SAG3 Toxoplasma gondii cloning reveals unexpected fivefold infection in the blood of feral cats in the Mexican Caribbean

Abstract

Background Currently, more than 300 genotypes of Toxoplasma gondii (T. gondii) have been described throughout the world, demonstrating its wide genetic diversity. The SAG3 locus is one of the genes included in the genotyping panel of this parasite. It is associated with its virulence since it participates during the invasion process of the host cells. Therefore, cloning, sequencing, and bioinformatic analysis were used to deepen the understanding of the SAG3 locus genetic diversity of T. gondii in blood samples from feral cats. Results Six different SAG3 sequences were detected, five of which were detected in one feline. Three sequences were first reported here; one of them was an intragenic recombinant. In the cladogram, four out of ten SAG3 sequences did not share nodes with others reported worldwide. Conclusions Cloning and sequencing of samples with more than one restriction pattern by PCR-RFLP were very helpful tools to demonstrate the presence of more than three genotypes of T. gondii in the blood of feral cats from southeastern Mexico. This suggests a potential mixed infection of multiple T. gondii strains and high genetic diversity of the parasites in felines in this tropical region of Mexico.

High prevalence and diversity of Toxoplasma gondii DNA in feral cat feces from coastal California

“…This observation likely represents the presence of more than one strain in a fecal sample from one animal, as it is not feasible for a single copy gene to have two different bases at a given nucleotide site. Mixed T. gondii genotype infections have previously been documented in felid tissues [18,58] but to our knowledge, the presence of two different parasite strains from feral cat feces has not been documented in North America. The presence of mixed strains in a cat fecal sample can indicate that a cat ate prey that was co-infected with two T. gondii strains and therefore has bradyzoites representing different strains passing through the gut, and/or a cat that is shedding T. gondii oocysts representing two different strains due to reactivation of previous infection following ingestion of a different genotype (Fig 5 Scenario A) or co-ingestion of two genotypes (that can result in sexual recombination) (Fig 5 Scenario B).…”

Genotyping of Toxoplasma gondii in domestic animals from Campeche, México, reveals virulent genotypes and a recombinant ROP5 allele

“…To date, at least 318 genotypes have been reported worldwide, and tropical regions usually have greater genetic diversity (Shwab et al ., 2014 ; Meireles et al ., 2022 ). Previous reports about the genotyping of T. gondii isolates obtained from feral cats and stray dogs from Quintana Roo and Chiapas, respectively, revealed the great genetic diversity of this protozoan and strong infection pressure, with individuals infected with up to 5 different T. gondii strains in the same urban environment shared by different species, including humans (Valenzuela-Moreno et al ., 2019 , 2020 , 2022 b ). Campeche is a southeastern Mexican state that has favourable climatic conditions for the replication and dissemination of this protozoan, since 80% of its territory is rainforest.…”

Toxoplasmosis in cats from a dairy-producing region in Hidalgo, Mexico

“…(12−15) ELISA, histopathological examination, PCR, and direct isolation have been used to diagnose T. gondii infection. (2,7,16) Depending on the virulence of each isolate, mice can develop either an acute infection with a high tachyzoite load in 8-12 days, or a chronic infection, with low to null mortality and several tissue cysts, most often located in the central nervous system and heart. (3,17) Diagnosis cannot rely solely on the clinical picture, since clinical signs and postmortem findings are non-specific.…”