Diagnóstico y ecoepidemiología molecular de toxoplasma gondii mediante el gen SAG3 y análisis filogenéticos

Abstract

Toxoplasmosis is a reemerging zoonotic disease whose etiological agent is Toxoplasma gondii, an intracellular protozoan parasite, where its definitive reservoir is Felis catus and intermediate hosts such as rodents, birds, wild animals, farm or domestic animals. A diagnostic and molecular ecoepidemiology matrix was generated with the aim of performing a phylogenetic analysis of specific sequences of Toxoplasma gondii that can be used for the rapid molecular identification of any T. gondii isolate in the country and in the region. The optimal molecular marker for the diagnosis of T. gondii was analyzed. The SAG3 marker was found to be suitable for phylogenetic analysis with 170 sequences. MEGAX software was used for phylogenetic analysis by first performing multiple alignment with the CLUSTALW algorithm and manual purification to a size of 566bp. Subsequently, the Maximum Parsimony method with the Tree-Bisection-Regrafting (TBR) algorithm was used to generate the phylogenetic tree. It was observed that SAG3 shows a high genetic variability as it is highly polymorphic, finding a direct relationship between the circulating lineage and virulence, geographic expansion and evolutionary success, which allows its use for diagnosis, as well as in molecular epidemiology and genomic surveillance. In addition, lineage I predominates in the Americas with small introductions in Europe and Asia, while lineage II predominates in Europe and directly affects livestock production and lineage III is found circulating around the world in both definitive and intermediate hosts.