Kate Johnson

September 21, 2015

SAN DIEGO, State — Routine screening for Chagas disease should be considered for immigrants from Latin America living in the United States, Canada, Europe, Australia, and Japan, according to results from a new study.

"There is good reason to screen all immigrants from Chagas-endemic areas because there are no signs or symptoms that are specific for this disease," said Herbert Tanowitz, MD, from the Jacobi Medical Center and Albert Einstein College of Medicine in Bronx, New York.

"The Centers for Disease Control estimates that more than 300,000 people in the United States are infected, and almost all are immigrants from Latin America," he told Medscape Medical News.

He presented the study results here at the Interscience Conference of Antimicrobial Agents and Chemotherapy 2015.

Chagas disease is caused by the Trypanosoma cruzi parasite, which is transmitted to humans by triatomine insects. In endemic areas, up to 80% of the population can become infected during childhood but show few signs of illness, Dr Tanowitz explained. However, Chagas infection can present decades later in the form of heart failure.

Arrhythmias and Bundle Branch Blocks

"Patients with Chagas cardiomyopathy can have any number of arrhythmias and bundle branch blocks, the most common being a right bundle branch block. And patients with end-stage Chagas cardiomyopathy may require heart transplantation," he said. "We hope that our study will alert doctors to this hidden danger."

Screening for asymptomatic Chagas could allow some patients to benefit from antiparasitic treatment, said Dr Tanowitz. It is not known whether treatment can prevent the development of cardiomyopathy, but for women, it could help prevent mother-to-child transmission during pregnancy, he added.

In fact, there are babies born with congenital Chagas disease in Europe and the United States, so it is important to screen pregnant women for this antibody and diagnose infected babies at birth, he said.

Dr Tanowitz and his colleagues evaluated 38 patients with Chagas disease treated consecutively in the tropical medicine clinic at the Jacobi Medical Center from 2006 to 2015. The median age of the patients was 49 years.

In the study cohort, 23.7% of the patients were asymptomatic and identified during screening and 39.4% were asymptomatic and identified because of positive serology prior to blood donation. In addition, 26.3% of patients were referred to the clinic because of clinical heart disease, 7.8% because a family member was seropositive, and 2.6% because of gastrointestinal symptoms.

In symptomatic patients, the most common presentations were shortness of breath (34%), chest pain (15%), palpitations (3%), and syncope (3%).

Of the 16 patients with abnormal electrocardiogram results, two had a left bundle branch block and three had a right bundle branch block. Of the 15 patients with abnormal echocardiogram results, two had a left ventricular thrombus and four had an apical aneurysm.

Fourteen patients were treated with antiparasitic drugs. However, treatment was discontinued because of adverse events in three of the six patients treated with benznidazole and in one of the eight patients treated with nifurtimox, Dr Tanowitz reported.

Locally Acquired Disease

It is "reasonable" to screen immigrants from endemic areas, but it is also important that clinicians recognize the significant risk for locally acquired Chagas disease, said Melissa Nolan Garcia, MPH, from the Baylor College of Medicine in Houston.

She was involved in a recent publication that described autochthonously acquired Chagas infections in a small pilot study of seropositive blood donors in southeast Texas (Am J Trop Med Hyg. 2015;92:325-330).

There is "an unrecognized risk of human vector-borne transmission in southeast Texas," Dr Garcia and her colleagues reported, adding that "education of physicians and public health officials is crucial for identifying the true disease burden and source of infection in Texas."

The authors and Dr Garcia have disclosed no relevant financial relationships.

Interscience Conference of Antimicrobial Agents and Chemotherapy (ICAAC) 2015. Presented September 19, 2015.