Not Just Pests: Bed Bugs Produce This Chemical In Large Amounts, Study Finds

Bed bugs may not only be unwanted visitors in our homes and beds but also creatures harboring a hidden risk. A team of researchers has found that they may actually be producing amounts of histamine that may potentially be problematic for humans.

Bed bugs are tiny, parasitic insects that can be found all over the world. At just 1 to 7 millimeters, they feed on people's and animals' blood and have been "spreading rapidly" in places like the U.S., Canada, the U.K. and some parts of Europe. They can be found even in hotels and resorts.

For their study, published in the Journal of Medical Entomology, a team of researchers analyzed the fecal materials that bed bugs deposit at different stages of their lives.

"Following a blood meal, bed bugs deposit fecal material indoors. The feces contain a variety of compounds, including histamine, which serves as a component of their aggregation pheromone," they wrote. "Histamine is a pivotal mammalian immune modulator, and recently it was shown to be present in high concentrations in household dust from homes infested with bed bugs."

Histamine is a chemical in the human body that can alert the immune system to threats and trigger inflammation, the University of Kentucky (UK) noted in a news release. While production of it normally leads to allergic reactions resulting in rashes or respiratory issues, an excess of histamine has been linked to reactions such as headaches, asthma and irregular heart rate, particularly among those with histamine intolerance.

The researchers found variations in bed bugs' histamine production in different life stages, but that "overall," they produce histamine "across all feeding life stages, populations and at various times after feeding, and that histamine excretion is directly related to blood feeding."

And the amount of histamine they can produce is no joke, with one bed bug capable of producing over 50 micrograms in a week. If there are 1,000 bed bugs in an infestation, they may produce 40 milligrams of histamine in a week, and 2 grams in a year, according to the university.

"That's an amount you can actually see, and we don't see that with any other containment," one of the study leads, Zach DeVries of UK, said in the news release. "When we talk about pesticides, allergens, any other thing in our home that some invading organism is producing, it's always on microscopic levels, not something where you could actually hold it in your hand."

More research needs to be done to find out the exact implications of the findings on human health, according to the researchers. It does, however, show that even if bed bugs aren't known to carry pathogens and spread disease as other bugs do, they may still be carrying potential risks beyond being annoying pests and the occasional allergic reaction to their bites.

"It's not only the fact that they're producing histamine, but they're producing it right next to where you spend the most time, generally speaking, within our homes, which is in our beds or sleeping areas," De Vries said.

"These results will be used to better understand the health risks associated with histamine excretion and potential mitigation strategies of environmental histamine," the researchers wrote.