Chagas Disease in a Domestic Transmission Cycle in Southern Texas, USA

Abstract

After three dogs died from acute Chagas cardiomyopathy at one location, an investigation was conducted of the home, garage, and grounds of the owner. A serologic study was conducted on stray dogs, and an ecologic niche model was developed to predict areas where the vector Tryiatoma gerstaeckeri might be expected.

The potential for emergence of Chagas disease in the United States

“…Despite the generally sylvatic nature of the triatomine species in the United States (Kagan et al, 1966;Ryckman, 1984;Herwaldt et al, 2000;Beard et al, 2003), and a lack of a suitable habitat in most homes within the country (Zeledón, 1974), studies throughout the Americas and within the United States report numerous cases of sylvatic species biting humans when an opportunity is present. Triatomines can enter a dwelling through an unscreened open window, which may be exacerbated by an attraction to lights that increases the triatomine's lure to the domestic dwelling (Usinger, 1944;Sjogren and Ryckman, 1966;Wood and Wood, 1967;Lent and Wygodzinsky, 1979;Monroy et al, 2003;VazquezProkopec et al, 2004VazquezProkopec et al, , 2006.…”

“…The range of the triatomine in the United States covers twenty-six states and Triatoma sanguisuga, T. lecticularia, and T. protracta, with the largest ranges in the country (Usinger, 1944;Lent and Wygodzinsky, 1979), have been reported in and around human habitations (Sjogren and Ryckman, 1966;Lent and Wygodzinsky, 1979;Navin et al, 1985;Herwaldt et al, 2000;Beard et al, 2003). Temperature, rate of defecation, prevalence of vector infectivity, and degree of domesticity play important roles in Chagas disease transmission.…”

“…Wood (1938) described the northward range expansion of T. protracta in California, but since that time, research on the triatomine's range has been limited in the United States with the exception of modeling the species' range in parts of Texas Beard et al, 2003). Modeling efforts have mapped the triatomine range in much of Latin America (Abad-Franch et al, 2001;Costa et al, 2002;Peterson et al, 2002;Guzman-Tapia et al, 2005;López-Cárdenas et al, 2005;Bustamante et al, 2007).…”

“…We specifically concentrated our efforts on the area deemed at highest risk for Chagas transmission based on temperature. While studies have examined the potential for Chagas disease emergence in specific regions of the United States Beard et al, 2003), no study has evaluated the potential across the country as a whole by examining both climatic factors and physician awareness. Our approach aims to do this and methodologically, it combines GIS and survey analyses as a way to more completely evaluate the potential for disease emergence.…”

A Paratransgenic Strategy for the Control of Chagas Disease

“…Although T. cruzi-infected vectors and animals are found in many parts of this country [12], there have only been 5 documented cases of autochthonous (indigenous) transmission in the US [13]. Surveys of Reduviid bugs in the American Southwest have shown high rates of T. cruzi infection in T. rubida (Figure 1(e)), T. protracta, T. sanguisuga (Figure 1(d)), and T. gerstaeckeri (Figure 1(b)) [12,[14][15][16]. Species-specific behavior of the north America triatomines may explain why more autochthonous transmission is not observed.…”