Histamine production in common urban arthropods

Histamine is a biogenic amine that regulates several physiological functions in multiple organisms. In mammalians, histamine plays a central role in the immune response. The common bed bug, Cimex lectularius, excretes histamine in large amounts in its feces as a component of its aggregation pheromone, inadvertently contaminating homes. The potential health risks associated with the presence of indoor histamine are still unclear, but to make future predictions of the possible exposure risks, it is critical we understand if other arthropods can produce histamine and if there are any patterns in environmental origin. In the present study, we evaluated histamine production among various arthropods, specifically those commonly found in large numbers indoors, other hematophagous species, and other closely related species in the order Hemiptera. To evaluate arthropods for histamine production, rearing containers for each arthropod were either swabbed or the harborage substrates were collected. Samples were then spiked with labelled histamine, extracted, derivatized, and analysed using the GC-MS. Results were evaluated for the presence/absence of histamine, and for those arthropods where histamine was present histamine was quantified over a period of two weeks. Our results indicate that histamine production is limited to hematophagous hemipterans (bed bugs, bat bugs, and kissing bugs), suggesting that indoor histamine contamination in the US can be primarily linked to bed bugs.