Amplification of a Specific Repetitive DNA Sequence for Trypanosoma rangeli Identification and Its Potential Application in Epidemiological Investigations

Detection of Trypanosoma cruzi and Trypanosoma rangeli infection in triatomine vectors by amplification of the histone H2A/SIRE and the sno-RNA-C11 genes

“…Besides, this findings are in accordance with those of VALLEJO et al (1999) 33 and VARGAS et al (2000) 36 who observed that the amplification of T. cruzi with the S35/S36 primers are dominant in most mixed infections, probably because the minicircles annealing sites of T. cruzi are present in greater quantity and could compete for the annealing of primers generating a typical T. cruzi profile that overlaps the presence of T. rangeli. It is important to highlight that eight salivary glands analyzed from the 29 R. colombiensis tested negative by PCR as well as by conventional methods, suggesting that at the time of the analysis, the parasite had not yet invaded the salivary glands of insects.…”

“…Later on, VARGAS et al (2000) 36 used three PCR systems: S35/ S36 (kDNA), D72/D75/RG3 (Variable domain of the ribosomal subunit (LSU) of trypanosomatids), and R1/R2 (specific repetitive element P542), found in 50% of R. colombiensis examined (6/12), T. rangeli was masked by the amplification of T. cruzi using the S35/S36 primers, concluding that this PCR does not allow the diagnosis of mixed infections in most of the insects. Afterwards, RAMÍREZ et al (2002) 22 detected T. cruzi and T. rangeli in an endemic area of Brazil using five PCR systems: S35/S36, D72/D75/RG3, R1/R2, D71/D72 (D7 domain of LSU gene from T. cruzi) and multiplex PCR for intergenic regions in the mini-exon gene.…”

“…Due to direct microscopic detection of trypanosomes, the traditional method for assessment of infection in vectors is not able to distinguish T. cruzi from T. rangeli infection, several polymerase chain reaction techniques have been developed 3,4,5,6,9,13,19,28,33,36,40,41 . However, current PCR assays used for mixed infection detection show some disadvantages such as the amplification of bands of similar size both in T. cruzi and T. rangeli 27,28 , the amplification of polymorphic fragments 11,19 , and bias to T. cruzi in the case of mixed T. cruzi and T. rangeli infection 9,33,36 .…”

“…However, current PCR assays used for mixed infection detection show some disadvantages such as the amplification of bands of similar size both in T. cruzi and T. rangeli 27,28 , the amplification of polymorphic fragments 11,19 , and bias to T. cruzi in the case of mixed T. cruzi and T. rangeli infection 9,33,36 . Therefore, it is necessary to develop new techniques as better options to specifically identify each of these parasite species in mixed infections.…”

The surface charge of trypanosomatids

“…It was not possible to distinguish epimastigote forms of T. cruzi and T. rangeli using cell electrophoresis since they present a similar mean EPM (Table I). However, they can be distinguished using other methods such as sialic acid content (Schottelius 1984), the presence of neuraminidase in the supernatant of cultures (Schottelius 1987) and PCR assays for the amplification of a specific DNA sequence for T. rangeli (Vargas et al 2000).…”