Abstract
Protozoan pathogen Trypanosoma cruzi (Chagas, 1909) is the etiologic agent of Chagas disease, which affects millions of people in Latin America. Recently, the disease has been gaining attention in Texas and the southern United States. Transmission cycle of the parasite involves alternating infection between insect vectors and vertebrate hosts (including humans, wildlife, and domestic animals). To evaluate vector T. cruzi parasite burden and feeding patterns, we tested triatomine vectors from 23 central, southern, and northeastern counties of Texas. Out of the 68 submitted specimens, the majority were genetically identified as Triatoma gerstaeckeri (Stal, 1859), with a few samples of Triatoma sanguisuga (LeConte, 1855), Triatoma lecticularia (Stal, 1859), Triatoma rubida (Uhler, 1894), and Triatoma protracta woodi (Usinger, 1939). We found almost two-thirds of the submitted insects were polymerase chain reaction-positive for T. cruzi. Bloodmeal sources were determined for most of the insects, and 16 different species of mammals were identified as hosts. The most prevalent type of bloodmeal was human, with over half of these insects found to be positive for T. cruzi. High infection rate of the triatomine vectors combined with high incidence of feeding on humans highlight the importance of Chagas disease surveillance in Texas. With our previous findings of autochthonous transmission of Chagas disease, urgent measures are needed to increase public awareness, vector control in and around homes, and Chagas screening of residents who present with a history of a triatomine exposure.
The sylvatic transmission cycle of Trypanosoma cruzi in a rural area in the humid Chaco of Argentina
