Some United States Southerners with Chagas disease may have acquired the infection locally, placing them at greater risk for heart disease, according to data presented at the American Society of Tropical Medicine and Hygiene annual meeting.
Additionally, many of these cases may go undiagnosed and are more frequent among the elderly, Hispanics and those living in poorer areas.
Melissa Nolan Garcia, MPH, of the Baylor College of Medicine, Houston, and colleagues followed 17 Houston-area residents infected with Trypanosoma cruzi. The cases were identified among a group of blood donors who tested for T. cruzi antibodies between 2008 and 2012 in the southern states. Presence of the parasite was confirmed by two or more testing formats, and a questionnaire also was distributed to evaluate the source of infection, cardiac symptoms and health comorbidities.
Thirty-six percent of the confirmed study participants were suspected to be autochthonous cases, and 41% had an electrocardiographic abnormality consistent with Chagas cardiomyopathy. High-sensitivity troponin serum levels increased linearly with cardiac severity, the researchers 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,” Garcia said in a press release. “We’ve been working with physicians around the state to increase awareness and diagnosis of this important emerging infectious disease.”
In a previous study published in Epidemiology and Infection, Garcia and colleagues collected data spanning 5 years from the AABB Chagas Biovigilance Network, and examined the frequency, demographics and geographic variables associated with Chagas infection. The blood donor population (N=907,398) was 50% male, with a mean age of 37 years and primarily white (52%) or Hispanic (38%).
Of those tested, 1 in 6,500 (n=140) tested positive for T. cruzi antibody, compared to the 1 in 300,000 national infection rate estimated by the CDC. Older age was associated with increased infection rates, and prevalence of cases was highest in Hispanics (34/100,000) and mixed races (33/100,000).
In addition, blood donors with T. cruzi antibodies were more likely to reside in zip codes where a higher percentage of residents lived in poverty, as defined by the US Census Bureau (P<.002). The estimated societal cost for health care and lost wages caused by chronic Chagas disease would equal approximately $3.8 million, the researchers wrote.
“People who give blood are usually generally healthy adults,” Kristy Murray, DVM, PhD, of the Baylor College of Medicine, said in the release. “The people [who] we worry about in terms of burden of disease here are from rural settings and people who live in severe poverty. So the burden of disease may be even higher than what we see in this study.”
For more information:
Garcia MN. Abstract #698. Presented at: American Society of Tropical Medicine and Hygiene Annual Meeting; Nov. 2-6, 2014; New Orleans.
Garcia M.N. Epidemiol. Infect. 2014;doi:10.1017/S0950268814002234.
Disclosure: The researchers report no relevant disclosures.