Efficacy of Recombinase Polymerase Amplification to DiagnoseTrypanosoma cruziInfection in Dogs with Cardiac Alterations from an Endemic Area of Mexico

Abstract

Chagas disease is a lingering Public Health problem in Latin America with ∼5.7 million people infected with Trypanosoma cruzi. Transmission is still taking place in most countries of the Americas, including the United States. Dogs are frequently infected with T. cruzi and its high infection prevalence is associated with increased risk of Chagas disease in humans. The city of Mérida in the Yucatan peninsula is endemic for Chagas disease and canines are frequently infected with T. cruzi. The objective of this study was to evaluate the performance of a qualitative point of care (POC) molecular test (RPA-LF, recombinase polymerase amplification-lateral flow) developed in our laboratory for identifying infected dogs. We used retrospective samples of dogs that came for consultation because of cardiac alterations and proved to be infected with T. cruzi as determined by enzyme-linked immunosorbent assay (ELISA), Western blot, and quantitative PCR (qPCR). The analytical sensitivity indicated that RPA-LF amplified T. cruzi DNA in samples containing almost equal to one to two parasites per reaction. Serial twofold dilutions of T. cruzi epimastigotes showed that the test had 95% (19/20) repeatability at concentrations of two parasites per reaction. The test showed no cross reactivity with human DNA or other protozoan parasites (Trypanosoma rangeli, Leishmania spp., and Plasmodium spp.). RPA-LF had the capacity to amplify all discrete typing units (DTUs I-VI) of T. cruzi that circulate in domestic or extradomestic environments. The RPA-LF had 93.2% (95% confidence interval 87.2-98.1) sensitivity and excellent agreement with qPCR used as gold standard (Cohen's Kappa test = 0.963). ELISA was positive in 96.6% (85/88) of dogs, which together with the molecular tests confirmed the frequent contact with infected triatomine bugs in the city of Mérida. These preliminary results on the diagnostic efficacy of the RPA-LF deserve further large-scale field testing of this POC test for T. cruzi infection in endemic areas.

A review on the occurrence of companion vector-borne diseases in pet animals in Latin America

“…Recommendations on serological tests in the chronic phase [74–81] and a detailed review [82] offer further information. Regarding dogs, there are few studies focusing on the diagnosis of T. cruzi infection [83–87]and even fewer in naturally infected dogs using recombinant antigens [88]. Different antigens have been tested by Brasil et al [82] for their suitability in dogs.…”

Cannabis, One Health, and Veterinary Medicine: Cannabinoids’ Role in Public Health, Food Safety, and Translational Medicine

“…Chagas disease in dogs is also of high prevalence in Latin America, and cardiac alterations are often present. [103][104][105][106] This suggests that a translational medicine study of both veterinary patients and disease progress in a natural occurring disease, and of human patients, may provide a better understanding of the disease and contribute to the development of novel treatments.…”

The burden of congenital Chagas disease and implementation of molecular diagnostic tools in Latin America

“… 46 A prototype RPA test coupled with lateral flow assay for product detection has been used to identify T. cruzi infection in dogs, showing similar performance to qPCR. 47 …”