Across a broad swath of the southern United States, residents face a tangible but mostly unrecognized risk of contracting Chagas disease – a stealthy parasitic infection that can lead to severe heart disease and death – according to new research presented at the American Society of Tropical Medicine and Hygiene (ASTMH) Annual Meeting.
Chagas disease (American trypanosomiasis) is typically spread to people through the feces of blood-sucking triatomine bugs sometimes called “kissing bugs” because they feed on people’s faces during the night. The disease, which can also be spread through blood supply, affects 7 to 8 million people worldwide and can be cured – if it is caught early. Often considered a problem only in Mexico, Central America and South America, Chagas disease is being seen in Texas and recognized at higher levels than previously believed, reported researchers from Baylor College of Medicine in Houston. Among those infected are a high percentage believed to have contracted the disease within the U.S. border, according to the scientists whose findings will also be published in the American Journal of Tropical Medicine and Hygiene.
“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,” said Baylor epidemiologist Melissa Nolan Garcia, one of the researchers who presented findings from a series of studies. “We’ve been working with physicians around the state to increase awareness and diagnosis of this important emerging infectious disease.”
And while this research was conducted in Texas, kissing bugs are found across half of the United States, according to the U.S. Centers for Disease Control. Bites from these insects may be infecting people who are never diagnosed, due to a lack of awareness of Chagas disease by healthcare personnel and the U.S. healthcare system.
Chagas Infection Rate Under-reported; Often Overlooked as Risk Factor For Heart Disease
Garcia’s team conducted an analysis of routine testing of Texas blood donors for Chagas between 2008 and 2012. In that study* published in Epidemiology and Infection (August 2014), the researchers found that one in every 6,500 blood donors tested positive for exposure to the parasite that causes Chagas disease. That figure is 50 times higher than the CDC’s estimated infection rate of one in 300,000 nationally, but according to Garcia, a rate that is consistent with other studies in the southern United States indicating a substantial national disease burden. Since 2007, all potential blood donors within the United States are screened for exposure to the Chagas disease parasite.
“We think of Chagas disease as a silent killer,” Garcia said. “People don’t normally feel sick, so they don’t seek medical care, but it ultimately ends up causing heart disease in about 30 percent of those who are infected.”
* Trypanosoma cruzi screening in Texas blood donors, 2008–2012. Epidemiology and Infection, Published online: 29 August 2014 DOI: 10.1017/S0950268814002234
**Global economic burden of Chagas disease: a computational simulation model. Published Online: 08 February 2013 The Lancet Infectious Diseases, Volume 13, Issue 4, DOI:10.1016/S1473-3099(13)70002-1