@entity1526 in the chronic phase may develop into cardiac and/or digestive forms. The pathogenesis of the disease is not yet clear and studies have been carried out to elucidate the role of parasite persistence in affected organs. The aim of this study was to detect and quantify @entity1527 in paraffin-embedded tissue samples from chronic @entity1 using NPCR (nested polymerase chain reaction) and QPCR (quantitative polymerase chain reaction) methods. These results were correlated to anatomopathological alterations in the heart and @entity344 ( @entity344 ). Of the 23 @entity1 studied, 18 presented the cardiac form and five presented the cardiodigestive form of @entity1526 . DNA samples were randomly isolated from @entity406 -fixed paraffin-embedded sections of heart and @entity344 tissue of 23 necropsies and were analyzed through NPCR amplification. @entity1527 DNA was detected by NPCR in 48/56 (85.7%) heart and 35/42 (83.3%) @entity344 samples from @entity1 with the cardiac form. For @entity1 with the cardiodigestive form, NPCR was positive in 12/14 (85.7%) heart and in 14/14 (100%) @entity344 samples. QPCR, with an efficiency of 97.6%, was performed in 13 samples (11 from cardiac and 2 from cardiodigestive form) identified previously as positive by NPCR. The number of @entity1527 copies was compared to heart weight and no statistical significance was observed. Additionally, we compared the number of copies in different tissues (both heart and @entity344 ) in six samples from the cardiac form and two samples from the cardiodigestive form. The parasite load observed was proportionally higher in heart tissues from @entity1 with the cardiac form. These results show that the presence of the parasite in tissues is essential to @entity1526 pathogenesis.

@entity1527 : parasite persistence in tissues in chronic chagasic Brazilian XXXX .

@entity1 :: ('9606', 'Species') :: ['patients'] @entity1527 :: ('5693', 'Species') :: ['Trypanosoma cruzi', 'T. cruzi'] @entity406 :: ('MESH:D005557', 'Chemical') :: ['formalin'] @entity344 :: ('MESH:D005767', 'Disease') :: ['GIT', 'gastrointestinal tract'] @entity1526 :: ('MESH:D014355', 'Disease') :: ['Chagas disease']
@entity1 :: (9606,Species) :: ['patients']
