Now a team of researchers from Baylor College of Medicine in Houston is challenging that assumption. During a presentation at the American Society of Tropical Medicine and Hygiene meeting in New Orleans, epidemiologist Melissa Nolan Garcia said her team had been following 17 Houston-area residents who had been infected. At least six of them appeared to have been infected locally as they had had insignificant travel outside the United States. Most of the patients spent a lot of time outdoors or lived in rural areas where the bugs are thought to live. The Baylor group also collected 40 kissing bugs near homes in 11 central-southern Texas counties and found that half had fed on human blood as well as that of a dozen kinds of animals ranging from dogs to raccoons.
The researchers analyzed blood donors in Texas between 2008 and 2012 and found that one in every 6,500 donors tested positive for exposure to the parasite -- a figure that is 50 times higher than the Centers for Disease Control estimate.
"We were astonished to not only find such a high rate of individuals testing positive for Chagas in their blood, but also high rates of heart disease that appear to be Chagas-related," Nolan Garcia said in a statement released by the tropical medicine society.
The researchers said that while the number of cases is growing, physicians' awareness of the disease is lagging. When caught in the early stages, the disease can be treated with two drugs, nifurtimox and benznidazole, but if asymptomatic infections are allowed to progress they can lead to serious complications. Many of those who are now recognized as having the disease were flagged after they donated blood and had never been treated for the disease before that.