Trypanosoma cruzi, the protozoan agent of Chagas disease, is split into six distinct genetic lineages TcI – TcVI, each associated with ecoepidemiological features and transmission cycles, and it has long been proposed that the differing lineages may contribute to the varying clinical forms of Chagas disease. The epidemiology is not fully understood as current knowledge is based on genotyping and may not give the full infection history due to the difficulty of isolating parasite during the chronic phase of infection. In this thesis work I performed lineage-specific serological assays, on human and mammalian sera from the Gran Chaco in Northern Argentina. I show that a novel RDT incorporating the TSSA-II/V/VI synthetic peptide is more sensitive than the corresponding lineage-specific ELISA and can be used to help identify ecological and epidemiological associations in the Argentine Chaco. Prior to my research project there was no known serological marker for TcI. I demonstrated that a glycosylated TSSA-I recombinant protein, produced through the L.tarentolae system, has increased sensitivity with chagasic sera, compared to linear synthetic peptides due to the addition of sugars. In addition, I assayed paired pre-and post-treatment samples against TSSApep-II/V/VI and whole cell lysate to determine changes in antibody titre and assessed the decline of IgG1 to be a potential biomarker for cure. Following the success above, I have established the L. tarentolae expression system at LSHTM and have successfully produced recombinant proteins of the TSSA peptides and demonstrated recognition by chagasic sera for glycosylated versions of TSSApep-II/V/VI and TSSApep-V/VI. On a second research visit to Argentina, I identified T. cruzi lineage by PCR from triatomine bugs from the Gran Chaco, the first documentation of this technique on direct rectal samples. Furthermore, I used bioinformatics to identify novel candidate epitopes for TcI serology.