University of Kentucky (UK) entomologists at the University of Kentucky (UK) made eye-popping discoveries in a recent study of bed bugs, finding that the insects produce large amounts of histamine that can pose risks to humans.
Histamine is a chemical compound that the human body produces naturally that can cause inflammation and alert the immune system to any threats. Normal reactions to histamine production include allergic reactions with side effects such as skin rash or difficulty breathing. A previous study showed associations between histamine excess, especially in patients with histamine intolerance, and health effects such as headaches, gastrointestinal problems, irregular heartbeat and asthma.
Sudip Gaire, postdoctoral scientist in the British Department of Entomology, and Zach DeVries, assistant professor of entomology, led the study on histamine excretion levels of bedbugs at different insect life stages, different populations and different lengths of time, and the effects of eating blood on the histamine production of the pests. The UK-based team also collaborated with scientists from North Carolina State University on the project.
The Journal of Medical Entomology recently published the study showing that 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 with a hypothetical infestation of 1,000 bed bugs, the insects could produce up to 40 milligrams in a week. That equates to over 2 grams of histamine per year without even taking into account natural population growth or the larger infestations common in the real world.
“That’s an amount you can actually see, and we don’t see that with any other inclusion,” DeVries said. “When we talk about pesticides, allergens, or anything else in our home that produces an invading organism, it’s always at microscopic levels, not something you could actually hold in your hand.”
Another important discovery was the role that bedbug diets play in the production of histamine. Researchers compared histamine production in three different diets, including blood-fed, saline-fed and starved bedbugs. Researchers found that blood-fed bedbugs produced “significantly higher” amounts of histamine compared to the other groups.
“Blood is the main factor for the production of histamine, but we don’t know exactly how they produce the histamine,” Gaire said.
Although bed bugs are a common problem in households around the world, scientists generally don’t consider them a major risk to human health, other than their bites, because they are not known to carry pathogens. However, the issue of high-level histamine production poses a new potential risk from the pest. While scientists don’t know the specific health effects of histamine produced outside the human body, such as producing bed bugs, DeVries, Gaire and their fellow entomologists suspect that the high levels of histamine secretion from bed bugs may have negative clinical effects. The effects of such close, often direct exposure to histamine, which is commonly seen in bedbug infestations, are also unknown, DeVries said.
“It’s not just the fact that they produce histamine, but they also produce it right next to where you spend most of your time, generally, in our homes, in our beds or sleeping quarters,” DeVries said.
Gaire said close exposure to histamine is not only a concern for humans, but it could also affect the agricultural sector. Poultry houses are a common place for bedbug infestations, with bedbugs living near chickens in infested facilities, Gaire said. In previous studiesresearchers found that histamine negatively affects egg production, but Gaire said finding the specific impact bedbug-produced histamine plays on egg production requires more research.
DeVries said the research also has implications for social justice.
“Anyone can get bed bugs, but it’s only those who have the resources and resources that can actually solve the problem. There’s a significant portion of the population that either don’t have the money or the resources to do this, and so they have to only dealing with bed bugs,” DeVries said. “So we have underserved communities, dealing not only with bedbugs, but perhaps with their health consequences.”
DeVries and Gaire said that while their study answered important questions, scientists need to do more research before sounding the alarm. To answer some of the remaining questions, DeVries, Gaire and others from the UK Department of Entomology plan to continue research on the topic and look at things like histamine distribution, bed bug histamine production mechanisms, the clinical relevance of histamine and mitigation strategies in homes.
Bed bug histamines are significant, persistent in infested homes
Sudip Gaire et al, Histamine secretion by the common bed bug (Hemiptera: Cimicidae), Journal of Medical Entomology (2022). DOI: 10.1093/jme/tjac131
Quote: Research shows that bed bugs produce potentially dangerous amounts of histamine (2022, September 28), retrieved September 28, 2022 from https://phys.org/news/2022-09-reveals-bed-bugs-potential-dangerous.html
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