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Happy hantavirus to all, and to all a good exterminator

December 2, 2021

Has your home been invaded by the children of Beelzebub? Let’s discuss. 

I don’t really mean “children of Beelzebub,” except that I sort of do. Colloquially, you probably know them as deer mice. Admittedly, they are adorable. They have large ears, lovely big eyes, and long, fuzzy tails. They are also harbingers of death.

Look at this adorable little hellspawn.

I spent my whole summer doing battle with legions of mice in my garage. How did this happen? Well, when you live in the boons, you have mice around you all of the time, just waiting for an opportunity to get inside your house or shed or garage so they can wreck all your stuff.

My garage is actually pretty mouseproof, but you can’t leave the roll doors unlatched because mice are evidently strong enough to lift the freaking roll doors and crawl inside. So one day last spring that’s pretty much exactly what happened … my husband left the roll doors unlatched, mice got inside, and somehow it all became my problem.

Hantavirus almost certainly won’t kill you. Probably. 

For an ordinary person, whatever. Put out some mouse traps, live happily ever after. For me … well, anyone who knows me knows that I have an irrational fear of diseases that kill almost no one ever. Cancer, heart disease, COVID-19 … pish. Fear of those diseases is so pedestrian. No, I fear real diseases, like plague, rabies, brain-eating amoebas, and hantavirus. 

Deer mice, as you may or may not know, are major vectors for hantavirus. And by “major,” I mean they almost never give anyone hantavirus. In fact, there were only 816 cases of hantavirus in the United States between 1993 (when the virus was first identified) and 2019, so let’s just stick to simple math and say that’s roughly 31 infections a year. Not super common. It does have a 30% fatality rate, though, so I feel like it’s not totally irrational to be afraid of it.

This is Sin Nombre, the virus that causes hantavirus pulmonary syndrome (HPS). Just to put it all into perspective, youd probably rather have COVID-19 than HPS.

I did manage to get rid of the mice in my garage, eventually. Here’s a hot tip if you find yourself in a similar situation: Don’t use wooden traps unless you plan on rewarding Satan’s children with lots and lots of tasty treats. The only time I have ever been successful with a wooden trap was when I literally zip-tied a piece of cheese to the trigger so the mouse couldn’t just pick up the cheese and walk off with it.

Anyway, I am bringing this up now because months after I believed I’d rid myself of my mouse problem, the kids drug the boxes of holiday decorations out of the garage and inside one of them there was a mouse nest. I’m not even going to get into how a mouse got into a latched plastic container and made a little home there, but I had to sterilize every single thing that goes on our tree. 

Fortunately, it was not a deer mouse nest. It was a house mouse nest. House mice are also nasty and carry lots of unpleasant microorganisms, but they are not hantavirus vectors. 

The difference between deer mice and house mice

The point of all my rambling is that I want to tell you what I have learned about deer mice vs. house mice. I had both types in my garage. It’s kind of important to know the difference. 

First, deer mice are cuter than house mice. There is a reason for this: because if they’re cute enough, you might not notice them twirling their tiny handlebar mustaches as evil things tend to do.

How do you tell the difference? Just look for the tiny handlebar mustache. “Deer Mouse Portal (Peromyscus maniculatus)” by Gregory ‘Slobirdr’ Smith is licensed under CC BY-SA 2.0 except for the handlebar mustache which was entirely my own doing.

House mice have smaller ears and beadier eyes than deer mice do. They also have shorter tails and solid coloring. Deer mice, on the other hand, get their name from their two-toned color: brown on the top and white underneath. 

House mice aren’t always gray, though, and that’s why you might mistake one for a deer mouse. A house mouse can also be brown and it can have a lighter colored belly, but never a white belly. 

A deer mouse also has a much longer tail — up to five inches long — and like its body the tail is brown on top and white underneath. A house mouse has a tail that’s only about as long as its body, and only one color. 

The less lethal but much more boring-looking house mouse. “House Mouse” by Mike Richardson and Sarah Winch is licensed under CC BY-NC-ND 2.0

Most of the time, though, you don’t see what kind of mouse you have until you catch one in a trap. So if you’re wondering what made that nest in your box of holiday decorations, it’s actually pretty easy to figure out. House mice are much cleaner than deer mice. They nest in tidy little balls of shredded paper or other soft materials. They almost never poop in their nests.

Deer mice nests are much bigger than house mice nests. Some may be up to a foot long. And remember, because deer mice are the minions of the devil, they don’t have any sense of personal hygiene. They poop and pee inside their nests until their nests are so disgusting that they have to build a new nest in another one of your holiday decor boxes. They also hoard food, so if you don’t find any seeds or nuts or whatever next to the nest, it’s probably not a deer mouse nest.  

Here is a deer mouse next to its disgusting, disgusting nest. “Deer mouse” by alsteele is licensed under CC BY-SA 2.0

Also, you can tell what kind of infestation you have by the smell. House mice have a very distinct mouse stink. Deer mice do not.

I have also heard that deer mouse droppings are pointed on one end, while house mouse droppings look more like black grains of rice. But I have never noticed droppings that are anything but pointed on one end, and I do know I was trapping house mice over the summer. 

Hopefully, you can use these handy tips to decide whether you need an exterminator or a priest. Either way, wear an N-95 when you’re cleaning up droppings or sterilizing your holiday decor. At least we all have plenty of those on hand.