Undiagnosed Chagas Disease Emerging as Public Health Threat

Chagas disease or 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 is often considered a problem only in Mexico, Central America, and South America, but Chagas disease is being seen in Texas in the USA and recognized at higher levels than previously believed and among those infected are a high percentage believed to have contracted the disease within the USA border.

Scientists at Baylor College of Medicine (Houston, TX, USA) conducted an analysis of routine testing of Texas blood donors for Chagas disease between 2008 and 2012. The also conducted separate pilot studies, which followed 17 Houston-area residents who were infected. They found that 41% of them had signs of heart disease caused by the infection, including swollen, weakened heart muscle and irregular heart rhythms caused by the parasite burrowing into heart tissue. Most of these individuals lived in rural areas or spent a significant amount of time outside. One of the individuals was an avid hunter and outdoorsman. At least six of them had insignificant travel outside the USA and they did not have mothers from foreign countries, indicating they had likely become infected locally in Texas.

The team 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 United States Centers for Disease Control and Prevention (CDC; Atlanta, GA, USA) estimated infection rate of 1 in 300,000 nationally. Since 2007, all potential blood donors within the USA are screened for exposure to the Chagas disease parasite, Trypanosoma cruzi.

Melissa Nolan Garcia, MPH, an epidemiologist and a coauthor of the studies, said, “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. We think of Chagas disease as a silent killer. People don't normally feel sick, so they don't seek medical care, but it ultimately ends up causing heart disease in about 30% of those who are infected.” The study was presented at American Society of Tropical Medicine and Hygiene (ASTMH) Annual Meeting held November 2–6, 2014, in New Orleans (LA, USA).

Related Links:
Baylor College of Medicine 
United States Centers for Disease Control and Prevention