Autor/a:
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Egüez, Karina E.; Alonso Padilla, Julio; Teran, Carolina; Chipana, Zenobia; García, Wilson; Torrico, Faustino; Gascón i Brustenga, Joaquim; Lozano Beltran, Daniel-Franz; Pinazo, María Jesús
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Abstract:
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Chagas disease is caused by the parasite Trypanosoma cruzi. It
affects several million people, mainly in Latin America, and
severe cardiac and/or digestive complications occur in ~30% of
the chronically infected patients. Disease acute stage is mostly
asymptomatic and infection goes undiagnosed. In the chronic
phase direct parasite detection is hampered due to its concealed
presence and diagnosis is achieved by serological methods, like
ELISA or indirect hemagglutination assays. Agreement in at least
two tests must be obtained due to parasite wide antigenic
variability. These techniques require equipped labs and trained
personnel and are not available in distant regions. As a result,
many infected people often remain undiagnosed until it is too
late, as the two available chemotherapies show diminished
efficacy in the advanced chronic stage. Easy-to-use rapid
diagnostic tests have been developed to be implemented in remote
areas as an alternative to conventional tests. They do not need
electricity, nor cold chain, they can return results within an
hour and some even work with whole blood as sample, like Chagas
Stat-Pak (ChemBio Inc.) and Chagas Detect Plus (InBIOS Inc.).
Nonetheless, in order to qualify a rapidly diagnosed positive
patient for treatment, conventional serological confirmation is
obligatory, which might risk its start. In this study two rapid
tests based on distinct antigen sets were used in parallel as a
way to obtain a fast and conclusive Chagas disease diagnosis
using whole blood samples. Chagas Stat-Pak and Chagas Detect
Plus were validated by comparison with three conventional tests
yielding 100% sensitivity and 99.3% specificity over 342
patients seeking Chagas disease diagnosis in a reference centre
in Sucre (Bolivia). Combined used of RDTs in distant regions
could substitute laborious conventional serology, allowing
immediate treatment and favouring better adhesion to it. |