Trypanosoma cruzi-triatomine associations and the presence of mixed infections in single triatomine bugs in Paraná state, Brazil

Abstract

Eighteen strains of Trypanosoma cruzi isolated from two species of triatomines in the state of Paraná, Brazil, were characterized molecularly using three strategies: RAPD (randomly amplified polymorphic DNA) with four primers, analysis of the D7 polymorphic region of the 24Sα rDNA, and RFLP (restriction fragment length polymorphism) of region 5' of the mitochondrial gene COII (cytochrome oxidase subunit 2). The phenogram constructed with the RAPD data showed that only three strains isolated from Panstrongylus megistus collected in the Municipality of Arapongas were grouped together in a sub-branch. None of the other 15 strains could be clustered according to triatomine species or geographical origin. The strains were grouped with the T. cruzi I reference sample, indicating closer association with the sylvatic transmission cycle of T. cruzi in the state of Paraná. However, analyses of the rDNA and COII gene polymorphisms revealed the presence of populations from both T. cruzi I and II major lineages. In half of the analyzed triatomines, we found parasites from both lineages coinfecting the same bugs. Of these, most (6/9) were isolated from Triatoma sordida, and 3/9 from Panstrongylus megistus. These results contribute to a better comprehension of the ecoepidemiology of Chagas' disease in Paraná, and raise questions about the role of studies of polyclonal population dynamics for controlling the transmission of T. cruzi to humans in this region.

Trypanosoma cruzi I–III in southern Brazil causing individual and mixed infections in humans, sylvatic reservoirs and triatomines

“…This result confirms that of Spitzner et al (2007), who also analysed isolates from the present study, and observed the occurrence of mixed infections in 50% of specimens of T. sordida and P. megistus captured in northwestern Paraná. Additionally, the 24S␣ rRNA, COII haplotypes, and microsatellite analyses performed in A316A, the isolate studied here and by Spitzner et al (2007), derived single cells separated by FACS Cell Sorter and showed that this strain is composed by two subpopulations, one belonging to TcII and another belonging to TcI. Furthermore, these two subpopulations displayed distinct microsatellite profiles (unpublished results).…”

“…The results of this study, together with those of Spitzner et al (2007) and Zafra et al (2008), showed that it was necessary to analyse also the COII gene in order to identify mixed infections in triatomines in southern Brazil and in chronic chagasic patients in Colombia, respectively. On the other hand, limitations to rRNA analyses were observed in this study and in others (Steindel et al, 2008;Zafra et al, 2008).…”

“…In previous publications from our laboratory, these two DTUs (T. cruzi I and T. cruzi II) were found together in the triatomines Triatoma sordida and Panstrongylus megistus from northwestern Paraná state in southern Brazil (Spitzner et al, 2007). This finding led us to investigate whether these mixed infections occur only in triatomines, or whether they can also be found in sylvatic reservoirs or in humans from the same region.…”

“…T. cruzi I and T. cruzi II are frequently associated with different hosts and transmission cycles, but they have also been reported from the same host, indicating a mixed infection (Bosseno et al, 1996;Spitzner et al, 2007;Steindel et al, 2008;Ramírez et al, 2010). T. cruzi III is associated with terrestrial transmission cycles, armadillo reservoir hosts, and human infections (Freitas et al, 2006;Llewellyn et al, 2009).…”

Induction of phagocytic activity and nitric-oxide production in natural populations of Trypanosoma Cruzi I and II from the state of Paraná, Brazil

“…The host may influence the parasite, affecting its metabolic versatility over the wide range of environmental conditions where the hosts live 50 . Also, another study found that half of the triatomines analyzed in Paraná were co-infected by parasites from both T. cruzi I and II lineages 43 .…”