Diagnosis Of Chronic Chagas Disease Research Articles

Chagas disease diagnosis using polymerase chain reaction, hemoculture and serologic methods

Different approaches have been used in the di-agnosis of chronic Chagas disease. Serologic testsare used to detect antibodies against Trypanosomacruzi and not the presence of the parasite itself.These tests have high sensitivity but lack specific-ity because of antigenic cross-reactivity with para-sites such as Leishmania sp. and T. rangeli(Schmunis 1991, Saldana & Sousa 1996). Parasi-tological tests such as hemoculture or xenodiag-nosis have proven to be highly specific, but thesensitivity of these techniques is low. Recently,molecular assays such as the polymerase chain re-action (PCR), which amplify certain repetitive se-quences of trypanosome kinetoplast DNA (kDNA)have been proposed as a good alternative too fordetection of T. cruzi in human blood (Avila et al.1993, Wincker et al. 1994, Britto et al. 1995a). The≈330-base pair (bp) fragment of the kinetoplastminicircles is normally used as a target for ampli-fication.The PCR assay has shown a variable degree ofefficiency. Initial sensitivity reports ranged from96% to 100% compared with serologic diagnosis(Avila et al. 1993, Wincker et al. 1994). A lowersensitivity level was observed by different research-ers (Britto et al. 1995b, Junqueira et al. 1996).These inconsistencies illustrate the need for addi-tional evaluation of large numbers of chagasic in-dividuals from different endemic regions in Brazildue to extensive variations in the incidence andclinical manifestations of Chagas disease in thiscountry.A new technique to verify cure in chagasic pa-tients who received specific treatment is needed.Conventional serologic tests such as the indirectimmunofluorescence (IIF) test, the indirect hemag-glutination test, and the ELISA are ineffective be-cause they are persistently positive in most treated

Saliva ELISA: a method for the diagnosis of chronic Chagas disease in endemic areas

An indirect enzyme linked immunosorbent assay (ELISA) was applied to saliva to detect chronic infection by Trypanosoma cruzi in humans. Saliva samples from 114 Chagas’ disease chronically infected individuals, characterized by three serological tests and clinical evaluation and from 100 healthy controls were tested for T. cruzi specific IgG antibodies. At dilution of 1 in 2, specific antibodies were detected in saliva samples from 103 of 114 samples from infected patients and 5 of 100 controls (sensitivity 90.4%, specificity 95%). There was no significant correlation between the antibody titre and cardiac or gastrointestinal tract disease. This assay possesses some advantages over other methods as saliva collection is non-invasive, requires no special equipment and whole saliva gave reproducible results. Although serology remains the gold standard for T. cruzi infection, these results suggest that T. cruzi specific salivary antibody detection may provide a screening diagnostic test and contribute to epidemiological studies of chronic trypanosomiasis infection in endemic areas.

A simple protocol for the physical cleavage of Trypanosoma cruzi kinetoplast DNA present in blood samples and its use in polymerase chain reaction (PCR)-based diagnosis of chronic Chagas disease.

A simple protocol for the physical cleavage of Trypanosoma cruzi kinetoplast DNA present in blood samples and its use in polymerase chain reaction (PCR)-based diagnosis of chronic Chagas disease.