PROBLEMS & SOLUTIONS

RODENT MISINFORMATION
Q So far this year my customers have asked me a lot of questions about rodent problems. There appears to be no shortage of rats and mice. Misinformation keeps popping up, including the old questions about secondary poisoning and some new questions concerning exposures to possible organisms. Can you help me answer these questions?

A First, I have some comments about the misinformation that’s out there. Although I have seen these topics addressed many times over the years it still amazes me that they persist. I am talking about statements like, “This rodenticide makes the rodents go outside and die,” “The rodent needs water to activate this and will have to go outside to drink,” or, “The reason the rat bait isn’t working is because the rodents are eating pet food and it contains vitamin K, an antidote.”

If anyone reading this considers himself or herself a professional in this business and believes any of the above then they should read on. I cannot find where this information originated…perhaps it was back in the days of strychnine, Compound 1080 and red squill (there’s one many readers won’t remember). The actives we have today in our rodenticide baits are extremely active compounds against rats and mice. In some cases the active ingredients stay active in the rodent’s body for many weeks. This is the primary reason most of the anticoagulants we use are considered single-feeding rodenticides (because of their activity and longevity).

Rodents do not need water to activate the active ingredient. Rodents do not go outside and die. (Why do we answer odor problems inside if this is true?) Finally, the vitamin K in pet food is not the vitamin K that is required to antidote a poisoned animal. There is no need to get real technical here. This speaks for itself.

The next issue is secondary poisoning. This comes up from time to time,usually in the question, “If a rat eats the bait and dies or is sick and my cat eats it (it’s always a cat) will it die too?” There could be a possibility of this if the cat eats the entire rodent (and if the cat eats enough of the poisoned rodents). A few things to consider here: First, body weight. Cats are usually larger than rodents. (I know you have seen rats as big as a cat but really cats are bigger and heavier animals.) “The dose makes the poison,” someone once said. The cat would have to eat the liver and stomach contents of the poisoned animal, which is a possibility for some cats and dogs. If anyone knows of documented secondary cases I would like to know about them. I have not run across any in my experience. The other concern is often for hawks and owls. Birds are extremely sensitive to anticoagulants and they do eat the entire animal. Again, there is a possibility here but slim. I do not know of documented cases. Our rodenticides are labeled for agricultural use in orchards, on farms, etc., where we know there are rodents and birds of prey.

Finally, I have some thoughts regarding increasing concerns for safety and the question of exposure to organisms when servicing traps that have killed or harbored rodents. First, for applicators, safety gloves and good personal hygiene will probably resolve any exposure issues. Respirators with HEPA filters are always an option in extreme rodent situations because not all of the “contamination” is in the station. Questions regarding cleaning stations are the ones we may have to deal with, especially in food facilities and other “sensitive” accounts. For the most part soap and water can clean the stations. Using alcohol or bleach solutions can also be done and may be done on site (alcohol wipes could be carried by the technician). Using registered sanitizers may also be a possibility in food facilities — this may be required because of needed documentation. However, some sanitizers may impart odors that could repel rodents from the traps and stations. This is a relatively new area so experience will be the teacher.

The author is president of George Rambo Consulting Services, Herndon, Va. Fax questions to him at 703/709-9637 or via e-mail at grambo@pctonline.com.