Rat Colony Disaster

I purchased two new female rats about a week ago. Both appeared (and still do) completely healthy--good coat, no sniffles, clear eyes, etc. I put them in a rack, separate tub, in my rat room. Since then, in the past week, I've had five of my adult rats, develop reddish discharge from the eyes, sniffles, labored breathing, hunched posture...and finally, they died. I have two separate rat racks, and rats in both racks have died. I now have another male who's looking sick, but everybody else appears healthy (including the two new girls). What happened?? I've never had trouble with my rats, and suddenly, I've got five dying in a week's time. How should I have introduced the new girls? Are they the cause of all this? I'm just really bummed and feel terrible that I might have introduced something that is killing my rats. Help?

what kind of substrate are you using?

shredded aspen

This is why you should quarantine any new arrivals for a minimum of 30 days. The new ones most likely brought something very nasty(Strep that caused pneumonia, etc) into your existing colony, and your rats died because they hadn't ever been exposed to it before. The new ones are fine because they've been exposed and have developed immunities against it(or were born with it). Don't worry about moving them now as everyone is already exposed to it anyway.

If you can get some cephalexin or amoxicillin from your vet, give it to your remaining colony so they can fight off whatever those new rats brought in. Streptococcus is very susceptible to cephalexin and other penicillin derivatives. If you can, take one of the deceased rodents, place it in the fridge and have your vet run a necropsy, gather a few samples of lung tissue, etc, and send it off for a culture/sensitivity. They should be able to find out what those rats brought in and you can inform the store you got the rats at.

I rarely buy pet store rats anymore but Becky's right, when you do try to keep them away from the colony for a few weeks at least to see if they've got any nasties. Heck I give the new ones a quick dunk in the sink too just to make sure they haven't brought any crawling "friends" home with them (I hate hate hate fleas and that sort of thing).

Best thing I can suggest other than the vet is just to keep them as unstressed as possible (cut numbers down in the enclosures as much as possible). Feed extra nutrition, keep them quiet, warm, clean and well hydrated and it will take it's course. Phone the vet and see if there's anything you can get from the feed/tack store as I know Becky's recommended that route for deworming meds for rat colonies but I don't know about antibiotics, for that you may have to go to the vet.

Thanks for the replies. One thing I don't understand though...if the new girls look and act healthy, how would quarantining them have helped? Wouldn't they still have "carried" in whatever they have, 30 days later? I'm not disagreeing with you, just trying to understand how the quarantine would have helped, and how to prevent this from happening again if I ever introduce new rats again. Thanks.

I was thinking the same thing...

I think it's just to give anything brewing time to actually show up (if it's going to) but in the end there really are no guarantees when you introduce any creature into a stable population. It's just not feasible to vet each and every breeder rat or your breeder/feeder efforts won't be cost effective. I don't always quaratine new rats, I do if I can though but every one of them gets a bath to get rid of that pet store stink. I think it also helps them lose their old colony smell so when they do go in with any of my rats, they are accepted better since they don't smell so different (no science behind this...just my own theory of how rat colonies work).

Sorry for your loss. Definitely a recommended quarantine time is in place for a reason, sucks that you would have needed stricter measures to save your colony.

And don't forget Typhoid Mary... some individuals will not fall prey to infectious diseases but can be carriers to infect others.

This is the reason that a lot of rodent breeders end up closing their colony, you have to make a choice between genetic diversity or bringing in pathogens. I know a few rodent breeders who have closed colonies that haven't added any new outside rodents in over 10 years.

Thanks again for the replies. I've had my current colony for about three years. I was at the point where I needed to start adding more female breeders, either holding back, or bringing in new girls. I kind of thought that at this point, pretty much every rat was related to every other rat in the colony, so thought some diversity would be good. What a costly mistake that was. I don't know. I think from now on, I'll just hold them back until/unless some problem (genetic deformities, etc.) develops with that. No more new gals/guys. Thanks again for the input.

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Originally Posted by dfisk5

I kind of thought that at this point, pretty much every rat was related to every other rat in the colony, so thought some diversity would be good.

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It seems to me that if you're wanting some "new blood" in the colony, it would be a little easier to hold back females, and get new males. That way one or two new males can be the equivalent of as many as 8 or 10 new girls as far as genetics goes (depending on the ratio you use). the way i see it, the fewer new specimens you introduce, the less risk you run, and also it is cheaper to by 2 rats than 10 rats.

I see your point, but there are other factors to consider. First, I already had enough males (I rotate females through the males) and didn't want to start a new breeding tub. Second, I wanted to buy females that were sub-adult, rather than raise them from pinkies (quicker to breeding size). When I need a new male, I can raise one up in five weeks, tops. And, I only introduced two new girls, not ten as you mentioned. Their babies could lead to a pretty large number of new genetic crosses, without breeding them back to relatives. Of course, now with the five rats who died, I need two new males (holdbacks this time, of course) and new females (same thing). I guess it all depends on your set up. But it's almost always easier to raise up new males than females, at least from a timeline perspective.

I guess i was looking from more of a general view point than this specific case. Good points.

i don't know anything about rats, but, i do know when i had my horse taken to a new place, a bunch of horses got the horse version of flu. diffrent animals can cary diffrent germs that they become immune to, and others are affected by...horses can just deal with it, rats are so small and a lot more fragile so they probably can't just shake it off. quarintine is always a safe idea.

The other option which I know some of our members use is to trade rats with other members or folks they know that also have very healthy breeder/feeder colonies going themselves. That way you both get some fresh blood in but you aren't risking the issues that can come with some pet store stock.

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Originally Posted by frankykeno

The other option which I know some of our members use is to trade rats with other members or folks they know that also have very healthy breeder/feeder colonies going themselves. That way you both get some fresh blood in but you aren't risking the issues that can come with some pet store stock.

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This is still not a perfect option, each seperate colony can carry any number of different pathogens. So although each colony may have been heathly for prehaps 10+ years, they could still carry a new pathogen to the other colony and cause disease. Although granted its much more unlikely to happen than it is with pet store rats.
The only option i can see is if new rats are being planned on being brought into a colony they should be kept in a very different part of the house/facility and after quarantine a single rat from your own colony should be introduced and then wait another 30 days, if the rat you introduced is still alive then it is (99% of the time, some pathogens have longer than 60 day incubation periods) safe to introduce the new rats into the colony.

Graham

Hey, now there's an idea I like! Not fool proof, of course, since some of my old rats were unaffected by the new girls, but definitely a better plan than just introducing the new girls without any quarantine. Plus, I could use a male as the guinea pig (so to speak), so less of a loss than the breeder females. I think it's a terrific idea. Thanks!

Just thought I'd post a follow-up. No more rats have died, or have any symptoms of illness. I think the plague has passed. The new girls of course, look as healthy as ever. Two female rats are pregnant by a male who died in the disaster, so I wonder how it will go with their pups? I assume, that whatever immunity the mothers obviously have, will pass to the pups? Let's hope so anyway. Also, I don't know if it's related, but two female rats that had pups during the disaster, have very small pups. Not typical for the two females. The pups seem healthy enough, but small. I assume it must be related, but it seems odd. Anyway, it seems that the worst is over. Thanks for everyone's replies.

Im glad to hear everything is doing better now. Hope it stays that way.