Anaphylactic Reactions Due to Triatoma protracta (Hemiptera, Reduviidae, Triatominae) and Invasion into a Home in Northern California, USA

Abstract

Background: Triatoma protracta is a triatomine found naturally throughout many regions of California and has been shown to invade human dwellings and bite residents. A man living in Mendocino County, California, reported developing anaphylactic reactions due to the bite of an “unusual bug”, which he had found in his home for several years. Methods: We conducted environmental, entomological, and clinical investigations to examine the risk for kissing bug invasion, presence of Trypanosoma cruzi, and concerns for Chagas disease at this human dwelling with triatomine invasion. Results: Home assessment revealed several risk factors for triatomine invasion, which includes pack rat infestation, above-ground wooden plank floor without a concrete foundation, canine living in the home, and lack of residual insecticide use. Triatomines were all identified as Triatoma protracta. Midgut molecular analysis of the collected triatomines revealed the detection of T. cruzi discrete typing unit I among one of the kissing bugs. Blood meal PCR-based analysis showed these triatomines had bitten humans, canine and unidentified snake species. The patient was tested for chronic Chagas disease utilizing rapid diagnostic testing and laboratory serological testing, and all were negative. Conclusions: Triatoma protracta is known to invade human dwellings in the western portions of the United States. This is the first report of T. cruzi-infected triatomines invading homes in Mendocino County, California. Triatoma protracta is a known vector responsible for autochthonous Chagas disease within the United States, and their bites can also trigger serious systemic allergic reactions, such as anaphylaxis.