Bedbugs are attracted to clothes that have been worn, and might be climbing into suitcases that have dirty laundry in them, researchers reported Thursday.
So people may be unwittingly helping to spread them by carrying around luggage full of dirty clothes, the team at Britain’s Sheffield University said.
They found bedbugs were twice as likely to creep into bags that held clothing that had been worn — usually for just a few hours.
“In the absence of a human host, bedbugs were twice as likely to aggregate on bags containing soiled clothes compared to bags containing clean clothes,” bug behavior expert William Hentley and colleagues wrote in their report, published in the journal Scientific Reports.
“Bedbugs are attracted to the odor of sleeping humans and we suggest that soiled clothing may present a similarly attractive cue, allowing bedbugs to ‘hitch-hike’ around the world after aggregating in the laundry bags of travelers,” they wrote.
“Consequently, soiled clothing left in an open suitcase, or left on the floor, of an infested room is likely to attract bedbugs. When packed into the suitcase, they will accompany their host back home.”
It didn’t take much dirt, either. Everyone washed first with unscented soap, and the clean clothing was also washed with unscented detergent. Volunteers wore clean clothing for just an afternoon before stuffing them into tote bags.
“It was an afternoon in the U.K.,” Hentley said. So the clothing wasn’t especially smelly.
But it was enough to attract the bedbugs, which were in a special bedbug house designed by the researchers. When four tote bags containing either clean or worn clothing were laid onto the floor of an empty room, the blood-sucking bugs preferred the bags with used clothing.
“It definitely has something to do with the human odor that they are attracted to,” Hentley said.
“Human odor is very complex.” Some of the odors linger, while others disappear within minutes or hours. Researchers are working to define just which particular odor or odors attract bedbugs, but they are not sure yet, Hentley said.
Protect your luggage and clothes
They’re also attracted to carbon dioxide, which we exhale with every breath, but not in an obvious way, Henley’s team found. When they filled an otherwise empty room with carbon dioxide, the bedbugs became active, but they didn’t head for the source of the gas.
Hentley believes that perhaps the odor of carbon dioxide activates the bugs, but, like mosquitoes, they use a different human odor to home in on a victim.
Hentley says he has already changed his habits when he travels because of his research.
One thing he has learned is that bedbugs cannot climb up the smooth legs of metal luggage racks, or other smooth surfaces. So he plans to use those racks.
“Or, failing that, I will probably put my dirty clothes in a sealed plastic bag,” he said.