Phylogenetic diversity of two common Trypanosoma cruzi lineages in the Southwestern United States

• Published in: Infection, genetics and evolution Vol. 99; p. 105251
• Main Authors: Flores-López, Carlos A., Mitchell, Elizabeth A., Reisenman, Carolina E., Sarkar, Sahotra, Williamson, Philip C., Machado, Carlos A.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.04.2022
• Subjects: Animals; Chagas Disease; DTU; Evolution; Genetic diversity; Insect Vectors - parasitology; Multilocus Sequence Typing; Phylogeny; Southwestern United States - epidemiology; Texas - epidemiology; Triatomines; Trypanosoma cruzi; Trypanosoma cruzi - genetics; Texas; Southwestern United States; Chagas disease; Evolution; Genetic diversity; DTU; Trypanosoma cruzi; Triatomines
• ISSN: 1567-1348; 1567-7257
• DOI: 10.1016/j.meegid.2022.105251

Trypanosoma cruzi is the causative agent of Chagas disease, a devastating parasitic disease endemic to Central and South America, Mexico, and the USA. We characterized the genetic diversity of Trypanosoma cruzi circulating in five triatomine species (Triatoma gerstaeckeri, T. lecticularia, T.indictiva, T. sanguisuga and T. recurva) collected in Texas and Southern Arizona using multilocus sequence typing (MLST) with four single-copy loci (cytochrome oxidase subunit II- NADH dehydrogensase subunit 1 region (COII-ND1), mismatch-repair class 2 (MSH2), dihydrofolate reductase-thymidylate synthase (DHFR-TS) and a nuclear gene with ID TcCLB.506529.310). All T. cruzi variants fall in two main genetic lineages: 75% of the samples corresponded to T. cruzi Discrete Typing Unit (DTU) I (TcI), and 25% to a North American specific lineage previously labelled TcIV-USA. Phylogenetic and sequence divergence analyses of our new data plus all previously published sequence data from those four loci collected in the USA, show that TcIV-USA is significantly different from any other previously defined T. cruzi DTUs. The significant level of genetic divergence between TcIV-USA and other T. cruzi DTUs should lead to an increased focus on understanding the epidemiological importance of this DTU, as well as its geographical range and pathogenicity in humans and domestic animals. Our findings further corroborate the fact that there is a high genetic diversity of the parasite in North America and emphasize the need for appropriate surveillance and vector control programs for Chagas disease in southern USA and Mexico. •Sequence variation from 4 Trypanosoma cruzi loci was surveyed in 55 samples from infected Triatomines from the US Southwest.•75% of the samples were TcI, while 25% of the samples clustered with the lineage known as TcIV-USA.•Phylogenetic analysis places TcIV-USA as a monophyletic group distinct to South American TcIV.•The divergence between TcIV-USA and other T. cruzi DTUs is comparable or greater than the divergence among recognized DTUs.•Evidence of hybridization was also uncovered in 3 of the samples.