ABSTRACT
A loop-mediated isothermal amplification assay was evaluated as a surrogate marker of treatment failure in Chagas disease (CD). A convenience series of 18 acute or reactivated CD patients who received anti-parasitic treatment with benznidazole was selected-namely, nine orally infected patients: three people living with HIV and CD reactivation, five chronic CD recipients with reactivation after organ transplantation and one seronegative recipient of a kidney and liver transplant from a CD donor. Fifty-four archival samples (venous blood treated with EDTA or guanidinium hydrochloride-EDTA buffer and cerebrospinal fluid) were extracted using a Spin-column manual kit and tested by T. cruzi Loopamp kit (Tc-LAMP, index test) and standardized real-time PCR (qPCR, comparator test). Of them, 23 samples were also extracted using a novel repurposed 3D printer designed for point-of-care DNA extraction (PrintrLab). The agreement between methods was estimated by Cohen's kappa index and Bland-Altman plot analysis. The T. cruzi Loopamp kit was as sensitive as qPCR for detecting parasite DNA in samples with parasite loads higher than 0.5 parasite equivalents/mL and infected with different discrete typing units. The agreement between qPCR and Tc-LAMP (Spin-column) or Tc-LAMP (PrintrLab) was excellent, with a mean difference of 0.02 [CI = -0.58-0.62] and -0.04 [CI = -0.45-0.37] and a Cohen's kappa coefficient of 0.78 [CI = 0.60-0.96] and 0.90 [CI = 0.71 to 1.00], respectively. These findings encourage prospective field studies to validate the use of LAMP as a surrogate marker of treatment failure in CD.
ABSTRACT
Orally-transmitted acute Chagas disease (CD) is emerging as an important public health problem. The prognosis of acute infection following oral transmission is unknown. The aim of this study was to analyze and summarize data on orally-transmitted acute CD. We searched for publications from 1968 to 31 January 2018. We included studies and unpublished data from government sources that reported patients with acute orally-transmitted CD. We identified 41 papers and we added 932 unpublished cases. In all, our study covered 2470 cases and occurrence of 97 deaths. Our meta-analysis estimated that the case-fatality rate was 1.0% (95% CI 0.0-4.0%). Lethality rates have declined over time (Pâ =â .02). In conclusion, orally-transmitted acute CD has considerable lethality in the first year after infection. The lethality in symptomatic cases is similar to that from other routes of infection. The lethality rate of orally-acquired disease has declined over the years.