Abstract
Trypanosoma cruzi, the protozoan agent of Chagas disease in the Americas, is comprised of six genetic lineages (TcI-TcVI) and a possible seventh (TcBat, related to TcI). Identification of T. cruzi lineages infecting reservoir mammalian species is fundamental to resolving transmission cycles. However, this is hindered by the limited sensitivity and technical complexity of parasite isolation and genotyping. An alternative approach is serology using T. cruzi lineage-specific epitopes, such as those of the trypomastigote small surface antigen (TSSA). For surveillance of T. cruzi lineage infections in mammal species from diverse Brazilian regions, we apply a novel rapid diagnostic test (RDT, Chagas Sero K-SeT), which incorporates the TSSA peptide epitope specific to TcII/V/VI (TSSApep-II/V/VI) and Protein G detection of antibodies. Chagas Sero K-SeT RDT results with sera from experimentally infected mice, from tamarin primates (Leontopithecus spp.) and from canines (Canis familiaris) were concordant with corresponding TSSApep-II/V/VI ELISAs. The Chagas Sero K-Set detected TcII/V/VI infections in Leontopithecus spp. from the Atlantic forest (n = 46), in C. familiaris (n = 16) and Thrichomys laurentius (n = 2) from Caatinga biome and Chiroptera (n = 1) from Acre, Amazonia. The Chagas Sero K-SeT RDT is directly applicable to TcII/V/VI-specific serological surveillance of T. cruzi infection in several different mammalian Orders. It can replace ELISAs and provides efficient, point-of-sampling, low-cost detection of TcII/V/VI infections, with at least equivalent sensitivity, although some mammals may be difficult to trap, and, not unexpectedly, Chagas Sero K-SeT could not recognise feline IgG. Knowledge of sylvatic hosts of T. cruzi can be expanded, new reservoir species discovered, and the ecology of transmission cycles clarified, particularly with adaptation to further mammalian Orders.
Highlights
The protozoan Trypanosoma cruzi is the etiological agent of Chagas disease, infecting 6–7 million people (https://www.who.int/en/news-room/fact-sheets/detail/chagas-disease-(americantrypanosomiasis)
The elucidation of the sylvatic distribution of T. cruzi lineages in Brazil has been subject to extensive research [9, 10], the TcI, TcIII and TcIV lineages are widely distributed in Brazilian mammals and biomes [11], tamarins Leontopithecus spp. [12] and dogs [13, 14] have been implicated by isolate genotyping as natural hosts of TcII/V/VI
We demonstrate the versatility of the Chagas Sero K-SeT to recognise TSSA peptide (TSSApep)-II/V/VI specific IgG in experimental murine T. cruzi infections, and in natural infections across several Orders of Brazilian mammals, namely Primata, Carnivora, Rodentia and Chiroptera
Summary
The protozoan Trypanosoma cruzi is the etiological agent of Chagas disease, infecting 6–7 million people (https://www.who.int/en/news-room/fact-sheets/detail/chagas-disease-(americantrypanosomiasis). T. cruzi is zoonotic, carried by more than 100 mammal species and 40 species of triatomine insect vectors [5]. The range of infected vectors and mammalian hosts in the Americas is from the USA in the North to southern Argentina and northern Chile. Of particular interest is greater understanding of the cryptic natural sylvatic cycles of TcII and the hybrid lineages TcV and TcVI [8], which are associated with severe chagasic cardiomyopathy and megasyndromes in the Southern Cone countries of South America, especially in Bolivia. The elucidation of the sylvatic distribution of T. cruzi lineages in Brazil has been subject to extensive research [9, 10], the TcI, TcIII and TcIV lineages are widely distributed in Brazilian mammals and biomes [11], tamarins Leontopithecus spp. The elucidation of the sylvatic distribution of T. cruzi lineages in Brazil has been subject to extensive research [9, 10], the TcI, TcIII and TcIV lineages are widely distributed in Brazilian mammals and biomes [11], tamarins Leontopithecus spp. [12] and dogs [13, 14] have been implicated by isolate genotyping as natural hosts of TcII/V/VI
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