deer mouse whose become a pet

Question
Hi Tamarah,

About 3 months ago my sister-in-law, who volunteers for our local wildlife rescue org., obtained an orphaned female baby deer mouse(furred but eyes closed).  She asked my teenage daughter( who helps out with the w.l. rescue and has a knack for working with animals) if she would like to keep this baby for awhile.  My daughter took the mouse, fed it every 2 hours etc...  The mouse thrived and my daughter became very bonded to this cute little critter.  Now, she's my daughters pet.
Here's our problem/questions:  We just found out that deer mice are carriers of Hantavirus.  I know we should have known that before taking the mouse.  As we've had her since she was a baby straight from the nest, is it possible for her to have the virus?  Can she have contracted the virus from her mother?  Would she be able to survive as other deer mice if we had to release her?  She's very well cared for, with everything she could want in her little habitat.  We suspect she doesn't even know she's a mouse!  My daughter is very sad about the thought of releasing her.  But maybe that's the right thing to do.  Any input would be greatly appreciated.  Thanks for your time.

Lisa

Answer
Hi Lisa,

Hantavirus is in fact carried by deer mice, but your chances of it depend mostly on your location.  Certain regions are more prone than others.  Here's a map from 2003 showing the frequency across the nation (if you are outside of the U.S., just Google "hantavirus map" and your location to find one of your area).  http://www.scchealth.org/docs/eid/images/hantavirus.jpg

The chances of the mouse being a carrier are probably very small, as it is spread by infected urine or feces inlcuding those in aerosol form (like when you shake up dirty bedding, or from momma mouse), or bites.  She wasn't in the wild very long, so I wouldn't put your chances at very high.  However, since HPS (hantavirus pulmonary syndrome) is very serious when contracted by humans (read more about it here:  http://www.scchealth.org/docs/eid/docs/faqs/Hantavirus_faq.html ), what I would do is call around to your local vets or colleges with laboratories or vet programs and see if any of them can refer you to some place that might test the mouse for it.  Better safe than sorry, as it can be lethal in people.  It won't affect her, just you, so it's very probably in the *mouse's* best interest to stay in captivity with you.  It sounds like she has already become accustomed to living as a pet, and releasing her into the wild without preparing her for it could lead to her becoming an easy target for predators.  There aren't any water bottles in the wild, or prepared foods, you know?  So unless you want to condition her to living without the interference of people before releasing her, I'm sure she'd prefer to stay with you.

I would definitely make those calls and see if anyone nearby to you can take a sample from her and test for hantavirus.  In the meantime, practice the very best sanitation when cleaning her cage and try not to breathe in anything you shake up while doing so.  Like I said - your chances are slim, but it's a pretty serious disease to people.

Best of luck in your decision!
-Tam