A Battle Against the House Mites (Dani ダニ) - The Japanese Bed Bug

Updated: Aug 17, 2020

Summer time: A time of beaches and all the fun in the sun. But there are also the vast amounts of creepy crawlies.

Unfortunately in Japan, there are cockroaches. And centipedes. And hornets (that are too big for its own good). And the other usual creepy suspects such as mosquitoes (who seem to enjoy taking foreigners' blood) and spiders.

One type of bug that's often overlooked are house mites and bed bugs.

I tried my best to find the least triggering photo of a bug...

One common type of bug is called "dani" (ダニ), or often known to foreigners as tatami bugs. These tiny, tiny bugs dwell deep within tatami mats and feed on human blood at night, leaving tiny bumps on the skin. If you find yourself waking up one day with two red bumps in a row on your arm or on your leg, chances are there may be a dani bug hiding in your home. Dani bite marks often appear in pairs, but if there are more than one bug (which is often the case by the time you notice the bites), it can look like a cluster of tiny red bumps.

What's not talked about with dani is that they often dwell in carpets, futons, pillows, clothes and mattresses as well. So even if you don't have tatami, you can very well have yourself a dani infestation over the summer humidity.


The easiest way for prevention is keeping on top of your cleaning. Vacuum your apartment often, especially if you have carpets. Air out your futon and blankets in the summer heat. Take your tatami mats outside on a nice sunny day.

If reading this article has now gotten you slightly paranoid, there are dani traps you can place around the home that attracts dani and traps them. They often come in fabric sheets that last a duration of 3 months, and can easily be bought at your nearby drug store or home improvement store.

There are also sprays you can purchase at the drug store that prevents dani. You can use a fabric spray on sofas, carpets and other surfaces. Some advertise the spray to have killing abilities, but I have yet to see the effectiveness of it.

Keeping your apartment windows open and airing it out has said to help. It keeps the humidity and mildew in the house down, keeping the dani away.

Of course, none of these methods are foolproof. As with my situation, you may very well bring along the pest back home from your travels or your workplace. If you lived in Japan long enough, you will come across them. So then, now what?

Prevention After Travel

Because of the struggles I had getting rid of these bugs, I usually try my best now to prevent and nip the issue in the butt before it gets bad.

I travel a lot in my own leisure, and one of the most common ways to bring bugs back into your home is through the hotels you stay in. (if you're thinking this is very much like bed bugs, you're very much right!)

That's why after every trip now, I always do a laundromat run. The night before I return home, I wrap all the clothes and other fabric materials (towels, etc) I used during this trip into a plastic bag for easy transfer.

Once I arrive at my door step, I strip down and dump the clothes I am currently wearing into the same plastic bag and run straight into the shower or a bath. After my bath, I take all my things to the laundromat for that high-heat cycle. After the laundromat, I wash all my clothes and hang dry outside.

For the things I cannot laundromat, I unfortunately just have to pray that no bugs have chosen those places as hiding spots... but I just try to wipe down and hang whatever I can hang outside on my balcony.

Too Late? Getting Rid of Dani

Dani bugs may sometimes look like normal mosquito bites. Some telltale signs of dani bites are the way you are bitten by them. They often appear in pairs. The bites also often don't disappear for days, and can linger for about 7-10 days and can still linger for longer, even if it's no longer red.

Swelling can differ for different people. Mosquito bites often swell for a few hours before disappearing, while a dani bug bites will only create small red bumps and linger for days. For me, I have a reaction to mosquito bites and it often looks very swollen. But the dani bites were small, almost looking like an spot of ingrown hair or razor bumps after shaving.

So now that you suspect if may be dani, what should you do?

Several people I've spoken to have easily taken care of the dani using the dani aisu sprays with the needles. Wipe the tatami and vacuum to suck up the carcasses. Dispose of the trash in your vacuum immediate to prevent any bugs from escaping back into your room.

Keep up with the vacuuming for the next week or so. You maybe also want to consider purchasing smoke bombs/gas bombs. Here's a great article on how to use these bombs.

However, some friends and other people on the internet have mix feelings on smoke bombs, especially if you have lots of furniture and other great hiding spots such as sofas with thick cushions. It is possible that the bugs may be hiding there, and the gasses cannot penetrate those spots - leaving you back at square one.

More Complicated Cases of Dani

If you find yourself waking up to a few pairs of new bites every day, you will want to take more action than just sprays and bombs.

First of all, you may want to contact your landlord if your are at a rental property. Some landlords may be able to help you fight this situation by hiring professional to deal with it, but if you were like me in my situation........ you may have to battle this alone.

(I was in the dreaded Leopalace rentals, and when I called, they refused to help)

Vacuum and use the dryers at the laundromat frequently. Heat kills dani. Put your washed items in the dryer for 30 minutes or more under high heat to kill your menacing roommates. Make sure you run the dryers for at least 30 minutes in high heat, or it will not be enough to kill them.

