WILD MOUSE ATTACKED MY MOUSE!

Question
Hi, Natasha.
I was hoping you can help me.
Today I found out that a wild mouse is in my home. I saw him/her in my room.
And all in one hectic night, I had a showdown with this mouse.At first I was trying to be humane, catch him and set him free somewhere else.
But I have a pet mouse, Marley.I was trying to protect Marley, so I put him in a diffrent room while I try to catch the mouse. But the mouse is too fast, and I gave up and went to sleep in the same room with Marley.
The middle of the night comes, and I wake up to him biting crazily at his cage bars.
I turned on the light and I saw the little brown mouse on Marley's cage, before he ran off.
My sweet little angel didn't get seriously injured, but he DOES have a cut on his toe and small cuts on his tail. At first he seemed upset. He curled up in a ball in the corner and cleaned himself. He would respond to me and come to my hand, but he wouldn't eat his treats(I wanted to calm him down.)
NOW, he seems ok. He's eating his treats and is running on his wheel again.
I'm guessing the mouse was on his cage, Marley got upset and bit him, because there are small spots of blood on the bars. Marley's cuts don't look big enough to cause spots of blood.
But I'm now dead set on getting this mouse out of my house.
My question is, with his minimal injuries, what should I look out for? Certain behaviors that seem off? Is there anything I can do or give him so he can remain healthy?
Is ok if I put a towel over his cage to protect him from another attack while I'm at work?
And does having a mouse attract wild mice? Or is this a freak accident?

Thank you.

Answer
Dear Nikki,

Yes, wild mice are attracted to tame mice. At least, males are certainly attracted to females, which ends in a lot of apparent "Virgin births" in cages of female fancy mice, since wild mice are small and can sneak into barred cages. And any wild mouse will be attracted to the easy food in a mouse cage. I would not be surprised if that wild mouse had actually gotten into Marley's cage and Marley chased him out; or he may have just been trying and not yet have succeeded. So I'm afraid it was not a freak accident, and may very well happen again.

One way to avoid this in the future is to have the cage on a surface that would be impossible to scale up to. A table with sheer legs. A tall dresser. Wild mice are good climbers, so you have to think from the level of the mouse.

As for injuries, the only danger is infection. A vet might give him antibiotics as a preventive measure, depending on the vet. I would probably do a real easy antibiotic treatment - get tetracycline formulated for FISH, often called Fish-Cycline, and put the contents of one capsule in a larger or of 1/2 capsule in a smaller water bottle. Shake well, cover with tin foil to keep the light out, change every 2-3 days, and continue to use this water for ten days.

There is one other thing to look out for-- the most likely thing a wild mouse will give a pet mouse is mites. Watch for scratching, thinning hair,  bald spots, or scabs.

As for a towel- he does need daylight, so that won't do :(. A wild mouse would just go under it anyway.

The best things to do are to limit access to the cage and to continue to try to live trap and release the mouse. Make sure you take the mouse over 1 mile away to make sure it doesn't come back.

Squeaks,

Natasha