Circulating extracellular vesicles in sera of chronic patients as a method for determining active parasitism in Chagas disease.

Background: Chagas disease, once restricted mainly to the Americas, Chagas disease has become a global health problem due to migration from endemic to non-endemic areas. In non-endemic regions, transmission is limited to vertical transmission from infected mothers to newborns or through blood and organ donations. A major challenge in the management of the disease lies in the diagnosis of chronic cases, as blood-borne parasites are often absent and antibodies persist for life, complicating the evaluation of treatment.

Use of sera cell free DNA (cfDNA) and exovesicle-DNA for the molecular diagnosis of chronic Chagas disease.

Chagas disease, a neglected tropical disease, is now considered a worldwide health concern as a result of migratory movements from Central and South America to other regions that were considered free of the disease, and where the epidemiological risk is limited to transplacental transmission or blood or organ donations from infected persons. Parasite detection in chronically ill patients is restricted to serological tests that only determine infection by previous infection and not the presence of the parasite, especially in patients undergoing treatment evaluation or in newborns. We have evaluated the use of nucleic acids from both circulating exovesicles and cell-free DNA (cfDNA) from 50 samples twice randomly selected from a total of 448 serum samples from immunologically diagnosed patients in whom the presence of the parasite was confirmed by nested PCR on amplicons resulting from amplification with kinetoplastid DNA-specific primers 121F-122R.