If you have stuffed animals, vacuum and run them to the dryers. They can very well be hiding there as well.

Keep your items in a plastic bag until every item in your house has been through to the dryers. This way you can eliminate those items from being infected and take items to the dryers at your own pace. This is a good but slow way, especially if you do not have access to a car or if the laundromat is far.

Clean and wipe down your house. Keep other household items in bags and ziplocs until you have the situation under control. I highly recommend enlisting some help from your friends. The faster you can clean, the less likely they'll have a chance to multiply!

Vacuuming Your Mattress

If you have a mattress, you might be in a bit more of a pickle than someone with a futon. A futon you can simply hang outside and beat the living crap out of, in normal traditional Japanese fashion. But mattresses and dani (especially if you had a carpet, like I did), oh boy!

There are a lot of "preventative/repel" spray products like this one on fabrics and the like nowadays, but not "treatment products" like they have for tatami, which is honestly not helpful unfortunately......

I had found some articles in Japanese at the time about deal with dani on sofa, and really, the only solution to it is vacuum, vacuum and vacuum some more! And a good dose of dani traps.

Japanese people seem to swear by the vacuum with the UV lights, which sells themselves to being able to kill the dani on contact. Raycop vacuums are particularly popular and was recommended to me by a few people. I actually had the honour to try it out myself, as a friend of mine's daughter happened to have one. I actually already had owned a Dyson Mattress at the time, which had really amazing suction power and you can physically see all the dust you can pulling out of the mattress (a false sense of safety, perhaps??).

So I honestly cannot tell you if the Raycop worked, but if you can fork out money for that Dyson, it is a great vacuum regardless of whether you have bugs or not.

The Use of Steam Irons

This is by no means a proven method, so you should take this with a grain of salt... but I had come across this method through a Japanese blog(highly recommended read!), and at the time, there wasn't lots of information on how to deal with dani with tatami, but not on carpet. It was one of the very few sources I found with any mention on treatment with carpets. If you had a serious dani problem with no end in sight and running out of options, it wouldn't be the end of the world to try it out.

If you have a steam iron at home, it MAY be very effective on items that maybe be difficult to carry out of the house or just simply cannot be removed such as carpet.

Lay a (wet) towel on the carpet and run your steam iron slowly on the carpet with the towel in between. The steam is often hot enough to kill the bugs, however some other Japanese blogs I consulted have mix feelings about this. Even though the steam is hot enough, the steam iron doesn't treat a huge area fast enough (dani can move quite fast). So again, try it at your own risk.

The method is a bit tedious especially if you have a big room. My small apartment had carpets I could not remove, making it difficult to treat otherwise, so I thought it was worth a shot. You can do the same on your futon and pillows too.

Other Products

Other netizens have suggesting buying edible-grade diatomaceous earth (DE) and sprinkling it around the house. I looked at this method, and it seemed to work for some people battling bed bugs. As mites are smaller in size, I wasn't sure what to make of the method, but I thought I would look into it.

I found that DE may not be too easiest thing to come by in Japan, so I opted for this product instead:

It promises to be a pet-friendly product and that you could vacuum the powder, no hassle. I sprinkled them in the corners and a light layer into the carpets. Although it was obviously bad for my lungs, I actually left it in the carpet for some days (I don't recommend this, please don't do it).

Whether it worked or not, I'm not sure... But perhaps worth a shot?

Professional Treatment Scams?

Like with most things in life, there's always people who try to profit from your misery. In Japan as well, unfortunately.

I actually tried to hire a "professional" company to try and see if they may have a different solution to the problem I was having. I called them up, and we scheduled a time for them to come over.

Two men showed up empty handed and "assessed the situation", and proceed to quote me 15000 (about $150 CDN) yen for a treatment. I told them 15000 yen was way too expensive. After some back and forth, they offered to drop it to 10000 yen (about $100 CDN). Desperate, I was willing to try so I agreed.

However, they proceeded to pull out a smoke bomb. Much like the ones I had mentioned earlier in my article that I was able to buy for 600 yen at the supermarket. I stopped them, and basically said (in more words, of course) that their services were no longer necessary. They didn't make a fuss, thankfully, and left.

Was it a scam? I can't be sure. For all I know, it could be a professional-grade smoke bomb, but I still think it's ridiculous to pay 20x the price for something you can do yourself......

So please be wary out there! When you are desperate to try to get rid of these bugs who are wasting a lot of your precious energy and time, you want to believe that people you are paying are genuinely wanting to help - but that's not always the case. Always make sure to inquire about their services before paying.

Keep at it and don't give up! I've was battling them for 2 months before I had fully stopped seeing new bites on myself. You will have to live in bags, do extra laundry work and house chores every day, but I promise you will get there!

I live without any bites now, but as a preventative measure, I always make a trip to the laundromat after every overnight trip. I definitely don't want to see these critters again.

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