poison, can it still be harmful to my cat?

Cheers,

Kim
Australia

The most common forms of mouse and rat poison contain products that make it impossible to clot blood. These so-called anticoagulant rodenticides are seriously poisonous to cats and dogs. Pets that ingest anticoagulant rodenticides will be symptom-free for several days, but then will start to suffer from bleeding that can be fatal. Very small quantities of the most modern poisons are sufficient to kill a pet. Click the link above for more information.

This leads to a question. Say a mouse consumes anticoagulant rodenticide. After a few days it will become weak and lethargic–and therefore much less likely to escape from a hunting house cat. If the cat catches and consumes the mouse, will the poison in the mouse’s system affect the cat?

This phenomenon is called secondary intoxication. It is a big concern in theory. Fortunately, in practice it appears to be a rare event.

There is little doubt that if a mouse’s stomach is full of poison when a cat consumes it then the cat will be poisoned. However, poison in a mouse’s blood stream does not appear in practice to harm cats very often.

Nonetheless, as I mentioned above, anticoagulant rodenticides are very serious business. Any cat or dog who may possibly have been exposed to such poisons in any way–including by secondary intoxication–should be seen by a vet. Blood clotting tests run at appropriate times can detect the poison in pets’ systems. Fortunately, there is an antidote to the poisons: vitamin K.

I strongly recommend that cat and dog owners not stock or use any forms of mouse or rat poison. The risks to pets are simply too great.

Photo: Arwen is not likely to be poisoned by this mouse.