Mattress Bugs Produce Probably Harmful Quantities of Histamine, Research Reveals

In a study published in September in the Journal of Medical Entomology, researchers found that a hypothetical infestation of 1,000 bed bugs (Cimex lectularius) could produce up to 40 milligrams of histamine in a week. Excessive histamine exposure can cause health effects ranging from skin rashes to headaches to breathing problems. (Photo by Matt Barton, University of Kentucky College of Agriculture, Food and Environment)

By Haley Simpson

Entomologists from the University of Kentucky’s College of Agriculture, Food and Environment recently made revealing discoveries about a bed bug to learnfind the bugs produce large amounts of histamine that can pose risks to humans.

Histamine is a chemical compound that the human body naturally produces that can cause inflammation and alert the immune system to threats. Normal reactions to histamine production include allergic reactions with side effects such as a rash or difficulty breathing. a previous one to learn showed links between excess histamine, particularly in patients with histamine intolerance, and health effects such as headaches, gastrointestinal problems, irregular heart rate and asthma.

Sudip Gaire, Ph.D., postdoctoral researcher in the British Institute of Entomology, and Zach DeVries, Ph.D., assistant professor of entomology, led the study, in which they examined the histamine excretion levels of bed bugs (Cimex lectularius) across the different life stages of the bugs, different populations and different time periods, as well as the effects of blood feeding had an impact on the histamine production of the pests. The UK-based team also worked with researchers from North Carolina State University on the project.

The Journal of Medical Entomology is published in September released The study that showed bed bugs can produce large amounts of histamine, with a single bed bug producing more than 50 micrograms of histamine in just one week. Researchers found that in a hypothetical infestation of 1,000 bed bugs, the bugs could produce up to 40 milligrams of histamine in one week. That adds up to more than 2 grams of histamine per year, not even counting natural population growth or the larger infestations that often occur in the real world.

“That’s a lot that you can actually see, and we don’t see that with any other contaminant,” says DeVries. “When we’re talking about pesticides, allergens, or anything else in our home that an invading organism produces, it’s always on a microscopic level, not something you can actually hold in your hands.”

Another important discovery was the role bed bug diets play in histamine production. The researchers compared histamine production across three different diets, including blood-fed, saline-fed, and starved bed bugs. The researchers found that blood-fed bed bugs produced “significantly higher” levels of histamine compared to the other groups.

“Blood is the main factor in histamine production, but we don’t know exactly how they produce the histamine,” says Gaire.

While bed bugs are a common problem in homes around the world, scientists don’t usually consider them a major risk to human health, aside from their bites, since they are known not to transmit pathogens. However, the problem of high-level histamine production poses a new potential risk from the pest. While scientists do not know the specific health effects of histamine produced outside of the human body, such as that produced by bed bugs, DeVries, Gaire and their fellow entomologists suspect that bed bugs’ high histamine secretion may have negative clinical implications. The effects of such narrow, often direct, exposure to histamine, which is commonly seen in bed bug infestations, are also unknown, DeVries says.

“It’s not just the fact that they produce histamine, but they produce it right next to where you generally spend most of your time in our homes, which is our beds or sleeping areas,” says DeVries.

Gaire says close exposure to histamine is not only a problem for humans, but could also affect agriculture. Poultry coops are a common site for bed bug infestations, with bed bugs living near chickens in infested facilities, Gaire says. in earlier ones studiesResearchers found that histamine negatively affects egg production, but Gaire says more research is needed to find out what specific effects the histamine produced by bed bugs has on egg production.

DeVries says the research also has implications for social justice.

“Anyone can get bed bugs, but only those who have the tools and resources can truly get rid of the problem. There is a significant portion of the population that either doesn’t have the money or resources to do it, and so they have to deal with bed bugs themselves,” says DeVries. “So we have disadvantaged communities that not only have to deal with bed bugs, but maybe the health consequences of it.”

DeVries and Gaire say that while their study answers important questions, scientists need to do more research before sounding the alarm. To answer some of the remaining questions, DeVries, Gaire and others at the UK Department of Entomology plan to continue research on this topic, looking at things like histamine distribution, histamine production mechanisms in bed bugs, the clinical relevance of histamine and mitigation strategies deal houses. DeVries received funding for the study through the 2019 National Institutes of Health Director’s Early Independence Award, which will fund similar future studies through 2024.

Haley Simpsons is a marketing specialist at the University of Kentucky’s College of Agriculture, Food and Environment in Lexington, Kentucky.

Adapted with permission from a news article published by the University of Kentucky College of Agriculture, Food and Environment on September 28, 2022.

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