Molecular detection of Trypanosoma cruzi in reservoir hosts by quantitative polymerase chain reaction - a systematic review

Animal reservoirs contribute considerably to the dissemination of Trypanosoma cruzi, the etiological agent of Chagas disease, through various zoonotic routes. Consequently, the implementation of molecular methodologies for the identification and surveillance of these reservoir hosts is paramount. Real-time polymerase chain reaction (qPCR) has become a prominent tool due to its high sensitivity in detecting T. cruzi DNA. Herein, a systematic bibliographic search and review was conducted within the PubMed database, from 2013 to 2024, searching for the qPCR methods employed for T. cruzi detection in reservoir animals, focusing on methodology, inherent advantages and limitations. A considerable proportion of these studies were published in 2024, coinciding with a documented surge in Chagas disease cases in preceding years. The geographical distribution of these investigations predominantly featured endemic countries, although contributions from non-endemic regions, such as the United States and France, were also observed. Approximately half of the reviewed studies centered on domestic reservoirs, which play a pivotal role as sentinel species for assessing transmission risk. A substantial degree of heterogeneity was observed across the protocols, including thermal cycling parameters, DNA template and reagent concentrations. Satellite DNA was the most frequently employed target (84.6 %), attributed to its high specificity for T. cruzi. Blood samples and the TaqMan™ probe were predominantly used (57.7 and 53.8 %, respectively). While the inclusion of negative controls was generally observed, cross-reactivity testing was infrequent. The establishment of standardized qPCR protocols is imperative for the advancement of effective surveillance strategies targeting reservoir animals within the T. cruzi transmission cycle.