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Organisms highly similar to Blastocrithidia triatomae, a pathogenic parasite of Chagas disease triatomine bug vectors, were detected using polymerase chain reaction amplification and DNA sequence analysis of a segment of the small subunit rRNA gene in 3 of 203 triatomine specimens collected in Texas from June 2005 to October 2006. The parasite was identified in three species of triatomine bugs (Triatoma gerstaeckeri, T. indictiva,and T. neotomae) collected from three distinct geographic locations. Flagellated organisms indistinguishable from Trypanosoma cruziwere observed by direct microscopy in hindgut material of two of the three specimens. Coinfection with T. cruziand Blastocrithidiawas detected by molecular methods in one of the specimens. Parsimony analysis provided strong support for clustering of the new sequences within a Blastocrithidiagroup, clearly separated from other flagellated protozoans. Confirmation of Blastocrithidiain U.S. triatomine species complicates microscopic diagnosis of T. cruzidue to the morphologic similarity of the parasites. [ABSTRACT FROM AUTHOR]

Data were pooled from multiple sources including newly collected triatomine specimens, preserved specimens, government reports, and scientific articles to create a biogeographical profile of triatomine vector species found in Texas. Triatomine specimens were documented in 97 of 254 counties, and Trypanosoma cruzi-infected specimens were reported from 48 counties. Triatomine specimens were distributed in 11 of the 12 ecoregions in Texas, with all but one species found in multiple ecoregions. Of the 241 newly collected specimens, 50.74 were infected with T. cruzi. Triatoma gerstaeckeriwas the most frequently collected and most geographically dispersed species followed by T. sanguisuga. Three species, T. gerstaeckeri, T. sanguisuga, and T. lecticularia, were associated with human dwellings, and over half of the new specimens found inside or near houses were infected with T. cruzi. Chagas disease vectors in Texas are widely distributed and have adapted to ecologically diverse settings. The high T. cruziinfection prevalence of specimens found in close proximity to human settings suggests the presence of an active peridomestic Chagas disease transmission cycle. [ABSTRACT FROM AUTHOR]