Genomic Characterization of a Locally Transmitted Leishmania mexicana Isolate from Texas.

Cutaneous leishmaniasis, which is caused by Leishmania species transmitted by sandflies, is increasingly recognized in subtropical, higher-resource regions, including the southern United States. The first whole-genome sequence of Leishmania mexicana (L. mexicana) is reported from an autochthonous US case in a 3-year-old boy from Ellis County, Texas, with no travel history. Genomic DNA was sequenced using Illumina (San Diego, CA) technology. Phylogenomic analysis of nuclear and mitochondrial single-nucleotide polymorphisms (SNPs) confirmed the isolate as L. mexicana, clustering within the L. mexicana complex. The parasite displayed a predominantly disomic karyotype, with chromosome 30 exhibiting trisomy. A total of 172 genes were identified, with notable copy number variation and 9,920 SNPs unique to this genome, highlighting substantial genetic diversity. These variants affected genes involved in host-pathogen interactions, metabolism, and signaling. Overall, this study emphasizes the need for molecular surveillance in regions where competent sandfly vectors are present.