Innovative LAMP Molecular Diagnostic Test Diagnoses Chagas Disease in Newborns
Posted on 04 Jul 2024
T. cruzi infection leads to Chagas disease in newborns, with vertical (congenital) transmission accounting for 20% of new cases. This transmission occurs when an infected mother transfers the parasite to her baby during pregnancy. Consequently, early detection of the parasite in both women and newborns is a critical public health concern. However, the challenge lies in the absence of simple, rapid, and reliable testing methods. In affluent nations like Spain, newborn diagnosis can be conducted using PCR, but this method is costly and requires trained professionals. In regions where the disease is endemic, typically two microscopy tests are administered—one at birth and another at two months. These tests have low sensitivity and are usually followed by a serological test months later to identify antibodies against the parasite. The multiple tests and the delay between them heighten the risk of delayed treatment for affected children. Now, an innovative test combining a DNA extraction system, inspired by a modified 3D printer, with loop-mediated isothermal molecular amplification (LAMP), could potentially detect T. cruzi infection in newborns.
This was the conclusion of a group of researchers at the Barcelona Institute for Global Health (ISGlobal, Barcelona, Spain) after a study conducted in Bolivia’s Chaco region, a hotspot for Chagas disease. In this study published in the journal The Lancet Microbe, the team tested a novel diagnostic method that integrates the LAMP technique with a 3D printer modified to extract DNA from a small blood sample. The effectiveness of this method was benchmarked against PCR and traditional diagnostic approaches (microscopy and serology). The study tracked 224 infants born to mothers seropositive for T. cruzi over eight months, identifying 23 cases of congenital transmission—nine detected by microscopy at birth and an additional 14 by serology eight months later.
The LAMP test successfully identified 13 out of the 23 cases early in the process, detecting four more cases than microscopy and nearly matching the 14 cases detected by PCR. This indicates that LAMP’s sensitivity surpasses microscopy and is comparable to PCR. An added benefit of the LAMP test is its potential cost-effectiveness and minimal infrastructure needs. In accordance with national guidelines for diagnosing and treating congenital Chagas disease, all detected cases were treated successfully, underscoring the vital role of early detection and intervention. The research team emphasized that this study served as a proof of concept for the LAMP diagnostic test’s viability, suggesting that further trials should be conducted on a broader scale and in more centers. If its efficacy is validated, this test could also be employed to detect acute infections in adults or to evaluate the efficacy of treatments.
"In endemic regions, it would be very useful to have a simple, rapid and sensitive test to detect the parasite in newborns, when treatment is most effective," said Julio Alonso Padilla, researcher at ISGlobal.
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