Rapid Tests for Chagas Disease Improves Diagnostic Access

Chagas disease, caused by the parasite Trypanosoma cruzi, affects between six and seven million people across the Americas. It is primarily transmitted by insect vectors and remains largely underdiagnosed, with less than 1% of those infected receiving treatment. The disease is most commonly diagnosed through serological techniques, which detect antibodies to T. cruzi in the blood during the chronic phase of the disease. However, these methods require specialized personnel and equipment, which are often unavailable in resource-limited areas, making it difficult for people in endemic regions to access proper diagnosis and care. A new approach, combining rapid diagnostic tests (RDTs) with conventional serological techniques, has been proposed to improve access to diagnosis in such settings.

Researchers at the Barcelona Institute for Global Health (ISGlobal, Barcelona, Spain), in collaboration with Paraguayan health authorities, conducted a study involving a screening campaign in an indigenous community in the Paraguayan Chaco, where 999 people were tested. The researchers evaluated the effectiveness of using RDTs for initial screening, followed by confirmation with conventional serological tests such as recombinant and lysate ELISA. The combination of these two methods was found to be highly effective, providing an accessible and rapid solution for diagnosing Chagas disease in remote areas.

Image: Combining rapid diagnostic tests with conventional serology proves to be a useful strategy for diagnosing Chagas disease (Courtesy of Adobe Stock)

The study, published in PLOS Neglected Tropical Diseases, demonstrated that the algorithm using RDTs showed high agreement with the standard algorithm, with a sensitivity of 94.6% and a specificity of 98.6%. The algorithm validated in the study suggests using RDTs for an initial screening of at-risk individuals in endemic areas, thereby reducing the need for serological testing to confirm positive results. The prevalence of the disease was found to be significantly higher in the indigenous community of Casanillo compared to the capital, Asunción, highlighting the health inequalities in urban and rural areas. The researchers plan to further evaluate this approach in other regions and adapt it for broader use in endemic areas to improve access to diagnosis and treatment.

“The results obtained are particularly relevant in the context of a global re-evaluation of guidelines for the diagnosis and treatment of Chagas disease,” said Irene Losada, coordinator of the Chagas Initiative at ISGlobal and senior author of the study. “The adoption of RDT-based algorithms adapted to each region could improve access to diagnosis for thousands of people in remote areas.”

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