Warfarin-Resistant Norway Rats!

[Susan BAV]

I'm going to put a P.S. in first... It's so good to be able to post again! For quite some time, I couldn't post -- either a computer glitch on my end or whatever! Anyway, I was posting as Susan W but ended up needing to reregister with a new name. So now I'll go by Susan BAV.


Anyway, back to Warfarin-Resistant Norway Rats! I was in the local feed store yesterday to get some rat traps for our orange grove and some mouse traps for my son's new apartment when I saw a huge advertisement for rat poison that even promised to kill "Warfarin-Resistant Norway Rats!" Has anyone else heard of this?

I'm on aspirin therapy and don't take Coumadin, so this isn't an issue for me right now but I'm wondering:

How did they get Warfarin-Resistant? Does anyone know if there has been a study done on this? And how Warfarin-Resistant are they? I have one wild idea... Avocadoes totally mess up your INR (and in an unpredictable and inconsistant way) and should you choose to consume them, you will probably have to take a higher dose of Coumadin and check your INR more frequently (as I recall from the few months I had to take Coumadin after my valve surgery) and grove rats are also extremely common in the local Hass Avocado groves. Does anyone think there's a possible connection there? Maybe this is basic "Coumadin 101," but it's all new to me! And I'm not sure what a Norway rat is either.

 

[Cris N]

I think this has to do with the reproductive cycle and mutation. Norway rats have 6-8 litters per year. They become sexually mature at the tender age of 3 months. Since natural mutation occurs in all species it becomes more apparent as more generations have passed. It's survival of the fittest out there so the rats that have the mutated gene of warfarin resistance survive and breed with other rats that have the same resistance. And, because, the generations are produced so rapidly the warfarin resistant rats become prominent. We would probably see it in humans over many generations... but I suspect that by that time a new method of anticoagulation will be available for human use. Obviously, the Norway rat population will need to be reduced by a different poison, until they become resistant to that, and so on & so on. Same thing happened to the cockroach!

Cris

 

[gadgetman]

Chris,

You worry me about being so knowledgeable about RATS!!!!!! Too much GOOGLE time!!!!!!!

However, you are probably right. Survival of the fittest is common in nature. Adapt or be destroyed. That old cockroach will be around long after we are all gone. At least his relatives will be. Unless you know of a 300 year old cockroach?????

Susan,

Welcome back. Our barn cats seem to keep the rat (and mouse) population down very well. Removal of the mice also keeps down the snakes. No food, no visit. Anyway, we can't use Rat Poison due to the cats. Boy, our battle with mother nature never ends.

May God Bless,

Danny

 

[Susan BAV]

Hello and thanks for the replies; it's so nice to be able to post again!

Our dogs will kill rats, and maybe chew on them a bit, but they won't eat them. But our cats are too well fed to bother with such an insult to their dignity as to stoop to rodent consumption or destruction. I like having the king and gopher snakes out there, because they help gobble up on the enormous gopher problem we have out there, and the dogs and cats are afraid of the snakes and so hopefully won't mess with any rattlers that might encroach on our space. I won't put poison out there for the rodent problem for several reasons, including because of our pets and the neighbors' pets and all of the birds of prey and such, so we have to use traps and such for the rodents.

But I was just totally surprised that there was such a thing as warfarin resistance in rats!

 

[JimL]

I bought some D-con a while back for a critter problem, and checked out the ingredients carefully, since I had the idea in the back of my mind that I might be able to beat the high coumadin prices, if only I could figure out the dosing. But the D-con had no warfarin at all. Al Lodwick reported that all (if I remember correctly) the rats are immune to warfarin, and so they use something stronger. So I have to continue buying my warfarin from Walgreens.

 

[Georgia]

I read an article several years ago about the problem with warfarin resistance in rats. My understanding was that these rats nibbled food and waited to see if they got sick; if they felt sick they wouldn't eat the warfarin-laced bait. I seems they'd developed a rapid response to warfarin.

I know it sounds awfully smart, but rats are a rather spectacularly successful species.

 

[Granbonny]

Move to a Mountain

Move to a Mountain

If you never want to see a rat or a Mouse. Or a roach or an ant... Or a wasp...any small critters. Lived here ..now for 7 years.......Amazing... they just don't like living up here....Too many Larger animals. Like, Bear, Fox, Raccoons, skunks, ect........Lunch for them .....and No mosqultoes... ...Neighbor and I were looking at what..looked like the remains of a Rabbit..fur, that ventured too far up.. Figured a hawk got him for xmas dinner. ..Now, worry about my fat, cat..but don't think a hawk could lift him.. .....Bonnie

 

[Granbonny]

P.s.

P.s.

Just let my big, fat cat inside. no..New year's dinner for him.. Now, I am worried about Owls....think an Owl maybe got the rabbit?..but, Rufus is eating his 3rd..can of Fancy Feast... for today... He needs to go on a diet with me.. Bonnie

 

[Susan BAV]

All very interesting!

And, Granbonny - We're pretty sure that the HUGE owls we've seen around here have carried off three of our cats over the past few years. One of our friends saw what looked to him like a Persian cat in the clutches of an owl once and we've heard a lot of other similar owl experiences. We try to put all of our cats in the garage every night -- especially our favorite, Oscar. Lots of groves around here put up owl boxes and such to reduce their rodent problems; but in the fall, some owls seem to prefer hunting from the enormous eucalyptus trees behind our house. And, as I mentioned, our cats are well-fed, even porky...or should that be catty... They also prefer Fancy Feast!

We also have enormous turkey vulture pairs around and I'm afraid if I poisoned the rats, that it could also be a systemic poison for the carrion-loving vultures; I think I once read that they "mate for life," by the way.

So, does anyone think my avocado-INR idea (from my first post) is possible?

 

[Cris N]

So, does anyone think my avocado-INR idea (from my first post) is possible?

I suppose it's possible that the avocado idea might have some merit. According to my info 1 oz of raw avocado has 28.35 mcg vitamin K. Probably more if you eat the skin. If the rats are consuming great quantities of avocadoes (sp?), it might require more warfarin to counter-act the effect. However, it still shouldn't make them resistant... that's a function of genes.

Cris