A Southwestern United States Pilot Investigation of Triatomine–Mite Prevalence

Abstract

Background: Chagas disease is a leading cause of cardiac failure in Latin America. Due to poor safety profiles and efficacy of currently available therapeutics, prevention is a priority for the millions living at risk for acquiring this clinically important vector-borne disease. Triatomine vectors of the Chagas disease parasite, Trypanosoma cruzi, are found in the southwestern United States, but risk for autochthonous transmission is thought to be low. The role of ectoparasitic mites is under-explored regarding the ecology of triatomines and Chagas disease transmission. Methods: Triatomine collections were performed using three common entomologic techniques in 2020–2021 from four different locations in southern Arizona and New Mexico. Triatomines were analyzed visually under a 112.5× microscope for the presence of externally attached mites. Following mite removal, triatomines were tested for T. cruzi infection by PCR. Results: Approximately 13% of the collected triatomines had mites securely attached to their head, thorax, abdomen, and legs. More than one mite attached was a common finding among ectoparasitized triatomines. Mite presence, however, did not statistically influence triatomine T. cruzi status. Conclusions: Our findings add to a growing body of literature demonstrating the sustainability of mite-infested triatomine populations throughout the Western Hemisphere. Future investigations are warranted to better understand the biologic impact of triatomine mites and their potential to serve as a potential biological control tool.

Evidence of likely autochthonous Chagas disease in the southwestern United States: A case series of Trypanosoma cruzi seropositive blood donors

“…Therefore, we cannot exclude the possibility that these donors' infections were acquired in Texas, where the majority of US-acquired cases have been identified. 20,35,36 California does have a long history of sylvatic enzootic transmission, and the reported frequency of camping and other nocturnal outdoor supports the potential for vector-borne infection in that state. 37 Additional overlapping risk factors among these positive donors were ever living in a rural area in a state with known vectorhuman transmission and having lived on property surrounded by open land (suggestive of potential exposure to sylvatic transmission cycles).…”

“…Though these positive donors were identified in California and Arizona, two confirmed donors had lived in Texas for multiple years. Therefore, we cannot exclude the possibility that these donors' infections were acquired in Texas, where the majority of US‐acquired cases have been identified 20,35,36 . California does have a long history of sylvatic enzootic transmission, and the reported frequency of camping and other nocturnal outdoor activity supports the potential for vector‐borne infection in that state 37 .…”