The molecular epidemiology and phylogeography of Trypanosoma cruzi and parallel research on Leishmania: looking back and to the future

• Published in: Parasitology 2009-10, Vol.136 (12), p.1509-1528
• Main Authors: MILES, M. A., LLEWELLYN, M. S., LEWIS, M. D., YEO, M., BALEELA, R., FITZPATRICK, S., GAUNT, M. W., MAURICIO, I. L.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Chagas disease; Chagas Disease - epidemiology; Chagas Disease - parasitology; Chagas Disease - transmission; Disease control; Ecosystem; Epidemiology; Fundamental and applied biological sciences. Psychology; General aspects; General aspects and techniques. Study of several systematic groups. Models; Genetic diversity; genetic exchange; Genetic markers; Genetics; Hybrids; Invertebrates; Leishmania; Leishmania - classification; Leishmania - genetics; Leishmaniasis - epidemiology; Leishmaniasis - parasitology; Leishmaniasis - transmission; microsatellites; Molecular Epidemiology; multilocus sequence typing; pericardial effusion; Phenotypic variations; Phylogeny; phylogeography; Population genetics; South America - epidemiology; taxonomy; Trypanosoma cruzi; Trypanosoma cruzi - classification; Trypanosoma cruzi - genetics; Vector-borne diseases
• ISSN: 0031-1820; 1469-8161
• DOI: 10.1017/S0031182009990977

Trypanosoma cruzi is the protozoan agent of Chagas disease, and the most important parasitic disease in Latin America. Protozoa of the genus Leishmania are global agents of visceral and cutaneous leishmaniasis, fatal and disfiguring diseases. In the 1970s multilocus enzyme electrophoresis demonstrated that T. cruzi is a heterogeneous complex. Six zymodemes were described, corresponding with currently recognized lineages, TcI and TcIIa-e – now defined by multiple genetic markers. Molecular epidemiology has substantially resolved the phylogeography and ecological niches of the T. cruzi lineages. Genetic hybridization has fundamentally influenced T. cruzi evolution and epidemiology of Chagas disease. Genetic exchange of T. cruzi in vitro involves fusion of diploids and genome erosion, producing aneuploid hybrids. Transgenic fluorescent clones are new tools to elucidate molecular genetics and phenotypic variation. We speculate that pericardial sequestration plays a role in pathogenesis. Multilocus sequence typing, microsatellites and, ultimately, comparative genomics are improving understanding of T. cruzi population genetics. Similarly, in Leishmania, genetic groups have been defined, including epidemiologically important hybrids; genetic exchange can occur in the sand fly vector. We describe the profound impact of this parallel research on genetic diversity of T. cruzi and Leishmania, in the context of epidemiology, taxonomy and disease control.