Identification of Bloodmeal Sources andTrypanosoma cruziInfection in Triatomine Bugs (Hemiptera: Reduviidae) From Residential Settings in Texas, the United States

Abstract

The host–vector–parasite interactions in Chagas disease peridomestic transmission cycles in the United States are not yet well understood. Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae) infection prevalence and bloodmeal sources were determined for adult and immature triatomine (Hemiptera: Reduviidae) specimens collected from residential settings in central Texas. Sequenced cytochrome b DNA segments obtained from triatomine digestive tract identified nine vertebrate hosts and one invertebrate host in four triatomine species (Triatoma gerstaeckeri, Triatoma indictiva, Triatoma protracta, and Triatoma sanguisuga). The broad range of wild and domestic host species detected in triatomine specimens collected from residential sites indicates high host diversity and potential movement between the sylvatic and peridomestic settings. Domestic dogs appear to be key in the maintenance of the peridomestic transmission cycle as both a blood host for the triatomine vectors and a potential reservoir for the parasite. The high rate of T. cruzi infection among triatomine specimens that were collected from inside houses, outside houses, and dog kennels (69, 81, and 82%, respectively) suggests a current risk for Chagas disease vector-borne transmission for humans and domestic animals in residential settings in Texas because of overlap with the sylvatic cycle.

Triatoma sanguisugaBlood Meals and Potential for Chagas Disease, Louisiana, USA

“…Our study provides evidence of frequent vector/human/ T. cruzi contact in Louisiana and reveals the potential for transmission in the United States. Even if this finding does not apply to all localities (e.g., human blood has rarely been detected in triatomines from Texas [ 15 ]), the risk for vectorial transmission of T. cruzi in the United States may increase because of expansion of human settlements into formerly sylvatic areas. Moreover, the low number of Chagas disease cases reported in the United States is probably caused, at least in part, by a lack of awareness ( 4 , 5 ).…”

Risk reduction and management strategies to prevent transmission of infectious disease among dogs at dog shows, sporting events, and other canine group settings

“…Currently, leishmaniasis and American trypanosomiasis are perhaps most well known as high-risk diseases associated with travel to endemic areas. These have the potential for extension into Canada and the United States given the presence of competent vectors, 69,[91][92][93] but other infectious diseases are likely to emerge in the near future. Given the evolving nature of infectious disease emergence, a single specific high-risk region cannot be predicted.…”

Evidence of Autochthonous Chagas Disease in Southeastern Texas

“…6 Blood meals consisting of multiple mammalian hosts, particularly dogs, have been shown in four Triatoma species in Texas; dogs are thought to be a bridge vector between sylvatic and domestic transmission cycles. 7 Up to 82% of the T. cruzi positive vectors in a study by Kjos and others 7 were collected near human residences and dog kennels, suggesting risk for establishment of domestic transmission cycles in Texas.…”