Bed bugs may travel to new homes in your dirty laundry

You really don’t want to bring these guys home.
You really don’t want to bring these guys home.
Image: AP Photo/Alex Brandon
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Bed bugs are incredible world travelers.

In the past couple of decades, bed bug populations have exploded all over the world, particularly in the US, parts of Europe, and Australia. According to a 2015 survey by National Pest Management Association and the University of Kentucky, these critters show up in nursing homes, hospitals, schools, and even office buildings.

These horrific nuisances shouldn’t be nearly as prevalent as they are. They hate to travel on their own and they have particular tastes, feasting exclusively on blood and living only in the hardest-to-reach nooks and crannies. One of the explanations researchers have come up with for why bed bugs can be found all over the world is that we humans may be enabling their spread through the laundry we lug around when we travel.

In a study published on Sept. 28 in Scientific Reports, scientists from the University of Sheffield found that indeed, dirty, smelly clothes are the preferred to be hiding spot of these pests when compared to clean laundry. This suggests that if you’re traveling, you should be extra wary of keeping your dirty clothes stored away tightly, so no parasitic hitchhikers can catch a ride back to your home.

The researchers selected four people to wear cotton clothing for three hours while they went about their days. After the three-hour period, volunteers took their clothing and sealed them into bags. Researchers stocked an air-tight room with two bags of dirty clothes and two bags of clean clothing alternating in a circle. They then placed a container carrying a family of bed bugs in the middle of the circle, and opened it up, allowing the insects to venture around where they wanted. After four days (about the amount of time it typically takes for bugs to find a new home), more bed bugs had moved from their original container to settle in the dirty laundry than the clean clothing.

The scientists also wanted to see whether or not the presence of a living human being influenced the bugs’ travel decisions. When we humans breathe, we exhale carbon dioxide. Although we can’t smell this gas, mosquitoes and some stinging insects, like wasps, can. They use it as a cue to tell them that there’s a meal (in the case of a mosquito) or a threat (in the case of a wasp) in the vicinity. The researchers thought that maybe the same would be true for bed bugs, who love to slurp up our blood. So they pumped these same rooms with carbon dioxide to mimic people. Only a few more bed bugs migrated to dirty or clean laundry in the presence of carbon dioxide, which suggests that the real draw for them is the smelly laundry.

“Soiled clothing left in an open suitcase, or left on the floor, of an infested room is more likely to attract bed bugs,” the authors write. “When packed into a suitcase, they will accompany their host back home.”

To be sure, this was a relatively small study with just a handful of bugs and a small amount of clothing. Everyone produces different body odor, and different types of clothing smell differently when worn. Polyester gives off a completely different stench than the cotton that was tested, for example. But even so, if you’re traveling, it’s probably best to keep dirty clothes in a separate compartment in your suitcase, and wash them immediately when you get home. That way, if you unintentionally bring any insect souvenirs back with you, you’ll kill them before they have a chance to infest your home.